高产棉田土壤碱性磷酸酶及脲酶空间变异特征分析

Research on the Spatial Variability of Soil Alkaline Phosphatase and Urease Activity in High-yield Cotton Field

以10 m×10 m网格布点连续采集棉田3个生长期的土样,测定土壤碱性磷酸酶和脲酶活性,运用地统计方法建立其空间变异模型和等值线图,探讨棉田土壤在棉花生长的不同阶段,土壤碱性磷酸酶和脲酶活性在时间及空间上的变化特征。结果表明,3个时期的碱性磷酸酶和脲酶均属于中等变异性。土壤碱性磷酸酶和脲酶垂直空间变异性不同,棉花在3个生长期0～20 cm土层脲酶和碱性磷酸酶活性的变异系数均大于20～40 cm土层,而碱性磷酸酶的变异系数在垂直方向是底层大于上层。棉田土壤酶活性也存在时间变异规律,棉花生长发育至吐絮期,酶活性逐渐增加。在垂直空间分布上,3个时期土壤碱性磷酸酶和脲酶活性均随土壤深度的增加而降低。

The spatial variability of soil alkaline phosphatase and urease activity at different cotton growth stages was researched by sampling and testing the activity of alkaline phosphatase and urease in soil samples collected from the 10 m × 10 m sample plots in a high-yield cotton field. Their semi-variogram figures and contour figures were charted using the method of geostatistics, and their horizontal and vertical spatial variability and temporal variability with cotton growth were lucubrated. The results showed that the variability of activity of alkaline phosphatase and u- rease in soil was moderate at three cotton growth stages. In vertical direction of soil, urease activity （0 -20 cm） was higher than CV of urease activity （20 -40 cm）, the same as alkaline phosphatase activity. The vertical spatial variability of soil alkaline phosphatase and urease activity was different, the variability coefficient of urease activity in soil layer of 0 - 20 cm was higher than that in soil layer of 20 - 40 cm, but the vertical spatial variability of soil alkaline phosphatase was opposite. There was also the temporal variability of soil enzyme in cotton field, and the activity of soil alkaline phosphatase and urease was decreased with the increase of soil depth at three cotton growth stages.