不同覆盖方式对中度盐渍土壤的改良增产效应研究
Improving effect of mulching methods on moderately saline soil and sunflower yield
-
摘要: 地膜与秸秆覆盖是干旱半干旱地区防治土壤次生盐渍化, 提高土壤水分利用效率的重要措施。为探索不同地面覆盖方式在盐渍土壤的应用效应及机理, 在内蒙古河套灌区中度含盐土壤进行田间试验, 试验共设7个处理: 玉米粉碎秸秆覆盖量9 000 kg·hm-2(F0.9)、玉米粉碎秸秆覆盖量6 000 kg·hm-2(F0.6)、玉米整秆覆盖(YZ)、葵花整秆覆盖(KZ)、新地膜覆盖(DM)、地膜二次使用免耕(MG)、未覆盖(CK), 研究不同地面覆盖方式对中度盐渍化向日葵农田的土壤水盐运动、向日葵产量和种植经济效益等影响, 分析不同覆盖措施的改良增产效应。结果表明: 在0~5 cm土层, 处理F0.9、YZ、DM的含盐量收获后较播前降低, 土壤表层脱盐, 而MG、F0.6、KZ、CK土壤表层积盐。0~20 cm土层, 土壤含盐量收获后与播前相比, 处理F0.9、DM土壤耕层脱盐, 而F0.6、YZ、MG、KZ、CK在土壤耕层积盐。各覆盖处理主要影响0~20 cm的土壤含盐量, 随着土壤深度的增加, 覆盖层因素对土壤含盐量的影响趋于一致。耕层土壤含盐量相比较, F0.9的含盐量最低, 抑盐效果最好, DM与F0.6抑盐效果相近, 不同秸秆覆盖处理间, F0.9、F0.6强于YZ、KZ, 地膜覆盖之间, DM强于MG。在0~5 cm土层及0~20 cm土层, DM的生育期平均土壤含水率高于秸秆覆盖处理, 粉碎秸秆覆盖(F0.9、F0.6)的生育期平均土壤含水率高于整秆秸秆覆盖(YZ、KZ)。处理DM、F0.9较CK显著提高了向日葵生育期内0~100 cm土壤储水量均值, F0.9、DM处理显著降低了0~100 cm土壤储水量变异系数, 在生育期内保持了较稳定的土壤墒情。各覆盖处理均较CK显著增产, 各处理产量效应是: DM>F0.9>YZ>F0.6>MG>KZ> CK。覆盖措施通过改善农田小环境提高了作物水分利用效率, DM、F0.9、YZ处理的作物水分利用效率显著高于其他处理。处理DM、MG、YZ、F0.9、F0.6的产投比显著高于CK, 增收效果明显, DM和MG的纯收入及产投比显著高于秸秆覆盖处理。对于中度盐渍化耕地, 新地膜覆盖DM是最有效的覆盖方式, 秸秆覆盖处理中, F0.9为最优覆盖方式, 与其他覆盖处理相比较, KZ处理的保墒、抑盐、增产等效果较差, 因此向日葵秸秆不适合用作地面覆盖材料。结果可为覆盖技术在内蒙古河套灌区农业生产中的应用提供理论与技术支持。Abstract: Soil surface mulching with plastic film or crop straws can prevent secondary soil salinization and improve crop water use efficiency (WUE). An experiment was conducted in a moderately saline field to investigate the effects of different mulching methods on soil characteristics and sunflower yield. Seven treatments were conducted in the study, including 9 000 kg·hm-2 chopped maize straw mulching (F0.9), 6 000 kg·hm-2 chopped maize straw mulching (F0.6), whole maize straw mulching (YZ), whole sunflower straw mulching (KZ), plastic film mulching (DM), second-used plastic film mulching (MG) and no mulching (CK). The study analyzed the effects of different mulching methods on soil water and salt movement, sunflower yield and economic benefits of moderately saline soils. The aim of the study was to improve production effects of surface mulching of saline soils. The results showed that salt contents in the 0 5 cm soil layer under treatments of F0.9, YZ and DM decreased while those under MG, F0.6, KZ and CK treatments increased at harvest compared with thoes at sowing. Also salt contents at the 0 20 cm soil layer under F0.9 and DM treatments decreased while those under F0.6, YZ, MG, KZ and CK treatments increased at harvest compared with those at sowing. Different mulching treatments had significantly different effects on soil salt content in the 0 20 cm soil layer. The effects of different mulching methods on soil salt content were inclined to similar with increasing soil depth. In terms of salt content in the 0 20 cm soil layer, F0.9 treatment was the lowest, which suggested that F0.9 treatment had the best salt inhibitory effect. The inhibitory effects on soil salt of mulching measures of DM and F0.6 were similar. For different straw mulching treatments, the inhibitory effects on soil salt of F0.9 and F0.6 were better than those of YZ and KZ. For different plastic film mulching treatments, the inhibitory effect on soil salt of DM was better than that of MG. In the 0 5 cm and 0 20 cm soil layers, average soil water content under DM treatment was higher than those under straw mulching treatments throughout the entire growth period of sunflower. Average soil water content under chopped straw mulching treatments (F0.9 and F0.6) were higher than that under whole straw mulching treatments (YZ and KZ) throughout the growth period. Compared with CK, DM and F0.9 improved 0 100 cm soil water storage significantly. Treatments F0.9 and DM decreased soil water variation coefficients in the 0 100 cm soil layer and thereby maintained stable soil water content throughout the growth season. The order of sunflower yield for different treatments was DM > F0.9 > YZ > F0.6 > MG > KZ > CK. The different mulching methods enhanced crop WUE by improving farmland environment. WUE under DM, F0.9, YZ treatments was higher than those under the other treatments. Output-input ratios of DM, MG, YZ, F0.9 and F0.6 treatments were significantly higher than that of CK. The net income and output-input ratios of DM and MG treatments were significantly higher than those of straw mulching treatments. For moderately saline soils, plastic film mulching was the most effective method. Among the straw mulching treatments, F0.9 treatment was the best mulching method. Compared with the other mulching methods, water retention, salt inhibition, and yield effects of KZ treatment were bad. Thus sunflower straw (KZ) was not a suitable mulching material in the study area. The results of the study were suitable for application in guiding the use of mulching methods in Hetao Irrigation District.