| The experiment was located at sanjia village of Tuogu town, Zhaozhou county in Heilongjiang Province. There were nine treatments to improve saline-alkali soil fertility by using different straw returning treatments, and corn was put as the instruction crop. Some soil indexes——soil water, soil pH, available nutrients, CEC, ESP, soil enzyme activity (Urase, Catalase), organic matter, soil active matter, the carbon pool management index and yield of corn——were monitored periodically. The best fertilization model of improving saline-alkali soil fertility was to be established through studying physico-chemical properties of saline-alkali soil,carbon pool ,soil enzyme activities and changes of corn yield and correlations among all indexes. Establishment of improvement measures adapted to local soil, and rational development and utilization of local resources of saline-alkali soil should play a vital role to Zhaozhou County as well as the entire Northeast agriculture and economic development.According to field trial and indoor experiment results of the analysis, by using software SPSS analysis of variance, multiple comparisons and stepwise regression statistical analysis, obtained results was as follows:1.Various improvement measures could improve the physical properties of the soil, mainly in: the soil moisture and field moisture capacity increased by varying degrees, and there were significant differences between the moisture contents of the treatment 4 ( tall stubble returning + decomposer + organic fertilizers) and treatment 1. There were very significant differences between treatment 8 ( half straw returning +decomposer + organic fertilizers ) and CK. Soil moisture of half straw returning was more improvement than that of tall stubble returning and tall stubble returning. It was thus clear that the content of straw returning should be the critical factor which affected soil water condition.2.Various improvement measures could improve the chemical properties of the soil, mainly in: there were greatly significant differences between treatment 8 ( half straw returning +decomposer + organic fertilizers ) and CK for enhancing CEC of soil. Both of treatment 4 ( tall stubble returning + decomposer + organic fertilizers) and treatment 9 ( half straw returning +decomposer + N fertilizers ) had significant differences with CK. Different treatment could decrease pH readings and ESP, and could enhance the release of NPK nutrients. Organic fertilizers treatment was the best3. Various improvement measures could improve soil enzyme activities, mainly in: organic fertilizers treatment was the best, followed decomposer treatment, and each of them reached a significant differenct level with the control treatment. 4. Various improvement measures could enhance the activity of soil organic matter and carbon pool management index and raise the level of the soil carbon pool. It was showed that these improvements had effects of fertility-improving and sound development of soil properties. The organic fertilizers treatment had the best effect.5. The analysis of the correlation among the index showed that: soil organic matter had good positive correlations with soil moisture content, cation exchange capacity, Urase, Catalase (correlation coefficients R were as follows:0.9261**,0.9382**,0.9104**,0.9771**), but soil organic matter showed a good negative correlations(correlation coefficients R were as follows: 0.9824**,0.908*,0.9749**) with salt content, ESP, and soil pH,6. Various improvement measures could improve the corn yield. The best treatment was half straw returning +decomposer + organic fertilizers, and followed by treatment decomposer + N fertilizers, decomposer, and each of them achieving a significant difference with the control treatment.To conclude from above results: considering manipulating difficulty, the best effect of straw returning was treatment 4 (tall stubble returning +decomposer + organic fertilizers )... |
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