The present study was carried out to evaluate the effects of different sowing times (15th May, 1st June, 15th June and 1st July) and planting spacing (10, 12 and 15 cm) on cluster bean production in Multan, Pakistan. Results revealed that cluster bean sowing at 1st June showed higher values of growth, yield, and physiological parameters as compared to the other sowing times (15th May, 15th June and 1st July). In addition, wider plant spacing (15 cm) showed better response as compared to narrow plant spacing (10 and 12 cm).
The sowing time 1st June with planting spacing 15 cm significantly increased the plant height, chlorophyll contents, clusters plant-1, pods plant-1, pods per cluster, leaf area index, transpiration rate, photosynthetic rate, grains per pod, pod length, 100-grain weight and grain yield. Adequate temperature and supply of nutrients increased growth, physiological and yield attributes of cluster bean in current study might be the possible reasons for increase of cluster bean productivity. These findings are in line with the literature. In study of Nikam et al. 32 cluster bean showed maximum plant height when cluster bean was sown in late (1st February) as compared to other early sowing times (1st January and 15th January).
The cluster bean sown in February obtained the longer duration of growth period with suitable climatic conditions as compared to other sowing times. In another study conducted by Meena et al. 12 early sowing of cluster bean increases the crop growth rate and yield parameters as compared to late sowing. Meen et al. 12 found that sowing time (1st July) obtained higher cluster bean yield as compare to 11th July and 21st July which was due to increase the number of clusters plant-1, pods r plant-1, 100 grain weight and optimum environmental conditions during the crop period 22. Ayoub and Hussein 34 reported that unfavorable environmental conditions due to improper sowing time have great influence on cluster bean yield attributes like clusters per plant-1, pods cluster-1, and clusters pod-1.
Dhedhi et al. 22 reported adverse environmental effects on cluster bean yield due to late sowing. The reduction in photosynthetic rate in study of Dhedhi et al. 22 was found the main reason behind low yield of cluster bean. In other study, James et al. 35 found that early sowing system combined with slower developing wheat genotypes could exposed to longer season and 0.54 t ha-1 increased in yield is possible under reduced rainfall and increasing temperature regimes. Early sowing also allows deeper root growth, more access to water and less loss of water through evapotranspiration 35. Therefore, management of sowing time is highly important under changing climatic conditions to provide plants optimal environmental conditions to flourish up to its maximum pick in respect of growth, physiological and yield development.
Zimmermann et al. 11 studied a crop, economic and environmental model for six important crops, for 27 countries of the European Union (EU27) to assess climate change impact to 2050. Zimmermann et al. 11 found that sowing times and thermal time requirement have great impact on crop yields, production, land use and environment quality. The sowing time and selection of appropriate cultivars proved helpful to optimize yields and yield changes as compared to other management practices under changing climate scenario.
The wider plant spacing (15 cm) showed better effect on growth, yield, and physiological parameters of cluster bean in current study as compared to 10 and 12 cm. This might be due to less competition between plants for space, nutrients, and light. The plants might be got suitable space for the extension of roots and uptake of nutrients from large area as compared to 10 and 12 cm plant spacing plants. These findings are in line with the studies reported in literature. In study of Nandini et al. 36, higher plant height and number of leaves plant-1 were recorded with wider planting density (45×15 cm) as compared to lower planting density (30×15 cm and 45×10 cm) 37.