Rice Slow / Controlled Release Fertilizers And Application Technique

This experiment was conducted in paddy fields with three different fertility levels (high, medium and low) at Xinyang Agricultural Research Institute in 2009. Six fertilizer application methods including common way used by local farmer, slow/controlled release fertilizer single application and split application.The tested variety was pearl glutinous. Effects of using slow/controlled release fertilizer on the rice growth and development, the dry weight production, the SPAD of rice leaf color, N, P and K content and accumulative absorption of rice plants, mainly agronomy properties and yields as well as the nitrogen efficiency in the current season were studied. The main results were summarized as follows:1. Effect of slow/controlled release fertilizer on the rice growth and development: Compared with common compound fertilizer, using slow/controlled release fertilizer prolonged the rice growth period, but there was no significant difference between supplying slow/controlled release single application and split application. Using common compound fertilizer, the nutrient release rate was higher in the early and slower at the end of tillering stage. So, the tillering of rice was faster at start and slower later. However, slow/controlled release fertilizer offered constant nutrients during all stages, smoothed the tillering in rice and effectively inproved the rice group quality.2. Effect of slow/controlled release fertilizer on dry weight production: Before active tillering stage, the dry weight production of utilizing common compound fertilizer was higher than slow/controlled release fertilizer, but after active tillering stage, it was reverse. At harvest stage, in high fertility field, the dry matter accumulation of the treatment using slow/controlled release fertilizer was increased by 13.0% to 16.2% compared with CK, and 3.2% to 6.1% compared with the common compound fertilizer treatment, respectively. In the medium field, slow/controlled release fertilizer and CK increased by 26.1% to 31.1%, and 2.1% to 6.1% compared with the treat common compound fertilizer, respectively. In the low fertility land, slow/controlled release fertilizer and CK increased by 37.2% to 42.4%, and 4.5% to 8.5% compared with the treat common compound fertilizer, respectively. There was no significant difference between applying of slow/controlled release fertilizer once before sowing and several times during growth.3. Effect of slow/controlled release fertilizer on SPAD of leaf color: In the high fertility field, there was no difference of SPAD among all treatments in rice grain filling stage. In the medium and low fertility fields, the SPAD of four treatments using the slow/controlled release fertilizer was higher that common compound and no nitrogen fertilizers. There was no significant difference on SPAD between supplying slow/controlled release fertilizer under single application and split application. Compared with common compound fertilizer, using the slow/controlled release fertilizer increased the conten of chlorophyll in rice leaves at middle and late growth phase, especially in the grain filling stage.4. Effect of slow/controlled release fertilizer on the N,P,K content and accumulative absorption of rice plant: In all tested lands, the content of N,P,K of all treatments were reached to the highest point at active tillering stage. Among all the treatments, the N,P,K content of common compound fertilizer treatments was the highest before active tillering stage. However, the N,P,K content of slow/controlled release fertilizer treatments were higher than the CK and common compound fertilizer treatments in the middle and late growth phase. The accumulative sbsorption amount of N,P,K of slow/controlled release fertilizer treatments were higher than common compound fertilizer treatments before the active tillering stage, but not after. At harvest stage and in the high fertility field, the accumulative absorption amount of N per hm2 under slow/controlled release fertilizer treatments and common compound fertilizer treatments increased by 24.9 to 39.2 Kg, the accumulative absorption amount of P was increased by 4.1 to 10.7 Kg, and that of K was increased by 16.3 to 26.3 Kg. In the medium field, the accumulative absorption amount of N per hm2 under slow/controlled release fertilizer treatments was 31.2 to 37.7 Kg higher than common compound fertilizer treatments. The accumulative absorption amount of P was increased by 3.6 to 11.3Kg, and that of K was increased by 27.4 to 38.1 Kg. In the low fertility field, the accumulative absorption amount of N per hm2 under slow/controlled release fertilizer treatments was 27.9 to 34.3 Kg higher than common compound fertilizer treatments. The accumulative absorption amount of P was increased by 1.1 to 7.9 Kg, and that of K was increased by 36.5 to 52.1 Kg.5. Effect of slow/controlled release fertilizer on yield: The yield of slow/controlled release fertilizer treatments and common compound fertilizer treatments increased by 2.8% to 5.8% in the high fertility field, 5.5% to 11.1% in the medium fertility field, and 4.6% to 8.0% in the low fertility field. The slow/controlled release fertilizer under single application compared with split application, the yield of split application were higher than single application treatment in the high fertility field, but not in the medium and low fertility field.6. The effect of slow/controlled release fertilizer on mainly agronomy properties: In all tested land, slow/controlled release fertilizer obviously increased panicles and setting grains per panicle. There was little influence on 1000-grains weight. The slow/controlled release fertilizer treatments also improved the ratio of grains to the straw. Using slow/controlled release fertilizer under single application compared with split application, panicles of the latter were higher in the high fertility field, but not in the medium and low fertility land. The setting grains per panicle of slow/controlled release fertilizer under single application were obviously higher than split application in all the tested fields.7. The effect of slow/controlled release fertilizer on nitrogen recovery: The nitrogen recovery of slow/controlled release fertilizer treatments compared with common compound fertilizer treatments are displayed as follows: the medium fertility field> the low fertility field> the high fertility field. In all tested lands, Nitrogen agricultural utilization efficiency of slow/controlled release fertilizer treatment were all higher than equivalent nitrogen of common compound fertilizer treatments. The results are shown as follows: the low fertility field> the medium fertility field> the high fertility field.