秸秆腐解液对玉米幼苗根际土壤生态微环境的影响

发布时间：2018-04-29 03:03

本文选题：玉米秸秆腐解液 + 根系生长　；参考：《东北农业大学》2015年硕士论文

【摘要】：中国作为全世界每年秸秆生产量最大的国家,目前农作物秸秆年生产量达8亿t,黑龙江省作为我国保证粮食产量的重要生产基地,在全国有着举足轻重的作用。为了研究黑龙江省三江平原地区秸秆还田对下茬作物的影响。国家开展了专项课题研究。在我国北方小麦—玉米两熟种植制度下,玉米秸秆连年还田已显著影响了小麦的生长发育,而在黑龙江省农田生态系统中,目前连作玉米是否有自毒效应,这还不明确,玉米秸秆还田的正面影响也不明确。本文以室内腐解模拟田间还田状态,探讨不同还田量即不同腐解强度的玉米秸秆腐解液对后茬玉米苗期根系生长、根系土壤酶活性、根系土壤理化性质及根际土壤微生物的影响,通过探索玉米秸秆还田后对下茬玉米幼苗的影响,完善秸秆还田的理论和技术,为避免秸秆还田的他感负效应、合理的茬口选择和优化种植制度提供科学依据。本试验以玉米为研究对象,根据不同的玉米秸秆腐解时间(0,60,120,180d),提取腐解液后设置成三个浓度(0.5,0.25,0.125gDW/ml)。以清水为对照,以盆栽方式探究对玉米苗期根际生态环境的影响,通过测定幼苗在四叶、五叶、六叶期根系生理特征、根系活力、土壤酶活性、土壤理化性质、土壤微生物数量以及在五叶期时土壤细菌群落结构多样性,形成主要研究结果如下:玉米秸秆腐解液对玉米幼苗根长、根表面积、根体积、根干重的影响,随腐解液浓度增加,有“低促高抑”的化感效应;随腐解天数的增加,对其影响先增大后减小,在60、120d腐解液处理下与对照差异显著,玉米幼苗四叶、五叶、六叶期,表现出在腐解120d、低(0.125gDW/ml)浓度处理下各项根系指标达到最大值,在腐解120d、高(0.5gDW/ml)浓度处理下达到最小值;随叶龄增加,其影响逐渐减弱。玉米幼苗根际土壤蔗糖酶、脲酶、酸性磷酸酶、过氧化物酶的活性随腐解液浓度的增加而增加;随着玉米秸秆腐解天数的增加,呈现先升高后降低的趋势;随叶龄增加,腐解液对根际土壤酶活性的影响逐渐减弱。玉米幼苗根系活力随着秸秆腐解液浓度的增大先升高后降低;低(0.125gDW/ml)、中(0.25gDW/ml)浓度下对根系活力的促进作用也随叶龄增加逐渐减弱。玉米秸秆腐解液改变了幼苗根际土壤的理化性质,120d腐解天数,高浓度(0.5gDW/ml)玉米秸秆腐解液改善了幼苗生长的土壤养分环境。玉米秸秆腐解液对幼苗根际土壤细菌、真菌、放线菌数量的影响,随腐解浓度升高,幼苗根际土壤细菌数量增加,真菌、放线菌数量减少。随腐解天数增加,幼苗根际土壤细菌、放线菌数量先增多后减少,真菌数量先减少后增多。本试验利用高通量测序技术研究土壤细菌群落结构多样性及组成的结果表明:玉米秸秆腐解液提高了土壤细菌菌群的多样性水平并改变了玉米幼苗根际土壤细菌群落结构组成。180d腐解天数,低浓度(0.125gDW/ml)处理下土壤细菌菌群多样性水平最高。
[Abstract]:China is the country with the largest annual straw production in the world. At present, the annual crop straw production reaches 800 million tons. Heilongjiang Province, as an important production base of ensuring grain production in China, plays an important role in the whole country. In order to study the effect of straw returning to the next crop in Sanjiang Plain of Heilongjiang Province. The state has carried out research on special topics. Under the wheat-maize double cropping system in the north of China, the successive return of corn stalks to the field has significantly affected the growth and development of wheat. However, it is not clear whether continuous cropping maize has self-toxic effect in the farmland ecosystem of Heilongjiang Province at present. The positive effect of corn straw returning to the field is also unclear. In this paper, indoor decomposition was used to simulate the field return state, and the effects of corn straw decomposing solution with different returning amount, I. e., different decomposition intensity, on root growth and soil enzyme activity in the seedling stage of next crop maize were studied. The physical and chemical properties of root soil and the effect of rhizosphere microorganism were studied in order to avoid the negative effect of straw returning to the field by exploring the effect of corn straw returning to the next crop maize seedling and perfecting the theory and technology of straw returning to the field. Reasonable crop selection and optimization of planting system provide scientific basis. In this experiment, corn was used as the research object. According to the different decomposing time of corn straw, the decomposed solution was extracted and set into three concentrations of 0.25 ~ 0.25 ~ 0.125g / ml ~ (-1) DW 路ml ~ (-1) ~ (-1) ~ 0.125g / ml ~ (-1) ~ 0.125g / ml ~ (-1). The effects of water on the rhizosphere ecological environment of maize seedlings were studied by pot culture. The physiological characteristics of roots, root activity, soil enzyme activity and soil physical and chemical properties were measured at four, five and six leaf stages. The main results were as follows: the effects of cornstalk decomposing solution on root length, root surface area, root volume and root dry weight of maize seedlings increased with the concentration of decomposed solution. The allelopathic effect of "low promotion and high inhibition" increased first and then decreased with the increase of the days of decomposition, and the difference was significant between the treatment of 60120 days and that of the control. The four leaves, five leaves and six leaves of maize seedlings were significantly different from those of the control. It was shown that the root system index reached the maximum value at 120 days after decomposing, and reached the minimum value at 120 days after decomposing with 0.125 g DW / ml concentration, and the effect gradually weakened with the increase of leaf age. The activities of sucrase, urease, acid phosphatase and peroxidase in rhizosphere soil of maize seedlings increased with the increase of the concentration of decomposed solution, and increased firstly and then decreased with the increase of decomposition days of maize straw. The effect of decomposed solution on the enzyme activity of rhizosphere soil decreased gradually. The root activity of maize seedlings increased at first and then decreased with the increase of the concentration of straw decay solution, and the promoting effect of low concentration of 0.125 g DW / ml and 0.25 g DW / ml on root activity decreased with the increase of leaf age. The physical and chemical properties of rhizosphere soil were changed by cornstalk decomposing solution, and the soil nutrient environment of seedling growth was improved by cornstalk decomposing solution with high concentration of 0.5 g DW / ml. The effect of corn straw decomposing solution on the number of bacteria, fungi and actinomycetes in rhizosphere soil of seedlings increased with the increase of decomposition concentration, but the number of fungi and actinomycetes decreased with the increase of decomposition concentration. The number of actinomycetes in rhizosphere soil increased first and then decreased with the increase of decomposing days, and the number of fungi decreased first and then increased. In this experiment, high-throughput sequencing technique was used to study the diversity and composition of soil bacterial community. The results showed that the cornstalk decomposing solution increased the diversity of soil bacterial flora and changed the rhizosphere soil bacteria of maize seedlings. The composition of community structure. 180 days, Under low concentration of 0.125 g DW / ml, soil bacterial flora diversity was the highest.
【学位授予单位】：东北农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S513;S154

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