秸秆心土混合犁改良白浆土效果

    Effect of planosol improvement by using straw subsoil mixed layer plough

    • 摘要: 为将表层秸秆施入心土,改善贫瘠的心土层创造有利条件,该文设计了将白浆土“上翻20 cm,下混30~40 cm,同时将有机物料施入心土层”的秸秆心土混合犁。该研究通过设置秸秆心土混合区和浅翻深松区田间对比试验,调查机械作业后土壤理化性质,指示作物农艺性状以及产量指标等,明确秸秆心土混合的改土增产机理,进一步拓宽白浆土改良途径,为机械改土技术的广泛应用提供技术支撑。研究结果表明:与浅翻深松相比,秸秆心土混合改善心土层土壤物理性质,20~40 cm土层土壤含水率提高2.69~4.90个百分点;硬度降低44.45%左右,且没有出现峰值;改善土壤通透性,固相降低幅度为4.51~2.14个百分点,液相增加幅度为1.17~4.13个百分点,气相增加幅度为0.38~0.98个百分点,容重下降幅度为0.16~0.11 g/cm3;提高心土层养分含量,碱解氮提高17.33%,有效磷提高116.39%,速效钾提高37.86%,有机质提高36.66%,同时提高心土层全量养分含量,缓解土壤酸性。连续2 a调查大豆产量,秸秆心土混合区比对照区增产15.77%~16.33%,一次改土后效时间长,增产效果显著。该研究结果可为白浆土及其同类低产土壤改良及作物高产提供技术支撑。

       

      Abstract: Abstract: The subsoil of planosol is usually extremely hard, compacted and poorly nutrient during the growing stage of upland crops. These unreasonable physical-chemical properties of the subsoil trigger the problems on its topsoil, which makes upland crops frequently suffer dry and wet damage so called the surface dry and surface wet damage. Meanwhile it also functions as an obstacle layer limiting root extension, and hence the effective layer of root system of planosol is only about 20 cm. The research formerly carried out has proved that it could cease the problems of subsoil when the Aw (planosol layer) horizon and the B horizon (illuvia horizon) were mixed with the ratio of 1:1 while leaving the topsoil undisturbed. Through this method, the permeability and the water storage capability of the subsoil were increased. As a result, the machine named the three-stage subsoil mixing plough was developed. Since its working is deeper more than 50 cm, the plough provides the opportunity to return stalks into the mixed subsoil, and the poor nutrient condition of the subsoil can be therefore improved. Based on such kind of principle of planosol improvement, the machine so called the stalk-subsoil mixing plough was developed. This machine can make it come truth to leave the Ap (topsoil) horizon in depth of 20 cm undisturbed, while mixing the subsoil and stalk in depth of 30-40 cm. In this study, the large-size field tests were carried out with the stalk-subsoil mixing plough and the conventional plough at the 854 State Farm of the Sanjiang Plain, Heilongjiang Province of China. The physical-chemical properties after the machine operation were investigated. The agronomic characteristics and yield of the indicating crops were checked. The results showed that compared with the conventional plough, the stalk-subsoil mixing plough could significantly improve the soil physical properties. In the depth of >20-40 cm, soil moisture was increased by 2.69-4.90 percent points; soil hardness was reduced by 44.45%, and there was no hardness peak appearing. In 2014 and 2015, it also could improve soil permeability; solid phase was reduced by 4.51 to 2.14 percent points, water phase was increased by 1.17 to 4.31 percent points, air phase was increased by 0.38 to 0.98 percent points, and soil bulk density was decreased by 0.11-0.16 g/cm3. The soil chemical properties were also improved. In the depth where subsoil was mixed with stalks, available nitrogen (N) was increased by17.33%, available phosphorus (P) was increased by 116.39%, available potassium (K) was increased by 37.86%, and organic matter was increased by 36.66%. By the way, soil total N, P, and K and soil pH value were increased. During the 2 years the soybean yield in the field operated by the stalk-subsoil mixing plough was increased by 15.77%-16.33% compared with the field operated by the conventional plough. Thus long term effect for Planosol improvement can be achieved by using the technique of returning stalks.

       

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