Physiological performance of pigeonpea (Cajanus cajan) in different cropping systems and moisture conservation practices under rainfed conditions

A field experiment was conducted at IARI farm, New Delhi during kharif season of 2013. Among cropping systems, net photosynthetic rate, stomatal conductance, transpiration rate, instantaneous water use efficiency (instantaneous WUE) and Ci/Ca (intercellular CO₂/ambient CO₂) ratio found significant, except grain yield of pigeonpea. Sole cropping system showed the highest response for net photosynthetic rate (23.59 μmol CO₂/m²/s) and transpiration rate (6.52 mmol H₂o/m²/s) which resulted in lowest instantaneous WUE (3.63 μmol CO₂/mmol H₂o). But, the higher response to instantaneous WUE (3.96 μmol CO₂/mmol H₂o) for pigeonpea found in 1: 2 pigeonpeagreengram intercropping system was due to low in transpiration rate (5.12 mmol H₂o/m²/s), although net photosynthetic rate (20.12 μmol CO₂/m²/s) was also reduced. Among moisture conservation practices, plots with mulching had the better response to net photosynthetic rate (22.54 μmol CO₂/m²/s), instantaneous WUE (4.01 μmol CO₂/mmol H₂o) and grain yield (5.5 q/ha) over the control. The better physiological performance for pigeonpea was denoted in 1: 2 pigeonpea-greengram intercropping system and mulching, because of efficient space utilization and soil moisture conservation.