Download or read book Irrigation Scheduling Strategies for Tomato Production in Southwestern Ontario written by Felix Jaria and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Precision irrigation scheduling is critical to improving irrigation efficiency. It is a combined technical and managerial tool that determines accurately when, how much and how often irrigation is applied to meet optimum crop response. This is particularly challenging in humid regions such as Southwestern Ontario, where soil moisture is often influenced by periodic rainfalls. The overarching goal of this three year research project was to investigate different irrigation scheduling strategies for tomato production in Leamingtion, Ontario. There were four specific objectives. The first sought to develop an optimum irrigation schedule for intensive cultivation of processing tomatoes by examining different irrigation trigger levels. Moisture triggers were expressed as a fraction of field capacity and soil tension, which are also related to soil available water content (AWC). Triggers with moisture depletion levels of ≤ 40 % (AWC) produced the higher yields. However, the best yields were obtained from the tension treatment with an upper and lower moisture threshold of -10 kPa and -30 kPa, which represented 20 to 24% depletion in AWC.The second objective sought to develop a robust protocol for implementing an irrigation scheduling. Three different types of soil moisture sensors were evaluated. The tension based senor emerged with the highest evaluation score. However, all three sensors could be used to effect irrigation scheduling. The sensor based irrigation data was subsequently compared with the Peman-Monteith model. It was found that the soil moisture treatments with a moisture depletion level of ≤ 40 % soil available water content (AWC) adequately met crop water requirements throughout the season.The third objective examined the spatio-temporal variability of soil moisture under drip irrigation in a controlled greenhouse environment. The study indicated that soil moisture content was not uniformly distributed prior to or after an irrigation event. For double row planting of tomatoes with a central drip line, a row spacing of 50 cm was adequate for planting of seedlings, due to the higher soil moisture contents within that zone. Further, due to the lack of uniform distribution of moisture in the soil profile, paired sensors (with one either side of the drip line) can provide a better estimate of soil moisture depletion for sensor based irrigation scheduling.The fourth objective investigated the nutrient dynamics along the soil profile over the growing season. Soil nutrients (P and N) were monitored at three different levels of the profile (0 to 30, 30 to 50 and 50 to 70 cm) and at the pre-planting, mid-season and end of season stages. Statistical significance in Olsen P and NO3-N was obtained both across the season and along the profile for each of the three years. The variability among treatments was not significant. The P and N concentrations at the 50 to 70 cm depths were found to be high, with the potential of being leached through the subsurface drainage system. A modification in the application of P and N can help reduce leaching of nutrients below the rooting zone. This would necessitate a split application of P and more frequent application of liquid N in smaller quantities." --