The researchers studied how sunlight and humidity affect the growth of dry-land pigeon pea plants. They measured factors like photosynthesis, water use, and leaf water content during different growth stages. They found that the plants grew better during the flowering phase, but high sunlight and humidity levels could still harm them. Even when the plants had enough water, too much sunlight could be bad for them. The plants were less efficient at using water during the pod-filling stage compared to earlier growth stages.