Water–fertilizer coupling effect on the growth traits of winter wheat under conditions of light and small sprinklers

Light and small sprinklers were used to irrigate winter wheat fields. The distribution and migration of water and nitrogen in soil during winter wheat growth period were analyzed. Moreover, the growth traits of winter wheat were monitored. It is demonstrated that water–fertilizer coupling effect had a significant impact on the migration of water and nitrogen in soil and the growth traits of winter wheat under conditions of light and small sprinklers. Under the same condition of irrigation quota, although the content of moisture in soil was slightly reduced with the increase of the amount of fertilizer, the impact of the amount of fertilizer on the content of moisture in soil is much more insignificant than that of irrigation quota. The content of nitrate nitrogen (NO 3 --N) in soil was increased with an increasing amount of fertilizer, especially when the value of irrigation quota was low. On the other hand, under the same condition of amount of fertilizer, the content of nitrate nitrogen (NO 3 --N) in soil was decreased with an increasing value of irrigation quota, especially when the value of irrigation quota was high. Hence, an ultra-high value of irrigation quota will aggravate the leach of nitrate nitrogen in soil. The water–fertilizer coupling effect and yield of winter wheat could be optimized by improving irrigation scheme, optimizing irrigation quota, and optimizing the amount of fertilizer.