滨海盐渍土原土滴灌水盐调控对土壤水力性质的影响

为研究滨海盐渍土滴灌原土水盐调控不同处理对土壤导水率(K)、土壤孔隙大小分布常数(Gardnerα)、土壤孔隙对水流贡献率等水力性质的影响,在滨海盐渍土上进行滤层及基质势(-5、-10、-15、-20、-25kPa)处理的原土水盐调控试验。用圆盘入渗仪在-15、-6、-3、0cm4个连续增大的负压下进行入渗测定,并计算不同负压下导水率、土壤孔隙大小分布常数、孔隙级别对水流的贡献率。结果表明:经原土水盐调控后,各处理的饱和导水率、土壤孔隙大小分布常数较对照增大,在-6和-15cm水头下的导水率较对照减少,在-3cm水头下的导水率无明显变化规律。滤层处理下土壤的饱和导水率、-6cm水头下的导水率、土壤孔隙大小分布常数较无滤层处理有显著提高;各处理土壤大孔隙对水流的贡献率大于对照处理,中等孔隙2及小孔隙对水流的贡献率小于对照处理。滤层处理是不同级别土壤孔隙对水流贡献率大小的主要影响因素,其中滤层的土壤大孔隙、中等孔隙1对水流的贡献率显著高于无滤层。可见,经原土水盐调控后,土壤饱和导水率、-6cm水头下的导水率、土壤孔隙大小分布常数明显增加,土壤大孔隙增加,小孔隙减少,土壤结构得到改善。

Effect of water and salt regulations under drip irrigation on soil hydraulic properties in local coastal saline soil

In order to study the impact of filter and soil matric potential (-5、-10、-15、-20、-25 kPa) treatments on soil hydraulic conductivity K,Gardner α,and the contribution of pore size classes to flow in coastal saline soil,disc infiltration experiments at pressure heads of-15,-6,-3,and 0 cm were implemented.The results showed that,after local soil salt-water regulation,the hydraulic conductivity Ks and Gardner α were higher than that of the control (CK),and the K6,K15 were smaller than that of the CK,and K3 had no obviously changes.Through the tests of between-subjects effects with two factors of filter and soil matric potential treatments,filter treatment was the main factor to the hydraulic conductivity K,Gardner α,the Ksand K6,Gardner α of filter treatment was significantly larger than non-filter treatment.Contribution of macropores (>0.5 mm) to flow of filter and soil matric potential treatments was higher than CK,and the contribution of mesopores2 (0.25-0.1 mm) and micropores (<0.1 mm) to flow was less than CK,respectively.After the tests of between-subjects effects with two factors of filter and soil matric potential treatments,filter treatment was the main factor to the contribution of pore fraction to water flow.The contribution of macropores (>0.5 mm) and mesopores1 (0.5-0.25 mm) to flow under filter treatment had a significantly difference to the non-filter treatment (sig:0.038,0.014,respectively).The soil hydraulic conductivity Ks,K6 and Gardener α had a significantly increase,the contribution of large pore classes to flow increased too.The contributions of small pore classes to flow decreased after local soil salt-water regulation,so it was concluded that the soil structure was getting better after salt-water regulation.