Studies On Autotoxity And Mitigation Measures Of Vegetable Continuous Cropping Obstacles

As the sustain support from No.1documentation of CPC central committee on intensive agricultural, facilities gardening production of industrialization continued developing and growing up. There have emerged out a large number of professional vegetable origins across the country, which improved the old farming system, increased the efficiency of agricultural production and units output, solved the problems of farmers’employment and increased their income, etc. Meanwhile, due to single farming system and crop varieties, and pursuit economic benefits excessively, the problem of continuous cropping obstacles in facilities gardening increased, which bring out pest outbreaks, as well as vegetable autotoxicity, resulting in reducing of crop yields and quality year after year. Continuous cropping obstacles effect production and quality of crop, which aroused general concern. Many experts are looking for effective way to fundamentally solve continuous cropping obstacles of vegetable. However, cause there are many factors of continuous cropping obstacles, involved plant itself, and soil and other biological and non-biological factors in the rhizosphere, and the factors effect each other. So it is very difficult to overcome continuous cropping obstacles. Autotoxicity is considered to be one of the main reasons of continuous cropping obstacles in vegetable, which being the key point for majority researchers. Therefore, it is very important to do further study on the autotoxicity in continuous cropping obstacles of vegetable.This paper mainly focuses on vegetable--autotoxicity in continuous cropping obstacles, and carries out relevant research about plants, soil micro-organisms, as well as mitigation measures. The main results are as follows:1. In order to collect root exudates, we applied continuous collection method for different kinds of plants, such as scallion, ginger, garlic, maize, sorghum and cowpea. We got the composition of root exudates of different plants through GCMS analysis. It is found that continuous collection method could collect the root exudates of the plants well. In addition, allelopathic substances were extracted from roots of the plants. After analysis and identification of GCMS, the compositions were determined. 2. Plants have allelopathy through secreting allelopathic substances, which will interact with microorganisms and plants in rhizosphere. The different kinds of soil were collected from several major grain-producing regions of the country, such as Northeast China, Northwest China, Shandong, Zhejiang, Jiangxi, and so on. Assay the physical and chemical properties of soil in different parts, for example, soil pH, soil moisture, soil conductivity, and so on. At the same time, under the environment of25℃. added0.5mM cinnamic acid into soils for7days. Then analyze the effect of the exogenous cinnamic acid on microbial population in different types of soil. Coated plate count method was use to count the number of bacteria, actinomycetes, and fungi in the soil. Results showed that exogenous cinnamic acid will have an inhibitory effect on soil microbial populations, and different types of soils due to different background of soil microbial activity, cinnamic acid inhibition varies. In addition, it is analyzed by using GCMS that residues of exogenous cinnamic acid were different. Results showed that exogenous cinnamic acid in soil was decreased significantly after7days. Also, Inhibition of microbial populations affected by exogenous cinnamic acid is inversely proportional to the amount of residue.3. Some research before showed that by adding into hydroponic solution, toxic substances can be adsorpted by activated carbon thus alleviating the allelopathic effects. Therefore, based on these studies, further explore the mitigation measures for the autotoxicity. Bamboo charcoal was added into the cultivation soil of cucumber. After5days’ treatment by cinnamic acid, we measured the root growth, photosynthesis of cucumber, and activity of antioxidant enzymes in root and leaf. It is found that bamboo charcoals can effectivly mitigation autotoxicity of cinnamic acid, and can be used in the soil. Meanwhile bamboo charcoal cost greatly lower than activated carbon and bamboo charcoal in Jiangsu and Zhejiang provinces is easy to get, so this method could be well applied.