水稻生理生化特性对氮肥的反应及与氮利用效率的关系

选用水稻氮高效基因型IR72和9311及氮低效基因型Lemont和PECOS,采用土培方法,在5个施氮量（0、0.51、1.02、1.53、2.04 g N 钵^-1,分别相当于0、75、150、225、300 kg N hm^-2）处理下,研究了生理生化特性对氮肥的反应及与氮效率的关系。结果表明,在幼穗分化期,氮高效基因型水稻的可溶性蛋白含量相对低,而谷氨酰胺合成酶（GS）活性高;不同氮效率基因型间1,5-二磷酸核酮糖羧化酶/加氧酶(Rubisco)含量的差异不大;两种氮效率基因型间的净光合速率（P_n）在幼穗分化期差异不明显。而在齐穗期,氮低效基因型的P_n比高效基因型的低28.66%左右;氮低效基因型在两个时期的单位叶绿素光合速率（P_n/Chl）比氮高效基因型分别低18.51%和29.67%左右。在成熟期,氮高效基因型干物质积累能力强,籽粒产量高。这些结果说明氮效率不同的基因型对氮肥的生理反应差异大。相关性分析表明,低氮水平时(0~1.53 g N 钵^-1), GS酶活性与收获时生物量呈显著或极显著正相关;氮肥偏生产力（PFP）、氮肥农学利用率（AE）及氮素生理利用率（NUEb）分别与GS活性、P_n/Chl和齐穗期的Pn呈显著正相关,而与可溶性蛋白含量、Rubisco含量显著负相关;氮肥吸收效率（RE）与这些生理指标没有显著相关。结果表明水稻光合特征及氮代谢与水稻氮效率间存在紧密的关系,GS活性和可溶性蛋白含量对评价水稻氮肥利用率具有重要的参考价值。     

不同控释肥品种对大白菜产量、氮素吸收和品质的影响

采用田间试验研究了不同控释氮肥品种(脲醛、线型和S型包衣尿素)一次性基施对大白菜产量、氮肥利用率和品质的影响。与常规施氮措施中尿素300 kg/hm2的施用量相比,脲醛、线型和S型包衣尿素的施氮量分别为300,240(减量20%)和225 kg/hm2(减量25%),其中S型包衣尿素处理中的化学氮肥由33%的普通尿素和67%的S型包衣尿素均匀混合而成。结果表明:在大白菜上施用氮肥(有机肥和化肥)均会不同程度地增产,其中施用有机肥增产8.22%,在有机肥的基础上施用化学氮肥的增产效果不明显,普通尿素、脲醛、线型和S型包衣尿素分别增产1.15%,4.27%,4.62%和4.97%。有机氮的利用率为33.0%,在有机肥基础上施用化学氮肥的利用率降低,普通尿素的氮肥利用率不到1%,脲醛、线型和S型包衣尿素的氮肥利用率分别为8.9%,13.1%和8.4%。施氮对大白菜的品质影响不大,各处理的鲜菜硝酸盐和Vc含量差异不明显。     

Physiological evaluation of nitrogen use efficiency of different apple cultivars under various nitrogen and water supply conditions

Nitrogen(N) deficiency is a common problem for apple(Malus×domestica) production in arid regions of China. However, N utilization efficiency(NUE) of different apple cultivars grown under low N conditions in arid regions has not been evaluated. In this study, NUE was assessed for one-year-old seedlings of six apple cultivars, Golden Delicious, Qinguan, Jonagold, Honeycrisp, Fuji and Pink Lady, grafted onto Malus hupehensis Rehd. rootstocks. Four treatments were used, including control water with control N(CWCN), limited water with control N(LWCN), control water with low N(CWLN) and limited water with low N(LWLN). Our results showed that growth indices such as biomass, plant height and stem diameter, and photosynthetic rate of all cultivars decreased in the order CWCNCWLNLWCNLWLN. When subjected to LWLN treatment, Qinguan showed better growth and photosynthetic characters than other tested cultivars. Additionally, Qinguan and Pink Lady had higher NUE, while Honeycrisp and Jonagold had lower NUE, based on the determination of biomass, photosynthetic parameters, chlorophyll content, the maximal photochemical efficiency of PSII(F_v/F_m), ~(15) N and N contents.     

不同整地方式下施肥对夏玉米产量及水氮利用效率的影响

通过连续两年田间试验研究了平作、垄沟及成垄压实等不同整地方式条件下施肥对夏玉米产量、氮肥利用率(NUE)及水分利用效率(WUE)的影响。结果表明，不同整地方式因影响田间土壤水分、养分的运动和分布，从而进一步影响到施肥效果，故不同整地方式条件下施肥可影响玉米产量及主要产量构成因素，如穗重、穗粒数、500粒重等。平地条件下玉米生物学产量及籽粒产量及其主要构成因素最小，成垄压实与垄沟条件下分别较平地条件下提高玉米籽粒产量9.5%～10.3%和4.2%～6.3%。成垄压实与垄沟条件下玉米产量构成因素差异不大。不同     

