陕西省农田土壤物理障碍评价

为了探明陕西省农田土壤物理障碍状况,2013年在全省选取了228个调查点,对1100多块地的农田土壤紧实度进行了调查,从土层厚度、土壤容重和紧实度几方面评价了农田土壤物理障碍状况。结果表明:(1)陕西省农田土壤耕层厚度平均为17.3 cm,其中陕北地区耕层较薄,平均为14.4 cm;全省犁底层平均厚度接近20 cm,其中陕北、关中和陕南犁底层厚度平均为14.5、18.1 cm和20.1 cm。(2)全省耕层土壤容重平均为1.25 g·cm-3,其中陕北耕层土壤容重平均为1.35 g·cm-3,容重偏大;全省犁底层土壤容重平均为1.49 g·cm-3,陕北、关中和陕南地区犁底层容重都明显偏大,影响作物根系生长。(3)陕西省农田耕层土壤紧实度平均为781 k Pa,犁底层紧实度平均为2901 k Pa。全省耕层土壤紧实度尚合适,但犁底层土壤紧实度过大,形成明显的障碍层。

Evaluation of soil physical obstacles on cropland in Shaanxi Province

In order to understand the situation of soil physical obstacles on farmland in Shaanxi Province, a comprehensive investigation of soil layer thickness, soil bulk density and compaction was conducted in 1100 plots from 228 sites over the whole province in 2013. Soil physical obstacles were evaluated based on the indicators mentioned above. The results showed that the average thickness of top soil was 17.3 cm in the whole province, and a thinner value of 14.4 cm was found in northern Shaanxi. The average thickness of plow pan was around 20 cm, and 14.5 cm, 18.1 cm and 20.1 cm were present in northern Shaanxi, Guanzhong and southern Shaanxi, respectively. In addition, the bulk density of topsoil averaged at 1.25 g·cm^-3 in the whole province. However, bulk density in northern Shaanxi Province was 1.35 g·cm^-3 in average. The average bulk density of plow pan was 1.49 g·cm^-3 in the province, which was higher than the threshold value of 1.45 g·cm^-3 and could be an obstacle for crop root growth. Moreover, the average compaction of tillage layer and plow pan in the province was 781 kPa and 2901 kPa, respectively. The compaction of tillage layer was suitable for crop growth; however, the compaction of plow pan was too tight for crops to growth normally.