Temporal stability of soil water content in typical paddy soil at Taihu Lake region of China

Soil water content plays an important role in crop production, especially in the main rice production areas of China. The temporal stability of soil water content was studied in a paddy field of Taihu Lake region, southeast China. There were two treatments in this experiment, one was mulch with rice straw and the other was without mulch. Soil water content of the two treatments was monitored at the interval of 10 days by the Time Domain Reflectometer probes which were installed in situ, and measured both at 14 and 33 cm soil layers. The data were evaluated by temporal stability methods and Spearman's correlation. Results showed that mulching with rice straw proved to be efficient in retaining the soil water at the 14 cm soil layer. Based on the relative difference method, the representative positions of the experiment field were identified, which accurately represented the field-mean soil water at the experiment field was detected in terms of root mean square error, less than 2.18%. The Spearman's correlation values were high, which indicates temporal dependence along the experiment period. The data of soil water temporal stability could provide scientific basis for adequate water management in paddy field. HIGHLIGHTS The deeper the soil layer, the better the temporal stability of soil moisture.; Temporal stability of soil moisture affects agricultural production.; The temporal stability of soil moisture can provide information in large area.; Straw mulching had significant effect on temporal stability of soil surface water.; The use of field water stability can reduce the number of observations required for soil water management.;