不同营养液浓度对莴苣生长特性的影响

 以长叶莴苣( Lactuca sativa var．1ongifolia Lam．)为试材，研究了NFT栽培条件下莴苣水分与养分吸收特性，以及NFT对其生长发育的影响。试验结果表明，莴苣蒸腾效率前期>中期>后期；整个生育过程中，P、K、Mg的吸收成分组成浓度(养分与水分吸收比，n/w)均低于原始营养液浓度，而Ca则相反；NO3^--N因处理浓度不同而异。叶片中各无机成分含量随生育过程而提高，同一生育期随营养液浓度提高而增加；综合莴苣产量因子与商品性状，以3/4倍园试均衡液最佳。     

大棚番茄优化施肥与土壤养分和盐分的变化特征

通过对不同尿素、羊厩肥配比下的秋茬和春茬番茄大棚栽培试验 ,探讨了大棚地膜栽培条件下 ,有机肥与无机肥施用配比与经济产量的关系。试验表明 ,大棚土壤养分含量水平较高 ,番茄最高经济单产 6 5 75 0 .33kg·hm-2 的化学纯氮施用量为N 2 5 5kg·hm-2 ,羊厩肥施用量为 2 6 .2 5t·hm-2 ;实际经济施肥量应低于上述施用量。本试验进一步探讨了施肥与土壤养分含量及盐分含量变化的关系 ,结果认为大棚地膜覆盖条件下 ,肥料的施用能以较快的速度改变土壤养分水平和盐分状况。尿素施用量增加能显著增加土壤速效氮和全氮的含量 ;羊厩肥的施用能明显提高土壤有机质、全氮、速效磷、速效硫和速效钾的含量水平。尿素、羊厩肥类有机肥的过量施用会引起土壤次生盐渍化。覆盖地膜条件下 ,尿素的施用能显著增加土壤水溶性铵盐的含量 ;羊厩肥通过提供K+ 、Na+ 、Ca2 + 、Mg2 + 、SO2 -4 及PO3 -4 来提高土壤水溶性盐分含量。     

Therapeutic management of copper deficiency in buffalo heifers: Impact on immune function

To evaluate the magnitude of copper deficiency in Northern India and to examine the various haematobiochemicals, enzymes, vitamins and immune functions affected by copper deficiency, and to identify the parameters which can be of diagnostic importance in copper deficiency, a survey was conducted in 12 districts of Northern India. Significant deficiency of copper was observed in soil, fodder and serum samples of buffalo heifers. Fifty hypocuperaemic buffalo heifers were selected from these areas and were randomly divided into two groups, A and B. The heifers in group A were provided with mineral mixture containing copper sulphate and in group B without copper sulphate. Significant (p < 0.01) improvement in serum ceruloplasmin level was observed within 30 days of treatment, while significant (p < 0.01) improvement in monoamine oxidase and liver cytochrome oxidase was observed at the 60th day of treatment in group A animals. Significant improvement was observed in T₃ and T₄, in the animals of group A within 60 days of treatment. The values of vitamin A and E showed significant (p < 0.01) improvement within 30 days of treatment. The phagocytic activity of neutrophils against Candida albicans significantly (p < 0.01) improved in group A within 60 days of treatment. Similarly, significant improvement in superoxide dismutase activity in red blood cells was observed at the 30th day, and in total leukocytes and whole blood at the 60th day in group A animals. Significant improvement in liver copper level was observed at the 30th day of treatment, while in group B the liver copper was significantly (p < 0.01) depleted at the 60th day of experimentation. Additional copper supplementation improved growth performance significantly in group A.     

Effect of varied soil nitrogen supply on growth and nutrient uptake of young Norway spruce plants grown in a shaded environment

To understand the effect of increased soil N supply on tree growth and nutrient uptake, three-year-old Norway spruce seedlings were grown in pots on low-nutrient mineral forest soil supplemented with N in mineral or organic form. Outdoor shaded growth conditions were used, to test the hypothesis that shaded plants are particularly susceptible to high soil N supply. Plants were harvested eleven months after planting. Shoot growth was not affected by the N supply, but N concentrations in needles and roots were increased in plants supplied with mineral N (150 or 300 mg N [kg soil]^—1). Root growth was drastically reduced and root/shoot ratios were decreased in plants with higher N uptake. A high supply of mineral N to soil also decreased the concentrations of other essential elements (P, K) in the needles and thus had effects on plant growth which may impair the stress resistance of trees. Organic N in the form of keratin (150 mg N [kg soil]^—1) did not influence plant growth significantly. The adverse effects of high mineral N supply were particularly pronounced under shaded conditions in comparison to results from other experiments using higher light intensity and temperature conditions.     

