IRRIGATION SCHEDULING: CLIMATOLOGICAL APPROACH FOR GROWTH, YIELD AND ECONOMICS ON SUMMER GROUNDNUT (ARACHIS HYPOGAEA)

Field experiments were conducted to optimize the irrigation scheduling and nutrient management practices for groundnut (Arachis hypogaea) under irrigated condition during summer season of 2017 at Central Farm, Agricultural College and Research Institute, Madurai, Tamil Nadu. The experiments were laid out in split plot design. Bunch variety, VRI 2 was chosen for the experiments. Soil of the experiment field were sandy clay loam in texture with low available nitrogen and medium available phosphorus and high available potassium. The main plot treatments consisted of three levels of irrigation scheduling namely 0.8 IW/CPE ratio (I1), 0.6 IW/CPE ratio (I2) and 0.4 IW/CPE ratio (I3) and four nutrient management practices in the sub-plots i.e. N1- 75% RDF with 5 t of charred rice husk, N2 - 50% RDF with 5 t of charred rice husk, N3 - 75% RDF with 5 t of charred rice husk along with seed treatment of arbuscular mycorrhiza and N4 - 50% RDF with 5 t of charred rice husk along with seed treatment arbuscular mycorrhiza. Among the irrigation scheduling and nutrient management practices, the growth parameters and pod yield were highest with the treatment combination of irrigation scheduling of 0.8 IW/CPE ratio along with 75% of RDF and 5 t of charred rice husk as basal with seed treatment of arbuscular mycorrhiza with a pod yield of 2003 kg/ha during summer’ 2017 season. Whereas, the lowest pod yield was recorded with irrigation scheduling of 0.4 IW/CPE ratio with 75% of RDF and 5 t of charred rice husk. The net return per hectare and B:C ratio increased with increase in the level of irrigation. The highest net return and B:C ratio were recorded with irrigation scheduling of 0.8 IW/CPE ratio and application of 75% of RDF and 5 t of charred rice husk as basal along with seed treatment of arbuscular mycorrhiza during summer season