减氮对不同氮效率小麦品种花后光合物质生产力和产量的影响

为明确不同氮效率小麦品种对减氮的响应特点,以前期筛选出的氮高效品种扬麦25、宁麦21和氮低效品种扬麦22、扬麦20为材料,研究减氮模式对产量、氮肥利用效率、光合生产能力和干物质积累量的影响。结果表明,氮高效品种扬麦25和宁麦21的籽粒产量和氮肥利用效率显著高于氮低效品种扬麦22和扬麦20,氮高效品种的平均籽粒产量和平均氮肥利用效率较氮低效品种分别高10.9%和23.9%。与常规施氮处理(CK)模式相比,减氮20%并采用基肥和拔节肥各施氮90 kg·hm~(-2)(M4)模式下,氮高效品种开花期LAI、旗叶SPAD值、净光合速率及乳熟期旗叶SPAD值和净光合速率均未显著降低,且乳熟期平均LAI提高16.0%,进而使花后干物质积累量增加,从而实现产量稳定和氮肥利用效率的提高;而氮低效品种花后光合生产能力、籽粒产量和氮肥利用效率随施氮量降低而出现不同程度的降低。这说明,氮高效品种较氮低效品种有着更多的减氮潜力,前者在适量减氮和合理施肥方式下,可通过延缓花后叶面积衰减、保持较强的花后光合能力和增加花后物质生产力,实现产量稳定和氮肥利用效率提高。     

Nitrogen Use Efficiency of Safflower as Compared to Sunflower

This study compares the nitrogen (N) use efficiency of safflower and sunflower in pot experiments, as the putatively high nitrogen use efficiency of the former is not sustained. Safflower out-yielded sunflower at low N supply, while at ample supply the opposite was observed. Both species accumulated similar amounts of N per pot at equivalent N supplies, but safflower was a better N accumulator due to lower dry matter production. Safflower utilizes absorbed N more efficiently than sunflower to produce seed yield at suboptimal N supply in terms of efficiency ratio and utilization index, but the opposite holds true at optimal and high supply. Functional analysis of utilization efficiency for dry matter and seed production substantiated the higher efficiency of safflower. It is concluded that in terms of N utilization safflower represents a low input crop and outperforms sunflower with respect to seed yield on soils low in available N.     

Combined use of millet glume-derived compost and mineral fertilizer enhances soil microbial biomass and pearl millet yields in a low-input millet cropping system in Niger

A two-year field experiment was conducted in Niger to explore the effects of integrated use of millet glume-derived compost (MGD-Compost) and NP fertilizer on soil microbial biomass carbon (C_mic), nitrogen (N_mic) and millet yields. Three compost rates (3000 kg ha^?1, 1500 kg ha^?1 and 0 kg ha^?1) and three NP fertilizer rates (100%, 50% and 0% of recommended NP fertilizer) were arranged in a factorial experiment organized in a randomized complete block design with three replications. Combined application of compost and NP fertilizer induced a synergistic effect on C_mic and N_mic. Compost application increased millet grain yield from 59% to 91% compared to control. Combined application of compost and NP fertilizer increased millet grain yields from 57% to 70% in 2013 and from 36% to 82% in 2014 compared to sole application of mineral fertilizer. Agronomic efficiency (AE) of nitrogen values increased by 3.7 and 2.3 times than those of sole NP fertilizer application in 2013 and 2014, respectively. Phosphorus AE was 1.6 times higher than that of the sole application of NP fertilizer. These findings indicate that integrated application of MGD-Compost and NP fertilizer enhances soil microbial biomass content and increases millet grain yield in a low-input cropping system.     

实时实地氮肥管理对不同杂交水稻氮肥利用率的影响

 【目的】探讨两系和三系杂交水稻在实时实地氮肥管理模式下对氮素的吸收和氮肥利用率的差异。【方法】试验于2004和2005年在大田条件下,以两优培九、汕优63为材料比较研究了实时实地氮肥管理模式下不同叶绿素仪（SPAD）预设阈值对其吸氮特性与氮肥利用率的影响。【结果】水稻叶片叶色存在基因型差异,汕优63顶叶的SPAD值比两优培九平均低1.7～2.0个数值单位。在实时氮肥管理模式下,施氮量与SPAD预设阈值呈指数相关关系。对于汕优63而言,Nrate=0.9956 e0.132 SPAD （r2=0.8338**）,对于两优培九则为Nrate=0.1565 e0.173 SPAD（r2=0.9508**）。在SPAD预设阈值介于36～40的范围内,若要保持两个品种同一时期顶叶的SPAD值相同,汕优63比两优培九需要多施用氮肥37.3 kg N•ha-1。【结论】在实时实地氮肥管理模式下,当氮肥平均用量接近160 kg N•ha-1时,两优培九的吸氮能力、氮肥吸收利用率和氮素籽粒生产效率与汕优63相当;其氮素干物质生产效率、氮肥农学利用率高于汕优63;其氮素收获指数低于汕优63。此外,两优培九比汕优63表现出较高的耐肥抗倒伏能力。     

小麦氮素高效育种研究进展

氮素是植物生长的必需元素,也是粮食作物产量的一个重要限制因素。培育氮素高效利用的农作物新品种不仅可以降低农业生产成本,还可以从根本上解决氮素施用不当造成的各种问题,是新一代绿色高效农业的发展方向。本文综述了当前小麦氮素高效利用育种研究进展,包括小麦氮素利用效率的评价、小麦氮素响应的基因型差异、影响小麦氮素利用率的形态及理化性状、小麦氮素利用相关基因的挖掘及分子育种与传统育种相结合提高氮素利用率等。