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1.
D.L. Barnes M. Swart M.F. Smith G.H. Wiltshire 《African Journal of Range and Forage Science》2013,30(3):92-98
Forty systematically‐placed observation points were established in a 1.5‐ha area of floristically unifoim veld in which productivity varied spatially. At each point grass yields were determined by harvesting quadrats at eight‐week intervals during the growing season, and the volumetric water content of the soil was measured weekly. In addition, root mass and root‐N content, and soil variables involving C and N contents, extractable P, K, Ca and Mg, cation exchange capacity and base saturation, pH, clay content and soil depth, were determined. The data were examined using linear correlations between variables, principal components analysis and multiple regression. The major factors associated with variations in yield were, in order of importance, soil water content, the N supply (as expressed by root‐N content or root‐N mass) and the cation supply (as expressed by the topsoil variables, extractable Ca or cation exchange capacity or percentage base saturation). There was a relatively weak positive association between yields and the H+ concentration in the subsoil, and a weak negative association between yields and the clay content of the topsoil. A multiple regression function involving all five factors accounted for 77.3% of the variation in dry matter yield. 相似文献
2.
对天山北坡放牧条件下的绢蒿草地进行野外调查,以探讨植物群落物种组成、多样性特征及其与环境因子之间的关系。结果表明:1)绵羊放牧过程中形成了明显的放牧强度梯度,草地利用率适中。通过除趋势对应分析 (DCA)将放牧区内的植物群落划分为8个类型,各类型植物群落的物种多样性有显著差异,且群落间存在异质性;2)采用除趋势对应典范分析法(DCCA)中的前项选择,对所获取的9个环境因子进行筛选,最终土壤有机质含量、粪便量、放牧强度、凋落物生物量、海拔、坡向等6个环境因子成为决定物种分布和群落结构组成的主导因素。DCCA排序结果反映出了实际的生态意义,有机质、放牧强度、粪便量在第一排序轴有明显的梯度变化,而坡向和凋落物则在第2轴上呈现出明显梯度变化,物种和群落也沿着上述环境要素的梯度变化而依次分布,很好地解释了放牧条件下绢蒿荒漠草地物种、群落与环境条件之间的关系。 相似文献
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新鲜绵羊粪尿对土壤和植物矿物质元素含量影响的试验于 1998年在贵州高原草地试验站进行。结果表明 ,绵羊新鲜粪尿加入土壤后 ,土壤 K呈波浪型升高。 K又显著影响土壤 Ca、Fe和Mn的浓度及土壤 p H值。土壤 Na水平呈下降趋势。土壤中 Ca含量与土壤可交换性亚硝态氮和硝态氮显著相关。土壤 Mg的变化不如其他元素变化明显。土壤 Cu受 Ca、Fe和亚硝态氮及硝态氮的影响显著。土壤 Zn比试验前有所下降 ,其含量与土壤铵态氮和亚硝态氮呈显著负相关 ,而与土壤Na、Mg和 Cu呈显著正相关。土壤 Fe在整个试验过程中呈上升趋势 ,UDT处理几乎呈直线上升。土壤 Mn的变化和土壤 K有显著正相关 ,还与铵态氮相关极显著 (R=0 .80 51,P<0 .0 1)。绵羊新鲜粪尿使植物体内 Fe、Zn水平降低 ,但促进植物 Mn的含量升高 ,而对植物 Cu水平影响最小。结果还表明 ,植物体内 K含量受土壤 Cu和 Na的抑制 ,同时还与植物吸收 Mg、Na和 Fe发生拮抗作用 ,促进了植物 Ca的吸收。植物吸收 Na与土壤 Na的浓度显著相关 ,但受到植物吸收 K、Ca和 Mn的抑制。植物 Ca水平与降雨及植物体内 Fe水平呈显著负相关 ,而与土壤可交换性铵态氮和植物体内 K、Mg含量呈显著正相关。植物体内 Mg含量受土壤可交换性铵态氮和硝态氮的显著影响 ,但受土壤 Ca的抑制 相似文献
4.
