Evaluation of radiation use efficiency and weed control in intercropping of sugarcane (Saccharum officinarum L.) and legumes

Ehsanipour, A., H. Abbasdokht, M. Gholipour and A.R. Abdali Mashhadi. 2019. Evaluation of radiation use efficiency and weed control in intercropping of sugarcane (Saccharum officinarum L.) and legumes. Iranian Journal of Crop Sciences. 21(1): 62-81. (In Persian). This experiment was conducted using randomized complete block design with 14 treatments and four replications in in two locations in Ahwaz, Iran, in 2016-2017. Treatments included: sole sugarcane, sole soybean, sole cowpea, sole soybean+rhizobium, sole cowpea+rhizobium, sole sugarcane+mycorrhizal, intercropping sugarcane with cowpea, intercropping sugarcane with soybean, intercropping sugarcane with cowpea+rhizobium, intercropping sugarcane with soybean+rhizobium, intercropping sugarcane+mycorrhiza and cowpea, intercropping sugarcane+mycorrhiza and soybean, intercropping sugarcane+mycorrhiza and soybean+rhizobium, intercropping sugarcane+mycorrhiza and cowpea+rhizobium. The results showed that the radiation use efficiency was higher in intercroppings than sole crops. The highest radiation use efficiency (1.9 g.Mj), the highest LER (2.06) and the highest stem yield of sugarcane (112.8 t.ha) belonged to intercropping sugarcane+mycorrhiza and cowpea+rhizobium treatments. Weeds were well controlled without using herbicides in intercropping treatments. Light extinction coefficient (K) for cowpea and soybeans was significantly different in locations, but there was no significant difference for sugarcane sole crop. The highest LAI obtained in cowpea (4.6) and the lowest K (0.427) was measured in the sole cowpea + rhizobium. The highest K in sugarcane (0.473) obtained in sole sugarcane crop while the highest K in cowpea (0.595) obtained in intercropping with sugarcane. The results of this experiment showed that the synergistic effects of mycorrhiza and cowpea and sugarcane was positive on studied traits. Therefore, the utilization of mycorrhiza and rhizobium as well as legumes in intercropping, improved soil fertility, increased land use and radiation use efficiency. In addition, weeds were effectively controlled in intercropping treatments.