Effect Of Fertigation With Nitrogen On Soil Solution, Leaf Nutrition And Fruit Quality At Apple Orchards In Shaanxi Province

The experiments of effect of six different fertigation treatments with nitrogen on growth, nutrition content of soil solution, leaf nutrition, yield and fruit quality were conducted in nine-year-old apple trees in Fengxiang orchard, Shaanxi province from April in 2006 to November in 2007. The optimal fertigation was analyzed; the main results were as follows:1,Leaf photosynthesis, nitrate contents and chlorophyll contents were enhanced significantly with different nitrogen fertigation treatment, which reached to maximum and were 166.33%, 149.95%, 107.85% of the control respectively when fertigation with 320g nitrogen per tree were applied.2,Leaf weight and thickness were increased significantly with different fertigation treatments, which were 124.66% and 118.99% of the control when fertigation with 1200g nitrogen per tree were applied. Leaf nitrate reductase reached to maximum which were 157.32% of the control when fertigation with 640g nitrogen per tree were applied.3,Leaf N content was increased significantly, Mn, Mg, Fe, Cu, Ca were also increased with the increasing of the amount of application N.4,Fertigation had relatively large effect on the nitrate contents of soil solution in different soil layers, but had less effect on ammonium nitrogen. NO3--N leached was serious relatively, especially nitrate contents was 2.57 times compared with the control in 80cm soil layer when fertigation with 1200g nitrogen per tree were applied. With the increasing of the amount of application N. therefore NO3--N leached of all soil layers were increased with the increasement of the amount of application N.5,Fertigation had relatively large effect on the yield and fruit quality, the yield was increased significantly with the increasement of the amount of application N of fertigation, High yield would be reached when more than 320g nitrogen per tree were applied. Surface blush and soluble solids content were decreased, while titratable acidity was increased with the increasing of the amount of application N.6,It will be beneficial to enhance tree vigor,increase leaf nutrition, improve fruit quality, and decrease soil NO3--N leached when 320-640g nitrogen per tree were applied, which were the reasonable fertigation criterion for high quality and yield apple production in Shaanxi Weibei orchards.