Abstract:

Using the slow-release fertilizer as base fertilizer, the influence of different topdressing periods on rice growth characteristics and yield was studied to provide scientific fertilization measures and decision-making basis for rice production in Nansi Lake basin. The rice variety ‘Jirudao 1’ was used as the test material and five different topdressing periods were set up to carry out the tests. The amount of nitrogen fertilizer in the whole growth stage was 264 kg/hm², the topdressing of nitrogen fertilizer was 69 kg/hm², and the phosphate fertilizer and potassium fertilizer were applied at one time. The stem tiller dynamics, leaf SPAD value, leaf area and dry matter, yield and yield structure data were determined at different growth stages. The results showed that with the topdressing period, rice yield tended to increase first and then decrease and the yield order was T₄>T₅>T₃>T₁>T₂. Before heading, especially during the booting stage, the tillers of T₁, T₂ and T₃ were higher than that of T₄ and T₅. After heading tillers decreased rapidly in T₁, T₂ and T₃, but kept steadily in T₄ and T₅. Finally T₄ had the highest number of tillers, followed by T₅. At heading stage, T₁, T₂, and T₃ had higher leaf area index than that of T₄ and T₅, but at mature stage the order of leaf area index was T₅>T₄>T₃>T₂>T₁. At the booting stage T₁ and T₃ were higher, followed by T₂ and T₅, and T₄ was the lowest. At the mature period T₄ and T₅ were significantly higher than that of T₁ and T₂, and not much different from T₃. Between treatments, the SPAD values varied less in the jointing and filling and more in maturity. At maturity stage, the value of SPAD in T₄ and T₅ decreased slowly. Under the premise of slow-release fertilizer as base fertilizer with side deep application, the effect of applying ear fertilizer was better than that of applying tiller fertilizer. The effect was better to pursue tiller fertilizer later, but better to pursue ear fertilizer earlier.

Key words: rice, topdressing, growth characteristic, yield, dry matter accumulation