施氮量和种植密度对川西平原区直播粳稻产量和氮肥利用的影响

Effects of Nitrogen Application Rate and Planting Density on Grain Yield and Nitrogen Fertilizer Utilization of Direct-seeded Japonica Rice in West Sichuan Plain Area

为研究施氮量和种植密度对川西平原区粳稻产量及氮肥利用的影响,以德粳3号为材料,采用裂区试验设计,主区因素为4种施氮量,即N180—纯氮用量为180 kg·hm^(-2),N210—纯氮用量为210 kg·hm^(-2),N240—纯氮用量为240 kg·hm^(-2)和N0—纯氮用量为0 kg·hm^(-2);副区因素为种植密度,即行距×株距为25 cm×20 cm、25 cm×16 cm和25 cm×12 cm,分别记为D20、D16和D12;测定水稻齐穗期叶面积指数、SPAD值和净光合速率,齐穗期和成熟期干物质积累量,成熟期产量及产量构成因素指标。结果表明,与N180处理相比,N210和N240处理有效穗数分别增加4. 14%和12. 84%,产量分别提高8. 42%和10. 05%。施氮量从180 kg·hm^(-2)增加至240 kg·hm^(-2),齐穗期和成熟期干物质积累量逐渐增加,而水稻氮肥偏生产力均逐渐降低。N180和N210处理中,增加种植密度可以明显提高成熟期有效穗数和干物质积累量、籽粒产量和氮肥偏生产力。可见,川西平原粳稻种植推荐施氮量为180～210 kg·hm^(-2),种植密度为25 cm×(12～16) cm。

In this study a field experiment was conducted to investigate the effects of nitrogen application rate and planting density on grain yield and nitrogen fertilizer utilization of direct-seeded japonica ice in West Sichuan Plain Area. In the N240 and N0, resexperiment, a split-plot design was set with nitrogen application rate (180 kg·hm ^-2 , 210 kg·hm ^-2 , 400 kg·hm^-2 and 0 kg·hm -2 , denoted by N180, N210,pectively) as the main factor, planting density (25 cm ×20 cm, 25 cm × 16 cm and 25 cm × 12 cm, denoted by D20, D16, and D12, respectively) as the sub-plot factor. Leaf area index, SPAD value and net photosynthetic rate at full heading stage, dry matter accumulation at full heading stage and mature stage, yield and yield components of direct-seeded rice were measured. The results showed that the effective panicles in N210 and N240 increased by 4.14% and 12.84% respectively, and grain yield increased by 8.42% and 10.05% respectively, compared with N180. The dry matter accumulation at heading and maturity stages increased gradually, and nitrogen partial productivity decreased gradually with nitrogen rate from 180 kg·hm -2 to 240 kg·hm ^-2 . In N180 and N210 treatments, increasing planting density could significantly increase the number of effective panicles, dry matter accumulation, grain yield and nitrogen fertilizer partial productivity. Hence, moderate nitrogen application rate was 180 - 210 kg·hm^-2 and the planting density was 25 cm ×(12-16) cm in direct-seeded Japonica rice in West Sichuan Plain Area.