Effects of fertilizer treatments on morphological and qualitative traits of Descurainia sophia (L.) Schur and Coriandrum sativum L. in agroforestry systems

The ecological, economic, and social benefits of agroforestry operations over the integrated agriculture are well-recognized, but failure to use the fertilizers and low profitability of the agroforestry systems may be a reason for the low acceptance of these systems by farmers. In this study, a factorial split-split plot experiment was conducted in a randomized complete block design with three replications to investigate the effects of bio-, organic, and chemical fertilizers on the improvement of yield, qualitative traits, and the greater profitability of this system. The medicinal species at two levels, fertilizer at five levels, and tree species at two levels were considered as the main-, sub-, and sub-sub plots, respectively. The tree species including cherry (Prunus avium L.) and walnut (Juglans regia L.) were selected for the agroforestry system and the medicinal species including coriander (Coriandrum sativum L.) and flixweed (Descurainia sophia (L.) Schur) were cultivated understorey of this system. Four fertilizer treatments including the organic manure (3 kg.m-2)+humic acid organic fertilizer (AgriPlus) (0.5 kg.100 l-1 of water.100 m-2), Mycomix endomycorrhizal biofertilizer (100 g.m-2), Bioazospir bacterial fertilizer (200 g.100 kg of seed), and chemical fertilizer based on the soil analysis (75 kg of urea, 150 kg of triple superphosphate, and 150 kg of potassium sulfate at the beginning of sowing+100 kg of potassium sulfate 30 days after sowing and another 100 kg two months after sowing per hectare) were examined with the control (without fertilizer). The results showed that the plant height and 1000-seed weight at the 5% probability level and the plant fresh and dry weight, number of seeds per spike, seed yield per plant and hectare, and percentage of protein, nitrogen, phosphorus, and potassium per seeds at the 1% probability level were significantly affected by the fertilizer treatments in flixweed. In coriander, the plant height, leaves and stems fresh yield, number of seeds per umbel and plant, biological and economic yield, and percentage and essential oil yield were significantly affected by the fertilizer treatments at the 1% probability level, too. In flixweed, the organic fertilizer, bioazospir, mycorrhiza, and chemical fertilizer caused the highest amount of studied traits, respectively and the control treatment caused the lowest one. In coriander, the mycorrhizal fertilizer, organic fertilizer, bioazospir, and chemical fertilizer resulted in the highest amount of studied traits, respectively and the control treatment caused the lowest one. Also, both medicinal plants showed much better performance in the combined cultivation with the cherry tree. Among the various combinations in the cultivation, the combined cultivation of coriander with cherry tree was selected as the best one.