Study of Quality and Quantity of Yield and Land Equivalent Ratio of Sunflower in Intercropping Series with Bean

Intercropping is an old and widespread practice used in low input cropping systems in many areas of the world. In fact, intercropping is claimed to be one of the most significant cropping techniques in sustainable agriculture, and many researches and reviews attribute its utilization to the number of environmental benefits from promoting land biodiversity to diversifying agricultural outcome. Furthermore, it is thought to be a useful mean for minimizing the risks of agricultural production in many environments, including those typical of under-developed or marginal areas. Intercropping systems, especially those employing non legumes with legumes, have several major advantages such as higher total yield and better land use efficiency (Dhima et al., 2007), yield stability of the cropping system (Lithourgidis et al., 2007), better utilization of light, water, and nutrients (Javanmard et al., 2009), improved soil conservation and better control of pests and weeds. Intercrops including of legume are common in agriculture ecosystems, but now are rarely used in developed countries, except for certain intercropping systems used for animal feed. Intercrops can use the available environmental resources more efficiently and thus result in higher yields than mono crops. The reasons for the higher yield in such systems is that the intercropped species do not compete for exactly the same growth resource niche and thereby tend to use the available resources in a complementary way. In particular, non legumes seem to be more competitive for soil inorganic nitrogen (N) than legumes due to faster and deeper root growth and higher demand in N. Consequently, the legumes usually increase their reliance on symbiotic N2 fixation. In the present study, it was aimed to assess the production of biomass, yield, grain quality and land equivalent ratio (LER) in plant society of sunflower/bean.
This experiment was carried out with aim of evaluation of the yield, seed quality and LER in sunflower and bean intercropping based on a randomized complete block design with three replications and nine treatments at Bu-Ali Sina University during growing season 2010-2011. Additive intercropping of 25, 50, 75 and 100% bean with sunflower, replacement intercropping of 25:75, 50:50 and 75:25 (bean:sunflower) and monoculture of sunflower and bean were the experimental treatments. SAS procedures and programs were used for analysis of variance (ANOVA) calculations. The significance of the treatment impact was determined using F-test by measuring significant differences between the means of the treatments, and least significant differences (LSD) were estimated at the probability level of 5%.
Results indicated that with shifting from sole cropping toward intercropping, seed weight, kernel weight, kernel to seed ratio, seed yield, biological yield, harvest index (HI), oil percentage and yield and protein yield decreased significantly, but protein percentage and SPAD reading increased. The highest sunflower seed yield (353 g.m-2) without significant difference with additive intercropping of 50% bean with sunflower observed at sole cropping of sunflower. Except seed number per pod and protein percentage, the effect of treatments was significant on pod number per plant, 100- seeds weight, seed yield, biological yield, harvest index, yield of protein and SPAD reading of bean. Maximum yield of bean recorded in bean sole cropping treatment. In all intercropping treatments, the value of LER was more than one and the value of competition index (CI) was less than one. Treatment of additive intercropping of 50% bean with sunflower had the lowest CI (0.03) and the highest LER (1.66).
Therefore, it seems that additive intercropping of 50% bean with sunflower treatment is suitable treatment for maximum production in society of sunflower and bean.