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Abstract The mechanized large ridge production technology of potato was summarized， including preparation before sowing， deep tillage and land preparation， deep application of chemical fertilizer， sowing， intertillage， disease and pest control， harvesting and other related contents. The comparative experimental study of large ridge and small ridge modes focused on the effects of ridge spacing on soil bulk density， temperature， water retention， crop growth and yield. The technology has the advantages of time saving， labor saving， seed saving， and fertilizer saving. It can significantly improve production efficiency， and is a high yield and high efficiency planting mode that increases potato yield. This model can increase yield by 370 kg/hm2 and improve income by 160 yuan/hm2. The results of this study have greatly promoted the promotion and application of mechanized largo ridge potato planting technology.
Key words Hailar District; potato; Large ridge planting; Mechanization; Planting technology; Economic benefit
In recent years， due to the strong support of the government， the potato industry has achieved initial and sustainable rapid development， and has become an important pillar industry for promoting agricultural production， increasing farmers income and promoting local economic development. Potato is one of the main planting industries in Hulunbeier area of Inner Mongolia. With the adjustment of industrial structure， the planting area of potato has increased year by year. At present， it has reached 1.12 million hm2， but its production operation has always been at the small ridge mechanization level， and in some places， seeding and harvesting are still in the stage of combining manual work with small machinery. Furthermore， the mechanized large ridge production technology of potato is almost blank currently. Therefore， in order to break away from the backward potato production status and reduce the labor intensity of farmers， the advanced mechanized large ridge potato production technology was introduced， demonstrated and promoted to the farmers in Hulunbeier City. Through the integrated application of agricultural machinery and agronomy， the purposes of improving yield and increasing efficiency are achieved.
Test Locations， Equipment and Techniques
Natural conditions of the test site
Hailar District is located in the northeast of Inner Mongolia Autonomous Region and in the southwest of Hulunbeier City. It is located at 119°28′-120°34′E and 49°06′-49°28′ N. The altitude is between 603.0 and 776.6 m. This area has a temperate continental semiarid continental climate. The annual average temperature is -1--2 ℃; the annual average precipitation is 350-370 mm; the annual average sunshine duration is 2 800 h; and the cultivated land area is 292 km2. The test project was implemented in Hailar District of Hulunbeier City. The unique natural climate and special geographical conditions of Hailar District of Hulunbeier City are very suitable for planting potato. The temperature difference between day and night is large， and the soil nutrients are comprehensive， which provides a suitable growth environment for potato.
Mechanical equipment
Harbin Woer 2CMF 4 multi function potato planter; Zhongji Meino 1600 potato harvester; JH 100 potato leaf shredder machine; Dongjin Woer 1GZML 210 deep scarification integrated tillage machine; Klass 210 tractor; Germany Grimme potato planter; potato cultivator; laminating machine; intertillage fertilizer applicator; Grimme potato harvester.
Harbin Woer 2CMF 4 multi function potato planter
The machine can complete multiple processes such as deep scarification， fertilization， trenching， sowing， watering， banking （covering soil） and compacting. The sowing depth， row spacing， hole spacing and fertilizing amount of the machine all can be adjusted. The machine has the characteristics of uniform seeding and high emergence rate. Its production efficiency is 1.2 hm2/h.
JH 100 potato leaf shredder machine
The machine can complete removal of plants on the ridges and in the furrows at one time without harming the potatoes. Its working efficiency is 0.27- 0.30 hm2/h.
Dongjin Woer 1GZML 210 deep scarification combined tillage machine
The machine is equipped with a power of 80-120 hp， and has a working width of 2 100 mm， a production efficiency of 0.6-1.0 hm2/h and a scarification depth of 120-150 mm.
Zhongji Meino 1600 potato harvester
The machine is characterized by one time excavation， conveying and strip operation， high recovery rate （≥98%）， low breakage rate （≤2%）， and fast cost recovery. It has a two stage separation screen which has the characteristics of forced vibration， good separation effect and strong adaptability. The combined excavation mechanism can ensure the same excavation depth. The floating disc cutter can effectively cut the weeds and reduce the excavation resistance.
Core techniques
Mechanized soil preparation technique
This technique can enhance the water storage and retaining capacity of the soil， thereby creating a good soil environment for the growth of potato.
Mechanized seeding technique
This technique can complete ditching， applying chemical fertilizer， sowing sprouted tubers， covering soil， making ridge （laying mulch） and other operations at one time. The sprouted tubers are arranged uniformly， and the plant spacing， row spacing and sowing depth are consistent. The covering soil is laid uniformly. After banking， the effects of retaining water， soil and fertilizer can be achieved. Mechanized intertillage
This is a key field operation in the potato growing season. The potato planted with machine has large row spacing， and the scarification depth and the quantity of to be hilled soil are large. The intertillage and soil banking machine can complete the operations of scarification， weeding and banking at one time. During intertillage， it is necessary to adjust the height， depth and width of the ploughing blade and ploughshare to ensure that the soil is tight and the seedlings are not injured.
Mechanized harvesting
Mechanized harvesting of potato has high efficiency and can achieve the effects of greatly shortening the harvest period， preventing the damage caused by early freezing damage， reducing losses and greatly reducing the labor intensity.
Technical process
According to the survey of farmland in the project area， the technical route included mechanized deep scarification in the previous year， soil preparation before sowing， mechanized fertilization， mechanized sowing， mulching， mechanized cultivating， mechanized plant protection， mechanized plant killing and mechanized harvesting.
Test Content and Methods
Selection of cultivated land
The potato tubers expand during growth， so the soil should be flat fertile loose sandy loam soil with deep soil layer. Meanwhile， in order to prevent soil borne diseases and pests and weeds， potato should be rotated with cereal crops and bean crops except Solanaceae crops， tuberous root crops and tuber crops. The test site was selected in the east direction of Dongshan Airport in Hailar District， Hulunbeier City.
Mechanized deep scarification soil preparation
After the harvesting of the preceding crops， deep scarification （ploughing）， stubble cleaning and rotary tillage should be performed in time. The time of deep scarification is selected according to the spatial and temporal distribution characteristics of local rainfall， so as to accumulate more natural precipitation. Deep scarification and sowing are carried out simultaneously. The 67-107 kW wheeled tractor is used for deep plowing of the potato planting area. The depth of the ploughing is 300-350 mm. Breaking the hard soil layer formed by shallow ploughing is beneficial to increase potato yield per unit area. At the same time， the soil is crushed and finely ground， providing a basis for sowing.