L G DuPisani W L J Van Rensburg D P J Opperman 《African Journal of Range and Forage Science》2013,30(2):52-55
Abstract The influence of soil pH and fertilization (N, P and Zn) on the dry matter (DM) production, chemical composition (crude protein, P, K, Ca, Mg and Zn content) and organic matter (OM) digestibility of Anthephora pubescens Nees was evaluated in pots. The highest Dm production was obtained in the neutral soil medium (pH 6,5 in H2O). Both the acid (pH 4,5 in H2O) and alkaline (pH 7,5 in H2O) soil mediums adversely affected DM yield, crude protein (CP), Zn content and OM digestibility of A. pubescens. Fertilization invariably increased DM production. 相似文献
5.
D L Barnes 《African Journal of Range and Forage Science》2013,30(2):30-36
Abstract Yield response of crownvetch (Coronilla varia) cv. Penngift, lucerne (Medicago sativa) cv. CUF 101, white clover (Trifolium repens) Dusi type and Kenya white clover (T. semipilosum) cv. Safari to differential application of lime and superphosphate were determined in a 5 × 4 factorial experiment on a virgin soil of the Griffin form. Lime rates varied from 0 to 7t/ha and phosphate rates from 0 to 150 kg P/ha. Patterns of response differed markedly between legumes. Clover yields were high even in the absence of lime and responses to differential lime rates were negligible. By contrast, yields of crownvetch and lucerne where no lime was applied were very low and yields increased markedly with successive increments of lime, the response of lucerne being greater than that of crownvetch. All the legumes responded to the application of phosphate, but yield increases decreased progressively with increasing phosphate level. Effects of the treatments on soil acidity and extractable nutrient elements were determined. A notable feature was an interactive effect between lime and phosphate on extractable phosphorus (0,25M NaHCO3, pH 8,5). Values increased progressively with successive increments of phosphate application, but decreased with increasing lime application. Depressive effects of lime were greater than at the lower levels of phosphate. 相似文献
6.
对多年生黑麦草Lolium perenne,草地早熟禾Poa pratensis和苇状羊茅Festuca arundinacea 3种冷季型草坪草生长季内在田间持水量(FC)30%～50%,50%～70%,70%～90% 3个水分梯度下的地上生物量、再生速度及其坪用质量进行了田间测定.结果表明:3种草坪草在FC 30%～50%下的再生速度与50%～70%下的再生速度具有显著性差异,当FC 50%～70%时,再增加水分并不能显著增强草坪草的再生速率.多年生黑麦草、草地早熟禾、苇状羊茅整个试验期间的地上生物量干物质累积在FC 30%～50%,50%～70%之间差异显著,FC 50%～70%与70%～90%下的地上生物量累积差异不明显.3种草坪草叶片组织含水量随着水分梯度的增加而增大,叶片组织含水量对水分梯度的响应基本显著.方差分析结果表明,3种冷季型草坪草在不同的水分梯度下,其坪用质量具有差异显著性(P＜0.05),灌水能显著提高草坪草的质量.但在FC 50%～70%的水分梯度下,3种冷季型草坪草都表现理想(得分＞6.5). 相似文献
7.
甘肃陇东地区紫花苜蓿草地土-草矿质养分含量及其相关性 总被引：1，自引：0，他引：1
为明确甘肃陇东地区苜蓿草地土壤矿质养分亏缺及牧草养分水平,对环县、合水、庄浪、泾川的苜蓿和土壤的N、P、K、Fe、Mn、Cu、Zn含量及其相关性进行研究。结果表明:试验区土壤N含量略高于我国平均水平、P含量低于我国平均水平,K素略低于我国平均水平;土壤矿质元素含量为有效Mn极富、有效Zn中等、有效Fe、Cu缺乏。苜蓿中N含量适中,P、Fe、Mn、Cu、Zn含量较低,K素含量高;苜蓿对K素需求量高于所测其他矿质养分;苜蓿微量元含量由高到低为FeMnZnCu,且苜蓿对Fe的需求高于Mn,Zn和Cu。土壤与苜蓿的全P含量极显著相关(r=-0.738,P0.01),全N含量显著相关(r=-0.522,P0.05),有效Fe含量显著相关(r=0.61,P0.05),有效Zn含量呈高度相关(r=0.742,P0.05);土壤与苜蓿全K、有效Cu、有效Mn含量未呈现出显著关系。 相似文献
8.
