Study On Effects Of Enhanced Ammonium Nutrition And Fertilization Technology Of Strawberry

"Guinugan" strawberry was used to study the effects of enhanced ammonium nutrition in pot culture and field condition,some methods of enhanced ammonium nutrition that used in production were studied.The result as follows:1.The nitrogen utilization rate of NH₄⁺—N was 2 times higher than NO₃^-—N in water culture conditions;when NO₃^-—N and NH₄⁺—N were applied together the nitrogen utilization rate was higher than NO₃^-—N and NH₄⁺—N applied singled.Fruit competitive ability of N source was lower than leaf organ when Ca(NO₃)₂ as the only source of N.When (NH₄)₂SO₄ as the only source of N,fruit competitive ability of N source was higher than that of leaf organ.2.At enhanced ammonium nutrition condition strawberry got the best nutrition growth,both root and shoot grow better than at one form of nitrogen condition.It grow better at only NH₄⁺—N condition than at only NO₃^-—N condition.Photosynthesis rate increased when it was at enhanced ammonium nutrition condition at greenhouse.The leaf's NR activity was higher than root's,leaf was the most important site to reduce NO₃^-—N.At only NH₄⁺—N condition NR activity was restrained and at enhanced ammonium nutrition condition it was increased.In the greenhouse condition the treatment of NO₃^-—N/NH₄⁺—N ratio as 2:5 got the highest yield.3.In short time,ammonium form of N increased soil NH₄⁺—N but in long time the effect was limited at greenhouse condition.Ammonium form of nitrogen fertilizer pocked in controlled release bag increased soil NH₄⁺—N significantly and kept it steadily and permanently.Ammonium form of nitrogen application with humus increased soil NO₃^-—N,not NH₄⁺—N. Humus increased fertilizer capacity and kept fertilizer capacity steadily and permanently.4.At greenhouse condition bag controlled-released fertilizer treatment has the highest yield and it pre-period yield lower than post-period.Spread application with humus got the next yield.It has higher post-yield than pre-yield when fertilizer spread application,but it yield lower than bag controlled-released fertilizer treatment significantly.