Mechanized seeding
The density during mechanized sowing should be adjusted according to different regions and different varieties to meet the agronomic requirements[1]. In the potato production area in Hulunbeier area of Inner Mongolia， the traditional ridge spacing is 60-70 cm， and the large ridge spacing is 80-90 cm. Attention should be paid to the temperature when sowing. Sowing can be performed when the temperature of the 10 cm soil layer is stable at 7-8℃， and the seeding depth is 6-8 cm. During ridging， the ridge height and ridge width should be kept consistent at 25-30 cm and 40-45 cm， respectively. When planting in spring， the 2CMF 4 potato fertilization planter is selected for sowing. It can complete ditching， sowing， fertilizing， covering soil and compacting at one time， and has the characteristics of good trenching effect， uniform sowing depth， uniform soil covering and moderate compacting. Taken together， the machine can enhance the water storage and retaining capacity of soil， thereby creating a good soil environment for the growth of potato.
Selection of virus free seed potato
The selection of excellent varieties is a prerequisite for ensuring the quality of potato， reducing pests and diseases， and achieving high yield[2]. This experiment selected the high quality virus free seed potato Kexin 1 produced by Inner Mongolia Heng Te Shu Seeds Co.， Ltd.
The emergence stage， bud stage and flowering stage of virus free potato are all earlier， so the potato tubers expand early and the expansion time is longer. Consequently， the potato has sufficient time for growth and development， and the potato yield is increased. The virus free seed potato has higher plants， thicker stems and more leaves， which enhance the photosynthesis of the plants. Photosynthesis is the most important component of potato productivity， so the yield of potatoes will increase. The virus free seed potato eliminates the damage of potato plants caused by viruses， so the leaves are flat， large， dark green， the root system is developed， the plant is strong with strong growth vigor， and the yield is improved[3].
The seed potatoes are taken out from the cellar 10-15 d before planting， or the cellar is ventilated every day 15 d in advance， so that the seed potatoes are at 15-20℃ and germinate. After germination， they are exposed to sunlight to allow the sprouts to turn purple green. When the sprouts grow to the size of the rice grain， the seed potatoes are cut into pieces. Combined with taking out from cellar and cutting， seed potatoes are finely selected by discarding diseased， rotten， wounded， inferior， deformed potato pieces， and the weight of the cut pieces is generally 25-35 g， preferably 30 g， which is beneficial to increasing the rate of emergence， but a too high seeding rate increases the cost of planting. The pieces should be thick and fleshy with two sprouts per piece. The leathery surface should not be less than 2.0 cm × 2.5 cm， and the sprouts should be in the middle of the surface as much as possible. The seed pieces are cut into a basket or the ground when cutting， not directly into an airtight nylon bag. The pile of the seed pieces should not be too high or too thick. The seed pieces should be ventilated and exposed to sunlight， and the cut surface should be dried as soon as possible. In order to prevent the spread of diseases through cutting， two cutting knives should be used alternately when cutting， and the knives should be alternately immersed and disinfected with 75% ethanol or 3% potassium permanganate solution. The cut and dried seed pieces should be sterilized by spraying with a certain agent. 58% metalaxyl mancozeb wettable powder produced by Zhejiang Heben Pesticide & Chemicals Co.， Ltd.， 70% mancozeb WP produced by Limin Chemical Co.， Ltd. and 75% chlorothalonil WP purchased from Jiangxi Zhongxun Agrochemical Co.， Ltd. are prepared into 100 times liquids， and sprayed with a manual sprayer with stirring， and the spraying amount for the seed pieces is 2-3 kg/150 kg.
After spraying， the seed pieces are dried and then filled with mesh bags. Then the mesh bags are stacked into ventilation flower stacks with the height of 4-5 bags， making the gaps not too high. Otherwise， it will easily cause the seed potatoes to rot due to excessive heat， which finally affects emergence. In addition， it is necessary to prevent the seed pieces from being damaged by freezing and rain. Moreover， the cutting of seed potatoes should be matched with the sowing time， preferably in the manner of cutting following seeding immediately， and the storage time of the seed pieces is not more than 3 d.
Sowing and fertilization
When planting， seeding can be performed when the temperature of the 10 cm soil layer is stable at 6-7℃. The suitable sowing period of potatoes in Hailaer district and its surrounding areas is May 5-20， and the best sowing period is May 10-15. Sunny and windless weather is chosen for seeding within the best sowing period. The amount of the seed potatoes is 10-125 kg/hm2， and the seeding density is 4 500 plants/hm2; and the number of harvested plants is about 4 000 plants/hm2. The seeding is performed according to the ridge pacing of 65 cm and the plant spacing of 25 cm. When the ridge spacing is 80 cm， the plant spacing is 15 cm.
During mechanized seeding， the operations such as ditching， fertilizing， seeding， covering soil and ridging can be completed at one time， and the soil is compacted on the seeding day. The thickness of the covering soil is 10-12 cm. When applying the seed fertilizer， it should be applied 2-3 cm below the seed pieces， and the seed pieces should not be in direct contact with the seed fertilizer， so as to avoid seed burning. The farmyard manure is applied before deep ploughing， and the base fertilizer is applied by the method of lifting the fertilizer and harrowing before seeding. During seeding， the fertilizer special for potato is randomly sprayed to prevent and control the pesticides transmitted by soil. The total amount of chemical fertilizer is 35-50 kg/hm2. The usual practice is to apply 50 kg/hm2 of fertilizer with seeding， which includes15 kg/hm2 of diammonium phosphate， 10 kg/hm2 of urea and 25 g/hm2 of 33% potassium sulfate. In this case， the uniformity of the fertilizer should be greater than 97%， and the proportion of the raw materials such as ammonium bicarbonate and urea is generally 20% to 30%. After sowing， the chemical fertilizer is mainly applied， and the base fertilizer （chemical fertilizer） is applied for the second time before banking at a rate of 20 kg/hm2 including 6 kg/hm2 of diammonium phosphate， 4 kg/hm2 of urea and 10 kg/hm2 of 33% potassium sulfate. When the potato seedlings are as high as 100 mm， they are watered and fertilized for several time. Lihua ZHANG et al. Large ridge Mechanized Planting Technology of Potato in Hailar District of Hulunbeier City
Irrigation
Irrigation is carried out by the spray irrigation circle and traditional irrigation method， and it is carried out 5-7 d in advance for tillage when ensuring the soil is wetted thoroughly. The soil water content is ensured to be 50%-60% in the seedling period. If the soil is too dry， it needs to be properly watered to maintain better soil moisture， which is conducive to root development and seedling growth. The flowering period to the tuber expansion period is the most important period of potato growth and development. At this time， irrigation has a great influence on potato yield and quality. The soil water content from the flowering period to the tuber expansion period should be maintained at 70%-80%. It is a period when the potato needs more water， and if the precipitation is less， irrigation should be performed in time. The lack of water at this time will seriously affect potato yield. Watering is stopped 15 d before harvesting， which is conducive to the suberification of the potato skin and the reduction of mechanical damage[4].
