Dr. K. S. SekhonSharma, Avni2024-04-022024-04-022024Sharma, Avni (2024). Effect of water quality and fertigation on yield and quality of onion (Allium cepa L.) under drip irrigation (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.https://krishikosh.egranth.ac.in/handle/1/5810207991An on-going experiment with cotton-onion cropping system was selected under to study the effect of different water qualities viz. canal water (CW), poor quality saline tube well water (TW) and alternate CW and TW (CW-TW) and three N fertigation levels [ 100% (N100), 120% (N120) and 140% (N140) of recommended dose of N (RDN)] under drip irrigation and with 120% RDN under conventional flood irrigation on bulb yield and quality of onion (Allium cepa L.) at Jodhpur Farm of PAU Regional Research Station, Bathinda. The experiment was triplicated in randomized complete block design on a permanent layout in three strips of four rows keeping one drip lateral, having in-line emitter spacing of 30 cm and discharge rate 2.4 L hr-1. The onion plants were partitioned into leaves and bulb at 60 days after transplanting (DAT) and at final harvest stages and analysed for N, P, K, Ca, Mg, S, Na and Cl elements. The plant height increased progressively till 90 DAT under drip irrigation (DI) and conventional irrigation (CI). At harvesting, CW gave significantly higher plant height than TW and CW-TW under DI which were superior than CI. Number of leaves per plant and dry matter (DM) accumulation in leaves and bulb in CW was at par with CW-TW. Dry matter accumulation (DM) in leaves and bulbs was recorded in the order- TW< CW-TW< CW. Under CI, DM accumulation with CW was at par with CW-TW. Onion bulb yield also decreased with increasing salinity. The highest total biomass at 60 DAT and bulb yield was obtained with CW which was at par with CW-TW. Among the fertigation levels, N140 recorded significantly higher DM which was at par with N120 biomass at 60 DAT. The increasing irrigation water salinity decreased N, P, K, Ca, Mg and S content whereas Na and Cl content increased in both plant parts. CW and TW under DI, registered the highest and the lowest macronutrient content in leaves and bulb at both the growth stages, whereas CW-TW held the intermediate values for the macronutrients. Highest fertigation of 140 % RDN under DI registered the maximum content of N, P, K, Ca, Mg and S at both the growth stages in both the plant parts. Increasing N dose decreased the Na and Cl content in leaves and bulbs at both the growth stages. CI recorded the significantly lower N, P, K, Ca, Mg, and S content in both plant parts with CW, TW and CW-TW at 120 % RDN than DI at the same 120% RDN. Ascorbic acid varied significantly with water quality under CI. The maximum content was observed with CW which was at par with CW-TW. DI recorded significantly higher TSS with TW and CW-TW at 120 % RDN than CI. The infiltration rate, mean weight diameter and organic carbon content decreased but bulk density, EC1:2 and pH1:2 increased with increasing water salinity. Increasing salinity decreased available N and P and increased available K, Ca,Mg,Na,Cl in the both surface (0-15 cm) and sub surface (15-30 cm) soil layers. Increasing N doses increased K and Ca content in the soil whereas Na and Cl decreased. It is concluded that cyclic use of good quality canal water and poor quality saline tube well water (CW-TW) with 20% higher N than the recommended dose can be adopted for irrigation on the sandy loam soil for sustainable production of rabi onion with minimal adverse effect on soil health in semiarid conditions using drip in case of scarce good quality water scenario.EnglishThesis