柳枝稷种植年限对盐碱土壤理化性质的影响

盐碱地的合理开发与利用是中国农业可持续发展的重要保障。能源作物柳枝稷(Panicum virgatum)具有一定的耐盐碱性,可在盐碱地种植。为探明柳枝稷对盐碱土壤的改良效应,在宁夏银北典型盐碱地区,通过田间试验研究了柳枝稷种植年限对盐碱土壤容重、孔隙度、全盐含量、pH值、有机质、碱解氮、速效磷及速效钾等理化性质的影响,并采用灰色关联度分析法评价了柳枝稷种植1年(T1)、3年(T3)、5年(T5)对盐碱土壤的综合改良效应。结果表明,盐碱地种植柳枝稷后,有效改善了土壤的水盐及养分情况,提高了土壤肥力水平,使土壤环境向着有利于植物生长的方向发展。与盐碱荒地(CK)相比,5年生柳枝稷田0-20 cm和20-40 cm土层土壤容重分别降低了8.97%和17.75%,土壤全盐含量分别降低了80.53%和80.68%,土壤pH值分别降低了13.26%和15.21%。盐碱地土壤养分含量随着柳枝稷种植年限的延长呈增加趋势。柳枝稷种植5年后0-20 cm和20-40 cm土层土壤有机质较盐碱荒地分别提高了131.42%和147.91%,碱解氮含量分别提高了149.27%和167.73%,土壤速效磷含量分别增加了103.28%和37.52%,速效钾含量分别增加了41.40%和29.71%。柳枝稷种植年限对土壤物理性质和土壤养分的影响主要集中在表层土壤,在0-20 cm和20-40 cm两个土层表现较为明显,改良效应总体优于40-60 cm土层。灰色关联度分析结果表明,柳枝稷种植年限对盐碱土的综合改良效应从大到小依次为T5>T3>T1>CK。可见,种植柳枝稷有利于改善盐碱土壤微环境,降低土壤pH和盐分含量,增加土壤有机质和养分,能有效改良盐碱土壤。

Effects of Planting Years of Panicum virgatum on Soil Physical and Chemical Properties

The rational development and utilization of saline-alkali land is an important guarantee for sustainable agricultural development in China. The energy crop Panicum virgatum has a certain tolerance to salt and alkali, which can be grown in saline-alkali land. In order to ascertain the effect of Panicum virgatum on the improvement of saline-alkali soil, we studied the effect of planting years of Panicum virgatum on physicochemical properties including the bulk density, porosity, total salt content, pH, organic matter, alkaline nitrogen, available phosphorus and available potassium of saline-alkali soil through field experiments in a typical saline-alkali area in Yinbei, Ningxia. In addition, we used the grey correlation analysis method to evaluate the comprehensive improvement effects of Panicum virgatum in 1 year(T1), 3 years(T3), and 5 years(T5) on saline-alkali soil. The result showed that it effectively improved the water, salt and nutrients in the soil, increased the level of soil fertility and made the soil environment develop in a direction conducive to plant growth after planting Panicum virgatum in saline-alkali land. Compared with saline-alkali wasteland(CK), the soil bulk density of 0-20 cm and 20-40 cm soil layers in 5-year-old Panicum virgatum fields decreased by 8.97% and 17.75%, and the total salt content of the soil decreased by 80.53% and 80.68%, and soil pH decreased by 13.26% and 15.21%, respectively. The soil nutrient content in saline-alkali land increased with the extension of Panicum virgatum planting years. Soil organic matter in the 0-20 cm and 20-40 cm soil layers after 5 years of Panicum virgatum cultivation increased by 131.42% and 147.91%, the alkaline nitrogen content increased by 149.27% and 167.73%, the available phosphorus content increased by 103.28% and 37.52%, and the available potassium content increased by 41.40% and 29.71%, respectively. The effect of Panicum virgatum planting years on soil physical properties and soil nutrients was mainly concentrated in topsoil, which was more obvious in 0-20 cm and 20-40 cm soil layers, and the improvement effect was better than that of 40-60 cm soil layers. The results of grey correlation analysis showed that the comprehensive improvement effect of Panicum virgatum planting years on the saline-alkali soil in descending order was T5>T3>T1>CK. It can be seen that planting Panicum virgatum is conducive to improving the microenvironment of saline soil, reducing soil pH and salt content, increasing soil organic matter and nutrients, and effectively improving saline soil.