【作者】 陈静；

【导师】 潘根兴；

【作者基本信息】 南京农业大学 ， 土壤学， 2013， 硕士

【摘要】 我国是缺水型国家,干旱半干旱地区缺水是农业长期生产力低下的主要原因。生物质炭是生物质在完全或部分限氧的情况下经热解炭化产生的一类高度芳香化难溶性固态物质,它具有较大的比表面积,孔隙度高,具有一定的保水能力。本研究以生物质炭为原料,选择保水性和黏结性较强的MW型、阴型和阳型等聚丙烯酰胺(PAM)对生物质炭进行亲水性改性,分析改性后的生物质炭保水剂吸水特性的变化,以及对土壤水分蒸发、苗期玉米生长和盆栽土壤理化特性的影响。此外,在华北平原农田土壤中施用生物质炭保水剂,了解其对土壤水分、玉米生长和土壤理化特性的影响。研究结果如下：(1)与对照相比,施用3%生物质炭两周后可降低土壤水分累积蒸发量4.1%,而施用3%MW型和阴型保水剂两周后可分别降低土壤水分累积蒸发量8.0%～10.4%和7.0%～13.5%。在抑制土壤水分蒸发作用方面,改性后的生物质炭效果好于生物质炭。(2)通过PAM改性生成的生物质炭保水剂的吸水能力显著增加,三种生物质炭保水剂的吸水倍率均表现为2：10型>1.5：10型>1：10型,说明生物质炭保水剂的吸水倍率随PAM的质量比升高而升高,且MW型的吸水效果最好。与生物质炭的吸水倍率相比,MW型和阳型1：10、1.5：10、2：10保水剂的吸水倍率分别显著提高52.6%～38.2%和16.5%～151.3%,阴型1.5：10、2：10保水剂的吸水倍率显著提高60.5%～114.5%。MW型、阴型和阳型1.5：10、2：10保水剂比各自1：10型的吸水倍率分别提高175.4%～252.6%、46.1%～95.2%和54.2%～115.8%。(3)MW型、阴型和阳型生物质炭保水剂在单质肥料溶液中的吸水倍率随PAM用量所占比例的增加而显著增大。除尿素外,磷酸二氢钙和硫酸钾溶液均降低了保水剂的吸水倍率,且吸水倍率随着肥料浓度的增大而逐渐下降。(4)盆栽试验表明,生物质炭的施用可显著提高土壤的水分含量,2.5%和5%生物质炭施用后盆栽土壤含水量分别比对照显著提高39.7%和50.4%。1：10型生物质炭保水剂的施用可显著提高土壤的水分含量,施用2.5%和5%时土壤含水量分别比对照显著提高54.3%～84.0%和119.5%～145.1%。与生物质炭相比,生物质炭保水剂的保水能力显著提高了10.5%～63.0%。过量生物质炭保水剂的施用会抑制玉米生长,从土壤保水作用和对作物生长两方面出发,2.5%的生物质炭保水剂施用量较适宜。此外,2.5%与5%生物质炭、MW型、阴型和阳型生物质炭保水剂的施用均显著提高了盆栽土壤的有机质、全氮和速效磷含量,且随着施用量增多逐渐增大。5%生物质炭、MW型、阴型和阳型生物质炭保水剂的施用也提高了盆栽土壤的速效钾含量。生物质炭保水剂的施用还增加了土壤碱解氮含量,且随着施用量增多增加越多。说明一定量生物质炭和生物质炭保水剂的施用均可有效保持土壤水分和提高土壤养分含量。(5)大田试验表明,在玉米吐丝期和成熟期,施用200kg/km2MW型1：10生物质炭保水剂与对照和施用100kg/hm2处理相比显著提高了表层土壤的水分含量,土壤水分含量分别显著提高7.5%、6.5%和10.1%、9.8%。说明一定量生物质炭保水剂施用有保持土壤水分的作用。施用生物质炭保水剂对玉米各生育期的土壤硝态氮含量均无显著性影响,收获时各处理的玉米株高、植株鲜重、产量和千粒重间亦无显著性差异。此外,除200kg/hm2处理的土壤碱解氮含量比对照显著提高11.6%外,施用生物质炭保水剂对土壤其他理化特性均无显著性影响。更多还原

