The present study deals with the study of yield response factor (Ky) for onion crop cultivated under deficit irrigation for Rahuri region (Maharashra). The field experiment was conducted to determine the yield response factor of the onion (Allium cepa L.) cv. N-2-4-1 crop under the deficit irrigation approach during summer season of 2012 and 2013 at Instructional Farm of the Department of Irrigation and Drainage Engineering, Dr. Annasaheb Shinde College of Agricultural Engineering, Mahatma Phule Krishi Vidyapeeth Rahuri. Experiment was carried out in Randomized Block Design (RBD) with 27 treatments and two replications based on different combinations of the quantity of water stress during different crop growth stages. Water applied per irrigation and soil moisture contents before and after irrigation were monitored throughout the season, while onion bulbs were harvested at the end of season and weighed. Average daily crop water use (crop consumptive use) were estimated from the soil moisture content using the soil moisture depletion method. The seasonal yield response factor (Ky) was obtained by relating relative yield decreases to relative crop water use deficit by the regression analysis. The relative yield decreases of the onion crop were proportionally greater with increase in evapotranspiration deficit. It shows the response of yield with respect to the decrease in water consumption. In other words, it explains the decrease in yield caused by the per unit decrease in water consumption. Seasonal crop response factor for onion crop was determined as 1.58, 1.48 and 1.54 during 2012, 2013 and average of both year (2012 &2013) respectively. The yield response factors developed in this study could be used in irrigation design and scheduling for onion in the study area.

Eight different promising cropping systems of important crop of Marathwada region were tested in varied weather condition under rain fed agriculture. At the end of two year experiment it was investigated that, sowing of all the cropping systems in 26 th MW recorded the highest mean productivity as compared to delayed sowing after 26 th MW. The data further revealed that the parlimillet + pigeonpea (C 5), sorghum + pigeonpea (C 4), greengram-Rabi sorghum (C 8), soybean + pigeonpea (C 6) showed the better performance over the sowing dates as compared to all the other cropping systems.The lowest mean productivity of 537 kg/ha was obtained when sorghum + pigeonpea ICS sown in 32 nd MW (D 4 C 4) followed by

Crop models are useful for different purposes; primarily, to interpret experimental results and as research tools for research knowledge synthesis. Lengthy and expensive field experiments, especially with a high number of treatments, can be pre-evaluated through a well-proven model. Optimum management practices, either strategic or tactic, such as planting date, cultivar selection, fertilization, or water and pesticides usage, can be assessed through proven simulation models for making seasonal or withinseason decisions. The capability of AquaCrop model is tested and confirmed by various researches throughout the world. Findings of the field study were used to calibrate the AquaCrop Model for summer chilli in Marathwada region. Results from this study provided a set of first estimates for the calibration of the AquaCrop model on chilli for Marathwada conditions and for further testing and validation of the model at other agroclimatic conditions. AquaCrop model was calibrated by using field data of full irrigation treatment with harvesting index of 75% and water productivity 30 g/m 2 as there was close match between observed and simulated canopy cover with high value statistical parameter of R 2 NS =0.97 and CRM = -0.051. It was also cleared that the canopy cover was overestimated by model particularly during 36 to 84 DAT i.e. during development stage. But the scatter plot clears that as the canopy cover lie on both sides of 1:1 line, there was no consistent over or under estimation.

A field experiment entitled "Impact of Irrigation and Fertigation Levels on Growth, Yield and Quality of Summer Chilli (Capsicum annuum L.)" was carried out during summer season of 2018, in split plot design having main plot treatments as drip irrigation levels viz. I1: at 0.7 ETc, I2: at0.8 ETc,I3: at 0.9 ETc, I4: at 1.0 ETc, and I5: at 1.1 ETc and Sub-plot treatments as fertigation levels viz. F1= 60 per cent of RDF, F2= 80 per cent of RDF and F3= 100 per cent of RDF with fifteen treatment combinations, replicated thrice. Results of the study indicates that the significant differences on chilli yield and quality attributes viz., per cent fruit set, fruit length, girth and number of fruits per plant were observed for different drip irrigation and fertigation levels. As drip irrigation levels between 80 to 100 per cent of crop evapotranspiration were found statistically at par with each other for fruit quality and yield of chilli, irrigation level of 80 per cent of crop evapotranspiration was found optimum among the all tested treatments. Whereas, for different levels of fertigation in eleven splits had significant effect on fruit quality and yield of chilli. Fruit quality and yield of chilli was found highest in F3 (fertigation with100% of RDF) treatment. Further fertigation levels with100 per cent of RDF and 80 per cent of RDF was found statistically at par with each other for the fruit quality and yield of chilli. Therefore, fertigation with 80 per cent RDF in eleven splits was found optimum. Interaction effect of different irrigation and fertigation level was found non-significant.

A field experiment entitled "Impact of Irrigation and Fertigation Levels on Growth, Yield and Quality of Summer Chilli (Capsicum annuum L.)" was carried out during summer season of 2018, in split plot design having main plot treatments as drip irrigation levels viz. I1: at 0.7 ETc, I2: at0.8 ETc, I3: at 0.9 ETc, I4: at 1.0 ETc, and I5: at 1.1 Etc and Sub-plot treatments as fertigation levels viz. F1= 60 per cent of RDF, F2= 80 per cent of RDF and F3= 100 per cent of RDF with fifteen treatment combinations, replicated thrice. Results of the study indicates that for different drip irrigation levels, the ascorbic acid content of chilli was found optimum with drip irrigation at 0.80 of crop evapotranspiration and fertigation with 80 per cent of RDF applied in eleven splits, with 20 per cent saving of irrigation water and fertilizer. Oleoresin content of chilli was not influenced by different drip irrigation levels, however, it was found to be optimum to fertigation with 80 per cent of RDF. The significant differences on dry matter yield and nutrient uptake were observed for different drip irrigation and fertigation levels. As drip irrigation levels between 80 to 100 per cent of crop evapotranspiration were found statistically at par with each other for dry matter yield and nutrient uptake by chilli, irrigation level of 80 per cent of crop evapotranspiration was found optimum among the all tested treatments. Whereas, for different levels of fertigation in eleven splits had significant effect on dry matter yield and nutrient uptake by chilli. Dry matter yield and nutrient uptake were found highest in F3 (fertigation with 100% of RDF) treatment. Further fertigation levels with100 per cent of RDF and 80 per cent of RDF was found statistically at par with each other for the dry matter yield and nutrient uptake. Therefore, fertigation with 80 per cent RDF in eleven splits was found optimum.