The effect of different levels of saline, irrigation water depth and Forage harvest time on operation and quality of Forage Sorghum in subsurface drip irrigation

Water and salinity tensions is one of the agricultural products Problems in many parts of the world. The effect of different levels of saline (2, 5, 8ds/m),different levels of irrigation (120, 100, 75 and 50 percent for crop water requirement) and harvest of some qualitative and quantitative parameters of forage Sorghum were studied in the region of Sistan in this research.Testing was conducted in Factorial split-plot designin time by12 treatments and 3 replications in three harvest period. The results showed that the performance of fresh forage is decreased by increasing salinity and irrigation water depth reduction, but significant difference was not observed between full irrigation treatment of 100 and %75 crop water requirement. Also, significant difference was not observed between water treatments with Salinity 2 and 5 dS/ min terms of forage production. The effect of harvest showed that the amount of fresh forage yield in second harvesting is better than the first and the third harvesting.The amount of Cell wall Density free from Cellulose (ADF) of plant decreased by increasing salinity and decreasing irrigation water depth and the amount of Cell wall Density hemicellulose (NDF) and total digestible nutrients increased. Also, the percentage of Plant protein percent decreased and the amount of Carbohydrate and proline increased by increasing salinity and decreasing irrigation water depth. The highest amount of protein (16.79 percent) in the second harvest, Salinity2 dS/m and the highest amount of carbohydrates (10.79 mg per of fresh weight) and proline (42% mg per gram of fresh weight) in the third harvest, with Salinity 8 dS/m was observed. Therefore, according to Results, it can be reduced 25 percent of the sorghum crop water use and can be done irrigation with 75% of water requirement and salinity 5 dS/m. The best harvesting forage was obtained in the second cutting without any significant effect on the amount of forage produced.

Keywords:

Protein , carbohydrate , ADF , NDF , TDN