The Research Of Salinization On Greenhouse Soil In Yangling

The vegetable green-house industry greatly promoted the local country-side economy In Yangling, but accompany with the time lengthen of vegetable green-house cultivation, some soil barriers problem was appear. For the sake of research the secondary salinization problem of the soil in different vegetable green-house ages In Yangling, finding the change regulation; use the soil samples which it from 0-11 years green-house for research materials; by outdoors survey and laboratory analysis etc method to test, analysis and integrate research the the soil salinity, the microorganism fauna, Inorganic P gradation,N mineralization etc factors, and find out the evolvement characteristic and predominant factor of soil secondary salinization in plastic vegetable green-house; and provide theories basis on fertilizing quantity and suitable reasonable water management for assurance sustainable development of plastic vegetable green-house soil.The result show:(1)Along with the extension of the cultivation time, the contents of water-soluble total salt presents in the soil of plastic green-house to increase high trend gradually,the plastic greenhouse soil total salt content (0~10cm) is 1.5856g/kg, increased 0.7454g/kg, the growth rate has reached 88.47%compared to the open-air vegetable plot. The salt components were 27.42% anion SO42- and 21.46% cation Ca2+; By analysis of variance, the total salt content of the 0~40cm soil layer of 3a plastic green-house is show the significant difference with outdoor vegetable soil, 1.5a, 5a, 8a and 11a green-house; the salt content in different depth soil of plastic vegetable also show significant difference; The soil PH of the plastic vegetable green-house accompanies with the time of cultivation extension to downward trend gradually, but it not to acidification; in the mass,the soil electric conductivity rate (EC value) of the plastic vegetable green-house are upward with extension of cultivation time, the EC value and total the salt present in 0~10cm surface layer to show the significant positive relativity, R2=0.9106, the relativity is bad below the 20cm. the soil EC value present is descend trend with plant of the different growing stage.(2)Input large quantity N fertilizer directly to cause a sharp rise of soil nitric N content in the plastic vegetable green-house, the plastic greenhouse soil nitric nitrogen content achieves 12.13 times with the field soil, the nitric N accumulation has obvious gather phenomenon and has a serious migration phenomenon, the soil water-soluble total salt content and nitric N content present to show the significant positive relativity. Along with the extension of the cultivation time, the soil nitric N content increases; the soil pH drop slowly; intensify soil acidification trend was by unreasonable use the N fertilizer. The quality of tomato affect by nitric N constantly increase because continue use N fertilizer in green-house vegetable growing period .(3)The total quantity of Microorganism was slightly increased in many years plastic green-house soil. It increased year-by-year and its varieties increased also. The total soil animalcule in green-house soil was more than farmland soil, more bacteial quantity in green-house soil. The main bacterias are pseudomonas, arthrobacter and bacillus; the soil epiphyte quantity in the 0~10cm surface of green-house soil was more than outdoor soil, and the number of Microorganisms colony increased as cultivation years increased. However, the number of Microorganisms colony in the 20~40cm depth soil of green-house was not so distinct. The main soil Microorganisms varieties of green-house soil are Mucor,Penicilium, Aspergillus, Rhizopus and a little of trichoderma. The total quantity of Actinomyces in 0~40cm green-house soil was less than outdoor soil, Streptomyces and micromonspora are the main actinomyces. The situation of green-house increased the number of bacteria significantly, but not significantly increased the number of epiphyte, and decreased the number of actinomyces evidently.(4)The plastic greenhouse soil inorganic phosphorus content is 1135.79mg/kg, compared to the open-air vegetable plot what was grows 15.17%.Different forms of inorganic P were rich in the surface of 0~10cm green-house soil, inorganic P decrease evidently as the soil depth increased, most P form is Inorganic P, 73.61~77.11% Ca-P of total P content of inorganic P, 74.99% on average. Ca-P (Ca10-P,Ca8-P)was the most form in 0~40cm deep green-house soil. As the year increased Ca-P still remain the dominant degree of forms of inorganic P , Ca10-P,Ca8-P come out top. The sequence and proportion of Ca2-P and other forms kept the same as a balance with other P form. The distributing and proportion of inorganic P is nothing to do with the years when green-house was used. The condition of green-house increased the proportion of Ca8-P,Ca2-P content in inorganic P, thereby improve the biologic effectiveness of P components in soil.(5)The quantity of soil mineralization was related to the quadratic root of cultivation time. The quantity of cumulative soil mineralization increased gradually as time went, and it changed greatly at this early stage, but gradually at this late stage. After 35 days, it became stable. The quantity cumulative soil mineralization became less as the soil get deeper, and on the whole, decreased gradually as time extend. It decreased greatly at the first four weeks, but gradually for the following 3 weeks, and came to nought after 7 weeks. The potential of soil mineralization of elder green-house was a little more than that of green-house. However, the correlation between the potential and the years of green-house was not significantly. The correlation of mineralized N/ organic matter/total N was stable, and had nothing to do with soil and its levels. The quantity of soil N mineralization had Correlation with organic matter and total N of topsoil, and also to do with those of different layers of soil.