保水剂与氮肥混施对土壤持水特性的影响

测定聚丙烯酰胺(PAM)、凹凸棒/聚丙烯酸(WT)和聚丙烯酸钠(HM)3种保水剂在浓度分别为2‰、5‰8、‰的NaCl、MgCl2、CaCl2、FeCl3、尿素、硝酸钾、氯化铵等7种溶液中的吸水倍率;用离心机法测定保水剂与氮肥混施条件下土壤的持水特性。结果表明:与去离子水比较,保水剂在盐溶液中的吸水倍率显著下降,且随着溶液浓度升高,保水剂的吸水倍率明显下降,对于同一盐溶液浓度,离子类型对保水剂吸水倍率的影响表现为:Na+Mg2+Ca2+Fe3+,WT保水剂表现出较强的抗离子特性;保水剂在不同氮肥溶液中的吸水倍率有较大差异,氮肥类型对保水剂吸水倍率的影响表现为:尿素硝酸钾氯化铵;保水剂与氮肥混合施入土壤能提高土壤的持水能力,但施入氮肥降低了保水剂的性能;推荐保水剂与氮肥混合使用时,施氮量不超过0.50 gN/kg干土,保水剂用量不超过6‰。

Effects of super absorbent polymer application to soil mixed with nitrogenous fertilizer on soil water retention properties

This paper studied three kinds of super absorbent polymer (SAP), Polyacrylamide (PAM), Attapulgite/Polypropylic acid (WT) and Polyacrylate sodium (HM) and their water absorbing capacity with the solution of 2‰, 5‰ and 8‰ NaCl, MgCl_2, CaCl_2, FeCl_3, CO(NH_2)_2, KNO_3 and NH_4Cl, and the effect of SAP application to soil mixed with nitrogenous fertilizer on soil water retention properties. The result showed that the water absorbing capacity of SAP decreased significantly in salt solution and with the increment of solution concentration compared with deionized water. For the same salt solution concentration, the effect of ion type on the water absorbing capacity of SAP was: Na~+