| The use of organic materials to improve the primary saline alkali soil can not only improve the utilization rate of agricultural resources,reduce the environmental pollution caused by the irrational utilization of resources,but also have great significance for promoting the development of the local agricultural economy.The effects of different kinds of organic materials and different modality of the same organic materials on the physical properties,chemical properties,components of organic matter,soil nutrient,microbial and crop yield were studied in two consecutive years of field experiment.32 indexes were selected to carry out the principal component analysis and membership function analysis,and the formula of soil improvement evaluation index was established.The study is to provide the theoretical and practical basis for the improvement of primary saline alkali soil,and to provide new ideas and methods for the utilization of organic materials.And further improve the research results of organic materials in the field of saline alkali soil improvement.The results were as follows:1.Effects of different organic materials on the chemical properties of paddy field in saline alkali soilThe content of p H,EC,total salt,exchangeable sodium and ESP in each treatment were first decreased and then increased and final decreased after the organic material was applied.The order of each treatment p H were KL(granular straw)<MC(grass)<YF(sheep manure)<JG(rice straw)<CK,and reduced by 2.91%-9.96% compared with initial value.The order of each treatment EC and total salt content were KL<YF<JG<MC<CK and reduced by 30.00%-45.68% and 77.48%-132.46% respectively compared with initial value.The order of each treatment exchangeable sodium content were CK<KL<JG<YF<MC and reduced by 20.17%-32.89% compared with initial value.The order of each treatment ESP were YF<KL<JG<MC<CK and reduced by 32.55%-46.57% compared with initial value.The CEC of organic material treatment were increased,but CK was not greatly changed.The order of each treatment CEC were YF>JG>KL>MC>CK and increased by 26.59%-46.01% compared with initial value.2.The effect of different organic materials on physical properties of paddy field in primary saline alkali soilThe composition of water-stable aggregates in each treatment was mainly composed of micro-aggregates,of which 0.05 mm 0.25 mm in diameter.The stability of soil water-stable aggregates which treatment with the organic material was better than CK.The optimum improvement on MWD(Mean Weight Diameter)is sheep manure treatment which was increased by 104.00%.KL treatment has the best effect on increasing water stability coefficient and reducing PAD(Failure Rate).The different organic materials treatment had a positive effect on the morphology of water stable aggregates,and the KL was the best.This shape was round,this surface was rough,and this size distribution was moderate.KL had significant difference with other treatments in fractal dimension of soil aggregates,and there was no significant difference among other treatments.The fractal dimension of particle treatment was the lowest,which was 2.62% lower than CK.The average mass specific surface area of each organic material treatment was significantly different from CK,among which the best straw treatment was better than 171.01% of CK.3.Effects of different treatments on nutrients and components of organic matter of paddy fields in saline alkaline soilsThe content of alkaline hydrolysis nitrogen,available phosphorus,available potassium,total nitrogen,total phosphorus and total potassium in each treatment was increased and then decreased and final increased after the organic material was applied.Each treatment significantly increased the content of total nitrogen,total phosphorus and alkaline hydrolysis nitrogen,increased by 15.90%-59.32%,17.61%-33.81% and 10.55%-46.00% respectively compared with initial value,and the KL was the best.The content of total potassium and available potassium were no significant difference compared with initial value,but the content available phosphorus was decreased,but there was no significant difference from the original value.The trend of the content of organic matter,HM,HA and FA all increased,increased by 52.78%-111.92%,10.23%-17.52%,143.78%-439.39% and 27.87%-87.64% respectively compared with initial value.The content of water soluble organic matter in each treatment was decreased and then increased.The CK,KL and JG were increased by 3.70%-27.78%,but water soluble organic matter content of MC and YF was lower than initial value.Each treatment makes the HA and FA structure simple.4.Effects of different treatments on biological properties of paddy field in primary saline alkali soilThe composition of soil microorganisms was mainly bacteria,followed by actinomyces and the least fungi.Compared with initial value,each treatment increased the population of soil bacteria by 73.82%-142.41%,the population of soil actinomyces by 7.81%-59.75% and the population of soil fungi by 87.95%-256.92%,soil microbial biomass carbon by 49.31%-143.71%,soil microbial biomass nitrogen by 49.31%-143.71%,soil respiration intensity by 29.12%-88.81%,catalase activity by 37.51%-62.31%,invertase activity by 66.64%-105.33% and cellulase activity by 117.18%-289.45%.And the KL was the best.5.Effects of different treatments on the growth and yield of rice in saline alkali soilCompared with indicators of corn test in 2016,except the effective spike number per plant of KL,the total grain number per ear of YF and the rice yield of MC,each treatment increased the ear length by 5.37%-24.01%,the effective spike number per plant by 4.95%-13.37%,the total grain number per ear by 13.69%-22.05%,the 1000-grain weight by 3.78%-24.26%,the setting rate by 14.86%-44.89% and rice yield by 4.24%-31.74%.And the KL was the best.6.Construction of formula for evaluating index of soil improvement and evaluation of effect of different treatmentsThe soil hardness,alkaline hydrolysis nitrogen,available phosphorus,cellulase,microbial biomass carbon and intensity of soil respiration were found to be the key indicators of the minimum data set.Liner evaluation formula is more accurate than non-liner evaluation formula.The comprehensive improvement effect of KL treatment was the best compared with the evaluation index of soil improvement,and the next was JG treatment,MC treatment,YF treatment and CK treatment.There was no significant difference in the overall improvement effect of different kinds of organic materials in the early stage of primary saline alkali land improvement.However,the improvement effect of different modality of the same organic materials is obviously.In this experiment,the improvement effect of the grain straw treated by crushing high temperature and high pressure is better than that of the normal straw,which can effectively shorten the improvement time and improve the improvement efficiency. |
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