内生多粘类芽孢杆菌S-7对甜菜光合作用及产量和品质的影响

研究了内生多粘类芽孢杆菌（Paenibacillus polymyxa）S-7对甜菜叶片光合参数和产量的影响.结果表明：接种内生多粘类芽孢杆菌S-7能显著促进甜菜光合作用,其中叶片净光合速率(P_n)、气孔限制值(L_s)、气孔导度(G_s)和蒸腾速率(T_r )的平均值分别提高了16.11%、23.82%、41.91%和34.80%;叶片胞间CO₂浓度(C_i)平均值降低了21.09%.生物学产量和含糖率分别提高了25.63%和17.46%,促进了甜菜产量和品质提高.表明内生菌不仅影响甜菜光合参数,而且对甜菜产量和品质的提高具有明显的促进作用.     

家庭生态农场的氮素营养生产分析

引言土地的沙漠化也许是人类文明进程所付出的最沉重代价。我国北方干旱地区是一个巨大的潜在“沙漠化温床”,巳沙化土地达3.34×     

氮素水平对初花后棉株生物量、氮素累积特征及氮素利用率动态变化的影响

在大田栽培条件下,分别在长江流域下游棉区(江苏南京)和黄河流域黄淮棉区(河南安阳)设置棉花氮素水平试验,定量研究氮素水平对花后棉株生物量、氮素累积特征及氮素累积利用率动态变化的影响,结果表明:棉株总生物量和氮素累积量随花后棉株生育进程的动态变化符合S型曲线,安阳、南京试点分别以360kg.hm-2、240kg.hm-2氮素水平的总生物量、氮素累积最多,其动态累积模型的特征参数值最为协调,皮棉产量最高。因此,可以通过改变施肥量来调节初花后棉株生长特征值,从而获得高产。棉株氮素累积利用率随初花后棉花生育进程的推进,呈现为不规则的S型曲线变化趋势,计算两试点的氮素累积利用率、瞬时利用率,安阳试点以360 kg.hm-2的施氮水平为最优,南京以240 kg.hm-2最高;施肥过多不仅利用率低,而且易造成营养器官比例加大,棉株虽可获得较大的干物质和氮素累积,但不能适时向生殖器官转移,皮棉产量降低。     

水分管理调控水稻氮素利用研究进展

水、氮是调控水稻生长发育的两个重要环境因子。通过"以水调氧"增加根际溶氧量(如干湿交替、好氧栽培等)能够提升土壤硝化势和氧化还原电位,刺激土壤氮的矿化作用,使水稻处于NH+4与NO-3混合营养中,并能通过诱导水稻的生理特性及改善根系的吸收功能增强其抗旱性能,提高水稻产量及氮素利用率。光合作用是形成干物质的主要途径,土壤氮水平、氮形态与水稻光合速率紧密相关,提高叶片光合速率将有助于提高水稻的氮素利用率和产量。从稻田水分管理对土壤氮素形态特征、水稻氮吸收利用、光合速率及氮环境效应的影响等方面综述了国内外相关研究进展,并指出进一步的研究方向。     

覆膜对旱地麦田土壤水分及氮素平衡的影响

通过大田试验研究了平膜穴播和垄膜沟播等覆膜方式对晋南旱地麦田土壤水分、氮素平衡及产量的影响,以期在当地确立一套适宜的科学覆膜方式,为晋南旱塬地区乃至我国旱作小麦的高产优质提供理论依据。结果表明,垄膜沟播和平膜穴播处理的冬小麦增产效果显著,且以平膜穴播处理的效果最优,较测控施肥处理的籽粒产量和生物产量分别提高22.71%和25.45%。经过冬小麦一个生育期对土壤水分的吸收利用,两种覆膜处理的耗水量较不覆膜处理有较大的提高,而其水分利用率略低于不覆膜处理,但差异不显著。两种覆膜处理也能提高麦田的降水生产效率和休闲效率,较不覆膜处理分别提高9.46%—30.16%和9.95%—39.22%。覆膜有利于氮的矿化,并能促进小麦对氮素的吸收利用,同时也可以在一定程度上降低氮素在土壤中的残留,最终有利于小麦增产。     