The objective was to evaluate the content of P, Ca, Mg, K, Na, Cu, Fe, Zn, Se, and Mn in soil, forage, and serum of horses in several production units (PU) during rainy and dry seasons and predict their concentration in serum from their content in soil and forage. Soil and pastures were sampled in the dry (November–December) and in rainy seasons (June–July), and blood samples were collected from the jugular vein of 76 horses in both seasons at four PU. The experimental design was a completely random design within a 4 × 2 (PU × season) factorial arrangement of treatments. Concentration of minerals in soil differed (P < .05) among PU, and contents of P, Ca, Mg, and K were low; Zn and Fe were high; and Cu and Mn were adequate. Mineral concentrations in forage differed among PU and season, and among PU within season (interaction P < .05). Contents of Ca, Mg, Na, Zn, and Cu were low; Fe was high; and P, K, Se, and Mn adequate. The mineral concentration in equine blood serum differed (P < .05) among PU and season. Overall, there were deficiencies of P, Ca, Mg, Na, Cu, and Se, but adequate amounts of K, Zn, and Fe. There are imbalances of minerals in soil and forages which effected their concentration inequine blood. 相似文献
9.
为了解新余蜜橘养分状况,对新余市37个橘园土壤和叶片的营养元素含量进行了测定。结果表明,27%的新余蜜橘园土壤偏酸性,35.1%的土壤有机质含量低于适宜标准。土壤碱解N、速效P和K含量不足的比例分别54%、94.6%和67.6%。土壤交换性Ca和Mg含量在所有果园土壤中均不足。相反,土壤有效Fe、Mn和Cu含量的超标比例分别为100%、48.6%和48.7%。树体叶片元素分析表明：N含量偏低比例为32.4%,超标比例为43.2%;叶片P和K含量以偏低为主,比例分别为62.2%和75.7%;Ca含量有16.2%的果园偏低;Mg含量偏低和适量的比例均为43.2%;微量养分Fe和Mn含量偏高比例分别为54.1%和43.2%,Cu含量普遍适量,Zn含量偏低和缺乏比例均为40.5%。相关分析表明,除P、Mg和Cu外,其他元素含量在相应的土壤和叶片中均显著正相关。综上所述,新余蜜橘管理过程中需重视提高土壤pH值和有机质含量,补充P、K和Zn营养,同时控制Fe、Mn和Cu使用量。 相似文献
10.
江苏省种茧育桑园土壤肥力状况调查 总被引：1，自引：0，他引：1
采用化学分析的方法研究江苏省 36个蚕种场种茧育桑园土壤养分供应状况。不同土层的供肥能力相差较大 ,土壤有机质、全氮、速效磷、速效钾、有效铁、有效锰、有效锌和有效铜等所有养分含量均是上层 (0～ 2 0cm)大于下层 (2 0～ 4 0cm) ,上、下层养分含量的相对相差从 14 5 %～ 5 3 8% ,说明种茧育桑园土壤的养分主要集中在上层。不同地区种茧育桑园土壤的供肥能力有较大的差距 ,太湖地区肥力水平较高 ,淮北地区和江淮地区的供肥能力较差 ,而宁镇扬丘陵地区和盐城地区的肥力水平中等 ,因此 ,在淮北地区和江淮地区要加强桑园的肥培管理。土壤微量元素中有效锰和有效铜的供应尚可 ,但盐城地区土壤有缺铁的可能 ,淮北地区和江淮地区有缺锌的可能。 相似文献
11.