Cultivation and banking
The intertillage stage is the key period for potato growth. The cultivating time， the scarifying depth of soil and the height and thickness of the hilled soil must meet the agronomic requirements. In one production season， it is generally necessary to perform soil scarification， weeding and banking for 3 times consecutively. After the seedlings have emerged tidily （about June 20）， the soil is cultivated with a tractor once every 10-15 d， continuously for 3 times. The soil loosening depth is 8-10 cm， and each time， about 3 cm of soil is banked up. The total thickness of the banked soil does not exceed 10 cm. Intertillage plays a role of loosening the soil to retain water， earthing up and killing weeds. The last intertillage is completed before the rows are sealed and should be accompanied by watering in time.
During cultivating and banking， the height， depth and width of the ploughing blade and ploughshare must be adjusted to ensure that the soil is tight and the seedlings are not cut. The land after cultivating should be with no large clods; and the spacing of the cultivating should be the same as the distance of sowing， so as to protect the potato seeds from damage. After cultivating and banking， ridges with a width of 30-40 cm and a height of 20-25 cm are formed. The cultivating and banking can not only kill the weeds， but also concentrate the fertilizers close to the seed potatoes. It can also widen and compact the ridges， which is conducive to the growth of the potatoes and avoid the greening of the potatoes. Spaying of microbicides and pesticides
The herbicide is applied on the second day after the cultivating and banking， and then the microbicide and the pesticide are sprayed at different times according to the situation of the field pests and diseases. The main pests and diseases that are controlled are early blight， late blight， and aphids. Late blight is a common disease in potato production， and it is also the most harmful and most harmful disease of potatoes. Aphids are widely found in potato production in Hailaer district. Aphids mainly stab young leaves to absorb juice， so that the leaves are dry in large areas， which directly affects the yield. Aphids can also spread the virus， causing a large number of plants to infect diseases and degrade seriously in the field and finally the yield to reduce. Prevention method： The agents are applied since the beginning of the flowering period （about the end of June）， about 4-5 times in one production season. The spraying is performed 1-2 times every 7-10 d after the potato is 15 cm. The agents can be selected from 75% mancozeb WP produced by Shanghai Ruida Chemical Co.， Ltd.， 53.8% Kocide WP produced by Hunan Jindadi Agricultural Materials Co.， Ltd. and 64% Oxadixyl WP purchased from Tianmen Kechuang E commerce Co.， Ltd.， each 90 g/hm2. When aphids are found， 10% aphid pesticide spray produced by Tianjing Chitian Pest Control Co.， Ltd. is added at a rate of 30 g/hm2. The above pesticides should be used alternately. These agents are filled into spray cans and mixed with water at 45 kg/hm2， obtaining the mixtures in the cans which are then carried by a tractor and sprayed.
The concentrations of the agents should meet the requirements of the corresponding agricultural production at the time of spraying. The distance between the nozzle and the potato should be maintained at about 50 cm during the spraying process. The application process should not be too fast， ensuring the overall uniformity. The spraying is performed at an interval of one week， and the total number of spraying is 5 times.
Weed control
At the seedling stage， herbicides are sprayed at the weed stage of 2-4 leaves. 10 g/hm2 of acetochlor is mixed with 30 kg of water， obtaining the liquid which is sprayed near the ground to reduce drift of the agent. The weeding depth is 3-8 cm， and the weed control adopts agronomic measures combining mechanical and manual weeding， and if necessary， a herbicide with small side effects is used. Removal of the aboveground part and harvesting
10-15 d before harvesting， when most of the stems and leaves of potato plants are yellow and the tubers are easy to separate from the stolons， in order to promote the hardening， thickening and aging of the potato skin， reduce damage and prevent potato plants from winding the vibrating screen， the potato plants are cut with a cutting machine and removed from the field in a sunny weather. Before the operation of the cutting machine， the hammerclaw is first raised to 20-25 cm from the ground， and operated for 1-2 cm after connected to the power output shaft， and then， the gear is stopped. When removing the plants， the height of the depth roller and the angle of the cutting knife are adjusted. If the cutting knife is too high， the potato plants cannot be completely removed. If it is too low， the upper potato will be easily damaged. The cutting machine should go straight to avoid pressing the ridges and damaging potatoes.
Potato harvesting is the most labor intensive part of potato production. The labor consumed by harvesting accounts for 80% of the total labor. Due to the short harvest season and labor shortage， if the harvest is not timely， it often affects the seed potato shipment and causes potato freezing. The suitable harvest period for potatoes in Hailar and surrounding areas is from August 25 to September 30， and the best harvest period is September 5-25. The mechanized harvesting of potatoes is carried out using the Zhongnong Meinuo 1600 potato harvester. The potatoes are harvested when the weather is fine， during which the digging depth is adjusted， because if the digging shovel enters into the soil too shallowly， it will damage the potato pieces， and if it enters the soil too deep， the working load of the tractor will be increased. During the harvesting， the harvester should be prevented from going wrong， avoiding the wheels going up the ridge and rolling the potatoes. Much attention should be paid to safety during work. The soil and weeds on the digging shovel and the vibrating screen must be cleaned when the machine is stopped.
The harvested seed potatoes are stacked and buried in the soil after slightly drying， and the bags are sorted at any time. At the same time， the seed potatoes are protected from rain， freezing damage and long term sunshine. If you plant more than two varieties， you must pay special attention to prevent mixing between varieties. It is necessary to strictly classify， harvest， bag， transport， and ship the potatoes. Test design
In this test， a demonstration base was built near the Dongshan Airport in Hailar， with a test scale of 10 000 hm2. 600 hm2 of demonstration field was taken as a test plot， and two test plots were set. This study investigated the soil temperature， humidity and bulk density under the large ridge spacing （80 cm） and traditional ridge spacing （65 cm） at different soil levels （10， 20， 30 and 40 cm） and the effects of different ridge spacing on various indexes including potato plant height， stem diameter， main stem density， number of potatoes， large and medium potato rate， small potato rate， yield， and starch content， and analyzed the economic benefit.
Determination of soil temperature， humidity and bulk density
The soil temperature and humidity can be measured by the soil moisture temperature tester. The instrument can directly display the soil moisture and temperature values. When measuring the deep soil， an extension rod and soil drill can be selected. It can be seen from the measurement that the soil water content and soil temperature are affected by the environment， and lower degrees of temperature and humidity variations can improve the appearance quality and nutritional quality of the tubers.
The soil bulk density is usually measured by a ring knife method. The soil sample under the natural state free of agitation was cut with a ring cutter which was then filled with soil thereby， and the mass of the dried soil per unit volume was calculated after drying. From the soil bulk density， the porosity of the soil can be calculated， and the tightness and structural condition of the soil can be estimated.
