| Paddy-Upland Rotation is a sustainable way of planting can improve land productivity, it has a great effect on alleviating grain pressure of population growth.Water-dry conversion process as the rotation system of paddy field environment change is one of the most intense.Because of the frequent changes in moisture conditions during this period,makes the oxidation reduction status of rapid transformation in soil,Therefore,it has great influence on soil nutrient cycling.In this paper,using water-dry conversion changes of soil chemical properties in the process as the main research object.Through plot experiment,set up 3 treatments including drought,flood and drought,and water treatment.Around"In the rotation system,the influence of water-dry conversion process on soil chemical properties"research propositions to carry out in-depth study.Interpretation in the water and dry the conversion process,Changes in space and time of treatment on soil chemical properties. Re veals the upland and paddy upland rotation processing,difference of soil nutrients in soil preparation before sowing next season’s crop.Analysis of the correlation between environmental factors,soil and available nutrient.The main results are as follows:(1) Because of the difference of dry rice and water and heat conditions, upland conversion process of rice for processing organic matter,total nitrogen and available nitrogen content aspect was significantly higher than that of dry farming and soil available phosphorus,available potassium content in,until the next crop soil preparation before sowing remains the same and in planting crops should according to the actual adjust the N,P and K fertilizer application.(2) Alternating wet and dry period,in addition to the soil organic matter,available nitrogen,available potassium,may due to alternating wet and dry strength is relatively not enough reason,did not appear obvious cyclical changes,other chemical characteristics are showing with irrigation and the stem with a periodic variation;In rice harvest after the fall dry during water treatment in the harvest of rice after flooding,soil pH and eh,gradually restored to the paddy rice and the level of trend,organic matter and total nitrogen and available nitrogen content increased,denitrification was enhanced. At the same time,flooding can increase solubility of phosphorus and potassium.And flood and drought treatment after rice harvesting natural fall during the dry,except available potassium and ammonium nitrogen still reduces other soil chemical properties change and waterlogging treatment instead.The above results fully explain the changes of water condition had significant effects on soil chemical properties.(3) The alternation of wetting and drying before and after the treatment of soil nutrient analysis showed that the alternation of wetting and drying strengthened soil carbon mineralization,and promote the organic nitrogen to inorganic nitrogen transformation and soil ammonification and phosphorus solubility decreased.and influence of Soil K fixation capacity,but effect on the soil total nitrogen and nitrification was not significant.(4) The correlation between soil nutrients and environmental factors analysis showed that soil pH and available N,available P.there was a significant positive correlation,and in terms of available potassium,aerobic treatments was extremely significant positive correlation,rice processing but no significant correlation,which may and rice as strong leaching irrigation environment of potassium ions,eh value and the correlation between available nutrient and soil pH instead. |
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