عنوان مقاله [English]
Low sustainability, soil erosion and loss of soil fertility in conventional systems are the major threats to the agricultural production systems. These threats leads researchers towards more attention to different agroforestry systems including alley cropping as a solution in different regions of the world. Agroforestry has attracted considerable attentions because of its potential to maintain or increase productivity in areas with high energy input in which large scale agricultural systems are impractical. It is often assumed that appropriate agroforestry systems can provide the essential ecological functions needed to ensure sustainability and maintain microclimatic and other favorable influences, and that such benefits may outweigh their enhanced use of water in areas of limited water availability. Evidences suggest that diversity in agroecosystems, in particular the integration of different perennial crops or trees (agroforestry), augments nutrient capture and cycling processes; processes that in turn lead to reduced reliance on nutrient or water inputs, abatement of air and water pollution, and enhancement of other ecosystem services across multiple spatial and temporal scales. Agroforestry is viewed as providing ecosystem services, has many environmental benefits and economic advantages as part of a multifunctional agroecosystem. Conventional cultivation of barley and wheat systems in Saman Region has many problems about sustainability of production, erosion of soil, yield stability and soil nutrient properties. On the other hand, planting of Almond is a good option for farmers to make orchards, in compare to Nut. Although some farmers do Agroforestry as an innovative practice, but studying the advantages of these systems and finding their rewards, because of its unique benefits in dry, poor and endangered areas, could help farmers to increase their cultivation area as they wish, particularly in Saman region.
Materials and Methods:
In order to evaluate the benefits of a tree-based intercropping system, a study was conducted in an almond-based agroforestry plantation located in Saman region of Shahrekord, Iran (32˚43ꞌ N latitude and 50˚49ꞌ E longitude, with an altitude of 2085 m) based on a completely randomized design with four replications in 2014-2015.,The region is a semi-arid area receives 346 mm precipitation annually distributed only in 5-6 months.. Treatments include different types of cultivation systems: almond - wheat, almond - barley, and sole cropping of Wheat and Barley. Measured traits were leaf area index, plant height, spike length, dry matter, number of grains per spike, number of spikes per m², 1000 grain weight and grain yield (per unit area) and actual yield, biological yield and harvest index of wheat and barley.
Results and Discussion:
Results showed that the highest yield (456 g.m-2) was acquired from almond-barley agroforestry system and the lowest from almond-wheat (233 g.m-2). Cultivation of barley in almond-barley system increased dry matter (14%) and grain yield (28%). Intercropping with almond tree increased leaf area Index, plant height, number of tillers, spike length and dry weight, especially for barley. So Agroforestry may increase morphological characteristics rather than the others. But number of spike, seed number and 1000 seed weight increased just for barley and decreased in wheat, However agroforestry increased biological yield in both barley and wheat, but the trend for grain yield was only in barley and some decrement were seen for wheat. It could be due to difference in filling period length and commence, and accordance with crucial developmental stage in almond.
Results of this study showed that the highest biological and grain yields were obtained from barley at agroforestry system with almond tree, indicating that barley is a more suitable option for multiple cropping compared to wheat. It may be due to higher dry matter accumulation of barley before bud developing and shading of almonds lead to higher dry matter accumulation, the situation that will occur for wheat latter. so barley- almond agroforestry system could be an effective technique to increase productivity and satisfying economical purposes in Saman region, Iran.