Effect of Aquasorb and Organic Compost Amendments on Soil Water Retention and Evaporation with Different Evaporation Potentials and Soil Textures

Abstract

Aquasorb PR3005A, a hydrophilic polymer (a salt copolymer polyacrylamide), and garden waste compost were added to a loamy sand and a loam soil in pots to assess their impact upon soil physical properties at two different evaporation potentials. Compost was mulched and incorporated, the Aquasorb was incorporated, and their effect on temperature and amelioration of soil water content and evaporation was investigated. Mulching with compost reduced evaporation and increased soil temperature. Maize (Zea mays var. single cross 704) was sown in the same pots later, and growth indicator factors (plant height, fresh and dry weight, root weight, and leaf area) were compared. It was concluded that compost mulch application is beneficial to soil water retention whereas compost incorporation did not show these benefits. Compost mulch advances seedling emergence and enhances early growth through hydrologic soil amelioration. High rates of Aquasorb were also beneficial in advancing the emergence and early growth of maize seeded in loamy sand. The hydration capacity of Aquasorb is reduced as the electrolyte concentration and electrical conductivity are increased. Increased electrolyte concentration in soil solution, through drying, may result in gel dehydration and water release at potentials greater than field capacity, which may be lost to drainage. Furthermore, it is concluded that pot experiments with amendments fail to simulate field conditions.     

保水剂与水分控制对辣椒生长及水分利用效率的影响研究

栽辣椒应用保水剂和实施 3种水分控制处理结果表明 ,施用保水剂对辣椒生长及水分利用效率有明显促进作用 ,辣椒叶面积、叶数、株高、生物量和水分利用效率均优于未施保水剂处理。水分控制对辣椒的影响表现为充分供水促进辣椒生长 ,水分胁迫延缓辣椒生长速度。灰色关联分析发现是否施用保水剂对辣椒生物量、叶面积、叶数、株高、干物质含量、根冠比与耗水量相关性的影响存在差异 ,施用保水剂处理耗水量与各性状关联度顺序依次为生物量 >茎叶干物质量 >根干物质量 >叶数 >株高 >叶面积 >根冠比 >干物质含量 ,而未施用保水剂处理耗水量与各性状关联度顺序依次为生物量 >叶数 >茎叶干物质量 >根干物质量 >株高 >叶面积 >干物质含量 >根冠比。     

Skygel保水剂与供水方式对黄瓜幼苗生长的影响

采用穴盘育苗,研究了不同质量浓度Skygel保水剂与供水方式对黄瓜幼苗生长的影响。结果表明,不同供水方式与不同质量浓度保水剂对黄瓜幼苗生长、生理指标等均有不同程度的促进作用。保水剂在一定范围内可以促进黄瓜幼苗生长,提高秧苗质量和生理活性。黄瓜整个幼苗期,在相同的管理条件下,底部供水保水剂质量浓度为4 g/L的处理明显优于传统的上部供水方式,可减少供水次数与灌水量,节水率达到40%,而且对株高、茎粗、叶绿素含量、根系活力均有明显的促进作用,秧苗质量也得到了进一步增强。     

土壤特性对保水剂持水性能的影响

为研究土壤特性对保水剂持水性能的影响,测试了4种保水剂分别与砂壤土、壤砂土、砂粘壤土1和砂粘壤土2共4种土壤混合后的保水率,混合时土壤为风干土,保水剂与土壤混合的质量百分比为0.5%。结果表明:与单纯保水剂或者保水剂与砂子混合相比,保水剂与土壤混合后可明显降低保水剂的释水速度,提高保水剂的持水能力。土壤特性对保水剂释水速度有明显影响,土壤粘粒含量高,保水剂的释水速度慢,反之,则快。土壤粘粒含量高,土壤含水量高,保水剂表面水势梯度变低,使释水速度变慢;粘粒含量低,水势梯度变大,保水剂释水速率加快。经过7 h的恒温蒸发后,4种保水剂在粘粒含量较高的砂粘壤土(粘粒含量25%)中的保水率比在粘粒含量低的壤砂土(12.5%)中的保水率高43.7%~71.3%,且具有明显的差异。     

化学覆盖与干湿变化对玉米生长及水分利用效率的影响

采用干旱防雨棚下盆栽的方法,研究不同土壤含水量下土壤表面化学覆盖对玉米抗旱成苗及水分利用效率(WUE)的影响。结果表明,利用保水剂和土壤改良剂PAM进行土壤表面覆盖能够提高玉米出苗率,有效降低土表蒸发,同时土壤干湿变化对玉米的生长更为有利,它可以引起强烈的生长补偿效应。     

保水剂在草坪上的应用研究

为了减少草坪耗水问题,进行了保水剂在草坪上的应用研究.试验分保水剂盆栽试验、田间小区试验、大面积示范试验3个阶段,主要进行了保水剂不同品种、不同剂量、不同施用方法的试验研究,主要对草坪的浇水次数、生长状况进行了调查,为保水剂在草坪上的推广应用提供重要依据.