Effects Of Stalk Decomposing Liquid On Maize Seedling Rhizosphere Soil Ecological Environment

At present, the straw production capacity of China up to 800 million t and China has become the country of the world’s largest annual national production of straw. The Heilongjiang Province play an important role in protecting our country grain security for it was the important production base to ensure that food production of China. To study the impact of straw returning on xiacha crops of the Sanjiang Plain in Heilongjiang province, our country launched a special research. In north of China, corn stalks year after returning to the field has significantly affected the growth of wheat in the wheat- corn two cropping system, while the self- toxic effects of the continuous corn planting and the positive impact of corn straw returning were all not clear in farmland ecosystem of Heilongjiang Province. In this paper, we chose indoor decomposed state to simulate the straw returning in field,to explores the effect of different time decomposing corn straw decomposition liquid on root physiological characteristics, rootvitality, andenzyme activity, physical and chemical properties, the number of microorganisms and bacterial community structure in soil to determine the allelopathic effects after straw returning. aiming to explore the impact on xiacha maize seedlings after the straw returning, consummate the theory and technology of straw returning and to provide a scientific basis for avoiding the his sense of negative effects of straw returning, choosing rational crops and optimizing the cultivation system.Drawing on the basis of previous research, the pot experiment was used to analyzed the effects of maize stalk decomposing liquid on seedling rhizosphere ecological environment under different decomposing time(0,60,120,180d), and different decomposing solution concentrations(0.5,0.25,0.125gDW/ml), with water as the control and maize as material. By measuring the root physiological characteristics, root activity, soil enzyme activity, soil properties, soil microbial quantity and diversity of soil bacterial community structure of four-leaf, five-leaf, six-leaf stage of seedlings, the formation of the main findings are as follows:These indicators of maize seedling reached the maximum value at 120 d decomposing fluid, 0.125 gDW/ml concentration and reached the minimum value at 120 d decomposing fluid, 0.5 gDW/ml concentration in four-leaf, five-leaf and six-leaf stage. Effects of stalk decomposing liquid on maize seedling root length、root surface area、the root volume and dry weight of root had allelopathy which showed a promoting effect at low concentration and a inhibiting effect at high concentration with the increasing straw decomposing liquid concentration; the effects increased at first and decreased subsequently with the increasing straw decomposing liquid days; the effects was weakened gradually with the aging leaves.Maize seedling rhizosphere soil enzyme activity increased with the increasing straw decomposing liquid concentration, the effects increased at first and decreased subsequently with the increasing straw decomposing liquid days, the effects was weakened gradually with the aging leaves. Maize seedling root activity increased at first and decreased subsequently with the increasing straw decomposing liquid concentration. The low(0.125 gDW/ml) concentration and medium(0.25 gDW/ml) concentration promoting effect to root activity was weakened gradually with the aging leaves.The maize straw decomposing liquid changed the soil physicochemical properties around seedling rhizosphere and the maize straw decomposing liquid of high concentration decomposed for120 d improved soil nutrient environment of seedling growth.The effects of maize straw decomposing liquid on the number of bacteria, fungi, actinomycetes in soil around seedling rhizosphere. The number of bacteria decreased and the number of fungi and actinomycetes in soil increased with the increasing straw decomposing liquid concentration. The number of soil bacteria and actinomycetes decrease after the first increase and the number of soil fungi increased after the first reduction the increasing straw decomposing liquid days. In this experiment, we use the high-throughput sequencing technology to study the diversity and the composition of the soil bacterial community structure and the results showed that, the maize straw decomposing liquid improved the level of the diversity of the soil bacterial community structure and changed the composition of the soil bacterial community structure, and the level of the diversity of the soil bacterial community structure up to highest under the treatment of the maize straw decomposing liquid of low concentration decomposed for180 d.