| High temperature and rainy climate of Hainan formed the high acidity and poor fertilizer retention ability of soil, which also determines the low utilization ratio of nitrogen. Straw and biochar has a huge potential of amending the soil acidity and enhancing soil fertility ability, and may affect the utilization of nitrogen. For knowledge of the influence on the properties of latosol by corn straw and biochar in Hainan, as well as the change of soil properties that may impact on soil nitrification, with the typical granite and basalt latosol in Hainan as tested materials, and in the optimum soil moisture environment and waterlogged conditions, to study the effects on soil physical and chemical properties and nitrogen nitrification through the indoor cultivation experiment that com straw and biochar apply to latosol. Biochar (B), corn straw (CS) and biochar+corn straw (BCS) were applied into soil, respectively, and no organic material was also arranged as control (CK). The main research results are as follows:1、 Biological materials the is applied to soil can significantly reduce soil acidity. Granite latosol in75%field moisture capacity and waterlogged conditions, soil pH increased respectively0.67-1.24and0.30-0.49, exchangeable acid reduced respectively80.34-86.28%and50.22-68.90%; basalt latosol soil pH increased respectively0.39-0.73and0.12-0.22, soil exchangeable acid reduced respectively47.06-54.01%and26.91-35.38%. The soil acidity of granite latosol improved better than the basalt latosol because of biological materials,75%field moisture capacity of soil that the acidity effect is better than that of waterlogged conditions. The improvement effect of biomass material on different treatment latosol acidity was in order as CS, BCS and B.2. Nutrient content of soil increased significantly under the action of biomass materials. Biological material effect on soil organic carbon of granite latosol is better that which in the basalt latosol, the addition of biochar to soil, soil organic carbon content is relatively stable. Overall, corn straw treatment effect is best, followed by biochar+corn straw, biochar treatment had the lowest effect in the biomass materials. Exchange capacity of soil has enhanced because of biomass materials. Granite latosol in75%field moisture capacity and waterlogged conditions, soil CEC increased respectively0.95-1.54and0.36-0.46cmol/kg, soil exchangeable base increased respectively1.40-2.77and1.35-2.23times, soil base saturation increased respectively28.97-53.26%and28.18-46.18%; basalt latosol soil CEC increased respectively-0.03-1.26and0.50-1.33cmol/kg, soil exchangeable base increased respectively1.26-2.23and1.28-2.29times, soil base saturation increased respectively14.91-32.63%and15.64-24.81%. The effect of granite latosol is better in75%field moisture capacity and good treatment effect at the time of the flood basalt latosol. The influence of biomass materials on soil adsorption as:corn straw processing effect is best, second by the biochar+corn straw, biochar treatment effect that is minimum.3、Application of biological materials, due to soil type and culture difference of moisture on soil nitrification effect is different. Adding biochar, soil ammonium nitrogen in different water cultivation of latosol can be quickly converted to nitrate nitrogen and the soil nitrification rate is higher, increase the risk of nitrate nitrogen leaching in the soil at the same time. Because of difference content of cultivation water, the effect of corn straw is different. Soil nitrification more thoroughly in75%field moisture capacity cultivation and flooded cultivation has certain inhibitory effect on soil nitrification. It has certain biological fixation of soil mineral nitrogen because of adding straw to soil and reduce the nitrate nitrogen leaching that caused the loss of nitrogen in the soil.Synthesized the preparation process of biological materials, soil physical and chemical properties of modified and the effect of nitrogen nitrification, suggestions for improvement of soil with straw returning directly modes, soil water management for soil types or improved purposes can be appropriately adjusted. |
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