| In view of the fact that most saline-alkali soil reforms start from the point of view of soil fertilizer cultivation,less attention is paid to the regulation of plant resistance.In this paper,the effects of plant rhizosphere growth promoting bacteria and biological organic fertilizers combined with chemical modifiers such as sulfur and ferrous sulfate on the improvement of saline soil and crop growth were studied by field experiment.In order to provide a good solution for the improvement and utilization of saline-alkali soil.The main results are as follows:under the condition of mild salinization,the yield of corn was increased by 7.79%,and the contents of ammonium nitrogen and available phosphorus in soil were increased by59.04%and 21.44%,respectively.At the same time,the soil urease activity was increased,the contents of nitrogen,phosphorus and potassium in corn straw were significantly increased by24.70%,33.56%and 22.45%,respectively,and the nitrogen content in grain was increased by14.10%.The yield of single application of growth promoting agent was not significantly different from that of conventional fertilizer treatment,but it promoted the absorption of nitrogen by corn straw,and the nitrogen content was 21.71%higher than that of conventional fertilizer treatment.There was no significant difference in yield between the combined application of growth promoting agent and biological organic fertilizer and that of single application of biological organic fertilizer.The contents of ammonium nitrogen and available phosphorus in soil were significantly lower than those in biological organic fertilizer,but there was no significant difference in soil enzyme activity and plant nutrient absorption.Under the condition of moderate salinization,the yield and ammonium nitrogen content of corn were significantly decreased by 6.35%and 16.32%,respectively,compared with those of conventional fertilizer.There was no significant difference in yield between single application of biological organic fertilizer and conventional fertilizer.The contents of nitrate nitrogen,ammonium nitrogen,available phosphorus and available potassium in soil were significantly increased by 57.96%,18.86%,28.18%and 18.66%,respectively.The urease activity of soil increased by 32.43%,and the nitrogen content of plant straw and grain was increased.The yield of combined application of bio-organic fertilizer and growth-promoting agent was 11.11%higher than that of conventional fertilizer treatment,and significantly higher than that of biological organic fertilizer.Single application of growth-promoting agent significantly increased soil ammonium nitrogen compared with single application of growth-promoting agent.Available phosphorus content and straw nitrogen content significantly decreased soil conductivity.The application of sulfur and ferrous sulfate alone had no significant effect on the yield of corn.In the treatment of combined application of growth promoting agent and biological organic fertilizer,the yield of MS,PMS combined with sulfur was 7.36%and 7.43%higher than that of sulfur alone,respectively.There was no significant difference between the combined application of growth promoting agent and sulfur,but there was no significant difference in MS and PMS between the combined application of sulfur and sulfur alone.The yield of MFS,PFS and PMFS combined with ferrous sulfate was9.42%,4.51%and 13.40%higher than that of ferrous sulfate alone,respectively,and the growth promoting agent was 4.51%and 13.40%,respectively.The highest yield of biological organic fertilizer and ferrous sulfate treatment was 8076.96 kg·hm-2,which was 15.65%higher than that of conventional fertilizer treatment,which was significantly different from that of other treatments.There was no significant difference in soil pH value between sulfur and ferrous sulfate alone and conventional fertilizer application,but in the combined application treatment,biological organic fertilizer,The application of sulfur and ferrous sulfate in combination with biological organic fertilizer decreased by an average of 0.12 and 0.09 units,respectively,but there was no significant difference among the four treatments.Sulfur and ferrous sulfate alone had no significant effect on soil available nutrients.In the combined application of sulfur,MS,PS and PMS nitrate nitrogen,ammonium nitrogen and available phosphorus increased significantly by 30.77%and 40.79%,respectively,compared with sulfur alone.34.13%?82.41%and 16.37?27.65%,there was no significant difference between the treatments.The difference of nitrate content between MS,PS,PMS treatment and CK treatment was significant.The highest nitrate content of MS treatment was 19.75 mg kg-1,MS,PS,PM,which was 32.1%,22.7%and 31.0%higher than that of CK,respectively.Compared with ferrous sulfate alone,PFS,PMFS treated with ferrous sulfate significantly increased by41.24%and 47.14%,47.13%and 88.56%,14.94%and 21.31%,respectively.The content of ammonium nitrate in treated MFS was significantly higher than that in ferrous sulfate alone,but there was no significant difference in available phosphorus content.The combined application of ferrous sulfate and growth promoting agent increased the content of calcium ion and magnesium ion,and decreased the content of chlorine ion in soil,which indicated that the combined application of ferrous sulfate and growth promoting agent could promote the dissolution of fixed calcium and magnesium ion in soil.It is used to replace sodium ions in soil,which is helpful to the leaching of salt and reduces the harm caused by chloride ions to plants.Compared with the treatment of sulfur alone,the potassium ion and calcium content in the soil were significantly decreased by 20.81%and 25.58%,respectively.The combined application of growth promoting agent and ferrous sulfate significantly decreased sodium ion and increased the content of calcium ion and magnesium ion compared with ferrous sulfate alone.The application of biological organic fertilizer increased soil porosity compared with the control.Compared with the treatment of single application of sulfur,ferrous sulfate and growth promoting agent,the bulk density of soil decreased by 10.67%and 6.67%,and the porosity increased by 7.11%and 3.44%,respectively,but there was no significant difference between the treatment with combined application of biological organic fertilizer and the treatment with combined application of biological organic fertilizer.However,the proportion of soil aggregates in treated PMS was significantly higher than that in MS and PS treatments.The application of growth promoting agents alone was beneficial to improve soil porosity,and the combined application of biological organic fertilizer was more beneficial to the formation of soil aggregates. |
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