基于“三合结构”分析氮肥运筹对四川丘陵旱地小麦物质生产及产量形成的影响

Effect of Nitrogen Strategies on Dry Matter Accumulation and Yield of Wheat in Sichuan Hilly Areas Based on“Three Combination Structure”

为探究氮肥后移对四川丘陵旱地小麦物质生产与产量形成的影响,2013-2015年度以四川省小麦主推品种川麦104为材料,采用二因素随机区组设计,研究了2个施氮量(120、180kg N·hm-2)、3种施氮方式(底肥一道清、重底早追即底肥和苗肥比例7∶3、氮肥后移即底肥和拔节肥比例6∶4)对小麦干物质积累、平均叶面积指数(MLAI)、生育天数(D)、收获指数(HI)、平均净同化率(MNAR)的影响。结果表明,从三叶期至开花期,相对于120kg·hm-2施氮水平,增施氮肥后干物质积累量增加,而成熟期则以120kg·hm-2施氮处理的干物质积累量较大。不同施肥方式间比较,氮肥重底早追显著增加了三叶期至孕穗期干物质积累量和群体LAI,氮肥后移则显著增加了开花期与成熟期干物质积累量及开花期群体LAI,底肥一道清处理孕穗期、开花期、成熟期的干物质积累量均最小。从光合性能参数看,增施氮肥和氮肥后移均对MLAI、HI有促进作用,与120kg·hm-2施氮处理相比,增施氮肥后MLAI增加9.5%(2014-2015年),HI增加4.7%(2013-2014年);氮肥后移处理的MLAI较底肥一道清处理增加38.2%(2013-2014年),HI较氮肥重底早追处理增加10.6%(2014-2015年),差异均显著;而MNAR、平均作物生长率(MCGR)受施氮量的影响较小。氮肥后移处理的单位面积粒数(TGN)和粒叶比显著增加;180kg·hm-2施氮处理的产量及产量构成因素略高于120kg·hm-2施氮处理,但差异均不显著。综合生产成本与效益来看,四川丘陵旱地小麦的推荐氮肥用量为120kg N·hm-2,施肥方式为底肥和拔节肥比例6∶4。

In order to ascertain the yield increasing mechanism of postponing N fertilizer application, Chanmai 104, a major wheat cultivar in local production, was used as material to study the effect of two N rates （120,180 kg N·hm^-2）, three fertilization methods （all for base fertilizer, base fertilizer to topdressing fertilizer at seedling stage ratio as 7 ： 3,and base fertilizer to topdressing fertilizer at jointing stage ratio as 6 ： 4） on the dry matter accumulation,mean leaf area index （MLAI）,growth days （D） ,harvest index （HI） and mean net assimilation rate （MNAR） in 2013-2015 by using the two factor randomized block design. The results showed that the dry matter accumulation was increased with the increasing of N rate,reaching the maximum at the mature stage under the 120 kg N·hm^-2 treatment. Among the different fertilization methods,the type of base fertilizer to topdressing fertilizer at seedling stage with a ratio of 7 ： 3 increased dry matter accumulation and LAI significantly from seedling stage to booting stage,and the base fertilizer to topdressing fertilizer at jointing stage with a ratio of 6 ： 4 increased dry matter accumulation and LAI significantly at flowering and mature stages, and the treatment of all for base fertilizer decreased dry matter accumulation at booting stage, flowering stage and mature stage. As for photosynthetic performance parameters,both increasing N rate and postponing N fertilizer application had positive effect on MLAI and HI, with the increase of N rate, MLAI was increased by 9. 5% （2014--2015）,and HI was increased by 4. 7% （2013-2014）. The MLAI of the base fertilizer to topdressing fertilizer at jointing stage with a ratio of 6 ： 4 treatment was increased by 38.2% ,compared with the all for base fertilizer treatment （2013--2014） ,and HI was increased by 10.6% ,compared with the base fertilizer to topdressing fertilizer at seedling stage with a ratio of 7 ： 3 treatment （2014--2015）. However,the influence of N rate on MNAR and mean of crop growth rate （MCGR） was not significant. The postponing N fertilizer application significantly increased TGN （grain number per unit area） and grain-leaf ratio,and the yield and yield components under 180 kg N·hm^-2 were slightly higher than those of 120 kg N·hm^-2. Thus,the recommended N rate in Sichuan Hilly Area was 120 kg N·hm^-2 , and the fertilization method was base fertilizer to topdressing fertilizer at jointing stage with a ratio of 6 ： 4.