氮肥运筹对机械栽植早稻两优287根系特征和产量的影响

摘要

To test the role of nitrogen management patterns in the yield formation of early rice variety Liangyou 287,under the same total N application of 150 kg/hm2,five application patterns with the application ratio of base fertilizer,tillering fertilizer and panicle fertilizer at 7∶3∶0(N1),6∶3∶1(N2),5∶3∶2(N3),4∶3∶3(N4) and 3∶3∶4(N5),respectively were set,and the roots morphology and bleeding amount,chlorophyll content,dry matter transporting and yield formation were investigated.The results showed that,①the yield and N fertilizer agronomic use efficiency was both the highest in N3 treatment,and was significantly higher than other treatments; while of N5 was the lowest,and was significantly lower than other treatments.②As N fertilizer delayed,the total root length and root specific area were decreasing,the root number,root dry weight as well as root bleeding amount was the highest in N3 treatment.③Rice leaf in N5 treatment remained green when it was due to become yellow and ripe as the SPAD value was relatively high in pustulation period and harvest time.④The EPMSS (exporting percentage of matter of stem and sheath) and TPMSS (transporting percentage of matter of stem and sheath) of N3 and N4 were low;EPML (exporting percentage of matter of leaves) was negative.It was concluded that with machinery planting,the ratio of N in basal fertilizer,tillering fertilizer,panicle fertilizer at 5∶3∶2 could help improve the activity of root system at late growth stage,form root system that could uptake nutrient effectively,promote the photosynthetic ability of leaves,thus lead to high rice yield.%为了明确氮肥运筹对早稻两优287机械栽植产量形成的作用机制,在总施氮量(纯氮)为150 kg/hm2条件下,设置基肥、分蘖肥、穗肥比例分别为7∶3∶0(N1)、6∶3∶1 (N2)、5∶3∶2(N3)、4∶3∶3 (N4)和3∶3∶4(N5)5个氮肥运筹模式,分析水稻根系形态与伤流量、叶绿素、茎鞘干物质转运和产量构成因素等状况.结果表明,①各处理间产量及氮肥农学利用率均以N3最高,与其他处理间差异达显著水平;以N5最低,与其他处理间差异也均达显著水平.②随着氮肥的后移,水稻总根长和根比表面积呈降低趋势,根数和根干重以N3最大,其根系伤流量也最大.③N5水稻叶片SPAD值灌浆期和收获期相对较高,出现贪青现象.④N3和N4的茎鞘物质输出率和茎鞘物质转换率较低,叶片干物质输出率为负值.从而得知,早稻两优287机械栽植,在基肥、分蘖肥、穗肥中氮比例为5∶3∶2时有利于提高生育后期的根系活力、形成有效利用养分的根系特征、促进叶片光合能力的发挥,最终取得较高产量.