Determination of plant height and stem diameter
After the flowering period， the length of the aboveground part of the plant and the maximum stem diameter of the plant were measured.
Determination of the number of main stems
The number of main stems was measured during flowering.
Determination of tuber number and yield
During harvesting at the maturation stage， one row per plot was selected for the determination of the tuber number and yield.
Determination of large and medium potato rate and small potato rate
According to the weights of individual potatoes， they are divided into four grades： micro potato （0-25 g）， small potato （25-75 g） ， medium potato （75-100 g） and large potato （≥100 g）. After harvesting， each treatment was graded according to the above classification criteria， and the proportion of potatoes of each grade was obtained[5]. Determination of starch content
After harvesting， fresh potato samples were taken， washed with water， and air dried， and the starch content was measured with a starch analyzer.
Analysis of economic benefit
A comprehensive comparison was performed between the large ridge spacing and the traditional ridge spacing from the pre planting preparation to the total cost after harvesting and the yield benefit obtained after harvesting.
Results and Analysis
Soil properties under different ridge spacing
Allen[6] pointed out that the growth and development of the underground tubers of potato is affected by many factors （such as weather， soil， fertilizer， water， etc.）[6]. It can be seen from Table 1 that during the potato harvest period， the soil temperature of the plough layer under the large ridge cultivation was lower than that of the small ridge. As the soil ploughing layer deepened， the soil temperature also decreased. It can be seen that the large ridge cultivation mode has a good cooling effect and has a good promoting effect on potato tuber yield and quality.
It can be seen from Table 2 that large ridge cultivation can significantly improve the soil water content in the potato growing area， and increase the relative water content of the soil from the tuber formation stage to the maturation stage. The soil water content varied little and was stable at different soil levels. Under the large ridge cultivation， the soil water content and soil temperature were less affected by the environment， and the degree of alternating high temperature and drought with low temperature and wet was small， which reduced the deformity caused by secondary growth of tubers and improved the appearance quality and nutritional quality of tubers.
It can be seen from Table 3 that compared with the small ridge， the soil bulk density in the large ridge cultivation mode was relatively low， the soil porosity increased， and the soil was loose with good air permeability. Therefore， under the large ridge cultivation， it is easy to promote the absorption of nutrients in the soil by the root system， which is conducive to the growth and development of the aboveground organs， promotes photosynthesis， and lays a good foundation for the high yield of potatoes.
Effects of different ridge spacing on various indicators
It can be seen from Table 4 that the plant height， stem diameter， number of main stems， and number of potatoes increased in the large ridge cultivation mode compared with the traditional ridge spacing. In the large ridge cultivation mode， the number of potatoes can reach 51， which was 21% different from the traditional ridge spacing. Compared with the traditional ridge spacing， the large and medium potato rate in the large ridge spacing treatment increased， and was up to 93.2%， and the small potato rate decreased by about 20%. It can be seen from Table 5 that compared with the traditional ridge spacing， the yield and starch content of the potato in the large ridge spacing treatment both increased. The yield was higher than that in the traditional ridge spacing mode by more than 30%， and the starch content was also improved.
It can be seen from Table 6 that the potato planted in the large ridge spacing mode had the average yield 370 kg/hm2 higher than that in the small ridge spacing mode with the labor cost reduced by 30 yuan/hm2， and the economic benefit of the large ridge spacing mode was 160 yuan/hm2 higher than that of small ridge spacing mode. Therefore， the mechanized large ridge operation has an obvious effect of increasing farmers income， and not only increases the potato yield， but also saves production costs， and the economic benefit is obvious.
Brief summary
The large ridge cultivation of potato has the characteristics of heat preservation， water storage and moisture conservation， which are conducive to subsequent cultivating and weeding， banking， irrigation， plant protection and harvesting operations. Meanwhile， the mechanized large ridge operation is also conducive to loosening the soil， and conducive to reducing wind erosion and enhancing drought resistance in the spring with strong winds， particularly， which will promote the improvement of agro ecological environment. With small ridge planting， each person can only sow （harvest） 15 hm2/d， while mechanized large ridge operation can complete ditching， sowing， fertilization and banking at one time， and one person can sow （harvest） more than 19 hm2/d， which means that the efficiency is improved to 1.27 times. The sowing depth， plant spacing and row spacing of the mechanized large ridge sowing have high requirements on agronomic techniques with the characteristics of high germination rate， more branches and the average seed rate of 280-300 kg/hm2. Compared with the small ridge seeding method （320-350 kg/hm2）， it saved the seed potatoes by 40-50 kg/hm2， which meant a saving rate higher than 12.5%. The comparison between the mechanized large ridge potato planting and traditional planting showed that the average potato yield was 4 230 kg/hm2， 370 kg/hm2 higher than the traditional production method （3 860 kg/hm2）， with a yield increasing rate of 9.6%， and the cost was saved by 30 yuan/hm2. The economic benefit of large ridge planting was 160 yuan/hm2 higher than that of small ridge method. Conclusions and Discussion
Mechanized large ridge potato planting can not only improve mechanization efficiency and shorten farming season， but also can reduce labor intensity， energy consumption and production cost and improve production efficiency and crop yield， reflecting good economic benefits. It is an important way to promote potato production technology reform， promote the increase of farmers income and local rural economic development and promote the sustainable development of the potato industry. It is of great significance to safeguarding food security and promoting the development of modern agriculture and ecological civilization in the city.
The research results of Wu et al.[7] showed that an appropriate increase of row spacing can increase the number of tubers. The results of this study showed that under the same planting density， the number of potato tubers increased with the increase of the ridge spacing， and the effect of ridge spacing on yield is the same as that of Qin et al.[8].
Nowadays， people are paying more and more attention to transforming resource and production advantages into commodity economic advantages， and more and more attention to the increase in potato yield and quality[9-11]. The demand for potato quantity and quality have increased year by year. Changing the traditional planting mode to improve the yield and quality of potato is an urgent problem for potato producers[12]. In China， the large ridge planting technique is very mature in the cultivation of other crops， and the time spent on potato cultivation is not long， so it is the planting method mainly promoted for potato cultivation. This study combined the large ridge treatment and small ridge planting that are currently promoted to compare the effects of different ridge spacing on the growth and yield of potato variety Kexin 1. The results showed that the large ridge planting is more in line with modern mechanized agricultural production. The test was only for the potato variety Kexin 1， and different varieties have different characteristics， so further research is needed for other varieties.
