Subsoil fertilization plow and its effect on improving barren soil

There is a large area of low productive soil, many soil types, and different low productive reasons in Heilongjiang Province.So improving low productive soil has important significance for agriculture.Subsoil fertilization is a comprehensive soil improvement technology which can improve subsoil′s bad physical and chemical properties.Studying team has done research on improving planosol with subsoil fertilization, and this technology has the effect of continually increasing yield, but there is lack of the research on other soil types, and the practical mechanical tools.In this paper, the subsoil fertilization plow was researched according to the subsoil fertilization technology requirements, and applied on the improvement of carbonate meadow chernozem and thin layer black soil, which was aimed to clarify its soil improvement effect on soil physical and chemical properties and corn yield, and provide the mechanical and technological support for its wide application in low production soil.The field contrast method was applied in this study, and 3 treatments were set which included deep loosing(DL), subsoil fertilization(SF) and control(CK).The result showed that the effects of subsoil fertilization and deep loosing on soil physical and chemical properties, yield characteristics and yield were not consistent.The lasting effect of deep loosing and subsoil fertilization on deceasing soil shear strength was obvious.For carbonate meadow chernozem and thin layer black soil, the soil shear strength was decreased by 7.14 and 5.41 kPa under DL treatment, and by 12.16 and 8.20 kPa under SF treatment respectively compared with that of the CK in the first year after soil improvement; the soil shear strength was decreased by 0.68 and 2.25 kPa under DL treatment, and by 6.65 and 11.31 kPa under SF treatment respectively compared with that of the CK in the second year after soil improvement.The bulk density and hardness were the same as the above change.Subsoil fertilization could improve soil air permeability and saturated hydraulic conductivity; the air permeability coefficient was respectively 3.22 and 15.28 times higher than the CK on the 10-30 cm soil layer of carbonate meadow chernozem and thin layer black soil in the first year after improvement, and 5.17 and 3.78 times after the second year; the saturated hydraulic conductivity was respectively 8.93 and 7.68 times higher than that of the CK after the first year, and respectively 12.62 and 3.38 times after the second year.The effect of deep loosing was not obvious.The DL and SF treatment could improve water consumption of subsoil, and the order of water consumption was CK>DL>SF in 0-30 cm soil layer, and SF>DL>CK in 30-60 cm soil layer.The water consumption in subsoil layer was 30% of total water consumption, and 10% more than the CK.The total phosphorus and available phosphorus were increased by 0.05 g/kg and 3.21 mg/kg under SF treatment compared with the CK in 20-30 cm soil layer of carbonate meadow chernozem, and by 0.01 g/kg and 1.92 mg/kg in 30-40 cm soil layer, and the phosphorus offering intensity of the 2 layers was improved by 5.17 and 17 times compared with the CK; The total phosphorus and available phosphorus were increased by 0.09 g/kg and 15.05 mg/kg under SF treatment compared with the CK in 20-30 cm soil layer of thin layer black soil, and by 4.19 g/kg and 4.96 mg/kg in 30-40 cm soil layer, and the phosphorus offering intensity of the 2 layers was improved by 5.17 and 17 times compared with the CK.Subsoil fertilization and deep loosing could promote the corn growth, increase the length and width of ear, grain number per spike, 100?seed weight and yield.The yield was increased respectively by 18.01% and 14.28% under subsoil fertilization and deep loosing in the first year after soil improvement for carbonate meadow chernozem, and respectively by 6.82% and 2.87% in the second year after soil improvement; the increased yield was respectively 6.45% and 1.80% in the first year after soil improvement for thin layer black soil, and respectively 11.18% and 5.11% in the second year.The effect of increasing yield for carbonate meadow chernozem is more obvious than that for thin layer black soil.