黑土立体休闲技术改土增产效果

Effect of improving black soil and crop yield by using soil layer up-down fallow technology

为了打破犁底层障碍,消减连作障碍,分别在轮作和连作的黑土上采用分层深耕犁将0~20 cm耕层土与>20~40 cm下层土进行转换,以达到休闲表层土壤的目的。采用大区对比法连续2年调查改土后效果。结果表明:第1年、第2年立体休闲处理较对照组未改土,0~40 cm土层土壤平均容重分别降低0.05、0.11 g/cm^3;通气系数分别提高14.97×10^(-2)、16.69×10^(-2) cm/s;而饱和导水率较对照组第1年降低了3.14×10^(-3) cm/s,第2年提高了10.95×10^(-3) cm/s;抗剪强度较对照组第1年降低了0.72 kPa,第2年提高了0.82 kPa;土壤平均含水率提高分别提高4.07%、4.95%;温度分别提高0.78、0.13℃。立体休闲后表层土壤有机质、碱解氮、速效磷和速效钾降低、下层土土壤肥力增加。在轮作条件下,立体休闲后第1年马铃薯和甜菜分别减产5.63%和3.06%;第2年玉米和马铃薯分别增产5.20%和27.00%。在大豆连作条件下,立体休闲区植株干质量平均比对照提高7.63~7.82%;根干质量提高7.61%~13.41%;根长增加4.42%~6.26%;单株荚数增加18.83%~20.71%;株粒数增加幅度为32.43%~37.21%;根瘤数每株增加1.46~5.15个;产量比对照增加3.09%~22.38%。

Black soil is one of the most important cultivated land resources in Northeast China.Black soil has high soil fertility,and brings about high and stable yield.According to the survey,the humus layer of black soil is generally 30-70 cm.But black soil is on high terrain and the cultivation time is long,coupled with the neglect of enhancing soil fertility management,which lead to serious soil erosion,soil layer thinning,and soil fertility decline.Especially in the past 10 years,in order to save costs,farmers have widely used simplified technology,and the basic soil tillage method has changed from plowing to rotary tillage and stubble cleaning,which has resulted in shallow tillage layer and increased the bottom thickness.The depth of the plough bottom moves from 18-22 to 12-15 cm,and the potential productivity of black soil is restricted.People try to stop the decline of soil fertility and soil thinning by improving the application of organic fertilizer,straw returning and subsoiling technology.Our research group found that the straw deep buried and organic fertilizer application have effectively improved soil fertility.In view of removing the obstacle of continuous cropping,the existing technologies including the nutritional therapy,soil disinfection,and crop rotation technology had the problem of high cost and were difficult in the rotation of crops.Therefore,these techniques were limited to solve the problem of soil continuous cropping obstacles.According to the principle of land fallow for leisure,the technology of improving soil by stereo leisure was presented in this paper,which was aimed at continuous cropping obstacles in soils.Through making full use of the characteristics of black soil with deep humus layer,continuous cropping soil was regularly turned to lower leisure.By alternate use of upper and lower soil,the objectives of soil leisure and agricultural sustainable development would be achieved.In this paper,a machine developed to turn the top soil to the lower layer was operated in the black soil field for breaking its hard plough pan.As the depth of top black soil is more than 40 cm,it has good homogeneity from up part to low part,which can provide a choice for developing soil layer up-down fallow technology.Two test fields were selected.One was operated by above mentioned machine,and the other was operated by conventional machine.The results showed that in the up-down fallow field the soil bulk density was decreased by 0.05,0.11 g/cm3 respectively compared with that in the conventional field.The soil aeration coefficient was increased by 14.97×10^-2,16.69×10^-2 cm/s respectively in the first year and second year.The soil saturated hydraulic conductivity was reduced by3.14×10^-3 in the first year,increased by 10.95×10^-3 cm/s in the second year.The soil shearing strength was reduced by 0.72 in the first year,increased by 0.82 kPa in the second year,and the soil moisture content was increased by 4.07%,4.95%respectively in the first year and second year.It was also found that in the up-down fallow field,soil chemical index including soil organic matter,alkali-hydrolysable nitrogen,available phosphorus and available potassium tended to be lower in the upper layer but higher in the down layer.Under the rotation conditions,the yield of potato and beet in the up-down fallow field was decreased by 5.63% and 3.06%respectively in the first year,but the yield of corn and potato increased by 5.20% and 27.00%respectively in the second year.Under the soybean continuous cropping conditions,soybean grew well in the up-down fallow field,dry weight and root dry weight of soybean were increased by 7.63%-7.82%and 7.61%-13.41%respectively,root length was increased by 4.42%-6.26%,pod number and grain number per plant were increased by 18.83%-20.71% and 32.43%-37.21%respectively,and nodule number was increased by 1.46-5.15.During the 2 tested years,soybean yield in the up-down fallow field was 3.09%-22.38% higher than that in the conventional field.