References
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[3] WANG WZ， WANG YZ， LYU DQ， et al. Developmental status and strategy for potato enterprise in Heilongjiang Province[J]. Chinese Potato Journal， 2011（6）： 377-379.（in Chinese） [4] JIN GH， SUN XM， FENG XH， et al. Large ridge row planted in two lines in the row for high yield of potato in Heilongjiang reclamation area[J]. Chinese Potato Journal， 2013， 27（1）： 31-33. （in Chinese）
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[6] ALLEN EJ. Plant density[M]∥Harris PM. The potato crop. Boston：Springer， 1978：278-326.
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[8] QIN ZH， DENG LJ， XIA JH. The Influences of planting density or row spacing on the yield of potato Cultivar Xuan potato 2[J]. Agricultural Technical Services， 2012， 29（7）： 808-810. （in Chinese）
[9] QU DY， XIE KY， JIN LP， et al. Development of potato industry and food security in China[J]. Scientia Agricultura Sinica 2005， 38（2）： 358-362. （in Chinese）
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Key words Hailar District; potato; Large ridge planting; Mechanization; Planting technology; Economic benefit
In recent years， due to the strong support of the government， the potato industry has achieved initial and sustainable rapid development， and has become an important pillar industry for promoting agricultural production， increasing farmers income and promoting local economic development. Potato is one of the main planting industries in Hulunbeier area of Inner Mongolia. With the adjustment of industrial structure， the planting area of potato has increased year by year. At present， it has reached 1.12 million hm2， but its production operation has always been at the small ridge mechanization level， and in some places， seeding and harvesting are still in the stage of combining manual work with small machinery. Furthermore， the mechanized large ridge production technology of potato is almost blank currently. Therefore， in order to break away from the backward potato production status and reduce the labor intensity of farmers， the advanced mechanized large ridge potato production technology was introduced， demonstrated and promoted to the farmers in Hulunbeier City. Through the integrated application of agricultural machinery and agronomy， the purposes of improving yield and increasing efficiency are achieved.
Test Locations， Equipment and Techniques
Natural conditions of the test site
Hailar District is located in the northeast of Inner Mongolia Autonomous Region and in the southwest of Hulunbeier City. It is located at 119°28′-120°34′E and 49°06′-49°28′ N. The altitude is between 603.0 and 776.6 m. This area has a temperate continental semiarid continental climate. The annual average temperature is -1--2 ℃; the annual average precipitation is 350-370 mm; the annual average sunshine duration is 2 800 h; and the cultivated land area is 292 km2. The test project was implemented in Hailar District of Hulunbeier City. The unique natural climate and special geographical conditions of Hailar District of Hulunbeier City are very suitable for planting potato. The temperature difference between day and night is large， and the soil nutrients are comprehensive， which provides a suitable growth environment for potato.
Mechanical equipment
Harbin Woer 2CMF 4 multi function potato planter; Zhongji Meino 1600 potato harvester; JH 100 potato leaf shredder machine; Dongjin Woer 1GZML 210 deep scarification integrated tillage machine; Klass 210 tractor; Germany Grimme potato planter; potato cultivator; laminating machine; intertillage fertilizer applicator; Grimme potato harvester.
Harbin Woer 2CMF 4 multi function potato planter
The machine can complete multiple processes such as deep scarification， fertilization， trenching， sowing， watering， banking （covering soil） and compacting. The sowing depth， row spacing， hole spacing and fertilizing amount of the machine all can be adjusted. The machine has the characteristics of uniform seeding and high emergence rate. Its production efficiency is 1.2 hm2/h.
JH 100 potato leaf shredder machine
The machine can complete removal of plants on the ridges and in the furrows at one time without harming the potatoes. Its working efficiency is 0.27- 0.30 hm2/h.
Dongjin Woer 1GZML 210 deep scarification combined tillage machine
The machine is equipped with a power of 80-120 hp， and has a working width of 2 100 mm， a production efficiency of 0.6-1.0 hm2/h and a scarification depth of 120-150 mm.
Zhongji Meino 1600 potato harvester
The machine is characterized by one time excavation， conveying and strip operation， high recovery rate （≥98%）， low breakage rate （≤2%）， and fast cost recovery. It has a two stage separation screen which has the characteristics of forced vibration， good separation effect and strong adaptability. The combined excavation mechanism can ensure the same excavation depth. The floating disc cutter can effectively cut the weeds and reduce the excavation resistance.
Core techniques
Mechanized soil preparation technique
This technique can enhance the water storage and retaining capacity of the soil， thereby creating a good soil environment for the growth of potato.
Mechanized seeding technique
This technique can complete ditching， applying chemical fertilizer， sowing sprouted tubers， covering soil， making ridge （laying mulch） and other operations at one time. The sprouted tubers are arranged uniformly， and the plant spacing， row spacing and sowing depth are consistent. The covering soil is laid uniformly. After banking， the effects of retaining water， soil and fertilizer can be achieved. Mechanized intertillage
This is a key field operation in the potato growing season. The potato planted with machine has large row spacing， and the scarification depth and the quantity of to be hilled soil are large. The intertillage and soil banking machine can complete the operations of scarification， weeding and banking at one time. During intertillage， it is necessary to adjust the height， depth and width of the ploughing blade and ploughshare to ensure that the soil is tight and the seedlings are not injured.
Mechanized harvesting
Mechanized harvesting of potato has high efficiency and can achieve the effects of greatly shortening the harvest period， preventing the damage caused by early freezing damage， reducing losses and greatly reducing the labor intensity.
Technical process
According to the survey of farmland in the project area， the technical route included mechanized deep scarification in the previous year， soil preparation before sowing， mechanized fertilization， mechanized sowing， mulching， mechanized cultivating， mechanized plant protection， mechanized plant killing and mechanized harvesting.
Test Content and Methods
Selection of cultivated land
The potato tubers expand during growth， so the soil should be flat fertile loose sandy loam soil with deep soil layer. Meanwhile， in order to prevent soil borne diseases and pests and weeds， potato should be rotated with cereal crops and bean crops except Solanaceae crops， tuberous root crops and tuber crops. The test site was selected in the east direction of Dongshan Airport in Hailar District， Hulunbeier City.
Mechanized deep scarification soil preparation
After the harvesting of the preceding crops， deep scarification （ploughing）， stubble cleaning and rotary tillage should be performed in time. The time of deep scarification is selected according to the spatial and temporal distribution characteristics of local rainfall， so as to accumulate more natural precipitation. Deep scarification and sowing are carried out simultaneously. The 67-107 kW wheeled tractor is used for deep plowing of the potato planting area. The depth of the ploughing is 300-350 mm. Breaking the hard soil layer formed by shallow ploughing is beneficial to increase potato yield per unit area. At the same time， the soil is crushed and finely ground， providing a basis for sowing.
