基于数字土壤系统的县域土壤磷素流失风险简化评估

Effects of planting hole sealing methods on soil moisture, temperature, salinity and survival rate of tomato seedling

县域是中国基本的行政管理单元,探讨县域尺度下土壤磷素流失风险评估的简化方法,旨在为县域磷风险评估和生产实践提供指导。该文在充分考虑县域尺度的特点,简化磷指数评估方法指标和评估过程,并以北京市顺义区为例,基于数字土壤系统,采用地理信息系统和计量土壤学技术,采用简化后的磷指数法对顺义区磷素流失风险进行评估。结果显示,顺义区土壤磷素流失的风险程度呈现东部高,西部低和沿着河流呈条带状分布的特征,这种分布特征在一定程度上说明了导致顺义区土壤磷流失的主要原因是农业投入,顺义区土壤磷素流失风险程度以低为主,但中等风险的面积占总面积的30.05%,今后应加强研究区磷素管理,防止土壤磷流失。基于数字土壤系统的简化磷指数法能够很好地反映待评估区域磷素风险程度,为县域磷素风险评估提供了参考价值。

In order to improving tomato transplanting survival rate in saline and alkaline land in Hetao irrigation area, Inner Mongolia, taking the planting hole sealed by soil as control, soil moisture, temperature, salinity between plants and rhizosphere, and the growth of tomato seedling that the planting hole sealed by sand and planting hole with no seal were monitored. The result showed that soil moisture, temperature and salinity between plants of different treatments had no significant difference. Compared with the control, soil moisture of planting hole sealed by sand and planting hole no seal decreased by 11.73% and 14.80% in 0-10 cm soil depth, and decreased by 9.60% and 13.64% respectively in 〉10-20 cm soil depth; soil maximum temperature decreased by 1.2 and 3.6℃at 5 cm soil depth, and average daily temperature decreased by 1.6 and 2.2℃ respectively; soil salinity decreased by 19.11% and24.84% in 0-10 cm soil depth, and decreased by 11.84% and 19.67% compared to planting hole sealed by soil in 〉10-20 cm soil depth respectively. Tomato transplanting survival rate of planting hole sealed by sand and planting hole with no sealed increased by 20.57% and 19.4% compared to planting hole sealed by soil respectively. It was indicated that treatments of the planting hole sealed by sand or the planting hole with no seal at planting time when cultivating tomato in saline and alkaline land with mulching in Hetao irrigation area, Inner Mongolia, soil moisture and temperature in soil decreased, soil salt accumulation in soil hindered, tomato transplanting survival rate increased. This study provides guidance for saline-alkali soil planting tomato in Hetao irrigation area.