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|Title:||TENSIOMETER AUTOMATION DEVICE FOR GREENHOUSE IRRIGATION SCHEDULING|
|Publisher:||Division of Agricultural Engineering ICAR–Indian Agricultural Research Institute New Delhi|
|Abstract:||The rapid increase of human population is putting an incredible strain on our environment. Water demand already exceeds supply in many parts of the world and more areas are expected to experience this imbalance in near future. Agriculture is by far the largest consumer of the Earth’s available freshwater. Due to shrinking fresh water resources, micro irrigation plays an important role in sustainable use of water in agriculture. Automation of irrigation further helps in conserving the water by timely even distribution of water and thus prevents wastage of water. Hence, the present research entitled “Tensiometer Automation Device for Greenhouse irrigation Scheduling” was carried out in Rabi season of 2017-18 at farm Green-house, Centre for protected cultivation technology, Indian Agricultural Research Institute, New Delhi. The main objective of the Study was to design, develop and evaluate the performance of Piezo resistive based soil moisture sensor in green house irrigation scheduling under Chrysanthemum and Tomato crops. The experimental soil was found as sandy loamy soil. An experimental area of 300 m2 was selected to grow tomato and chrysanthemum crops irrigated by drip irrigation system. The area was divided in to two plots of size 10 × 15 m (150 m2) each. The piezo-resistive based soil moisture sensor was designed and was incorporated in automation of greenhouse irrigation scheduling. To evaluate the performance of sensors, both developed piezo resistive based soil moisture sensors and tensiometers were installed at 15 cm and 30 cm depth. The sensor readings and corresponding soil samples were taken on daily basis to measure the volumetric soil moisture content. The volumetric soil moisture content were calculated from the corresponding voltage readings recorded by the piezo resistive based soil moisture sensor and tensiometer using Soil characteristic curve and then they were compared with soil moisture content obtained by gravimetric method. The results revealed that the coefficient of determination (R2) was found to be 0.83 and 0.82 between volumetric soil moisture content calculated by piezo-resistive based soil moisture sensor (based on its voltage readings) and soil moisture content measured by the gravimetric method in Chrysanthemum at 15 cm and 30 cm depths, respectively, while, for Tomato it was 0.84 and 0.82, respectively for same methods. The coefficient of Determination (R2 ) between volumetric soil moisture content measured by tensiometer and volumetric soil moisture content measured by standard gravimetric method for chrysanthemum at 15 and 30 cm depth were found to be 0.72 and 0.71, respectively, while for Tomato it was recoded as 0.71 and 0.71. The results also revealed that the voltage readings were in inverse relation with the soil moisture status. The RRMSE of soil moisture content for tensiometer and piezo resistive based soil moisture sensor varied from 9.47 to 19.38 and 7.44 to 18.28, respectively. Lower RRMSE values and higher coefficient of determination (R2 ) were recorded by the piezo resistive based soil moisture sensor as compared to tensiometer indicating higher degree of accuracy. The paired t-test indicated that both piezo resistive based soil moisture sensor and tensiometer were significantly different at 5% significance level. The results showed that piezo resistive based soil moisture sensor measured soil moisture tension efficiently than the normal tensiometer for both greenhouse Chrysanthemum and Tomato crops|
|Theme:||TENSIOMETER AUTOMATION DEVICE FOR GREENHOUSE IRRIGATION SCHEDULING|
|Appears in Collections:||Theses|
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