Mechanized seeding
The density during mechanized sowing should be adjusted according to different regions and different varieties to meet the agronomic requirements[1]. In the potato production area in Hulunbeier area of Inner Mongolia， the traditional ridge spacing is 60-70 cm， and the large ridge spacing is 80-90 cm. Attention should be paid to the temperature when sowing. Sowing can be performed when the temperature of the 10 cm soil layer is stable at 7-8℃， and the seeding depth is 6-8 cm. During ridging， the ridge height and ridge width should be kept consistent at 25-30 cm and 40-45 cm， respectively. When planting in spring， the 2CMF 4 potato fertilization planter is selected for sowing. It can complete ditching， sowing， fertilizing， covering soil and compacting at one time， and has the characteristics of good trenching effect， uniform sowing depth， uniform soil covering and moderate compacting. Taken together， the machine can enhance the water storage and retaining capacity of soil， thereby creating a good soil environment for the growth of potato.
Selection of virus free seed potato
The selection of excellent varieties is a prerequisite for ensuring the quality of potato， reducing pests and diseases， and achieving high yield[2]. This experiment selected the high quality virus free seed potato Kexin 1 produced by Inner Mongolia Heng Te Shu Seeds Co.， Ltd.
The emergence stage， bud stage and flowering stage of virus free potato are all earlier， so the potato tubers expand early and the expansion time is longer. Consequently， the potato has sufficient time for growth and development， and the potato yield is increased. The virus free seed potato has higher plants， thicker stems and more leaves， which enhance the photosynthesis of the plants. Photosynthesis is the most important component of potato productivity， so the yield of potatoes will increase. The virus free seed potato eliminates the damage of potato plants caused by viruses， so the leaves are flat， large， dark green， the root system is developed， the plant is strong with strong growth vigor， and the yield is improved[3].
The seed potatoes are taken out from the cellar 10-15 d before planting， or the cellar is ventilated every day 15 d in advance， so that the seed potatoes are at 15-20℃ and germinate. After germination， they are exposed to sunlight to allow the sprouts to turn purple green. When the sprouts grow to the size of the rice grain， the seed potatoes are cut into pieces. Combined with taking out from cellar and cutting， seed potatoes are finely selected by discarding diseased， rotten， wounded， inferior， deformed potato pieces， and the weight of the cut pieces is generally 25-35 g， preferably 30 g， which is beneficial to increasing the rate of emergence， but a too high seeding rate increases the cost of planting. The pieces should be thick and fleshy with two sprouts per piece. The leathery surface should not be less than 2.0 cm × 2.5 cm， and the sprouts should be in the middle of the surface as much as possible. The seed pieces are cut into a basket or the ground when cutting， not directly into an airtight nylon bag. The pile of the seed pieces should not be too high or too thick. The seed pieces should be ventilated and exposed to sunlight， and the cut surface should be dried as soon as possible. In order to prevent the spread of diseases through cutting， two cutting knives should be used alternately when cutting， and the knives should be alternately immersed and disinfected with 75% ethanol or 3% potassium permanganate solution. The cut and dried seed pieces should be sterilized by spraying with a certain agent. 58% metalaxyl mancozeb wettable powder produced by Zhejiang Heben Pesticide & Chemicals Co.， Ltd.， 70% mancozeb WP produced by Limin Chemical Co.， Ltd. and 75% chlorothalonil WP purchased from Jiangxi Zhongxun Agrochemical Co.， Ltd. are prepared into 100 times liquids， and sprayed with a manual sprayer with stirring， and the spraying amount for the seed pieces is 2-3 kg/150 kg.
After spraying， the seed pieces are dried and then filled with mesh bags. Then the mesh bags are stacked into ventilation flower stacks with the height of 4-5 bags， making the gaps not too high. Otherwise， it will easily cause the seed potatoes to rot due to excessive heat， which finally affects emergence. In addition， it is necessary to prevent the seed pieces from being damaged by freezing and rain. Moreover， the cutting of seed potatoes should be matched with the sowing time， preferably in the manner of cutting following seeding immediately， and the storage time of the seed pieces is not more than 3 d.
Sowing and fertilization
When planting， seeding can be performed when the temperature of the 10 cm soil layer is stable at 6-7℃. The suitable sowing period of potatoes in Hailaer district and its surrounding areas is May 5-20， and the best sowing period is May 10-15. Sunny and windless weather is chosen for seeding within the best sowing period. The amount of the seed potatoes is 10-125 kg/hm2， and the seeding density is 4 500 plants/hm2; and the number of harvested plants is about 4 000 plants/hm2. The seeding is performed according to the ridge pacing of 65 cm and the plant spacing of 25 cm. When the ridge spacing is 80 cm， the plant spacing is 15 cm.
During mechanized seeding， the operations such as ditching， fertilizing， seeding， covering soil and ridging can be completed at one time， and the soil is compacted on the seeding day. The thickness of the covering soil is 10-12 cm. When applying the seed fertilizer， it should be applied 2-3 cm below the seed pieces， and the seed pieces should not be in direct contact with the seed fertilizer， so as to avoid seed burning. The farmyard manure is applied before deep ploughing， and the base fertilizer is applied by the method of lifting the fertilizer and harrowing before seeding. During seeding， the fertilizer special for potato is randomly sprayed to prevent and control the pesticides transmitted by soil. The total amount of chemical fertilizer is 35-50 kg/hm2. The usual practice is to apply 50 kg/hm2 of fertilizer with seeding， which includes15 kg/hm2 of diammonium phosphate， 10 kg/hm2 of urea and 25 g/hm2 of 33% potassium sulfate. In this case， the uniformity of the fertilizer should be greater than 97%， and the proportion of the raw materials such as ammonium bicarbonate and urea is generally 20% to 30%. After sowing， the chemical fertilizer is mainly applied， and the base fertilizer （chemical fertilizer） is applied for the second time before banking at a rate of 20 kg/hm2 including 6 kg/hm2 of diammonium phosphate， 4 kg/hm2 of urea and 10 kg/hm2 of 33% potassium sulfate. When the potato seedlings are as high as 100 mm， they are watered and fertilized for several time. Lihua ZHANG et al. Large ridge Mechanized Planting Technology of Potato in Hailar District of Hulunbeier City
Irrigation
Irrigation is carried out by the spray irrigation circle and traditional irrigation method， and it is carried out 5-7 d in advance for tillage when ensuring the soil is wetted thoroughly. The soil water content is ensured to be 50%-60% in the seedling period. If the soil is too dry， it needs to be properly watered to maintain better soil moisture， which is conducive to root development and seedling growth. The flowering period to the tuber expansion period is the most important period of potato growth and development. At this time， irrigation has a great influence on potato yield and quality. The soil water content from the flowering period to the tuber expansion period should be maintained at 70%-80%. It is a period when the potato needs more water， and if the precipitation is less， irrigation should be performed in time. The lack of water at this time will seriously affect potato yield. Watering is stopped 15 d before harvesting， which is conducive to the suberification of the potato skin and the reduction of mechanical damage[4].
