Microclimate Modification through Groundnut-Pigeon Pea Intercropping System and its Effect on Physiological Responses, Disease Incidence and Productivity

Background: Groundnut (Arachis hypogaea) is the predominant leguminous oilseed crop of India which has turned out to be a sensitive victim to climate change episodes like rising CO2 levels, erratic rainfall pattern, high temperature and moisture stress leaving deleterious imprints in physiology, disease resistance, fertility and productivity. Globally climate change is anticipated to pull down groundnut productivity by 11-25%. Agronomic manipulations like altered time of sowing, intercropping and irrigation management helps in microclimate modification towards reaping higher productivity and economic returns in groundnut. Methods: Field experiments were conducted during 2019-2021 on sandy clay loam soil (Fluventic Ustropept) in a Randomized Block Design with three factors viz., differential cropping systems (sole groundnut, groundnut + red gram intercropping), rainfed and irrigation systems and differential sowing windows (Second fortnight of June, first and second fortnights of July). Growth parameters, physiological traits viz., photosynthetic rate, transpiration rate, stomatal conductance, canopy temperature and light interception, incidence of foliar diseases viz., leaf spot and rust; soil borne disease viz., stem rot, root rot and productivity of groundnut were recorded at critical crop growth stages. Result: Canopy temperature was higher in sole groundnut system while light interception was higher in groundnut - redgram intercropping system, however system productivity did not register statistical superiority between the cropping systems. Irrigated system exerted its influence over rainfed system in terms of pod and kernel yield of groundnut. Sowing of groundnut during second fortnight of June was beneficial than July sowing in pod and kernel yield of groundnut due to uniform distribution of rainfall during the growth and reproductive phases of crop. Although differential cropping systems did not register their impact on disease incidence of groundnut, irrigated system and first sowing windows recorded minimum incidence of root rot, stem rot, early leaf spot, late leaf spot and rust diseases compared to rainfed system and July sowing.