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Aims: The main aim of this study was to determine the effects of residue management methods on the soil properties and crop yield in corn-wheat cropping system during four years research, and to introduce a proper residue management method for corn-wheat rotation in Fars province, Iran.
Study Design: The research was conducted in the form of a split-plot experimental design with three replications. Main-plots were wheat residue management with four levels, and corn residue with two levels was considered as subplots.
Place and Duration of Study: This study was conducted in Darab Research Station of Fars province, Iran from September 2005 to September 2009.
Methodology: This research was conducted in the form of a split plot experiment with the base of randomized complete block design (RCBD) with three replications in Darab Research Station of Fars province, Iran. Main-plots were wheat residue management methods including 1) shredding the residue using shredder and tilling the soil with moldboard plow (25 cm) and disk harrow; 2) shredding the residue using shredder and tilling the soil with chisel plow and rotivator; 3) retaining the crop residue on the soil surface without any tillage operation (no-till); and 4) burning the residue and tilling the soil with moldboard plow (25 cm) and disk harrow. Corn residue management methods including 1) stalk shredding using stalk shredder, burying the chopped stalk using moldboard plow (25 cm), and applying disk harrow; 2) burning residue (conventional method) were considered as sub-plots. Parameters consisting of bulk density, soil cone index, soil organic carbon, percentage of seed emergence, and crop yield were measured. Collected data were analyzed using SAS statistical software and Duncan's multiple range tests was used to compare the treatments means.
Results: Results indicated that shredding the residue by shredder and incorporation with soil decreased the soil bulk density and soil cone index. There was a significant difference between the burying crop residue and retaining the residue on the soil surface from the view point of soil bulk density and soil cone index. The percentage of seeds emerged, emergence rate index, and yield in shredding the residue by shredder along with applying chisel plow and rotivator had the highest amount because of the uniformity of residue distribution. After four years adding corn and wheat residue into the soil, the soil organic carbon increased for 13% and 10% in the residue management treatments and burning residue method, respectively.
Conclusion: The following conclusions could be drawn from the results of this study:
- Adding shredded crop (corn and wheat) residue to the soil increased the soil organic carbon.
- Soil bulk density and cone index (soil compaction) decreased by incorporating the chopped crop residue to the soil.
Adding chopped corn and wheat residue to the soil improved corn and wheat seed emergence and yield.