Effect of different tillage on soil properties and wheat yield in saline condition of temperate region of Fars province.

Selecting an appropriate tillage system in saline soil condition has a significant effect on crop production. This project aimed to evaluate the effects of different tillage and planting methods on wheat yield and soil physical and chemical properties in saline condition. The study was conducted in the form of a split block experimental design with six treatments and three replications for three years. The main plots included 1) pre-tillage irrigation (irrigating the plots before tillage operation) and 2) without pre-tillage irrigation (no irrigation before tillage operation) and subplots were including 1) conventional tillage, 2) reduced tillage, and 3) no-tillage. Soil moisture, changes in soil salinity, the coefficient of soil saturated hydraulic conductivity, soil bulk density, percent of organic carbon, fuel consumption, effective field capacity, water use efficiency, and wheat yield were measured in this research. Results showed that difference between the tillage methods was significant from the soil moisture point of view in samples taken 60 days after planting; while, this difference was not significant for the samples taken 120 days after planting. Significant difference was not observed between tillage treatments in term of organic carbon. No-till method had 8.7% higher soil bulk density compared to the conventional method, and reduced tillage had the lowest amount of soil bulk density. Pre-tillage irrigation practice reduced soil salinity in all the tillage methods. Tillage method had a significant effect on the soil salt amount and salt distribution in the soil profile. Soil salinity increased with soil depth in no-till method so that the soil surface had the least salinity. In contrast, there was no difference between soil layers form salinity point of view in reduced tillage method. Soil surface had more salinity compared to the deeper layers in the conventional tillage. The minimum water use efficiency was obtained from the no-till system; while, the reduced tillage had the maximum water use efficiency. Pre-tillage irrigation increased the water use efficiency in the conventional tillage and reduced tillage treatments; whereas, it reduced water use efficiency in no-till system. Saturated hydraulic conductivity was higher in the reduced tillage compared to the conventional and no-tillage methods. Pre-tillage irrigation treatment combined with reduced tillage had the highest wheat yield (3164 kg/ha) and combination of no-tillage and pre-tillage irrigation produced the lowest wheat grain yield (2416 kg/ha). The reduced tillage method along with pre-tillage irrigation had the highest benefit to cost ratio and consequently was the most economic treatment in this study. Keywords: Saline water, no-tillage, minimum tillage, conventional tillage, wheat