Effects Of Organic Materials On The Remediation Of Lightly Salinized Soil In Greenhouses

Soil salinization is an important problem in greenhouses due to over-fertilization,flood irrigation with high salinity groundwater,which would result in soil compaction and produce plenty of aegles on the surface of soil.Soil salinization inhibit the growth of roots and aboveground of vegetables.We found that there were soil salinization problems from the greenhouses in Yongqing County and Qing County.Therefore,the field survies were conduceted to investigate the characteristics of salinity in the soils and irrigation water at first.After that,the field experiment was carried out in Yongqing County to explore the effects of biochar/cow manure combined with microbial inoculants on the soil salinity in pepper greenhouse.Meanwhile,a soil pot experiment was set up to study the effects of three kinds of organic materials?cow manure,biochar and bio-organic fertilizer?on plant growth and reducing soil salinity with melon plants.The aim is to find a feasible and low-cost organic material to restore soil salinization in the vegetables greenhouses.The main results are as follows:1.Remediation of organic materials on the salinity of the anion-type of lightly saline soil in the greenhouseThe survey in Yongqing County showed that the content of total soluble ions is 3.20g/kg,which belongs to the lightly saline soil.HCO₃^-and SO₄^2-are the main ions of soil salinization.The EC of irrigation water is 1.52 mS/cm,and HCO₃^-and SO₄^2-are the main ions in irrigation water as well.The results from the field experiment illustrated that the application of cow manure?6.00 t/hm²?or cow manure with microbial inoculants?75L/hm²?significantly reduced the EC and salinity of the soil.There was no significant difference between two treatments in reducing soil salinity.However,the treatment of biochar or biochar with microbial inoculants did not affect soil EC and salinity.Therefore,cow manure would be a better organic amendent to restore anion-type of saline soil.2.Remediation of organic materials on the salinity of cation-type lightly saline soil in greenhousesThe survey in Qing County showed that the content of total soluble ions is 2.34 g/kg,which belongs to the lightly saline soil.Na⁺is the main ion of soil salinization.The EC of irrigation water is 2.44 mS/cm,and Na⁺is the main ion in irrigation water as well.Applying cow manure and bio-organic fertilizer at 6.00 t/hm²,biochar at 1.50 t/hm²significantly reduced the soil EC.The three kinds of organic materials increased the plant height,stem diameter and leaf chlorophyll content,and significantly enhanced the root length during the stretch tendril period.Moreover,cow manure and biochar increased biomass at the seedling stage as well.Thus,cow manure or biochar is a better pathway to reduce soil salinity,especially for biochar.In summary,the application of cow manure at 6.00 t/hm² is suitable in remediation of the anion-type of elightly saline soil.The application of biochar at 1.50 t/hm² is the best for restoration of cation-type of lightly saline soil.