Study of Soil Characteristics, Yield and Yield Components of Barley (Hordeum vulgare L.) under Different Tillage Methods and the Rate of Crop Residues

The study carried out to measure the impact of different tillage methods and the rate of crop residue on soil characteristics, yield and yield components of barley. Excessive traditional tillage and residue removal practices caused to soil erosion and physical, chemical and biological degradation. As a result, improved or new varieties of crops (such as barley) as well as the use of other inputs are not able to deliver their potential contribution. Recently, many concerned farmers have begun to adopt and adapt improved crop management practices that lead towards the ultimate vision of sustainable farming. The term Conservation Agriculture (CA) removes the emphasis from the tillage component and addresses an enhanced concept of the complete agricultural system; it involves major changes in many aspects of the farm cropping operation. Normally starting CA with reduced or zero tillage, it progresses to the retention of adequate levels of crop residue on the soil surface, then to appropriate crop/cultivar selection and rotations.
This experiment using a split-plot design based on randomized complete block with 3 replications was conducted at agricultural research station of Gonabad during 2012-13 growing seasons. Main factor was 3 tillage methods (conventional tillage (CT), reduced tillage (RT) and no tillage (NT)) allocated to main plots and 3 residue management (Zero (R0), 30% (R1) and 60% (R2) of residue retention) were assigned in sub plots.
Results showed that the highest level of potassium (K) was obtained from (NT) treatment and under this treatment the amounts of pH and EC were decreased. In addition, under residue management treatments the amounts of EC was decreased and the amounts of phosphorus (P) and K were increased. Furthermore, the nutrition use efficiency (NUE) of nitrogen (N), P and K, were higher in NT treatment in comparison with the other tillage treatments. Interaction effects of NT with 0% of residue (R0) had higher level of agronomic efficiency of nitrogen. On the other hand, different tillage methods and the rate of residue management had no significant effects on biological yield (BY), grain yield (GY), and harvest index (HI). The highest and the lowest level of BY were obtained from NT (8500 kg. ha-1) and RT (with 7470 kg. ha-1) treatments, respectively. The highest amount of BY (8398 kg. ha-1) were obtained from retention of 30% residue (R1) and the highest amount of GY (5224 kg. ha-1) from R0 treatment. The highest BY (9122 kg. ha-1) were obtained from NT retention of 60% residue treatment (R2). The highest of GY (3897 kg. ha-1) and harvest index (HI) were related to NT R0 treatments. Finally, change in tillage method from conventional to conservation (no tillage) had no significant effects on yield and yield components of barley. Moreover, increasing of crop residue had positive effect on increasing amount of P and K and decreasing of soil EC.