【Abstract】 China is a water shortage country, and water shortage is the main reason for the low long-term productivity of agriculture in arid and semi-arid areas. Biochar is the highly arimatic substance remaining after pyrolysis of biomass under complete or partial exclusion of oxygen, it has a large specific surface area, high porosity, water-holding capacity. A modified biochar water retaining agent (MBWRA) was made by combining polyacrylamide (PAM) with biochar to enhance the capacity of water retention. PAM is a material with strong ability of water retention and cohesiveness. Three kinds of PAM are collected, including MW polyacrylamide, cationic polyacrylamide and anionic polyacrylamide. The aim is to identify1) the changes of the water absorption characteristics of MBWRA,2) the effects of MBWRA application on soil water’s evaporation and on maize seedling,3) the physico-chemical properties of the pot soil,4) in addition, the soil water, the maize growth, the physico-chemical properties of the irrigation soil in the North China Plain with the application of MBWRA. The main results as follows:(1) Compared with the control, the evaporation of soil water decreased by4.1%under3%biochar application after two weeks, but it decreased by8.0%～10.4%and7.0%～13.5%under3%MW MBWRA and anionic MBWRA application after two weeks respectively. The modified biochar is better than biochar in inhibiting the evaporation of soil water.(2) The water absorption capacity was significantly increased with the modified biochar by PAM. The water absorbencys of three MBWRA were as follows,2:10>1.5:10>1:10, which showed that the water absorbency of MBWRA increased with the increasing of the ratio of PAM, and the highest water absorbency was found for the agent type with MW. Compared with biochar, the water absorbency of the MW MBWRA(1:10,1.5:10, 2:10), cationic MBWRA(1:10,1.5:10,2:10) and anionic MBWRA (1.5:10,2:10) increased by52.6%-438.2%,16.5%～151.3%and60.5%～114.5%respectively. Compared with1:10, the water absorbency of the MW MBWRA (1.5:10,2:10), anionic MBWRA (1.5:10,2:10) and cationic MBWRA (1.5:10,2:10) increased by75.4%-252.6%,46.1%-95.2%and54.2%-115.8%.(3) The water absorbency of MW MBWRA, anionic MBWRA and cationic MBWRA significantly increased with the increasing of the ratio of PAM in the fertilizer solution. In addition to urea, the water absorbency of MBWRA decreased in calcium dihydrogen phosphate and potassium sulfate solution, and the water absorbency of MBWRA gradually decreased with the increasing of the concentration of fertilizer solution.(4) The potting experiment showed that the soil water content significantly increased with the application of biochar, compared with the control, the potting soil water content significantly increased by39.7%and50.4%under2.5%and5%biochar application respectively. The potting soil water content significantly increased by54.3%-84.0%and119.5%～145.1%under2.5%and5%MBWRA (1:10) application respectively, compared with the control. The potting soil water content increased by10.5%-63.0%under the application of MBWRA, compared with the application of biochar.2.5%MBWRA was better to improve soil water-holding capacity and plant growth.In addition, the potting soil organic matter, total nitrogen and available phosphorus content significantly increased under2.5%and5%biochar, MW MBWRA, anionic MBWRA and cationic MBWRA application, and it gradually increased with the application rate. The available potassium significantly increased under5%biochar, MW MBWRA, cationic MBWRA and anionic MBWRA application as well. The available nitrogen significantly increased under the application of MBWRA, and it gradually increased with the application rate. It indicated that the soil water and soil nutrients can be effectively maintained by application of biochar and MBWRA.(5) The field trail showed that the soil water can be kept by application of MBWRA, compared with the control and the application of100kg/hm2MW MBWRA (1:10), the surface soil water content significantly increased by application of200kg/hm2MW MBWRA in the maize silking and mature stages, the soil water content significantly increased7.5%,6.5%and10.1%,9.8%respectively. There was no significant impact of the soil nitrate content in each maize growing stage, and there were no significant difference of the maize heights, plant fresh weights, yields and grain weights between treatments. Compared with the control, the available nitrogen content significant increased by11.6%under the application of200kg/hm2MW MBWRA, but there was no significant impact of other soil physico-chemical properties between treatments.更多还原