不同水分条件下保水剂对土壤结构的影响

为探明保水剂在不同水分条件下小麦生长过程中对土壤结构的作用过程与机理,在盆栽试验条件下研究了不同保水剂用量(T1:0 mg kg-1、T2:27 mg kg-1、T3:54 mg kg-1、T4:81 mg kg-1)对冬小麦拔节期和收获期的土壤结构和入渗能力的影响。结果表明:保水剂改善了冬小麦生长过程中的土壤结构,提高了土壤结构的稳定性和入渗能力。轻度胁迫条件下,随保水剂用量的增加,>0.25 mm水稳性团聚体含量提高,土壤结构稳定性增强,且拔节期效果更显著;充分灌水条件下,各处理中以T3和T4处理>0.25 mm水稳性团聚体含量较高。除T4处理外,随小麦生育期的推进土壤饱和导水率有所降低。而不同水分条件下,各处理中均以T4处理的饱和导水率较高,但轻度胁迫的处理高于充分灌水的处理。与充分灌水相比,在轻度胁迫条件下,保水剂的施用更有利于改善土壤结构,提高土壤结构稳定性和导水能力,但到小麦收获时土壤结构稳定性以充分灌水条件下的处理较佳。综合以上分析,各处理均有T4处理的改土效果为佳。

Impact of Water-retaining Agent on Soil Structure under Different Qater Moisture

In order to ascertain the action process and mechanism of water-retaining agent on soil structure in the growth of crop,the effects of different dosage of water-retaining agent(T1:0 mg kg-1,T2:27 mg kg-1,T3:54 mg kg-1,T4:81 mg kg-1) on soil structure and infiltration capacity were studied at jointing and harvest of wheat in a potting experiment condition.The results indicated that water-retaining agent improved soil structure during the growth of wheat and increased soil structure stability and infiltration capacity.Under mild stress condition,the amount of > 0.25 mm aggregate and soil structure stability improved with the increase of water-retaining agent,and there was more significant effect at jointing stage.Under filling irrigation,these of Treatment 3 and Treatment 4 were the best compared with other treatments.In addition to Treatment 4,soil saturated hydraulic conductivity decreased with the growth of wheat.Under different moisture conditions,saturated hydraulic conductivity of treatment 4 was highest in different treatments,but that of treatments under mild stress was higher than filling irrigation.Compared with condition of filling irrigation,the application of water-retaining agent improved soil structure and promoted soil structure stability and infiltration capacity under mild stress condition.However,soil structure under filling irrigation was more than that under mild stress condition when harvesting.It concluded that T4 could obtain the best effect in treatments under different water conditions.