两种新型保水剂对土壤-作物系统的影响
文献类型：学位论文
| 作者 | 李希 |
| 学位类别 | 博士 |
| 答辩日期 | 2013-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 贺纪正，郑袁明 |
| 关键词 | 保水剂 土壤 小白菜 冬小麦 盆栽 大田 土壤微生物 Super absorbent polymer Soil Chinese cabbage Winter wheat Potting Field Soil microorganisms |
| 其他题名 | Effects of the application of two new super absorbent polymers on the soil-crop system |
| 学位专业 | 生态学 |
| 中文摘要 | 保水剂可以大幅度提高土壤含水量，提高土壤渗透能力、减少水土流失，有效改善土壤容重、孔隙度、团粒结构等土壤物理性质，进而起到保持土壤养分的作用。因此，保水剂作为一种用途广泛的抗旱节水新型材料，在农业上已受到越来越多国内外研究者的重视。但是在实际应用中，不仅要考虑保水剂的实用性，还应关注其对环境的影响。鉴于保水剂在使用中曾经造成土壤板结等环境问题，对保水剂进行环境风险评价是其大规模使用的必要前提。目前国内外对保水剂的研究集中在其对植物生长、土壤物化性质的影响和自身材料结构的改进上，对土壤微生物生态的影响还处于空白。 本文以植物萃取物合成的新型保水剂为对象，通过不同给水条件、保水剂浓度及施用方法的处理设置，研究了温室盆栽条件下保水剂对小白菜生长和土壤物理性质的影响，以及大田条件下不同保水剂和施用方法对冬小麦生长和土壤物理性质的影响，并综合考察了保水剂对两种土壤-作物系统中土壤微生物的影响，主要研究结果如下： 1. 与空白相比，保水剂能够显著提高土壤含水量。在温室实验中，在相同浓度下，并且保水剂1（Super absorbent polymer 1，SAP1）的效果要好于保水剂2（Super absorbent polymer 2，SAP2）。在水分缺失条件下，保水剂对土壤含水量的增加最为明显，撒施和喷施处理是保水剂促进土壤含水量的最佳施用方法。在相同水分条件下，撒施SAP2 和喷施SAP1 分别能提高土壤含水量77.6%和71.3%。在不影响小白菜产量的前提下，喷施SAP1 可减少灌溉用水量约25%。在大田实验中，喷施和底施保水剂处理之间比较对土壤含水量的影响没有显著差异。 2. 在温室实验中，在不同水分条件，保水剂喷施、撒施和浸湿处理能够促进小白菜的生长，在水分缺失条件下，底施保水剂也能够促进小白菜生长。喷施保水剂是促进小白菜生长最佳施用方法，并且SAP1 的效果要好于SAP2。与缺水条件的空白相比，喷施SAP1 处理则可提高小白菜产量2 倍以上。但是在大田实验中，只有底施SAP1 能够显著增加小麦谷粒干重( 56%, P<0.05)。 3. 在温室实验和大田实验中，保水剂的不同施用方式均能显著影响土壤水稳定团粒结构。与空白比较，保水剂的应用能够显著提升土壤团聚体的形成，特别是 > 0.25 mm 的团聚体。但是不同保水剂处理之间的效果，差异不显著。总体而言，在当前的研究体系下，保水剂能够稳定土壤结构，增加土壤的保水保肥能力。 4. 在大田实验中，保水剂的应用能够显著影响细菌的丰度；在温室实验中，保水剂的应用对细菌丰度影响不显著。但是在温室实验和大田实验中，保水剂的不同施用方法均能显著增加了土壤微生物量碳和土壤微生物呼吸。喷施处理是促进土壤微生物活性的最佳施用方法。在温室实验中，在相同水分条件下，喷施SAP1 分别能够促进土壤微生物量碳和土壤微生物呼吸325%和208%。在当前的研究体系下，保水剂的应用对土壤微生物环境没有危害。 5. 大田实验中，在小麦生长的拔节期和孕穗期，保水剂的应用能够显著增加土壤有效水，在灌浆期，对土壤有效水没有增加效果，说明这时候土壤所有的水分不能被作物所利用。保水剂对土壤水分特征曲线的影响表明保水剂增加土壤含水率的同时，也增加了土壤中的无效水，不能被植物所利用的水分，而且保水剂浓度越高，对土壤中总有效水增加越少，随之也增加了不可利用水，说明保水剂的应用需要根据土壤性质使用选择适当的浓度最为适宜。 综上所述，温室实验的结果显示喷施和撒施保水剂的处理与空白比较能够促进小白菜的生长，不同保水剂的处理均能提高土壤含水率，改善土壤团粒结构，也能促进刺激微生物活性(土壤微生物量碳和土壤微生物呼吸)。大田实验结果得出保水剂的应用能够提高土壤含水率，改善土壤团粒结构，能够刺激细菌的丰度。适当浓度的保水剂使用才能最佳的增加土壤中的有效水，被植物所利用。总的来说，在当前的研究体系下，新型保水剂的应用未对土壤生态系统造成危害，在某种程度上还有所促进（土壤物理结构及微生物活性）。 本研究对作物、土壤物理性质和土壤微生物性质三个方面较为系统的研究表明，保水剂的使用对土壤-作物系统中作物生长、土壤物理性质和微生物性质有明显的促进作用，是环境安全的农业节水技术。研究结果可为建立较为全面的土壤生态风险评价体系提供更丰富的数据支撑。 |
| 英文摘要 | Super absorbent polymers (SAPs) can improve soil water holding capacity,stabilize soil structure, and thus reduce water use, soil nutrient loss and soil erosion in cropland. When polymers are incorporated with soil, it is presumed that they retain large quantities of water and nutrients, which are released as required by the plant.Therefore, they have the potential to be applied in water-saving agriculture and drought resistance and attracted more and more attention. Considering the soil hardening caused by SAPs, we should evaluate environmental safety of SAPs before practical use. At present, most studies on SAPs for agriculture have only focused on comparison and evaluation of soil physicochemical properties, plant growth, and the research and progress of new material structure composition and products at home and abroad. However, the effects of SAPs on the soil ecosystem and the soil microbial ecosystem are not well understood. The main purpose of this study was to evaluate the effects of SAPs particularly on soil physical properties, Chinese cabbage growth, and soil microorganisms under different water conditions and SAP treatments in the greenhouse experiment, effects of SAPs on soil physical properties, wheat growth, and soil microorganisms under different SAP treatments in the field experiment. We studied the effects of SAPs on soil microbial properties in two soil-crop system at first. The major contents and findings of the dissertation were listed as follows: 1. Application of SAPs significantly affected soil water content in both the greenhouse and the field experiments compare with control. In the greenhouse experiment, for soil water content, SAP1 was showing better effects than SAP2.Under water deficit, the most significant increases in soil water content were applications of SAPs. The best way to increase in capacity of soil water holding were to use top layer treatment and spray treatment. Under some water condition, top layer treatment of SAP2 and spray treatment of SAP1 increased the soil water content by 77.6% and 71.3%, respectively, compared with control. Compared with the control treatment under normal water condition, spray treatment of SAP1 could reduce irrigation water amount by about 25% without reducing the crop production. There was no significant difference in soil water content between spray treatment and bulk treatment in the field experiment. 