《African Journal of Range and Forage Science》2013,30(3):127-140
This study investigated dip-tank use effects on herbaceous vegetation and soil, and relationships between environmental and species variables. Eight dip-tanks, three each in sandy (DPBS) and loamy (DYRL) soils, and two in stony (ROSG) soils were used. Data were collected at 50, 100, 150, 300, 500, 700 and 900 m from each dip-tank. In DPBS, phosphorus and potassium contents were highest (P ? 0.05) on approaching dip-tanks. In all soils, forb and perennial grass abundances showed significant differences but there were no significant trends with distance. These variables are not sufficiently sensitive to form gradients or the gradient is diminished with heavy grazing. In DPBS, the canonical correspondence analysis showed negative correlation of distance with bareness, the abundance of Aristida rhiniochloa and Cynodon dactylon, which may suggest these variables may respond to grazing gradients around dip-tanks, but this pattern was not established on the other soil types. Therefore, caution is required in drawing conclusions of the piosphere effect around focal points. The abundance of highly palatable species was low except for Panicum maximum in DPBS. It is concluded that vegetation and soil changes are driven by abiotic (site and soil) and biotic (livestock) factors that have different influences at different scales. Therefore, any rangeland utilisation and management program should consider these drivers. 相似文献
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《Strength and Conditioning Journal》2020,73(2):276-284
Plant functional traits can be used to predict ecosystem responses to climate gradients, yet precipitation explains very little variation for most traits. Soil water availability directly influences plant water uptake and thus may assist with the improvement of plant trait–water relationships. However, this promise remains poorly realized due to rare tests. Here, we provide the first study that attempts to link climate factors, vertical soil water availability, and community composition at a regional scale. Our study paired field-measured vertical soil available water (0–300 cm) and community functional composition at 46 herbaceous grassland sites along a steep hydrothermal gradient in the Loess Plateau of Central China. Community functional composition was expressed via community-weighted means of eight traits. Structural equation modeling was employed to evaluate the role of vertical soil available water content, controlled by precipitation and air temperature, in affecting plant community-weighted traits. We found that soil available water content at depths of 20–100 cm was typically responsible for mediating the effects of precipitation and air temperature on plant community composition. This emerged as the predominant factor to explain variations in grassland response traits, including leaf area, specific leaf area, and leaf dry matter content. These traits exhibited clear drought-induced shifts along soil desiccation gradients and responded to drier conditions by reducing leaf area/specific leaf area and increasing leaf dry matter content. Our findings rehighlighted soil water availability as the core driver that needs to be considered in the restoration and management of dryland ecosystems. 相似文献
14.
《Strength and Conditioning Journal》2020,73(1):97-103
Accumulating data indicate the importance of fire in rangeland systems. Mowing is a common management technique sometimes considered a surrogate for fire. However, direct comparisons of fire and mowing effects are limited. Our objective was to determine whether mowing can substitute for fire in rangeland by comparing effects on plant biomass, composition, cover, soil nutrients, and forage quality. Three disturbance treatments (nontreated control, spring mowing with clipping removal, and spring fire) were randomly assigned to 21 plots (5 × 5 m) each on silty and claypan ecological sites in a completely randomized design, with seven replications per site. Current-yr biomass was similar among control, mowed, and burned treatments (1 003, 974, 1 022 ± 64 kg ● ha− 1). Mowing shifted functional group composition by reducing C3 perennial