Performance Evaluation of Long-Term Saline Water Application on Yield of Wheat Crop Using The SWAP Model

Lack of water and deterioration in the quality of soil and water resources are considered to be the prime cause of reduction in crop yield at northern regions of Golestan province of Iran. Present study was undertaken to investigate the response of wheat, under varying water quantity and quantity situations for a period of two years (2000-2002) and SWAP model was used for long term prediction of soil quality and corresponding crop yield. A field experiment with completely randomized block deisgn (RCBD) and three replications were undertaken having four levels of irrigation water i.e. 50 (W1), 75 (W2), 100 (W3) and 125 (W4) percent of the crop water requirement and four levels of irrigation water salinity with average 1.5 (S1), 8.5 (S2), 11.5 (S3) and 14.2 (S4) dS/m. The results indicated a reduction in wheat yield by 9% with 25% lowering of crop water requirement(W2), where as the yield reduction was about 10% with the application of saline water with 14ds/m salinity. It was revealed that of the use of saline water increased soil salinity during wheat harvest, but due to the autumn rainfall the salinity level got reduced at the initial growth of wheat in the next season. However, results from long-term application of saline water using the SWAP model showed that with the treatment of high salinity levels i.e. (S4), the natural desalinization process through leaching due to autumn rain will not be sufficient to bring the salinity to moderate level for the next season. As a result, after four years, solute leaching through non-saline water is necessary to bring the field amenable for sustainable wheat yiled.

کلیدواژه ها:

Saline water ، Deficit Irrigation ، SWAP model ، wheat ، Golestan Province