限水减氮对关中平原冬小麦氮素利用和氮素表观平衡的影响

研究限水减氮对冬小麦产量、氮素利用率和氮素表观平衡的影响,探讨限水减氮管理模式在关中平原冬小麦生产中的可行性,可为实现关中平原灌区冬小麦生产的稳产高效和环境友好发展提供科学依据.本研究于2017-2018和2018-2019年连续2年在陕西杨凌地区进行小麦田间裂区试验,灌水量为主处理,设置两个灌溉水平,1200 m3·...     

嫁接与施氮对甜瓜产量和氮素吸收、利用的影响

通过裂区设计田间试验,主区为2种栽培方式(嫁接栽培和自根栽培),副区为4个施氮水平(0、120、240、360 kg N·hm^-2),研究了栽培方式和施氮量对甜瓜产量和品质、氮素运移和分配,以及氮素利用率的影响.结果表明: 嫁接栽培的甜瓜商品瓜产量较自根甜瓜提高了7.3%,可溶性固形物含量降低了0.16%～3.28%;生长前期嫁接栽培甜瓜氮素累积量较自根栽培低,结果后嫁接栽培氮素累积量显著升高,收获时植株氮素累积量较自根栽培增加了5.2%,果实中的氮素累积量提高了10.3%;嫁接栽培植株氮素向果实的转移量较自根栽培提高了20.9%,嫁接栽培果实中的氮素分配率在80%以上,自根栽培的分配率在80%以下;在同一施氮水平下,嫁接栽培的甜瓜氮素吸收利用率较自根栽培提高了1.3%～4.2%,氮素农学效率提高了2.73～5.56 kg·kg^-1,氮素生理利用率提高了7.39～16.18 kg·kg^-1;从商品瓜产量、氮素吸收量和氮素利用率综合考虑,施氮量240 kg·hm^-2为本区域嫁接甜瓜较适宜的氮素用量.     

陕西果园主要分布区氮素投入特点及氮负荷风险分析

为了研究果园氮素投入特点及分析氮素负荷特征,加强果园氮素管理、指导果农科学合理施肥。以陕西省果园主要分布区土壤氮素分析、农户投入调查等统计数据为基础,采用盈余法从果树种类和区域角度分析果园生产体系中的氮素输入输出特点及氮素盈余状况。结果表明,陕西果园主要分布区平均化肥氮投入量927.2 kg/hm2,主要来源于尿素和复合肥,其中尿素占调查样本量的40%以上;通过有机肥投入的氮仅为139.4 kg/hm2。94.8%的果园氮素处于盈余,总体平均盈余量为876.3 kg/hm2,其中氮盈余量超过500 kg/hm2的样本占57.5%,盈余量超过1 000 kg/hm2的样本亦占了27.3%。不同果园相比,猕猴桃园氮素投入及盈余量最高,分别为1 432.9、1 186.9 kg/hm2。不同区域果园比较,土壤氮环境负荷以关中灌区果园较高,达1046.1kg/hm2。果园氮素施用与养分盈余量之间存在极显著的正相关。陕西果园氮素的高量投入给土壤环境带来较大的氮素负荷,这对土壤环境和周围水体造成很大威胁。     

