江苏如东草甸土水稻穗肥减氮运筹技术研究

Study on Nitrogen Reduction and Transport Technology for Rice Panicle Fertilizer in Meadow Soil in Rudong County,Jiangsu Province

为探明江苏如东草甸土水稻穗肥减氮运筹效应,以当地农户传统施肥模式(A)为对照,在穗肥减氮10%的情况下,设置B(2∶1)、C(1.5∶1.5)、D(2.5∶0.5)、E(3∶0)、F(0∶3)5个不同的促花肥和保花肥比例水平,开展田间试验,研究产量效益、群体质量和稻米品质变化情况。结果表明,与对照相比,穗肥减氮10%后,不同施肥比例茎叶干物质转运量、转运率和贡献率总体呈降低趋势,产量与之相反(除F减产6.67%),其中C增幅最大(2.47%),主要表现为结实率与千粒重的提高,其产值、纯收入和产/投比增幅分别为2.48%、17.31%和3.38%。成熟期和花后干物质积累量均与产量呈极显著正相关关系(P<0.01),相关系数分别为0.979和0.965。抽穗期上3叶(总叶)叶面积指数、叶面积衰减率均与成熟期叶面积指数变化呈相反趋势(除F处理),其中C成熟期叶面积指数最高,叶面积衰减率最低。适当提高保花肥比例有助于上3叶净光合速率的提高,且处理C、F始终保持较高水平,倒2、3叶增加趋势比倒1叶明显。穗肥减氮10%后,稻米加工品质和外观品质有改善趋势,直链淀粉含量和胶稠度有所提高,蛋白质含量亦呈增加趋势,其中C加工品质和外观品质相对较好,直链淀粉含量最低,胶稠度较长,蛋白质含量适中。与对照相比,C氨基酸总量增幅最大(8.05%),主要提高了蛋氨酸、缬氨酸2种必需氨基酸含量(增幅>5%)和谷氨酸、精氨酸、天冬氨酸、丝氨酸、组氨酸5种非必需氨基酸含量(增幅>10%)。综合考虑,草甸土水稻高产优质高效栽培适宜的氮素穗肥运筹方式为纯氮99 kg·hm-2情况下分促花肥(倒4叶期)和保花肥(倒2叶期)两次等量施用,切忌在倒2叶期保花肥作穗肥一次施用。本研究结果可为如东草甸土水稻绿色高质高效生产技术的规范提供基础数据和理论支撑。

In order to explore effect of panicle fertilizer on nitrogen reduction in meadow soil of Rudong County,Jiangsu Province,under the condition of reducing nitrogen by 10%,taking the traditional fertilization mode(A)of local farmers as a control,five different ratios of flower-promoting fertilizer and flower-protecting fertilizer B(2∶1),C(1.5∶1.5),D(2.5∶0.5),E(3∶0)and F(0∶3)were set up to carry out field experiments to study the changes of yield benefit,population quality and rice quality.Results showed that after a 10%nitrogen reduction in panicle fertilizer,there was an overall trend towards a reduction in stem and leaf dry matter translocation amount,translocation rate and contribution rate at different fertilizer rates compared to the control.While yield was the opposite(except for a 6.67%reduction in F),with the largest increase in C(2.47%),mainly in terms of increased seed setting rate and 1000-grain weight,with increases in output value,net income and output/input ratio of 2.48%,17.31%and 3.38%,respectively.The dry matter accumulation at maturity and after anthesis was extremely significantly-positive correlated with yield(P<0.01),and the correlation coefficients were 0.979 and 0.965,respectively.Moreover,the leaf area index of the upper three leaves(total leaves)at heading stage,leaf area attenuation rate all showed opposite trends to the changes in leaf area index at maturity stage(except for treatment F),while C had the highest leaf area index at maturity stage and the lowest leaf area attenuation rate.Besides,the net photosynthetic rate of the upper three leaves was increased by increasing the proportion of flower-protecting fertilizer,and remained high in treatments C and F,while the trend of increase was more obvious in the second and third leaf from top than that in the flag leaf.Additionally,after a 10%nitrogen reduction in the panicle fertilizer,there was a tendency for the processing and appearance quality of the rice to improve,the amylose content and gel consistency to increase,and the protein content to increase,with C having relatively better processing and appearance quality,the lowest amylose content,longer gel consistency and moderate protein content.Compared with the control,the total amino acids of C increased the most(8.05%),which mainly increased the content of two essential amino acids of methionine and valine with the increase rate larger than 5%and five non-essential amino acids of glutamic acid,arginine,aspartic acid,serine and histidine(>10%).Considering comprehensively,the suitable nitrogen panicle fertilizer application method for high yield,high quality and high efficiency of rice in meadow soil was to apply the same amount of flower-promoting fertilizer(the fourth leaf stage from the top)and flower-protecting fertilizer(the second leaf stage from the top)twice under the condition of pure nitrogen 99 kg·hm-2,and never apply flower-protecting fertilizer as a panicle fertilizer in the 2rd leaf stage from the top.It can provide basic data and theoretical support for the preparation of the technical regulations for green,high-quality and efficient production of rice in the meadow soils of Rudong.