Radiation Use Efficiency and Yield of Pepper (Capsicum annuum L. cv. California Wonder) under Different Irrigation Treatments

This study assessed the optimum water need of pepper (Capsicum annuum L. cv. California Wonder) and the critical irrigation level to be applied in order to achieve a reasonable economic yield in water shortage conditions. In a controlled field experiment involving five different treatments, seasonal evapotranspiration for pepper fluctuated from ۸۹ mm in the severe stress treatment (I۰.۰۰) to ۱,۰۱۸ mm in the excess water application (I۱.۲۵). The highest yield was obtained in the full treatment where water in the root zone was refilled up to field capacity. In cases of water shortage, applying water of ۶۹۰ mm ensures an economical yield. Maximum leaf area index was recorded in the full treatment (I۱.۰۰), which enabled the pepper to receive more benefit from total incoming solar radiation (average, ۲,۳۸۷ MJ m-۲). An average of ۵۵۵.۴۵ MJ m-۲ was held by the pepper canopy throughout the whole growing season. Radiation use efficiency values on a dry yield basis were ۰.۶۹ g MJ-۱ in ۲۰۱۱ and reached ۱.۰۷ g MJ-۱ in ۲۰۱۲, since the leaf area index increased from ۱.۴۶ to ۲.۴۴. Therefore, averaged over two years, the peppers in the full treatment converted irrigation water of ۸۸۸ mm and intercepted photosynthetically active radiation into the highest yield of ۷۵.۵ t ha-۱, which was more efficient than the excess and deficit water application treatments.

Keywords:

Intercepted photosynthetically active radiation , Pepper , Photosynthetically active radiation , Radiation use efficiency , Solar radiation