Cultivation and banking
The intertillage stage is the key period for potato growth. The cultivating time， the scarifying depth of soil and the height and thickness of the hilled soil must meet the agronomic requirements. In one production season， it is generally necessary to perform soil scarification， weeding and banking for 3 times consecutively. After the seedlings have emerged tidily （about June 20）， the soil is cultivated with a tractor once every 10-15 d， continuously for 3 times. The soil loosening depth is 8-10 cm， and each time， about 3 cm of soil is banked up. The total thickness of the banked soil does not exceed 10 cm. Intertillage plays a role of loosening the soil to retain water， earthing up and killing weeds. The last intertillage is completed before the rows are sealed and should be accompanied by watering in time.
During cultivating and banking， the height， depth and width of the ploughing blade and ploughshare must be adjusted to ensure that the soil is tight and the seedlings are not cut. The land after cultivating should be with no large clods; and the spacing of the cultivating should be the same as the distance of sowing， so as to protect the potato seeds from damage. After cultivating and banking， ridges with a width of 30-40 cm and a height of 20-25 cm are formed. The cultivating and banking can not only kill the weeds， but also concentrate the fertilizers close to the seed potatoes. It can also widen and compact the ridges， which is conducive to the growth of the potatoes and avoid the greening of the potatoes. Spaying of microbicides and pesticides
The herbicide is applied on the second day after the cultivating and banking， and then the microbicide and the pesticide are sprayed at different times according to the situation of the field pests and diseases. The main pests and diseases that are controlled are early blight， late blight， and aphids. Late blight is a common disease in potato production， and it is also the most harmful and most harmful disease of potatoes. Aphids are widely found in potato production in Hailaer district. Aphids mainly stab young leaves to absorb juice， so that the leaves are dry in large areas， which directly affects the yield. Aphids can also spread the virus， causing a large number of plants to infect diseases and degrade seriously in the field and finally the yield to reduce. Prevention method： The agents are applied since the beginning of the flowering period （about the end of June）， about 4-5 times in one production season. The spraying is performed 1-2 times every 7-10 d after the potato is 15 cm. The agents can be selected from 75% mancozeb WP produced by Shanghai Ruida Chemical Co.， Ltd.， 53.8% Kocide WP produced by Hunan Jindadi Agricultural Materials Co.， Ltd. and 64% Oxadixyl WP purchased from Tianmen Kechuang E commerce Co.， Ltd.， each 90 g/hm2. When aphids are found， 10% aphid pesticide spray produced by Tianjing Chitian Pest Control Co.， Ltd. is added at a rate of 30 g/hm2. The above pesticides should be used alternately. These agents are filled into spray cans and mixed with water at 45 kg/hm2， obtaining the mixtures in the cans which are then carried by a tractor and sprayed.
The concentrations of the agents should meet the requirements of the corresponding agricultural production at the time of spraying. The distance between the nozzle and the potato should be maintained at about 50 cm during the spraying process. The application process should not be too fast， ensuring the overall uniformity. The spraying is performed at an interval of one week， and the total number of spraying is 5 times.
Weed control
At the seedling stage， herbicides are sprayed at the weed stage of 2-4 leaves. 10 g/hm2 of acetochlor is mixed with 30 kg of water， obtaining the liquid which is sprayed near the ground to reduce drift of the agent. The weeding depth is 3-8 cm， and the weed control adopts agronomic measures combining mechanical and manual weeding， and if necessary， a herbicide with small side effects is used. Removal of the aboveground part and harvesting
10-15 d before harvesting， when most of the stems and leaves of potato plants are yellow and the tubers are easy to separate from the stolons， in order to promote the hardening， thickening and aging of the potato skin， reduce damage and prevent potato plants from winding the vibrating screen， the potato plants are cut with a cutting machine and removed from the field in a sunny weather. Before the operation of the cutting machine， the hammerclaw is first raised to 20-25 cm from the ground， and operated for 1-2 cm after connected to the power output shaft， and then， the gear is stopped. When removing the plants， the height of the depth roller and the angle of the cutting knife are adjusted. If the cutting knife is too high， the potato plants cannot be completely removed. If it is too low， the upper potato will be easily damaged. The cutting machine should go straight to avoid pressing the ridges and damaging potatoes.
Potato harvesting is the most labor intensive part of potato production. The labor consumed by harvesting accounts for 80% of the total labor. Due to the short harvest season and labor shortage， if the harvest is not timely， it often affects the seed potato shipment and causes potato freezing. The suitable harvest period for potatoes in Hailar and surrounding areas is from August 25 to September 30， and the best harvest period is September 5-25. The mechanized harvesting of potatoes is carried out using the Zhongnong Meinuo 1600 potato harvester. The potatoes are harvested when the weather is fine， during which the digging depth is adjusted， because if the digging shovel enters into the soil too shallowly， it will damage the potato pieces， and if it enters the soil too deep， the working load of the tractor will be increased. During the harvesting， the harvester should be prevented from going wrong， avoiding the wheels going up the ridge and rolling the potatoes. Much attention should be paid to safety during work. The soil and weeds on the digging shovel and the vibrating screen must be cleaned when the machine is stopped.
The harvested seed potatoes are stacked and buried in the soil after slightly drying， and the bags are sorted at any time. At the same time， the seed potatoes are protected from rain， freezing damage and long term sunshine. If you plant more than two varieties， you must pay special attention to prevent mixing between varieties. It is necessary to strictly classify， harvest， bag， transport， and ship the potatoes. Test design
In this test， a demonstration base was built near the Dongshan Airport in Hailar， with a test scale of 10 000 hm2. 600 hm2 of demonstration field was taken as a test plot， and two test plots were set. This study investigated the soil temperature， humidity and bulk density under the large ridge spacing （80 cm） and traditional ridge spacing （65 cm） at different soil levels （10， 20， 30 and 40 cm） and the effects of different ridge spacing on various indexes including potato plant height， stem diameter， main stem density， number of potatoes， large and medium potato rate， small potato rate， yield， and starch content， and analyzed the economic benefit.
Determination of soil temperature， humidity and bulk density
The soil temperature and humidity can be measured by the soil moisture temperature tester. The instrument can directly display the soil moisture and temperature values. When measuring the deep soil， an extension rod and soil drill can be selected. It can be seen from the measurement that the soil water content and soil temperature are affected by the environment， and lower degrees of temperature and humidity variations can improve the appearance quality and nutritional quality of the tubers.
