论文部分内容阅读
通过田间试验研究不同灌溉水矿化度和施氮量对土壤微生物数量、土壤呼吸及土壤微生物群落功能多样性的影响。试验设置3种灌溉水矿化度(电导率,EC1∶5)分别为0.35、4.61和8.04 d S·m-1(分别代表淡水、微咸水和咸水);同时,设置4个施氮水平:0、240、360和480 kg N·hm-2。结果表明:细菌数量随灌溉水矿化度的增加呈先增加后降低的趋势,施用氮肥可增加细菌数量,但当氮肥用量超过240 kg·hm-2后,细菌数量显著降低;真菌和放线菌数量随灌溉水矿化度的增加而增加,与不施氮相比,施用氮肥显著降低放线菌数量;淡水处理细菌/真菌显著大于微咸水和咸水处理,分别较微咸水和咸水处理高29%和86%,细菌/真菌在240 kg N·hm-2处理下最高;土壤呼吸随灌溉水矿化度的增加而显著降低,淡水处理分别较微咸水和咸水处理高12%和33%,土壤呼吸随施氮量的增加而增加,360和480 kg N·hm-2处理分别较不施氮处理增加48%和51%;AWCD值随灌溉水矿化度的增加而降低,淡水处理AWCD值分别较微咸水和咸水处理高3%和13%;灌溉水矿化度对丰富度指数、Shannon指数和Shannon均匀度指数无显著影响,但对Simpson指数影响显著,咸水处理Simpson指数最高,240 kg N·hm-2施氮处理土壤微生物群落多样性指数最高。因此,咸水灌溉显著影响土壤微生物数量和群落功能多样性,合理施用氮肥有助于保持土壤微生物活性和多样性。
Field experiments were conducted to study the effects of different irrigation water salinity and nitrogen rates on soil microbial biomass, soil respiration and functional diversity of soil microbial communities. Three kinds of irrigation water salinity (EC1: 5) were set as 0.35, 4.61 and 8.04 d S · m-1 respectively (fresh water, brackish water and brackish water respectively). At the same time, Levels: 0, 240, 360 and 480 kg N · hm-2. The results showed that the number of bacteria increased first and then decreased with the salinity of irrigation water. Nitrogen fertilizer increased the number of bacteria, but the amount of bacteria decreased significantly when the nitrogen fertilizer was more than 240 kg · hm-2. The number of bacteria increased with the salinity of irrigation water. Compared with no nitrogen application, the amount of actinomycetes significantly decreased with the application of nitrogen fertilizer. The bacteria / fungi in freshwater treatment were significantly more than those with brackish and brackish water, respectively Saltwater treatment was 29% and 86% higher, respectively. Bacteria and fungi were the highest under the treatment of 240 kg N · hm-2. Soil respiration decreased significantly with the salinity of irrigation water, while fresh water treatment was slightly brackish and saltwater 12% and 33% respectively. The soil respiration increased with the increase of nitrogen application rate, and increased by 48% and 51% respectively at 360 and 480 kg N · hm-2 compared with no-nitrogen treatment. AWCD value increased with the salinity of irrigation water Increase and decrease, AWCD value of freshwater treatment is respectively 3% and 13% higher than that of brackish water and salt water treatment; Irrigation water salinity has no significant effect on richness index, Shannon index and Shannon evenness index, but influence on Simpson index Significantly, the Simpson index of saltwater treatment was the highest. Soil microbial population was treated with 240 kg N · hm-2 nitrogen The highest diversity index. Therefore, salt water irrigation significantly affected the amount of soil microorganisms and community functional diversity, rational use of nitrogen fertilizer helps to maintain soil microbial activity and diversity.