The Effects of Different Tillage Systems and Fertilizer Resources on the Growth, Yield Component and Economic Efficiency of Chickpea (Cicer arietinum L.) under Rainfed Condition

Conventional tillage can reduce infiltration and hydraulic conductivity by disrupting macrospore networks and increasing bulk density, porosity, water use efficiency, and soil organic matter. Conservation tillage is one of the practices of crop residue management on the soil surface. Reduced tillage is one of the conservation systems that amount remain crop residues on the soil surface. Reduced tillage has some benefits, including higher soil organic matter, soil moisture maintenance by reducing evaporation, better penetration of water, and controlling water and soil erosion. Excessive use of chemical fertilizers caused serious environmental issues globally, such as reduction of plant diversity, instability of economic yield, increased pest, and disease damages, and intensification of soil erosion. These increasing concerns regarding the negative impacts of these systems on the environment and human health suggest that more effort is needed to develop sustainable agricultural systems. The application of vermicompost and biofertilizers is regarded as one of the promising approaches to increasing crop productivity. Chickpea (Cicer arietinum L.) is mainly cultivated as a rainfed crop, and water stress often affects both productivity and yield stability. The objective of this experiment was to evaluate the impact of different tillage systems and the application of vermicompost and arbuscular mycorrhizal fungi on the growth, yield, and economic efficiency production of Cicer arietinum L.

A field experiment was carried out as a split plot based on a randomized complete block design (RCBD) with 12 treatments and three replications at Firuzabad, Kermanshah, Iran, in 2019. The main factor was different tillage systems, including conventional tillage (moldboard plowing+ disking, tillage depth 25–30 cm- CT), reduced tillage (chisel plowing- tillage depth 15 cm- RT), and no-tillage (NT), and the sub factor was four different fertilization treatments (C: control, AMF: arbuscular mycorrhizal fungi (Funneliformis mosseae), VC: vermicompost (at 1.5 t/ha), AMF+ VC: arbuscular mycorrhizal fungi+ vermicompost). In AM fungi treatments, 80 g of the soil containing mycorrhizal fungi hyphae and the remains of the root and spores (1000 g spore.10-1 g soil) was added to the soil during planting times. Also, vermicompost (1.5 t ha-1) was applied to the soil before planting.

The Results demonstrated that the highest seed yield (116 g.m-2) and protein yield (24.2 g.m-2) was achieved in reduced tillage with the application of AMF+ VC. Also, reduced tillage increased the seed yield and protein yield by 19.6 and 17.1 %, respectively, when compared with CT. Different tillage systems and applications of vermicompost and arbuscular mycorrhizal fungi significantly impacted the number of pods per plant, plant height, number of lateral branches per plant, number of main branches per plant, and biological yield. The highest mentioned traits were obtained in reduced tillage and with the integrative application of AMF+ VC. Moreover, the application of AMF+ VC increased the number of pods per plant, plant height, and biological yield by 37.2, 35.2 and 19.7%, respectively, in comparison to control. The highest pod total weight (155.8 g.m-2), harvest index (40.5%), and seed protein content (21.2%) were obtained through integrative application of AMF+ VC, and the lowest these traits were reached in control. Based on the economic values, the best treatments were RT+ C, CT+ C, AMF+ RT, and AMF+ CT, respectively, with the highest net income and Marginal rate of return.

Overall, the results of this experiment showed that there was a significant difference between tillage systems. The highest number of pods per plant,  plant height, number of lateral branches per plant, number of main branches per plant, biological yield, total pod weight, seed yield, and protein yield were achieved in reduced tillage that increased by 26.4, 16.8, 27.4, 28.6, 10.9 19.6 and 17.1 %, respectively when compared with conventional tillage.  Also, integrative application of AMF+ VC increased harvest index, 100 seed weight, biological yield, seed yield, and seed protein content by 16.7, 21.1, 19.7, 40.1, and 21.8%, respectively, when compared with control. The highest values of the seed yield and protein yield were obtained in reduced tillage with the integrative application of AMF+ VC. In contrast, based on the economic values, the maximum marginal rate of return was achieved in reduced tillage without fertilizer, conventional tillage without fertilizer, reduced tillage+ AMF, and conventional tillage+ AMF, respectively.