北方草原牧户心理载畜率与草畜平衡生态管理途径

探讨牧户心理载畜率与草畜平衡生态管理的途径对于草原有效减畜、遏止草原退化、实现可持续发展具有重要意义。从生态学和社会科学相结合的角度,采用问卷调查、情景实验及综合分析等多种方法,探讨了北方草原牧户心理载畜率的存在、计算和影响因素,以及牧户生产决策行为特征和可能的生态管理途径。研究发现,在草甸草原、典型草原和荒漠草原,牧户行为属"有限理性",是有限理性的"生态经济人",风险规避是其基本特征,牧户生产决策表现出禀赋效应、损失厌恶、框架效应等;牧户草场所属草原类型和牲畜存栏数显著影响牧户对草场超载的认知和判断,在不同草原类型区,户主文化水平、性别、民族和是否嘎查干部等亦显著影响牧户对超载的认知和判断;需采取基于进化博弈的分步式、合作式及示范引导式的适应性减畜的生态管理途径,以实现牧户心理载畜率向生态优化载畜率的转移,实现优化牧户生产方式、减少牲畜数量、治理草原退化、北方牧区生态和牧民经济双赢的目标。     

华北平原种养一体规模化农场氮素流动特征及利用效率——以河北津龙循环农业园区为例

种养一体规模化、集约化是华北平原农业发展的必然趋势,而氮素是连接种植养殖的主要养分资源,以河北津龙循环农业园区为例,采用文献资料、实地调查方法分析农场水平氮素流动特征及利用率,并通过情景分析方法提出农场氮素管理措施,为实现农场水平氮养分资源高效利用、提高农场生产系统生产力和改善华北平原循环农业模式提供技术支撑和科学依据.结果表明: 在农场水平下,化肥和有机肥输入氮量674.6 kg·hm^-2·a^-1,占总输入氮量的88.3%,氮利用率为41.5%,种植系统氮盈余量190.7 kg·hm^-2·a^-1,施氮量过多是造成种植系统氮利用率低和氮素盈余量高的主要原因.养殖系统中外购饲料提供氮量占饲料总输入氮量的83.2%,粪尿排氮量为776.6 t·a^-1,而还田比例仅为36.3%,氮利用率19.7%.农场水平氮总利用率为40.7%.情景分析表明,农田减少化肥施氮量50%(情景1)、增加来自农场内部玉米籽粒产量(情景2)措施,可分别使种植系统氮利用率提高34.6%和15.6%,同时农场水平氮总利用率分别提高18.7%和9.8%;另外,优化养殖系统饲料结构(情景3),可使氮总利用率提高19.1%.因此,减少化肥氮施用量、调整作物种植结构、优化饲料结构等,是提高农场氮生产力和实现环境友好双赢效果的措施和途径.     

Occurrence of ceftriaxone-resistant commensal bacteria on a dairy farm and a poultry farm

Approximately 40 samples of animal feces, drinking water, feed, bedding, pine wood shavings, compost, and manure slurry were collected from two animal research farms (one dairy and one poultry) and analyzed for ceftriaxone-resistant bacteria. Our study revealed that the total percentage of aerobic bacteria with reduced susceptibility to ceftriaxone (minimal inhibitory concentration (MIC) > or = 16 micro g/mL) ranged from 0.9% to 10.8% in dairy feces and from 0.05% to 3.93% in chicken feces. The percentages of ceftriaxone-resistant bacteria (MIC > or = 64 micro g/mL) were in the range of 0.01% - 2.3% in dairy feces and 0.01% - 0.79% in chicken feces. Environmental samples contained a wide range of ceftriaxone-resistant bacterial populations. Among those environmental samples, fresh pine wood shavings used as chicken bedding contained the highest percentages (41.5%) of ceftriaxone-resistant bacteria, as determined by a plating method. A total of 105 ceftriaxone-resistant (MIC > or = 128 micro g/mL) bacterial isolates were isolated from the above samples and tested for resistance to nine antibiotics: ampicillin, ceftriaxone, streptomycin, kanamycin, gentamicin, chloramphenicol, tetracycline, ciprofloxacin, and nalidixic acid. The most prevalent resistance pattern (34.3%) among isolates included resistance to all nine antibiotics. Results from this study suggest that ceftriaxone-resistant bacteria exist in farm environments, and the ceftriaxone resistance was frequently associated with resistance to multiple antibiotics. Environmental sources such as pine wood shavings used as bedding can be a potential reservoir for transmitting the multidrug-resistant bacteria.     