2. In the greenhouse experiment, spray treatment, top layer treatment and soak treatment of SAPs increased in the growth of Chinese cabbage under different water condition. Under water deficit, bulk treatment of SAPs also improved growth of Chinese cabbage. The best way to increase in growth of Chinese cabbage was to use spray treatment. For plant growth, SAP1 was showing better effects than SAP2. Further compared with the control treatment under the same water condition with spray treatment of SAP1 (deficient), it could increase Chinese cabbage production by 287%. However, bulk treatment of SAP1 significantly impacted the grain dry weight (by 56%, P<0.05) in the field experiment, this result might need a further confirmation in the future study. 3. There were significant differences for soil water-stable aggregates among different treatments both in greenhouse and field experiments. Applications of SAPs could promote the formation of large aggregates, especially > 0.25 mm aggregates, compared with control. SAPs significantly increased in the soil aggregates. There were no significant differences in soil particle sizes between SAP treatments under different water condition. Totally, SAPs could stabilize the soil structure and raise the capability of soil water and nutrient retention under the current research conditions. 4. In the greenhouse experiment, applications of SAPs had significant effects on the abundances of soil bacteria. In the greenhouse experiments, there were no significant differences in abundances of soil bacteria between SAP treatments, compared with control. Meanwhile, higher values of microbial biomass carbon (SMBC) and soil microbial respiration (SMR) with the applications of SAPs indicate the higher diversities and activities compared with control. The best way to increase in SMBC and SMR were to use spray treatment. Under some water condition, spray treatment of SAP1 increased SMBC and SMR by 325% and 208%, respectively, compared with control. SAPs caused no adverse effects on soil microbial environment under the current research conditions. 5. Applications of SAPs had significant effects on soil available water at the jointing stage and booting stage, but there was no significant difference in soil available water between SAP treatments at the filling stage, the results had shown that all soil water could not be absorbed by crop at the filling stage. Soil water content was increased by adding SAPs, however, soil unavailable water was also increased by adding SAPs via result of soil water moisture characteristic curve. Soil unavailable water was not absorbed by plant. And the higher concentration of SAPs, the less soil total available water was. We should choose appropriate concentration of SAPs for different soil properties. In conclusion, results of greenhouse experiments had shown that the spray treatment and top layer treatment of SAPs could improve growth of Chinese cabbage. There were significant differences in microbial activities (Soil microbial biomass carbon and Soil microbial respiration) among SAP treatments. SAPs could stimulate abundance of bacteria, increase in soil aggregates and improve water content in field trial. Totally, SAPs caused no adverse effects on the soil ecosystem, and to some extent should be beneficial to the soil ecosystem (soil physical structure and soil microbial properties) under the current research conditions. It could be concluded that soil ecosystem was improved obviously by applications of SAPs based on the research about soil-crop system. Thus, SAPs were an environmental friendly water-saving technique in agricultural production. Our results will provide helpful data support for the establishment of soil ecological risk assessment system |
| 公开日期 | 2014-08-21 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/7632]  |
| 专题 | 生态环境研究中心_中国科学院环境生物技术重点实验室 |
| 推荐引用方式 GB/T 7714 | 李希. 两种新型保水剂对土壤-作物系统的影响[D]. 北京. 中国科学院研究生院. 2013. |
入库方式： OAI收割
来源：生态环境研究中心
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