Studies on Soil Water and Nitrate Distribution under Sprinkler Irrigation Conditions

摘要

Soil water and nutrition distribution is important for plant growth and environment protection. A field experiment was carried out to study the distribution characteristics of soil water and nitrate under sprinkler irrigation and surface irrigation in 2003. Results indicate that the main change of soil water content was within 0.6 m soil layers under sprinkler irrigation where main winter wheat roots distribute. Under surface irrigation, soil water could reach soil layer below the root zone. During the period of winter wheat growth, the concentration peak of soil nitrate appeared above 0.4 m soil layer and moved above 0.6 m under sprinkler irrigation. However, nitrate concentration peak appeared around 0.6 m and could move out root active zone under surface irrigation. The variation of average soil water content in 0～0.6 m layer and variation coefficient of soil water storage in 1.0 m layers under sprinkler irrigation were less than that under surface irrigation. Soil water percolates from root active zone under surface irrigation resulting in nitrate leaching. So, sprinkler irrigation can efficiently control water distribution depth and reduce irrigation water and nitrate percolation as well as control ground water pollution.