生物质炭保水剂的吸水保水性能研究

Research on Water Retention Capacity of Water-retaining Agent of PAM-Biochar

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）对生物质炭进行了亲水性改性，分析了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和苗期玉米生长的影响。研究结果表明，施用3％生物质炭两周后可降低土壤水分蒸发量4．1％；施用2．5％和5％的生物质炭后盆栽土壤含水量分别比对照显著提高了39．7％和50．4％。通过PAM改性后的生物质炭可显著提高保水能力，施用改性的生物质炭后盆栽土壤含水量较生物质炭本身提高了10．5％～63．0％。3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的质量比的升高而升高，且Mw型的吸水效果最好。施用2．5％和5％保水剂的土壤含水量分别比对照提高了54．3％～84．0％和119．5％～145．1％，但从土壤保水作用和对作物生长两方面出发，2．5％的生物质炭保水剂对其持水性和玉米植株的生长较为适宜。

With biochar modified by adding different types of water retaining agent polyacrylamide（PAM, a material with strong ability of water retention and cohesiveness） such as MW polyacrylamide, cationic poly acrylamide and anionic polyaerylamide, this article analyzed the influence of the biochar modification on the soil＇s water evaporation and maize growth in seedling stage. The results showed that the evaporation of soil water decreased by 4.1% with 3% biochar application after two weeks while the soil water content signifi- cantly increased by 39.7% and 50.4%with 2.5% and 5%biochar application in potting soil respectively. And with modified biochar application in the potting soil, the water-holding capacity significantly increased with the potting soil water content 10.5% to 63.0% higher. The order of the water absorbency with three modified biochar 2 ： 10〉1.5 ： 10 〉1 ： 10 showed that the water absorbency increased with the ratio of PAM addition. The highest water absorbency was found with the MW polyacrylamide while that with 2.5% and 5% modified biochar application significantly increased by 54.3% -84.0% and 119.5%-145. 1% respec- tively. Taking consideration with soil water retaining and plant growth, 2.5% modified biochar application was chosen to use in the agricultural production.