Leaf area profile and light use efficiency study in maize as influenced by changes in the planting geometry and N-Rates

Dry matter (DM) partitioning is function of the solar radiation intercepted by the crop canopy and their plant’s leaf area exposed within the canopy. Row orientation (RO) and Row-spacing (RS) within canopy influenced the leaf size and might be the light use efficiency. We, therefore, studied cob bearing leaf area and leaf-area-profile (LAP) of maize planted at different RO, RS and N-rates (0, 100, 150, and 200 kg ha -1 ). ANOVA results revealed that RO north-south (NS) then east-west (EW) showed better cob bearing leaf area (cm 2 ). Likewise, did by the RS 75x20 as compare to RS 50x30. Nitrogen 150 kg ha -1 was superior with highest cob bearing leaf area then rest of the any other given N-rates. Comparing the LAP, RS 75x20 showed relatively greater leaf area from node 5 to 8. For the RO difference was higher for all nodes expanded further from nodal position 1 st to 6 th and gradually declined from node 6 th onwards. Similarly, the N-rates also showed distinct differences at each rate in all nodes of a plant. Leaf area of the control plants was incomparable at any node with any level of the given N application rates. Interactive effect of treatments RO and RS with N-rates showed marked differences. Radiation use efficiency (RUE) was also found higher at NS than EW and in 75x20 than 50x30 spacing. The N-rate of 200 and 150 kg ha -1 was almost similar in RUE but was found higher than 100 kg ha -1 and the control plot. The study suggests that greater cob bearing leaf area of the treatments NS and 75x20 were due to greater spaces for the leaf elongation within the crop rows. However, overall response of treatment interaction supports 75x20EW geometry to yield better use efficiency of light for grain yield of maize.