不同秸秆覆盖量对盐渍土蒸发、水盐变化的影响

为探究不同秸秆覆盖量对盐渍化土壤蒸发量、含水率及含盐量的动态变化规律,于2009年在陕西省蒲城县卤泊滩试验基地进行了4个水平的秸秆覆盖量(1.05,0.75,0.45,0.15kg/m2)试验,以不覆盖为对照(C0)。试验结果表明:4个处理盐渍化土壤的日平均蒸发量较C0均显著减少,分别减少1.335 8,1.310 3,1.035 7,0.629 0mm/d;随着时间的延长,各土层土壤含水率逐渐增加,10cm土层平均土壤含水率变化幅度最大,较C0分别增加9.280%,9.000%,6.920%,2.450%;随着时间的延长,10,30cm土层土壤含盐量逐渐减少,盐分逐渐压制在50cm土层,10cm土层平均土壤含盐量变化幅度最大,较C0分别减少0.811%,0.802%,0.723%,0.381%;当秸秆覆盖量为0.75kg/m2时,再增加秸秆用量,保水和抑制盐分表聚的作用并无明显增强。研究表明,采用秸秆覆盖地表改良盐渍化土壤,减少了土壤水分蒸发损失,提高了水分利用效率,抑制了盐渍化土壤可溶性盐分的表聚作用,有效地提高了耕地面积的利用,且秸秆覆盖量以0.75kg/m2为宜。

Effect of Straw Mulching on Change of Evaporation and Water-Salt in the Saline Soil

In 2009,a field experiment was conducted at the Pucheng Lubotan Experimental Station in Shaanxi province to determine the dynamic change law of straw mulching quantity on saline soil evaporation,water content and salt content.The straw mulching quantity had four levels of 1.05,0.75,0.45 and 0.15 kg/m2,non-mulching(C0) was controlled trial.The results indicated that the daily average evaporation under the four different straw mulching quantity were 1.335 8,1.310 3,1.035 7,0.629 0 mm/d,respectively,significantly higher than that of C0.The soil water content of every soil layer was gradually increased with the time,change range of soil water content was maximum in the 10 cm soil layer,soil water content were 9.280%,9.000%,6.920% and 2.450%,respectively,significantly higher than that of C0.The soil salt content of 10,30 cm soil layers were gradually decreased with the time,salt was gradually suppressed in the 50 cm soil layer,change range of soil salt content was maximum in the 10 cm soil layer,soil salt content were 0.811%,0.802%,0.723% and 0.381%,respectively,significantly lower than that of C0.When straw mulching was 0.75 kg/m2,and then increased the amount of straw,the role of water retention and inhibited salt accumulation was not significantly enhanced.Using straw to cover soil surface is an effective measure to reduce soil water evaporation loss,to improve water use efficiency,to inhibit surface accumulation of the salt,to improve the utilization of arable land,and the straw mulching quantity of 0.75 kg/m2 is preferable for Lubotan area.