Application Of Controlled-Release Fertilizer On Strawberry (Fragaria Ananassa Duch.) In Greenhouse

Aiming at the problems: low use efficiency of ordinary fertilizer, waste of resources, environmental pollution and poor product quality and so on, in this experimentation, we studied the effects of controlled-release mixing fertilizer on growth, physiology process, yield of strawberry and the contents of N, P, K in soil compared to ordinary fertilizer used strawberry as materials in the greenhouse of Shandong Agricultural University from the year of 2007 to 2008. The objective of our study is to provide a scientific basis for constituting and optimizing the use scheme of controlled-release fertilizer in strawberry cultivation and afford technical support for the popularization and application of controlled-release fertilizer in strawberry cultivation in greenhouse. The main results are as follows:1. The growth indicators of strawberry increased significantly under the treatments of equivalent controlled-release fertilizers(T3) and 25% decrement of controlled-release mixing fertilizers (T4), and was higher than that under treatments of chemical fertilizer(T2) and blank treatment (no fertilizing, T1). Thereinto, the leaf number, the leaf area, the petiole length, the inflorescence number and the inflorescence length are significantly larger under T3 than under T2, respectively, increasing by 5.8%,5.9%,8.6%,10.5%和17.1%. The growth indicators above are also significantly larger under T4 than under T2, increasing by 2.3%, 5.5%, 5.8%, 3.9%, 12.9% respectively. The growth of strawberry had no significant difference with the treatments of 50% decrement of controlled-release fertilizers (T5) compared with treatments of chemical fertilizer (T2). The root-shoot ratio heightened significantly with the use of controlled-release mixing fertilizers. Compared with T1 control , the root-shoot ratio under T2, T3, T4, T5 treatment increased by 12.1%,20.9%,14.2%,8.7% respectively, root-shoot ratio are significantly larger under T3,T4, than under T2. 2. Under the treatments of controlled-release fertilizers, the net photosynthetic rate increased significantly compared with the use of chemical fertilizer(T2). .The content of total chlorophyll enhanced significantly under the treatments of controlled-release and chemical fertilizers compared to T1, and the former was higher, and compared with T2, T3,T4 and T5 increased by 9.3%, 5.8%, 2.5%, respectively. The root absorption area, the rate of absorbing area and ratio of surface area were significantly higher under the treatments of fertilizers than that of T1. Thereinto, that of T3 was highest, root absorption area, the rate of absorbing area and ratio of surface area, was 1.185m2,34.1%,0.420,respectively, and compared with T2 increased by 39.25%, 9.29%, 25.75%. In the whole, There were no significant difference among T2, T4 and T5, besides, T1 was smallest, T3 was highest. The root growth of strawberry were increased significantly under the treatments of equivalent controlled-release fertilizers (T3). This shows that the T3 treatment was more conducive to the growth of strawberry roots.3. The apply of different amount of coated controlled-release fertilizers improved the fruit quality of strawberry Compared with T2, the content of Vc in fruit under T3, T4 and T5 increased by 8.0%, 14.1% and 2.7%, respectively. Meanwhile, the soluble sugar increased by 20.2%, 15.4% and 14.55,respectively. All of CRF treatments makes nitrate and titratable acid The contents of nitrate and titratable acid decreased significantly under treatments of coated controlled-release fertilizers, in which titratable acid content under T3 was minimum, lower 19.4% than T2 and nitrate content under T4 was minimum ,lower 6.4% than T2. The yield under T3 and T4 were higher by 12.8% and 6.4% than T2, and that of T5 is slightly lower than the output of T2, but no significant difference.4. With the treatments of controlled-release fertilizers, the content of available nitrogen, available phosphorus , available potassium were improved significantly than treatments of chemical fertilizer(T2) and blank treatment (no fertilizing, T1), it was beneficial to the growth of strawberry. The relative fertilizer use efficiency (RFUE) under all CRF treatments were higher than that under T2. Under T3, T4 and T5 treatment, RFUE increased by 12.8%, 41.9% and 98.2%, respectively. In conclusion, the project of employing 75% CRF quantity (T4) is optimal.