微生物肥料新型功能作用机理与根际定殖增强策略

微生物肥料是支撑农业绿色发展的重要投入品,根际益生菌是微生物肥料菌种的主要来源。我国农业发展对促进作物根系发育、增强作物耐盐胁迫能力等新型功能的微生物肥料提出了需求,然而目前对根际益生菌促进作物根系发育和增强耐盐胁迫的分子机理研究仍然薄弱,成为制约优异菌种选育的瓶颈。另一方面,微生物肥料的根际定殖能力低也是导致其田间应用效果差的重要因素。本文综述了根际益生菌调控根系发育、增强植物耐盐的活性物质和作用机理,分析其根际定殖的过程和菌植互作机制,提出了增强根际定殖的策略,以期为微生物肥料研究提供参考。     

水肥互作对滴灌玉米氮素吸收、水氮利用效率及产量的影响

优化水、氮供应是实现作物高产与水肥资源高效利用的有效途径.本文研究了田间试验条件下,水(4500、6750、9000 m³·hm^-2)、氮(0、225、330、435、540 kg·hm^-2)互作对高密度(≥105000 株·hm^-2)滴灌玉米干物质积累、氮素吸收及产量的影响.结果表明: 玉米干物质积累与吸氮量均随灌溉和施氮水平的增加明显升高,当施氮量大于435 kg·hm^-2和灌溉量大于9000 m³·hm^-2时则呈减少趋势.完熟期玉米干物质积累对灌水的响应表现为W₆₇₅₀(36359 kg·hm^-2)>W₉₀₀₀(35077 kg·hm^-2)>W₄₅₀₀(33451 kg·hm^-2),施氮对玉米吸氮量的变化表现为N₄₃₅(459.9 kg·hm^-2)>N₅₄₀(458.1 kg·hm^-2)>N₃₃₀(416.3 kg·hm^-2)>N₂₂₅(351.3 kg·hm^-2),N₄₃₅比N₃₃₀、N₂₂₀分别升高9.1%、32.7%,N₅₄₀比N₄₃₅降低0.6%.在施氮量0～435 kg·hm^-2范围内,玉米最大氮素吸收速率随施氮量增加而升高,在施氮量为435 kg·hm^-2时达最大(6.57 kg·hm^-2·d^-1).灌水与施氮均可显著增加玉米产量、穗粒数和穗粒质量,二者有明显的正交互作用,且以氮为主效应.在施氮0～435 kg·hm^-2范围内,氮肥利用率随施氮量的增加而升高,此后反而降低;灌溉水分生产率随施氮量升高而增加,随灌水量增加而明显下降,灌溉定额为4500～6750 m³·hm^-2时,灌溉水分生产率可达2.57～3.80 kg·m^-3.玉米最高产量18072 kg·hm^-2的施氮量为567.0 kg·hm^-2.最佳经济施氮量为427.9～467.7 kg N·hm^-2时,玉米产量在17109～17138 kg·hm^-2,氮素偏生产力和氮肥利用率分别达122 kg N·hm^-2和45.0%.水氮一体化施肥可实现滴灌玉米高产协同水、氮利用效率的共同提高.     

生物炭影响作物生长及其与化肥混施的增效机制研究进展

利用秸秆型生物炭进行还田改土不仅具有提升作物产量的潜力,而且能够产生明显的环境效益,现已成为当今国内外农业领域的研究热点.本文综述了近年来国内外有关生物炭添加影响作物生长的分子调控机制研究,尤其关注了生物炭与作物根系的互作效应;介绍了生物炭与化肥混施的生物学效应及可能的增效机制;展望了今后的研究方向,以期促进我国相关领域的研究.国内外的最新研究表明:生物炭土壤添加改善植物生长的关键是生长素相关信号转导分子,通过促进植物细胞扩增、细胞壁松弛、水及营养的转运等相关基因的表达,有利于植物的新陈代谢及生长.生物炭及其与根系的相互作用能够直接或间接地影响土壤物理、化学、生物因子,从而在炭、肥互作增效过程中起主导调控作用.     

