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本文从土壤物理特性和作物生长的关系探讨了耕作的要求。土壤水分能量特性可被机械扰动改变,这是导致土壤粘闭的重要原因。水稻土的含水量和有效水均以表土高,而下层低,含水量和容重成线性负相关(n=62,r=-0.909~(**))。土壤扰动可提高持水量,长年免耕在干旱年份可能会出现水分不足问题。土壤含水量、气容量和机械强度三者的变化相互联系。由三个因素决定的小麦生长最佳范围是在水分吸力0.02—0.5巴内,而田间持水量大于塑性限,所以秋季耕作必然导致土壤粘闭。免耕土壤的容重一般在1—1.25g/cm_3之间,是稻麦生长的较佳环境,所以水稻土本身存在适合稻麦免耕生产的条件。根据水稻和三麦分别52和23组次对比试验,水稻免耕增产19斤/亩,三麦49斤/亩,均达到极显著水平(p=0.01)。平田地区连续三年免耕土壤不恶化,囊水型土壤第二年开始有变差趋势,但产量不减低。免耕有保护土壤结构的作用,但不利于结构发展。
In this paper, the relationship between soil physical properties and crop growth is discussed. Soil moisture energy characteristics can be changed by mechanical disturbance, which is the main reason leading to soil adhesion. Paddy soil water content and effective water are topsoil high, and the lower the lower, water content and bulk density into a linear negative correlation (n = 62, r = -0.909 ~ (**)). Soil disturbance can increase the water holding capacity. During the years of no-tillage, the shortage of water may occur in drought years. Changes in soil moisture content, gas volume and mechanical strength are interrelated. The optimum range of wheat growth determined by three factors is within the range of 0.02-0.5 bar of water suction, while the field capacity is greater than the plastic limit, so tillage in autumn inevitably leads to soil sticking. The bulk density of no-till soil is generally between 1-1.25g / cm_3, which is a better environment for the growth of rice and wheat. Therefore, the paddy soil itself has the suitable conditions for no-tillage of rice and wheat. According to the comparative experiments of 52 and 23 groups of rice and three wheat, the no-till rice yield increased by 19 kg / mu and 49 kg / mu of three wheat reached the extremely significant level (p = 0.01). Hirata area for three consecutive years no-tillage soil does not worsen, cystic water-soil began to have the second year of decline, but the yield does not decrease. Tillage has the role of protecting soil structure, but not conducive to structural development.