Hydraulics and field performance of a novel micro sprinkler

Abstract

This thesis work was undertaken to study the hydraulics and field performance of a simple and novel micro sprinkler developed by a farmer Mr. Avaran, M of Malappuram District, Kerala. It is made by fusing one end of a 3mm diameter, 4 cm long LDPE micro tube and making an incision just below the fused end. The manually made micro sprinkler samples of four different dimensions were used for the experiment. The micro sprinklers were tested for their hydraulic performance in the laboratory under four different pressures viz. 0.5, 1.0, 1.5 and 2.0 kg/cm 2 . The performance parameters of the micro sprinklers considered for the study were discharge, wetted radius, mean application depth, Christiansen‟s uniformity coefficient, coefficient of variation, distribution characteristics and soil moisture distribution pattern. The farmer developed micro sprinkler was found suitable to irrigate most of the perennial and vegetable crops of the study region. However, the micro sprinkler was showing considerable variability in discharge, wetted radius and application depth. To solve the deficiency of the farmer developed micro sprinkler, it was decided to manufacture standardised micro sprinklers through plastic injection moulding. The hydraulic performance of the industry manufactured micro sprinkler was not promising as revealed by the laboratory results and needed further refinement. A preliminary investigation has led to the conclusion that if moulding and cutting is done through two separate manufacturing processes better results can be brought out. Further, a field study was carried out with the farmer developed micro sprinkler to evaluate its field performance for the crop cucumber, with different levels of irrigation and mulching at the instructional farm, KCAET Tavanur. Randomised Complete Block Design was used for the study with 9 treatments and 3 replications. The various field performance parameters such as moisture distribution in the soil, temperature variation of the soil, number of female flower emergence, yield and yieldattributing characteristics viz. number of fruits per plant, fruit length, fruit girth and water use efficiency of the crop were evaluated. The micro sprinkler with 100% irrigation level with paddy straw mulching has been emerged as the best treatment for maximizing yield of cucumber in sandy loam soil and for the climatic condition of the region where experiment was carried out. Looking from the yield and water use efficiency angles together, the best treatment was 75% irrigation with paddy straw mulching. It has been concluded that this simple and low cost micro sprinkler, despite its minor limitations, can be used effectively for irrigating most of the vegetable crops of Kerala.