优质食味粳稻控混肥一次性基施效应

Effect of One-Time Basal Application of the Mixed Controlled-Release Nitrogen Fertilizer in Japonica Rice with Good Taste Quality

【目的】将控混肥(由2种不同释放期的控释肥组成)和常规氮肥在钵苗机插条件下掺混后一次性基施,以期筛选与优质食味迟熟中粳稻养分吸收相匹配的最优控混肥处理,为钵苗机插下优质食味迟熟中粳稻高产简化施肥提供科学依据。【方法】于2018—2019年的水稻季(5—10月)开展试验,以优质食味多穗型迟熟中粳品种南粳9108和丰粳1606为材料,在270 kg·hm^(-2)纯氮条件下,将控混肥和常规氮肥以5﹕5的固定比例组配,控混肥由2种释放期的控释肥以4﹕1组成,共设置6种组合方式,分别为60 d+40 d、60 d+80 d、80 d+60 d、80 d+100 d、100 d+80 d、100 d+120 d,并以常规分次施肥(CK)为对照,测定产量、群体质量指标及氮素吸收利用的特性。【结果】相较CK,南粳9108的100 d+80 d处理2年平均增产4.66%,丰粳1606的该处理平均增产4.29%,增产的原因是有效穗数和群体颖花量显著增加,而穗粒数和结实率无显著差异;除2019年的南粳9108外,100 d+120 d处理的产量均仅次于100 d+80 d处理。80 d+60 d、80 d+100 d处理2年产量均与CK无显著差异,而60 d+40 d、60 d+80 d处理则较之显著减产。播种至拔节阶段,控混肥处理的群体氮素积累量均较CK增加,平均增幅达14.86%,从而促进了群体茎蘖的发生,叶面积指数和净同化率的同步增加,光合生产能力提高,干物质积累增加。拔节至抽穗阶段,100 d+80 d和100 d+120 d处理的氮素积累、干物质积累与CK同处于最高水平,较最低的60 d+40 d处理分别增加47.02%—55.01%和14.52%—18.15%;和100 d+80 d、100 d+120 d处理相比,此阶段CK的净同化率虽相对提高,但抽穗期的叶面积指数却显著降低。抽穗至成熟阶段,100 d+120 d处理的氮素积累高于其他处理,其中较CK显著增加9.23%—22.03%,而干物质积累则以100 d+80 d和100 d+120 d处理同处于最高水平,较CK显著增加5.44%—8.58%,原因可能是100 d+80 d和100 d+120 d处理的养分释放能相对协调地提高光合叶面积和净同化率,致抽穗后的光合产物相对充足,而CK的净同化率虽较高,但其光合叶面积相对不足。对于氮素利用效率,100 d+80 d处理的氮肥偏生产力、氮肥农学利用率较CK分别增加3.90%—4.92%、9.42%—11.93%,100 d+80 d、100 d+120 d处理的氮肥表观利用率较CK分别增加5.29%—7.21%、5.79%—8.51%。【结论】100 d+80 d、100 d+120 d处理的养分释放与南粳9108和丰粳1606养分吸收最为匹配,促进了高产群体的形成,因此其可以作为钵苗机插下优质食味迟熟中粳稻高产简化施肥的氮肥运筹方式。

【Objective】In this experiment,the mixed controlled-release nitrogen(N)fertilizer(composed of two controlled-release N fertilizers with different release periods)and conventional N fertilizer were mixed and then applied as base fertilizers at one time under mechanical pot-seedling transplanting,with a view to select the optimal mixed controlled-release N fertilizer treatment that matched the nutrient absorption of late mid-season japonica rice with good taste quality,so as to provide a scientific basis for high-yield and simplified fertilization of that type of rice under mechanical pot-seedling transplanting.【Method】The experiment was carried out in the rice season of 2018-2019(May-October).The two late mid-season japonica rice and more panicles cultivars with good taste quality,including Nanjing 9108 and Fengjing 1606,were used as materials under the pure nitrogen condition of 270 kg·hm^(-2).A mixed controlled-release N fertilizer and a conventional nitrogen fertilizer were combined at a ratio of 5﹕5,and the mixed controlled-release N fertilizer consists of two kinds of controlled-release fertilizers with different release period at a ratio of 4﹕1.Six combinations were set up,including 60 d+40 d,60 d+80 d,80 d+60 d,80 d+100 d,100 d+80 d,and 100 d+120 d,and conventional urea split fertilization(CK)was used as a control.Then,the yield,population quality index and characteristics of nitrogen absorption and utilization were measured.【Result】The results showed that,compared with CK,the yield of Nanjing 9108 and Fengjing1606 under 100 d+80 d treatment were increased by 4.66%and 4.29%on average for two years,respectively.The increase of grain yield was due to the significant increase in effective panicles per unit area and total spikelet per unit area,and grain number per panicle and filled-grain percentage had no significant difference between 100 d+80 d,100 d+120 d treatments and CK.The grain yield under 100 d+120 d treatment was next to 100 d+80 d treatment,except for the 100 d+120 d treatment of Nanjing9108 in 2019.There was no significant difference in yield between 80 d+60 d,80 d+100 d treatments and CK for two years.Compared with CK,the yield under 60 d+40 d and 60 d+80 d treatments was significantly reduced.From sowing to jointing,the group N accumulation under the mixed controlled-release N fertilizer treatments increased,compared with CK,with an average increase of 14.86%,which promoted the occurrence of group tillers and the simultaneous increase in LAI and net assimilation rate,improved photosynthetic productivity,and then increased dry matter accumulation.From jointing to heading,the N accumulation and dry matter accumulation of only 100 d+80 d,100 d+120 d treatments were at the highest level with CK,which increased by 47.02%-55.01%and 14.52%-18.15%respectively,compared with the lowest 60 d+40 d treatment.Compared with the treatments of 100 d+80 d and 100 d+120 d,the net assimilation rate under CK was increased relatively,but the LAI at heading stage decreased significantly.From heading to maturity,the nitrogen accumulation under 100 d+120 d treatment was significantly higher than other treatments,which was increased by 9.23%-22.03%compared with CK.However,the dry matter accumulation under 100 d+80 d and 100 d+120 d treatments was at the highest level,which was significantly increased by 5.44%-8.58%compared with CK,which might be due to that N release under 100 d+80 d and 100 d+120 d treatments,and it could improve photosynthetic leaf area and net assimilation rate relatively coordinately,resulting in relatively sufficient photosynthetic production after heading;While the net assimilation rate of CK was relatively high,but the photosynthetic leaf area was relatively insufficient.With regard to N use efficiency,N partial factor productivity(NPFP)and N agronomy efficiency(NAE)under 100 d+80 d treatment respectively was increased by 3.90%-4.92%and 9.42%-11.93%,compared with CK;The apparent N use efficiency(ANE)under 100 d+80 d and 100 d+120 d treatments was increased by 5.29%-7.21%and 5.79%-8.51%,respectively,compared with CK.【Conclusion】The N release under the 100 d+80 d and 100 d+120 d treatments was most consistent with nutrient absorption of Nanjing 9108 and Fengjing 1606,which led to the formation of high-yield population and could be used as a nitrogen fertilizer management method for high-yield and simplified fertilization of late mid-season japonica rice with good taste quality by mechanical pot-seedling transplanting.