Soil physical characteristics and chickpea yield responses to tillage treatments

In the semi-arid areas of Iran, dryland crop production is limited by insufficient and inadequate rainfall distribution. Conventional tillage (moldboard plowing followed by disc harrowing) method used by farmers results in soil degradation and increases soil erosion. Reduced tillage has been proposed as a promising strategy to improve soil physical properties, increase soil profile water storage and crop yield in these areas. A field experiment was conducted to determine the feasibility of reduced tillage in a silty clay loam soil (Typic Xerorthens), with an average of 490 mm annual rainfall. This study compared the effects of three tillage systems, viz. moldboard plow (MP) followed by disc harrowing, single point chisel plow (CP), and sweep point chisel plow (SCP) on chickpea (Cicer arientinum L.) growth, and yield and soil physical properties of a fine-textured soil. The site had been under continuous wheat with MP for more than 20 years. A significant difference was found in dry bulk density between tillage treatments within the 0-20 cm depth range, soil water content within the top 1 m of soil profile, aggregate stability and chickpea biomass. Mean weight diameter (MWD) of soil aggregates in CP after harvesting was highest (1.6 mm) compared to other tillage treatments. Soil profile water storage in CP was greatest and MP was the lowest. The highest and lowest chickpea grain yield was found in CP (620 kg ha^(-1)) and MP (541 kg ha^(-1)), respectively. CP also resulted in the highest biomass (1308 kg ha^(-1)) compared to two other tillage treatments. Overall, chisel plow was the most effective tillage tools for improving topsoil physical properties and increasing chickpea dry matter and grain yield compared to other tillage tools evaluated.