氮肥运筹对小麦产量、氮素利用效率和光能利用率的影响

连续2年在西南冬麦区的重庆、仁寿、广汉、西昌4个地点,开展3种施氮水平(每公顷纯氮0、120、180 kg,简写为N₀、N₁₂₀、N₁₈₀)和3种氮肥分配模式(N_A:底肥100%;N_B:底肥70%+苗肥30%;N_C:底肥60%+拔节肥40%)的田间试验,监测小麦花后冠层叶片SPAD值、群体光合速率(CAP)、光能利用等生理参数和籽粒产量,计算氮素利用效率、光能利用率等.结果表明: 随施氮水平增加,小麦上三叶SPAD值、CAP、光合有效辐射(PAR)截获率和产量均呈增加趋势,而氮肥农学利用效率、生产效率、吸收效率和利用效率呈降低趋势.氮肥后移的增效作用因施氮水平而异,SPAD于N₁₈₀增效明显,而CAP于N₁₂₀增效明显,不同氮肥管理模式的光能利用率因地点而异.氮肥后移能明显提高小麦氮肥农学效率、生产效率、吸收效率和氮素表观回收率,但氮肥利用效率则略有减少.氮肥后移效果N_C总体优于N_B处理.不同地点比较,广汉的SPAD值、CAP、PAR截获率、氮肥利用参数较高,其产量也相应最高;西昌的产量、SPAD值及氮素利用效率较高,但其光能利用率和CAP较低;重庆和仁寿的SPAD值、光能利用率及氮素利用效率均较低,其产量也最低.小麦生物产量与各地点的籽粒产量、CAP、SPAD值和PAR累积截获量均呈显著或极显著的正相关关系.表明不同生态区域增施氮肥都能促进小麦增产,氮肥后移可进一步优化产量结构、改善氮肥和光能利用效率,但存在年份和地点差异,各地需要制定有针对性的氮肥管理模式.     

氮、磷、钾肥配施对桂花品种'金玉台阁'开花性状及叶片中叶绿素和营养元素含量的影响

以桂花品种'金玉台阁'(Osmanthus fragrans'Jinyu Taige')盆栽苗为供试材料,采用"3414"肥料效应试验设计方案,研究了不同单株施用量CO(NH2)2(0.0、1.0、2.0和3.0 g)、NH4H2PO4(0.0、1.5、3.0和4.5 g)和KCl(0.0、0.5、1.0、1.5 g)对秋冬生长期(2014年10月至2015年2月)'金玉台阁'开花性状及叶片中叶绿素和营养元素的影响进行了比较和分析,并筛选出适宜的氮、磷、钾肥施用量.结果表明:与CK〔CO(NH2)2、NH4H2PO4和KCl的单株施用量均为0.0 g〕组相比,各氮、磷、钾肥配施处理组'金玉台阁'的单株产花量、花瓣相对含水量、花径以及叶片中叶绿素、全氮、全磷和全钾的含量总体上显著升高.CO(NH2)2单株施用量对'金玉台阁'单株产花量、叶片中叶绿素含量和全氮含量的影响最大,NH4H2PO4单株施用量对这3个指标的影响次之;NH4H2PO4单株施用量对'金玉台阁'叶片中全磷含量的影响最大;KCl单株施用量对'金玉台阁'花瓣相对含水量、花径及叶片中全钾含量的影响最大.在秋冬生长期内叶片中叶绿素含量呈先降低后升高的趋势,均在12月份降至最低值.通过建立'金玉台阁'单株产花量(y)与CO(NH2)2、NH4 H2 PO4和KCl的单株施用量(分别为xN、xP和xK)间的肥料效应模型,得到的三元二次肥料效应模型为y=1.2027+0.7561×xN+0.2632×xP+0.4590×xK-0.2761×xN2-0.1201×xP2-0.5007×xK2+0.1901×xN×xP-0.0960×xN×xK+0.1185×xP×xK.以单株产花量为目标,'金玉台阁'的CO(NH2)2、NH4 H2 PO4和KCl的最佳单株施用量分别为2.58、3.56和0.86 g.     

Impacts of natural factors and farming practices on greenhouse gas emissions in the North China Plain: A meta‐analysis

Requirements for mitigation of the continued increase in greenhouse gas (GHG ) emissions are much needed for the North China Plain (NCP ). We conducted a meta‐analysis of 76 published studies of 24 sites in the NCP to examine the effects of natural conditions and farming practices on GHG emissions in that region. We found that N₂O was the main component of the area‐scaled total GHG balance, and the CH ₄ contribution was <5%. Precipitation, temperature, soil pH , and texture had no significant impacts on annual GHG emissions, because of limited variation of these factors in the NCP . The N₂O emissions increased exponentially with mineral fertilizer N application rate, with y  =  0.2389e^0.0058x for wheat season and y  =  0.365e^0.0071x for maize season. Emission factors were estimated at 0.37% for wheat and 0.90% for maize at conventional fertilizer N application rates. The agronomic optimal N rates (241 and 185 kg N ha^?1 for wheat and maize, respectively) exhibited great potential for reducing N₂O emissions, by 0.39 (29%) and 1.71 (56%) kg N₂O‐N ha^?1 season^?1 for the wheat and maize seasons, respectively. Mixed application of organic manure with reduced mineral fertilizer N could reduce annual N₂O emissions by 16% relative to mineral N application alone while maintaining a high crop yield. Compared with conventional tillage, no‐tillage significantly reduced N₂O emissions by ~30% in the wheat season, whereas it increased those emissions by ~10% in the maize season. This may have resulted from the lower soil temperature in winter and increased soil moisture in summer under no‐tillage practice. Straw incorporation significantly increased annual N₂O emissions, by 26% relative to straw removal. Our analysis indicates that these farming practices could be further tested to mitigate GHG emission and maintain high crop yields in the NCP .     

