Spatial and Temporal pattern of soil temperature in cotton field under mulched drip irrigation condition in Xinjiang

Temperate soil heat condition, together with suitable soil moisture condition, is of critical importance for crop growth. Film covering is a beneficial agronomic measure and changes the soil temperature dynamics significantly. To quantify such influences in the hyper-arid area, field experiments were implemented in Xinjiang Province in 2008 and 2009. Soil moisture and temperature time series data were obtained for different irrigation and agronomy treatments. The results indicated that: the spatial pattern of soil temperature along the horizontal direction would depend on the combinational influence of meteorological, growing, soil moisture, and mulching conditions. Soil temperature in the intra-film location was 1.6℃ higher than that in the inter-film location at 15cm depth in the seedling phase. The inter-film temperature exceeded the intra-film temperature in the bud phase and flowering phase, while the two temperatures collapsed together in the blooming of boll phase. Soil moisture and heat movements were intimately coupled. The amplitude of soil temperature with high soil moisture condition was small due to its big heat capacity. The average mulched soil temperature within 25cm depth was 2℃ higher than the bare soil temperature after irrigation under the same moisture condition. The experiment showed that the mulched drip irrigation can provide more suitable soil moisture and heat conditions for cotton growth.