Influence of Tillage Method and Residue Retention on Yield and some Agronomic Characteristics of Forage Maize in Water Stress Conditions

Minimal soil movement and retention of rational amounts of crop residue in crop rotation are the principles of conservation agriculture system. In order to study the effects of tillage method and residue retention on yield, yield components and water use efficiency of forage maize and some soil chemical characteristics in water stress conditions, this experiment conducted in Jolg-e-Rokh research station (Torbat-e-Heydarye, Razavi Khorasan Province) in 2015. Used farm, has been managed under the conservation agriculture system from 2012 (with similar treatments of this experiment and fixed plots in wheat-clover-beet-barley crop rotation). The experiment was conducted as split split plot in randomized complete block design with three replications. Treatments were Tillage method (no tillage, minimum tillage and conventional tillage), residue retention rate (0, 30 and 60 percent) and water stress (50, 75 and 100 percent of irrigation water). Results showed that various tillage methods were significantly effective on yield, and minimum tillage in compare with conventional tillage, increased forage yield over %6. Residue retention treatment did not have significant effects on yield and another studied characteristic but water stress treatment had significant effects on forage yield, forage quality index, stem diameter, water use efficiency and tasseling period. Applying minimum tillage with %60 residue retention with 41180 kg.ha-1 forage yield and 7.2 kg.m-3water use efficiency, was a good solution in comparison with other methods.