Effects of P organic and chemical fertilizers on yield and productivity indicators in barley and grass pea intercropping under rainfed conditions

To investigate the effect of phosphorus bio and chemical fertilizers on forage yield and useful indices in barley and grass pea intercropping, an experiment was conducted during growing seasons (2014-2015) at the Agricultural Jihad Research Farm of Abhar, Zanjan province, Iran. The experiment was performed in factorial based on randomized complete block design with three replications. The investigated factors included five replacement intercropping patterns consist of solo crop of barley and grass pea, various ratio of barley and grass pea (75:25, 50:50 and 25:75) and four levels of phosphorus fertilizer (100 g.ha-1 of  phosphorus bio fertilizer,100 kg.ha-1 phosphorus chemical fertilizer, 50% bio fertilizer+50% chemical fertilizer and control). The results of combined analysis showed that the year, various intercropping ratio and phosphorus fertilizers had significant effects (p≤0.01) on dry yield and fresh forage. Mane comparison showed that the highest fresh (6403.21 kg ha-1) and dry (2101.67 kg ha-1) forage yields, protein percentage and digestibility of dry matter were also affected by crop ratios and were obtained at 75:25 barley and grass pea. Besides, the study of the effect of different phosphorus fertilizer showed that the combination of 50% of bio + 50% of chemical phosphorus resulted in the highest fresh (5689.44 kg ha-1) and dry (1726 kg ha-1) forage productions and quality. The highest Land Equivalent Ratio (LER = 1.21), Monetary Advantage Index (MAI = + 124.32) and System Productivity index (SPI = 2.500) were obtained from 50 % of bio and 50% of chemical phosphorus and 75:25 mixture of barley and grass pea.