氮肥运筹对南方双季晚粳稻产量及品质的影响

Effects of nitrogen application regime on japonica rice yield and quality of the late rice in the double rice system in southern China

【目的】近年来"籼改粳"是我国南方双季稻区水稻产量及品质提高的有效措施之一,但何种氮肥运筹能使籼粳杂交稻在晚稻季中同步达到高产和优质目前还不清楚,需要进一步研究。【方法】2016—2017年,选用籼粳杂交稻甬优1538为晚稻材料,在总纯氮量255 kg/hm^2条件下,设置基蘖穗肥比分别为6∶2∶2 (A)、4∶2∶4 (B)、2∶2∶6 (C)三种氮肥运筹的比例(穗肥于倒3叶期一次性施用),并在基肥和分蘖肥分别占总施氮量40%和20%下,设置穗肥于倒4叶、倒2叶期两次均施(B_1)和基蘖穗粒肥比为4∶2∶2∶2 (B_2)。收获后,调查分析了晚粳稻产量和品质。【结果】与B处理相比,A和C处理产量分别降低1.9%~4.8%和4.9%~16.8%,而B_1和B_2处理产量分别增加1.2%~3.2%和3.8%~12.5%。B、B_1和B_2处理总干物质量均显著高于A和C处理(P <0.05),特别是在抽穗–成熟期阶段干物质量的积累优势突出,而B1处理高效叶及有效叶的叶面积指数大和B_2处理灌浆结实期剑叶SPAD值高分别是二者在灌浆结实期干物质生产能力强的主要原因。随着基肥比例的降低,加工品质、蒸煮与食味品质和营养品质变优,但外观品质和RVA谱变劣。此外,同一基蘖肥施用比例下,稻米加工品质和蒸煮与食味品质表现为B_2 <B_1 <B,外观品质和RVA谱特征值表现相反的变化规律,而营养品质表现为B_2> B> B_1。【结论】在本试验条件下,采用基蘖穗粒肥比为4∶2∶2∶2的氮肥运筹晚粳稻产量表现最好,采用基蘖穗肥比为4∶2∶4时可兼顾水稻高产和优质,其中穗肥二次均施的氮肥运筹表现优于穗肥一次施用。

【Objectives】“Indica to japonica”has been regarded as one of the effective measures to improve the rice yield and quality in the double-rice cropping systems in southern China.However,it is unclear how to achieve high yield and good quality of the late season indica-japonica hybrid rice simultaneously by nitrogen application regimes.【Methods】Field experiments were conducted in 2016–2017,the indica-japonica hybrid rice Yongyou 1538 was selected as the late season rice material.With the same total N application rate of 255 kg/hm2,nitrogen was applied in three regimes of basal,tiller and panicle fertilizer as 6∶2∶2(A),4∶2∶4(B)and 2∶2∶6(C).For A and C,the panicle-fertilizer was once applied at the final third leaf stage,whereas for B,matter accumulation,yield and quality of japonica rice were investigated and analyzed at harvest stage.【Results】Compared with the B treatments,the yield of the A and C treatments were decreased by 1.9%–4.8%and 4.9%–16.8%,respectively,while the yield of the B1 and B2 treatments were increased by 1.2%–3.2%and 3.8%–12.5%,respectively.The total dry matter accumulation of the B,B1 and B2 treatments was significantly higher than that of the A and C treatments(P<0.05),especially in the heading-mature stage.The main reasons for the strong dry matter production capacity was the high LAI of high effective leaf and effective leaf for the B1 plots and the high SPAD of flag leaf for the B2 plots during grain filling stage.With the decrease of the proportion of the base fertilizer,the qualities for industrial processing,tasting and cooking and nutrition were improved,but the appearance quality and RVA spectrum became worse.In addition,the qualities for industrial processing,tasting and cooking and nutrition under the same basal-tiller fertilization application ratio were shown as B2<B1<B,while the appearance quality and RVA spectrum characteristic value showed the opposite trend,with the nutrition quality was B2>B>B1.【Conclusions】The ratio of basal fertilizer:tiller fertilizer:panicle fertilizer:granular fertilizer as 4∶2∶2∶2 had the highest yields for the late japonica rice,and both the high yield and high quality can be achieved simultaneously with the ratio of basal fertilizer:tiller fertilizer:panicle fertilize of 4∶2∶4,and the split of panicle fertilizer was better than once application under the experimental conditions.