乳酪蛋白源生物活性肽的研究进展

酪蛋白是生物活性肽的重要来源,可以通过体内的胃肠消化和食品加工过程中的酶解将其释放出来。乳酪蛋白源的生物活性肽的生物学意义、对人类健康的影响和其在新型功能性食品加工中的作用具有重要的研究价值。     

Treatment of dairy farm wastewaters in engineered reed bed systems

The objective of an engineered reed bed is to manage the natural growth of the reeds in order to optimise the processing of the wastewater to be purified. Downflow reed beds, with two treatment stages, have been added in front of a previously installed horizontal flow bed on a dairy farm to treat parlour washings and standing yard wastewater. Recent results have shown that the BOD is being reduced from an average of 1006 mg/litre at the inlet to only 57 mg/litre at the exit from the small final lagoon.     

Social life cycle assessment of average Irish dairy farm

Purpose

The majority of sustainability studies of dairy farms focused on environmental performance and profitability; however, social aspect has been hardly assessed. This study aims to investigate the social impacts of dairy farm via a case study using a social life cycle assessment framework.

Methods

The assessment was carried out applying the social LCA Guideline by UNEP-SETAC. Nineteen suitable social indicators were selected from four stakeholder categories of the guideline. Characterization and normalization were further developed based on data availability. National farm survey data was used as foreground data for farm activities, supplemented with background data from public database and life cycle working environment (LCWE) data by Gabi database. All indicators were divided into three groups: functional unit-related quantitative indicators, non-functional unit-related quantitative indicators and semi-quantitative indicators.

Results and discussion

Irish dairy farming has positive social impacts on value chain actors and society, predominantly positive impacts for local community and generally positive values for workers. The main negative impacts are health and safety issue, equal opportunity for workers, and safe and healthy living conditions for the local community. Possible actions to improve the social performance include introducing more efficient and robotic milk production systems; applying better handling methods and using real time decision support to operational management for emissions reduction.

Conclusions

This study is the first attempt of social LCA in Ireland. It demonstrated a possible method to carry out SLCA for Irish dairy sector. The results identified the positive and negative social hotspot of dairy farm with recommendation for future improvement.

     

作用于奶牛生殖系统的乳酸菌菌属研究进展

乳酸菌菌属作为治疗性微生态制剂具有安全有效、无耐药性、环保无残留的优势,因其优势可成为治疗奶牛生殖道疾病的抗生素替代物之一。本研究就乳酸菌作用于奶牛生殖系统各个靶器官的研究概况,乳酸菌补给途径以及其作用机制进行了综述。     

Combined eradication strategy for CAE in a dairy goat farm in Japan

We conducted an eradication program from 2002 to 2006 against caprine arthritis-encephalitis (CAE) virus (CAEV) in an important farm that maintained goat breeds and had a high prevalence of CAEV infection. The program did not involve the slaughter and replacement of entire flocks, but rather the prevention of both vertical and horizontal transmission. The program consisted of (1) removal of kids immediately after birth, (2) segregation of each generation, and (3) culling of positive goats in periodical tests. All goats born before 2002 were regarded as infected and grouped into herd A. Kids born during the program were divided into several herds on the basis of CAEV infection risk, raised with calf milk replacer, and periodically tested by polymerase chain reaction (PCR) and the agar gel immunodiffusion (AGID) test. A total of 205 kids were produced from 137 parents in herd A, 92 of which were distinctly infected. Only 11 of the 205 kids were infected with CAEV and were culled. The remaining 194 kids and all other kids born from other herds were negative by PCR and AGID testing throughout the program. The milk yield of primiparous does was significantly increased after the eradication program. These findings indicate that the combine use of isolated and milk-deprived rearing and periodical detection testing are effective in establishing a CAEV-free flock from an infected flock.