Effects of irrigated field border length on grain yield and water use characteristics of winter wheat

Winter wheat is a high water consumption crop. As the main production area of winter wheat, Hebei Province also is one of the most serious water scarcity provinces in China. With further restriction of groundwater exploitation, it becomes more important to explore efficient water use technologies in the agricultural production. Surface irrigation is an old method which is being widely adopted in China. In Hebei Plain, most of the fields were irrigated using the ground furrow method. Border length in the furrow irrigation was about 10 m while border width was 5–6 m and there was water furrow about 5–6 m width. Under this irrigation system, the total area of water channel was 5%–10% of field area. By surface irrigation, there has been a significant difference in soil water content in different sections of a border. At the headwater of the border, there were water and fertilizer leakages, while at the border trail, the water and fertilizer were deficiency. It was important to study proper border length under restricted groundwater exploitation and water-saving agriculture. However, the effect of irrigated field border length on grain yield and water use characteristics of winter wheat was less reported up to now. In this study, winter wheat cultivar ‘Kenong2011’ was used in five border lengths 4 m, 5 m, 10 m (conventional length), 50 m and 100 m to determine the effect of border length on water use characteristics in 20142015 growing season in Luancheng Agro-Ecosystem Experimental Station of Chinese Academy of Sciences. All the treatments had the same border width of 5 m and were irrigated at jointing and grain-filling stages. Water was supplied by a jet pump, directed to headwater of the border through plastic pipes. A water meter was used to measure the amount of water applied and a stopwatch used to measure required irrigation time. Water consumption potential, required irrigation time, irrigation requirement, soil water contents in different border sections, yield and water use efficiency of winter wheat were analyzed under different border lengths conditions. The results showed that the irrigation amount, water consumption, proportion of irrigation amount to total water consumption and grain yield all increased with increasing border length from 4 m to 100 m. The differences in grain yield among different treatments were not significant. With increasing border length, soil water consumption, water use efficiency at grain yield level and irrigation water use efficiency decreased significantly. Compared with farm border length of 10 m, irrigation amount and total water consumption in border length of 4 m reduced by 34.50% and 1.61%, respectively. Soil water consumption of border length of 4 m increased 58.92 mm. Water use efficiency at grain yield level and irrigation water use efficiency at border length of 4 m increased by 1.15% and 51.96%, respectively. Required irrigation time at border length of 4 m decreased by 42.75%. On the other hand, between border lengths of 10 m and 100 m there was no significant difference in grain yield. Irrigation amount and total water consumption in border length of 100 m increased by 38.08% and 9.58%, respectively, over those of border length of 10 m. Water use efficiency at grain yield level and irrigation water use efficiency in border length of 100 m decreased by 9.88% and 26.20%, respectively, while the required irrigation time increased by 65.61%. Based on grain yield, irrigation amount, water use efficiency at yield level and irrigation water use efficiency, border length of 4 m was recommended as the best field border length for water-saving and high-yield agriculture in the study.