Effect Of Continuous Cropping On Properties Of Soil And Growth,Physiological Metabolism Of Pepper

Physical and chemical properties, microbial changes and root secretion was studied in pepper continuous cropping soil in Huang ma Town, Qingpu District, Huaian City, Jiangsu Province,and determine the continuous cropping acidification.On this basis,selects the hot pepper varieties’Sue pepper5’as the experiment material, Artificial acid driplets the casting simulation greenhouse continuous cropping soil acidification on pepper growth, fruit quality,photosynthetic characteristics,the antioxidant system,ion absorption and so on, and to study the effect of the soil conditioner on growth in acidification. Concrete results are as follows:1.With the cropping years increasing, soil pH was decreased and those values in continuous cropping years of pepper greenhouses soils were lower than those of the adjacent open field of wheat-pepper rotation. pepper rhizosphere oxalic acid,tartaric acid content increased; Citric acid content also increases with the increase of continuous cropping, after copping nine years its content declined again, but is still higher than control. Pepper root oxalic acid content is the highest, accounted for about50%of the contents of organic acid,citric acid content at least.2.The contents of soil nutrients and ions in continuous cropping soil of hot pepper were higher than those of control, and the correlation of soil nutrients (organic matter, total N, total P, available K, Cl-, SO42-, NO3-) between pH was significant (P<0.05). Principal component analysis showed that the soil nutrients (organic matter, total N, total P, available K, Cl-, SO42-and NO3-) in continuous cropping soil could affect the acidification level of soil.3.With the cropping years increasing, Soil fungal quantity increase, bacterial, actinomyces quantity is increased at early period and then decreased. The soil enzyme activity were significantly higher than CK. Soil bacterial quantity and organic matter, total P has significant correlation level, Fungi quantity and soil nutrient has no significant correlation. Actinomycetes quantity, catalase, Saccharase, urease activity and pH value were significant negative correlation level, and nutrient were significant correlation; Soil total P, total N, pH value great influence microbial quantity. Soil bacteria, actinomyces quantity, catalase, Saccharase, urease activity can be as index of soil fertility.4.soil mild acid(pH6.78)promote pepper growth and serious acid(pH5.48)make hot pepper height, stem diameter, dry fresh weight dropped significantly; Along with the acidification enhancement, the photosynthetic pigment contents in hot pepper leaves were decreased significantly, the net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2concentration (Ci), transpiration rate (Tr), actual light quantum Yield (Φ PS Ⅱ), electron transfer rate (ETR) and photochemical quenching factor (qP) present the trend of increased at first, then decreased, and reaches maximum in the pH6。78; And O2-· production rate, MDA contents, SOD, POD, CAT, APX activity also with acidification enhancement appears to decreased at first, then increase, reaches the minimum in the pH6.37.5.After application of soil amendments,considerably increase the soil pH, EC value change is not big.A marked increase in the number of soil bacteria,fungi and actinomycetes during the reproductive period were significantly reduced.Soil amendments can improve hot pepper plant growth, promote the photosynthetic pigment content; Increased significantly The Net photosynthetic rate(Pn), stomatal conductance(Gs), intercellular CO2concentration(Ci), transpiration rate (Tr), the actual light quantum yield(Φ PS Ⅱ), electron transport rate(ETR), coefficient of photochemical quenching(qP). To increase the production of pepper.