枯草芽胞杆菌发酵玉米秸秆后对家蝇的饲养效果

作物秸秆是重要的农业资源,为有效利用作物秸秆,本文利用枯草芽胞杆菌发酵玉米秸秆,配制成人工饲料来饲养家蝇。从菌液加入量和发酵天数来考察对家蝇饲养效果的影响,结果表明:枯草芽胞杆菌菌液加入量为3 mL(3.2×10~(11)cfu/mL),发酵天数3d时对家蝇饲养效果较好,幼虫质量为16.91g,与不加菌液的对照组(13.30g)相比存在显著性差异(P0.05)。经过枯草芽胞杆菌发酵和家蝇幼虫处理后,玉米秸秆的纤维素、半纤维素、木质素的绝对含量都显著降低(P0.05)。经过家蝇取食后的饲料残渣,经检测,有机质等均达到国家标准。最优家蝇饲料配方为:枯草芽胞杆菌菌液加入量3mL(3.2×10~(11) cfu/mL),发酵天数3d,玉米秸秆和麦麸各125g,每250g饲料添加初孵幼虫200mg。本研究利用枯草芽胞杆菌发酵玉米秸秆,提高其营养价值,并进一步饲养家蝇,为秸秆的资源化利用和家蝇规模化饲养奠定了基础。     

大棚辣椒最佳钾肥用量及运筹

以台湾‘长香’辣椒Capsicum frutescens品种为材料,通过设置钾肥横向与纵向施肥的田间试验,探讨辣椒最佳钾肥用量及其运筹。结果表明,在设定氮、磷肥施用量分别为15.0、3.5 kg·667m-2的条件下,钾肥不同施用量对辣椒的株高、幅宽、茎粗的长势及果长、果粗、单果重等品质均有明显的影响,辣椒产量(y)与钾肥施用量(x)两者呈y = -2.2743x2 + 53.402x + 802.45的相关性(r2 = 0.973),钾肥最佳施用量为11.74 kg·667m-2;在同样条件下,钾肥施用量12.00 kg·667m-2,按基肥与追肥不同比例进行施用,辣椒株高、幅宽、茎粗的长势及果长、果粗、单果重等品质与产量均有所差异,其基肥∶追肥按2∶8的配比进行运筹施用,辣椒品质与产量均明显优于其他配比。     

Challenges of reducing excess nitrogen in Japanese agroecosystems

Fertilizer N use in Japan has decreased by about 30% from 1960 to 2000, while keeping a little increase in cereal yields. This has resulted in a significant increase in apparent nitrogen use efficiency, in particular for rice. On the other hand, national N load on the environment associated with the production and consumption of domestic and imported agricultural products has almost tripled during this period, mainly due to the dramatic increase of imports of food and feedstuffs. The environmental problems, including water and air pollution, caused by the excessive loads of N are serious public concerns and there is an urgent need to minimize N losses from agricultural production. In order to meet the necessity for reducing the environmental impacts by excess N, political and technological measures have been taken at regional and country levels. In recent years, the Japanese government has embarked on a series of policies to encourage transition to an environmentally conscious agriculture. Promoting proper material circulation with reducing fertilizer impact and utilizing biomass and livestock wastes is emphasized in these policies. The effectiveness of environmental assessment and planning for reducing regional and national N load has been discussed. Implementation of environmentally friendly technologies and management, both conventional and innovational, have been developed and adopted in Japanese agriculture. The effectiveness of conventional technologies in reducing environmental reactive N has been re-evaluated. Innovative technologies, such as use of controlled availability fertilizers and livestock wastes compost pellets, are being investigated and extended. A comprehensive approach that applies political and technological measures with closer cooperation is necessary to control reactive N in the environment.     

长期施磷对黄壤旱地磷库变化及地表径流中磷浓度的影响

对贵州黄壤旱地进行采样以及盆栽试验,探索黄壤旱地磷库的变化及其对地表径流磷量的影响。结果表明,长期施磷后黄壤旱地无机磷占全磷的比例逐渐增高,Al-P、Fc-P和Ca-P积累的顺序为Fe-P>Al-P>Ca-P。长期施磷后黄壤旱地的有效磷和藻类可利用的总磷也不断积累,高磷（Olsen-P>25mg·kg^-1)旱地藻类可利用的总磷与Al-P、Fe-P和Ca-P的相关系数分别为0.859、0.903和0.650,Fc-P对藻类可利用磷量的影响起着最重要的作用。在模拟雨强为63.2mm·h^-1下,降雨30min后,低磷黄壤旱地（Olsen-P为4.62-15.9mg·kg^-1)径流中磷酸根磷含量仅为2.81-4.17μg·L^-1,生物有效性磷含量为0.723-0.876mg·L^-1;高磷黄壤旱地（Olsen-P)为29.4-59.2mg·kg^-1)径流中磷酸根磷含量达到0.026-0.714mg·L^-1,生物有效性磷含量增加到0.996-1.281mg·L^-1;高磷黄壤旱地地表径流磷量能加速水体富营养化的产生。