氮肥运筹对南方优质常规晚粳产量和品质的影响

Effects of Nitrogen Application on Yield and Quality of High-quality Conventional Late Japonica Rice in South China

为探明南方双季稻区优质常规粳稻金农香粳1267的适宜氮肥运筹模式,设置6个施氮水平(CK,0;N1,165 kg/hm^2;N_2,210 kg/hm^2;N_3,255 kg/hm^2;N_4,300 kg/hm^2;N_5,345 kg/hm^2),并在N_3水平下设置3个氮肥运筹方式(NT_1,基蘖穗肥比例为4∶2∶4,穗肥于倒3叶施用;NT_2,基蘖穗肥比例为4∶2∶4,穗肥于倒4叶、倒2叶分2次等量施用;NT_3,基蘖穗粒肥比例为4∶2∶2∶2,穗肥于倒3叶施用),研究不同氮肥运筹模式对南方优质常规晚粳稻产量和品质的影响。结果表明,随施氮量的增加,产量呈先增后降的趋势,与N_3处理相比,CK、N_1、N_2、N_4和N_5处理产量分别降低37.1%、8.2%、5.7%、4.9%和10.0%,晚粳稻产量增加的主要原因是每穗粒数和千粒重的提高;在N_3水平下,NT_3处理产量最高,主要是由于每穗粒数的提高。随着施氮量的增加,晚粳稻的加工品质、外观品质、蒸煮与食味品质和营养品质得到改善;在N_3水平下,出糙率、精米率、整精米率、垩白粒率、垩白度和胶稠度均表现为NT_1>NT_2> NT_3,而直链淀粉含量和粗蛋白含量则反之。随施氮量的增加,RVA谱特征值中峰值粘度、热浆粘度、冷胶粘度、崩解值和峰值时间均降低,而消减值、回复值和糊化温度呈增加的趋势;在N_3水平下,峰值粘度、热浆粘度、冷胶粘度、崩解值和峰值时间均表现为NT_1<NT_2<NT_3,而消减值、回复值和糊化温度则反之。综上所述,在本试验条件下,南方优质常规晚粳稻以施氮量为N_3(255 kg/hm^2)、氮肥运筹为NT_3(基肥∶蘖肥∶穗肥∶粒肥=4∶2∶2∶2)时,能较好实现水稻高产和优质的协调统一。

In order to explore the suitable nitrogen-fertilization model for the high quality conventional late japonica rice Jinnongxianggeng 1267 in southern China, the 6 N levels included CK(0), N1(165 kg/hm2), N2(210 kg/hm2), N3(255 kg/hm2), N4(300 kg/hm2) and N5(345 kg/hm2), 3 N application ratios were applied on different growth stages: NT1: 40% basal, 20% 7 d after transplanting(7DAT) and 40% panicle N-fertilizer;NT2: 40% basal, 20% 7DAT, 40% panicle N-fertilizer at the 4th and 2nd leaves emerged from the top;NT3: 40% basal, 20% 7DAT, 20% panicle N-fertilizer and 20% grain N-fertilizer, to study the effects of different nitrogen fertilization models on yield and quality of high quality conventional late japonica rice. The results showed that, with the increase of nitrogen application rate, the yield was increased first and then decreased. Compared with N3 treatment, the grain yields of CK, N1, N2, N4 and N5 treatment were decreased by 37.1%, 8.2%, 5.7%, 4.9% and 10.0% respectively, the main reason for the increase of yield is the increase of the grains per spike and the thousand grain weight. At the N3 level, the yield of NT3 treatment was the highest, the main reason for the increase of yield is the increase of the grains per spike. With the increase of nitrogen application rate, the processing quality, appearance quality, cooking and eating quality and nutritional quality were improved;at the N3 level, the brown rice rate, milled rice rate, head rice rate, chalky rice rate, chalkiness degree and gel consistency all showed NT1 >NT2 > NT3, the amylose content and crude protein content were opposite. With the increase of nitrogen application rate, the peak viscosity, thermal slurry viscosity, cold glue viscosity, disintegration value and peak time of RVA spectral eigenvalues were decreased, while the reduction value, recovery value and gelatinization temperature were increased;at the N3 level, the peak viscosity, slurry viscosity, cold adhesive viscosity, disintegration value and peak time all showed NT1<NT2< NT3, the reduction value, recovery value and gelatinization temperature were opposite. To sum up, when the nitrogen rate was 255 kg/hm2 and base fertilizer ∶ tillering ferilizer ∶ panicle fertilizer ∶ grain fertilizer was 4∶2∶2, it was easier to achieve high yield and good quality.