长期施肥对冬小麦产量、养分吸收利用的影响

为了解黄土高原黄绵土区长期施肥的效应,以1981年设置于甘肃天水黄绵土上的长期定位试验为基础,研究了长期(1981-2013年)施肥对冬小麦产量、养分吸收和肥料表观利用率的影响.结果表明,单施氮肥或有机肥对冬小麦的增产作用不明显,化肥配施或化肥与有机肥配施的增产作用显著.氮磷钾配施有机肥(MNPK)下,冬小麦平均产量最高,达到5 069 kg· hm-2,较对照(不施任何肥料)提高了173.41％,对冬小麦产量的贡献率为62.60％;地上部氮、磷、钾携出量均最多,分别为141.13、16.86和123.69 kg· hm-2,较对照分别提高了239.42％、218.11％和237.31％;氮、钾肥表观利用率最高,分别为55.68％和76.43％.磷肥表观利用率以氮肥配施有机肥最高,为19.57％.肥料单施不利于提高其利用效率,化肥配施有机肥后氮、钾表观利用率较不配施有机肥降低.因此,农业生产中肥料合理配施才是提高作物产量和肥料利用率的有效措施.     

果树的营养诊断方法

果树在种植过程中需要很多养分,一旦缺乏,容易导致根茎发育迟缓。开展有效的果树营养诊断,对提升水果产量和质量是十分必要的。本文主要介绍了果树的营养诊断的原理,列举了常见的诊断方法,以期充分发挥果树营养诊断的实效性,更好地维护果树生长,确保果实质量,促进果树种植业的发展,提升农户经济效益。     

不同种植模式对高粱晋糯3号产量和养分吸收的影响

为了明确高粱新品种晋糯3号的最佳种植模式,研究了不同行距及密度对晋糯3号产量和养分吸收的影响。试验共设3个行距：30、50和60cm,每个行距处理设4个密度：4.5万、7.5万、10.5万和13.5万株/hm ²。结果表明,行距50cm时,晋糯3号单株叶面积、叶面积指数（LAI）、单穗粒数及产量最高,其次为行距60cm,行距30cm处理最低;相同行距时,密度为13.5万株/hm ²时产量较高,但与密度10.5万株/hm ²的产量没有显著差异。密度为4.5万株/hm ²时晋糯3号单穗粒数是密度为10.5万和13.5万株/hm ²时的1.8~2.0倍,产量为同一行距最高产量的72%~88%,这表明晋糯3号具有较强的群体调节能力。行距50cm结合密度4.5万株/hm ²促进了开花后植物对氮的吸收,开花后植株较强的氮素吸收能力是低密度产量提高的主要因素之一。行距50和60cm密度为10.5万和13.5万株/hm ²时产量较高且没有显著差异,但行距50cm有利于氮磷钾养分的吸收,为此晋糯3号的最佳种植模式为行距50cm结合密度10.5万~13.5万株/hm ²。     

中国南部天然常绿阔叶林的地上生物量、净初级生产力、养分分布和养分利用效率

在中国南部的江西九连山自然保护区,观测研究了天然常绿阔叶林的地上生物量、地上NPP(净初级生产力)、养分的积累和分布,以及不同生活型树种的养分利用效率.在两个样地,用相对生长回归法和收获法测定了地上生物量,数值各约为340和270t/hm2,其中叶生物量约为9.6t/hm2.地上NPP约为年9.9t/hm2,其中叶生产力占44％.各种一般养分(N,P,K,Ca,Mg,Na)在森林生态系统中积累的特点是,Na和N在矿质土壤中有高的相对分布,K和Mg属中间地位,Ca和P则高分布于地上生物量中.氮的养分利用效率(NUE)、平均停留时间(MRT)和年生产力(A)表明,针叶树是氮的最高效的利用者,常绿阔叶树次之,落叶树在氮的利用上是最低效的.     

牧草的营养价值研究及其在反刍家畜中的应用

根据牧草的基本营养价值特性,综合了近年来人们对反刍家畜利用牧草及提高牧草营养价值的生物学研究成果。     

潮土区不同品种花生的干物质积累与氮磷钾养分需求的差异分析

采用大田随机区组设计,在麦套花生种植区潮土上,研究不同品种花生干物质积累和氮磷钾养分需求的差异,为科学施用氮磷钾肥料提供技术支撑。结果表明,花生干物质的阶段积累量和积累速率呈抛物线变化趋势,花针后期最大,施肥能增加花生不同生长发育阶段干物质的积累量和积累速率,‘豫花9719’的最大,分别为3687.0 kg/hm²、184.3 kg/(hm²·d)。花生氮钾阶段积累量、阶段积累速率呈抛物线变化趋势,‘豫花9326’的磷呈双峰曲线变化趋势,‘豫花9719’、‘豫花9620’的磷呈抛物线变化趋势。每形成100 kg荚果,‘豫花9719’所需的氮(N)、磷(P₂O₅)、钾(K₂O)养分量最大,为3.877、1.103、1.456 kg,‘豫花9620’ 所需的氮(N)、钾(K₂O)养分量最小,为3.773、1.375 kg,‘豫花9326’所需的磷(P₂O₅)养分量最小,为1.058 kg;与氮养分相比,‘豫花9620’所需的磷养分比例最大,‘豫花9326’所需的磷养分比例最小,‘豫花9719’所需的钾养分比例最大,‘豫花9620’所需的钾养分比例最小。在N、P₂O₅、K₂O施用量分别为180、120、150 kg/hm²条件下,‘豫花9620’是氮、钾需求量小而磷需求量大的品种,‘豫花9326’是磷需求量小的品种,‘豫花9719’是氮、钾需求量大的品种。