Effect of deficit irrigation on yield and yield components of sunflower on Gezira clay soil, Sudan

Abstract

Sunflower has become an important crop for both farmers and consumers in Sudan. It is a crop that fits well in the local cropping system and is considered to be the second most important oil crop after groundnut of the country. Regular irrigation intervals could be reduced in order to increase total yield and maximize water productivity. In contrast prolonged irrigation during sensitive growth stages may result in reduction in total yield. The application of water below the evapotranspiration requirements is termed deficit irrigation (DI).The objective of this research is to study the effect of deficit irrigation on yield and yield components of Sunflower (Hysun-33) hybrid. The experiment was conducted at Gezira Research Station, WadMedani, Sudan, in a randomized complete block design with three replications. In this study irrigation intervals every week (W) during all the season, 10 days interval (F1), 15 days interval (F2) and 20 days interval (F3) after flowering stage and 10 days interval (S1), 15 days interval (S2) and 20 days interval (S3) after seed formation stage – were applied to study the effect of full and deficit irrigation on yield and yield components of sunflower crop during the winter season 2011–2012. Results showed that water stress decreased the number of full seeds per head, weight of full seed and seed yield. The highest seed yield of 2810 kg ha-1 was obtained from normal irrigation (W) and lowest of 1880 kg ha-1 from irrigation every 20 days (S3). Results also indicated that there were no significant differences of water deficit on head diameter, plant height and stem diameter. Seasonal crop water applied measured were 17000, 17400, 16300, 16500, 16956, 17042, and 15655 m3 / ha for W, F1, F2, F3, S1, S2 and S3 respectively. Apart from S3, the difference between the highest (17400) and the lowest (16300) is about 6%. However, water productivity showed large differences from the highest 0.17 of W1 and the lowest 0.12 of S3. The small difference in water applied in 13 irrigations and 11 irrigations is due to the unique characteristics of Gezira clay, no deep percolation and evaporation from cracks.