The soil bulk density is usually measured by a ring knife method. The soil sample under the natural state free of agitation was cut with a ring cutter which was then filled with soil thereby， and the mass of the dried soil per unit volume was calculated after drying. From the soil bulk density， the porosity of the soil can be calculated， and the tightness and structural condition of the soil can be estimated.
Determination of plant height and stem diameter
After the flowering period， the length of the aboveground part of the plant and the maximum stem diameter of the plant were measured.
Determination of the number of main stems
The number of main stems was measured during flowering.
Determination of tuber number and yield
During harvesting at the maturation stage， one row per plot was selected for the determination of the tuber number and yield.
Determination of large and medium potato rate and small potato rate
According to the weights of individual potatoes， they are divided into four grades： micro potato （0-25 g）， small potato （25-75 g） ， medium potato （75-100 g） and large potato （≥100 g）. After harvesting， each treatment was graded according to the above classification criteria， and the proportion of potatoes of each grade was obtained[5]. Determination of starch content
After harvesting， fresh potato samples were taken， washed with water， and air dried， and the starch content was measured with a starch analyzer.
Analysis of economic benefit
A comprehensive comparison was performed between the large ridge spacing and the traditional ridge spacing from the pre planting preparation to the total cost after harvesting and the yield benefit obtained after harvesting.
Results and Analysis
Soil properties under different ridge spacing
Allen[6] pointed out that the growth and development of the underground tubers of potato is affected by many factors （such as weather， soil， fertilizer， water， etc.）[6]. It can be seen from Table 1 that during the potato harvest period， the soil temperature of the plough layer under the large ridge cultivation was lower than that of the small ridge. As the soil ploughing layer deepened， the soil temperature also decreased. It can be seen that the large ridge cultivation mode has a good cooling effect and has a good promoting effect on potato tuber yield and quality.
It can be seen from Table 2 that large ridge cultivation can significantly improve the soil water content in the potato growing area， and increase the relative water content of the soil from the tuber formation stage to the maturation stage. The soil water content varied little and was stable at different soil levels. Under the large ridge cultivation， the soil water content and soil temperature were less affected by the environment， and the degree of alternating high temperature and drought with low temperature and wet was small， which reduced the deformity caused by secondary growth of tubers and improved the appearance quality and nutritional quality of tubers.
It can be seen from Table 3 that compared with the small ridge， the soil bulk density in the large ridge cultivation mode was relatively low， the soil porosity increased， and the soil was loose with good air permeability. Therefore， under the large ridge cultivation， it is easy to promote the absorption of nutrients in the soil by the root system， which is conducive to the growth and development of the aboveground organs， promotes photosynthesis， and lays a good foundation for the high yield of potatoes.
Effects of different ridge spacing on various indicators
It can be seen from Table 4 that the plant height， stem diameter， number of main stems， and number of potatoes increased in the large ridge cultivation mode compared with the traditional ridge spacing. In the large ridge cultivation mode， the number of potatoes can reach 51， which was 21% different from the traditional ridge spacing. Compared with the traditional ridge spacing， the large and medium potato rate in the large ridge spacing treatment increased， and was up to 93.2%， and the small potato rate decreased by about 20%. It can be seen from Table 5 that compared with the traditional ridge spacing， the yield and starch content of the potato in the large ridge spacing treatment both increased. The yield was higher than that in the traditional ridge spacing mode by more than 30%， and the starch content was also improved.
It can be seen from Table 6 that the potato planted in the large ridge spacing mode had the average yield 370 kg/hm2 higher than that in the small ridge spacing mode with the labor cost reduced by 30 yuan/hm2， and the economic benefit of the large ridge spacing mode was 160 yuan/hm2 higher than that of small ridge spacing mode. Therefore， the mechanized large ridge operation has an obvious effect of increasing farmers income， and not only increases the potato yield， but also saves production costs， and the economic benefit is obvious.
Brief summary
The large ridge cultivation of potato has the characteristics of heat preservation， water storage and moisture conservation， which are conducive to subsequent cultivating and weeding， banking， irrigation， plant protection and harvesting operations. Meanwhile， the mechanized large ridge operation is also conducive to loosening the soil， and conducive to reducing wind erosion and enhancing drought resistance in the spring with strong winds， particularly， which will promote the improvement of agro ecological environment. With small ridge planting， each person can only sow （harvest） 15 hm2/d， while mechanized large ridge operation can complete ditching， sowing， fertilization and banking at one time， and one person can sow （harvest） more than 19 hm2/d， which means that the efficiency is improved to 1.27 times. The sowing depth， plant spacing and row spacing of the mechanized large ridge sowing have high requirements on agronomic techniques with the characteristics of high germination rate， more branches and the average seed rate of 280-300 kg/hm2. Compared with the small ridge seeding method （320-350 kg/hm2）， it saved the seed potatoes by 40-50 kg/hm2， which meant a saving rate higher than 12.5%. The comparison between the mechanized large ridge potato planting and traditional planting showed that the average potato yield was 4 230 kg/hm2， 370 kg/hm2 higher than the traditional production method （3 860 kg/hm2）， with a yield increasing rate of 9.6%， and the cost was saved by 30 yuan/hm2. The economic benefit of large ridge planting was 160 yuan/hm2 higher than that of small ridge method. Conclusions and Discussion
Mechanized large ridge potato planting can not only improve mechanization efficiency and shorten farming season， but also can reduce labor intensity， energy consumption and production cost and improve production efficiency and crop yield， reflecting good economic benefits. It is an important way to promote potato production technology reform， promote the increase of farmers income and local rural economic development and promote the sustainable development of the potato industry. It is of great significance to safeguarding food security and promoting the development of modern agriculture and ecological civilization in the city.
The research results of Wu et al.[7] showed that an appropriate increase of row spacing can increase the number of tubers. The results of this study showed that under the same planting density， the number of potato tubers increased with the increase of the ridge spacing， and the effect of ridge spacing on yield is the same as that of Qin et al.[8].
Nowadays， people are paying more and more attention to transforming resource and production advantages into commodity economic advantages， and more and more attention to the increase in potato yield and quality[9-11]. The demand for potato quantity and quality have increased year by year. Changing the traditional planting mode to improve the yield and quality of potato is an urgent problem for potato producers[12]. In China， the large ridge planting technique is very mature in the cultivation of other crops， and the time spent on potato cultivation is not long， so it is the planting method mainly promoted for potato cultivation. This study combined the large ridge treatment and small ridge planting that are currently promoted to compare the effects of different ridge spacing on the growth and yield of potato variety Kexin 1. The results showed that the large ridge planting is more in line with modern mechanized agricultural production. The test was only for the potato variety Kexin 1， and different varieties have different characteristics， so further research is needed for other varieties.
References
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