The Monitoring Of Farmland Soil Moisture And Water Management System For Cotton On Drip Irrigation Under Mulch

In this study, six water treatments, which included two irrigation quantities (mild drought (65% FC,65% field capacity of 0～60cm profile under drip irrigation pipe before every irrigation time), contrast (75% FC)) and four irrigation frequencies (low irrigation quantity and high frequency (LH) (3d18mm, irrigation with 18 mm every 3 days), high irrigation quantity and high frequency (HH) (3d30mm), low irrigation quantity and low frequency (LL) (5d18mm), high irrigation quantity and low frequency (HL) (5d30mm)) were conducted during flowering-bolling stage of hybrid cotton in National Agricultural Science and Technology Park of Shihezi in 2008 and 2009. In this experiment, spatial and temporal variation of soil moisture and its yield were investigated to derive soil moisture monitoring model of cotton cultivation under drip irrigation with plastic mulching in Northern XingJiang, which may provide a way to explore monitoring and forecasting of farmland soil moisture in arid area. Results showed that:(1) Compared with other water treatments, the volumetric soil moisture of 5d30mm can stay at 33.8% to 38.3% which suitable for cotton growth. Moreover, the yield of 5d30mm treatment was close to the potential productivity of cotton. Therefore, the volumetric soil moisture stay at 33.8% to 38.3% in 5d30mm treatment can be recognized as critical value of soil moisture for hybrid cotton in Northern XingJiang.(2) In the condition of critical value of volumetric soil moisture stay at 33.8% to 38.3%, the 0-60cm soil layer water content can be estimated by a testing location which at 18.25cm distance to pipe water emitter along horizontal direction and 30cm distance to soil surface along soil profile, and then soil moisture monitoring model was generated to serve as a guide for irrigation.(3) The soil moisture at different place with same soil texture in 2009 was detected to verify the soil moisture monitoring model. According to ANOVA, the RE, RMSE, R, LA and a were 9.95%,0.0192,0.9450,0.4838 and 0.0051 respectively. Which indicated a strong accordance between simulated and observed value, thus the model was suitable for soil moisture forecasting.(4) Relation between daily lowest temperature and the dew-point temperature was established and then integrated in Penman-Monteith to calculate crop potential evapotranspiration. According to ANOVA, the RE, RMSE, LA and a were 5.23%, 1.30%,0.9998 and 0.0465 respectively. Which indicated a strong accordance between simulated and observed value.(5) On the basis of the predigested Penman-Monteith model, we build the field soil moisture monitoring and water management system base on WEB.