Tillage and Potassium Management for Improving Yield, Physiological, and Biochemical Responses of Rainfed Lentil Under Moisture Stressed Rice-Fallow

Uncertainty of rainfall intensity and distribution in association with fast depletion of soil moisture content affects sowing time, seed germination, and establishment of lentil in rice-fallows. Mid-season and terminal droughts often retard growth and development of rainfed lentil by affecting its critical growth stages. Delayed sowing further accelerates the moisture stress. A two-year field experiment was conducted in split-plot design with tillage (ZT—zero tillage and CT—conventional tillage) in main plots and strategic K application methods (K0—no potassium, Kb—basal application, Kf—foliar application, and K(b+f)—basal-foliar application) in sub-plots using rainfed lentil ( var. B-77) as test crop in rice-fallow system. We assessed the yield, physiological, and biochemical changes of lentil and soil biological properties owing to the different treatments and treatment combination imposed. ZT appeared to have provided ~ 15 and 23.5% higher yield than CT during 2015 and 2016, respectively. Under both tillage practices, Kf and K(b+f) were able to boost lentil yield effectively. Also, soil microbial biomass carbon (MBC) and dehydrogenase activity (DHA) were seen to improve satisfactorily under Kf and K(b+f). Kf under ZT accumulated greatest amount water in leaves (RLWC) and provided the highest leaf area index (LAI), whereas K(b+f) showed similar results in CT. Irrespective of tillage and growth stages, there happened to be a corresponding hike in chlorophyll as well as carbohydrate content by ~ 24.3 and 41.5%, respectively, under K(b+f). In addition, the enhanced concentration of phenol, free amino acids, and proline in lentil apparently suggested suffering of moisture stress in K0 under both the tillage practices over the years. We can conclude that practicing zero tillage along with foliar application of potassium could be an efficient way to escape soil moisture stress sustaining lentil productivity by regulating the biochemical properties and improving physiological aspects of plants at initial stages in rice-fallow system.