grass 12% and increasing forbs 8%. Non-native species were a larger component of mowed (12%) than control (6%) or burned plots (4%). Fire increased bare ground 35%, reduced litter 32%, and eliminated previous yrs’ growth the first growing season. Plant-available soil N and S more than doubled with fire, and there was a trend for more P in burned plots. Mowing effects were limited to a trend for less soil Fe. Mowing affected 42% of the forage quality variables with a 2% average improvement across all variables. Fire affected 84% of the variables, with a 12% average improvement. Mowing increased forage P and K, whereas fire increased forage concentrations of N, K, P, S, Mg, Fe, Mn, and Cu. Total digestible nutrients increased 1.1% with mowing and 2.1% with fire. In vitro dry matter disappearance increased 2.2% with mowing and 6.7% with fire. Burned plots had greater in vitro fermentation than controls or mowed plots. Although mowing can be a useful management tool, it is not a substitute for the ecological effects of rangeland fire. 相似文献
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A study was conducted to determine the effect of dietary Mn on performance of growing and finishing steers, and to evaluate the effect of pharmacological concentrations of Mn on lipid metabolism and subsequent carcass quality in steers. One hundred twenty Angus cross steers were blocked by BW and origin and assigned randomly to one of six treatments (four replicate pens per treatment) providing 0 (control), 10, 20, 30, 120, or 240 mg of supplemental Mn/kg of DM from MnSO4. Steers were fed a corn silage-based growing diet for 84 d, and then switched to a corn-based finishing diet for an average of 112 d. The control growing diet analyzed 29 mg of Mn/kg of DM, whereas the control finishing diet analyzed 8 mg of Mn/kg of DM. Jugular blood samples were obtained on d 56 of the growing and finishing phase for plasma Mn and glucose analysis. Final BW, DMI, ADG, and G:F did not differ (P = 0.38 to P = 0.98) across treatments during growing and finishing phases. Plasma Mn concentrations were not affected by treatment; however, liver and LM Mn at slaughter increased linearly (P = 0.02 and 0.002, respectively) with increasing dietary Mn. Plasma glucose concentrations did not differ (P = 0.90) among treatments. Serum nonesterified fatty acid concentrations tended (P = 0.10) to decrease linearly with increasing dietary Mn on d 56 of the finishing phase. Longissimus muscle lipid concentration was affected quadratically (P = 0.08) by dietary Mn. Muscle lipid seemed to increase slightly when steers were fed 30 or 120 mg of Mn/kg of DM, but decreased with the addition of 240 mg of Mn/kg of DM. Carcass characteristics were not affected by dietary Mn. Manganese concentrations of 29 and 8 mg/kg of DM in the growing and finishing diets, respectively, were adequate for maximizing performance of growing and finishing steers in this experiment. Supplementing physiological or pharmacological concentrations of Mn affected lipid metabolism; however, this did not result in altered carcass characteristics. 相似文献
17.
"黑麦草-水稻"草田轮作系统研究Ⅶ黑麦草残留物的田间分解及营养元素的释放动态 总被引：16，自引：3，他引：13
采用尼龙网袋分解法,将一定量的黑麦草根系和地上留茬(统称黑麦草残留物)置于田间耕作层令其自然分解,分别于埋设后11,39,70,109,161和244 d收集尼龙网袋内的样品,洗净,烘干,称重后用于分析全量N、P、K、Ca、Mg、Mn和Fe的含量.结果表明,黑麦草残留物在大田中通过生物降解,将养分释放到土壤中,在后作水稻的生长发育过程中,分解初期的释放量较高,埋设10 d后黑麦草残留物样品中近90%的Ca和37%～50%的C、N、P、K和Fe被释放,Mn和Mg则只有0.4%～13.4%被释放.在早稻生长过程中黑麦草残留物有74.9%被分解,C、N、Mn和Mg的矿化率均在80%以下,表现出一定的缓释效应.晚稻收获时各养分的释放率达到92%～99%.理论上黑麦草根系可以为0～20 cm土层贡献有机质、N、P、K、Fe、Mn、Mg和Ca分别达到865.42 g/kg,26.92 g/kg,1.75 g/kg,23.83 g/kg,2 741 mg/kg,75 mg/kg,162 mg/kg和46 mg/kg. 相似文献
18.
内蒙古苏尼特右旗草原土壤营养元素有效态含量分析 总被引：2，自引：0，他引：2
本研究选择内蒙古苏尼特右旗天然草场主要6个草场类,8个草场型,分析了0~30 cm土壤营养元素(全N、P、K、Ca、Mg、S、Fe、Mn、Cu、Zn、B和Mo)有效态含量及与土壤有机质、pH值之间的相互关系。结果表明,1)研究区土壤pH(8.84±0.23),均为碱性土壤;土壤有机质含量与全N含量均较低,平均分别为(9.92±4.65) g/kg和(0.46±0.25) g/kg;营养元素有效态含量积累顺序为:河泛地、湖盆低地盐生草甸草场类>荒漠草原草场区“小针茅+无芒隐子草+葱属”植被型>沙丘植被草场类,河泛地、湖盆低地盐生草甸草场类土壤矿质元素有效态含量显著高于其他草场类。2)土壤富含K元素,B和Mo处于严重缺乏状态;除了河泛地、湖盆低地盐生草甸草场类以外草场类微量元素含量均处于轻度缺乏或缺乏状态。3)土壤pH与土壤N、P、Ca、Mn和Cu元素有效量存在显著负相关性关系;土壤有机质则与土壤N、P、Ca、S、Fe、Mn和Cu元素有效量存在极显著正相关性关系。 相似文献
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荒漠草原物种多样性、生产力与气候因子和土壤养分之间关系的研究 总被引：1，自引：0，他引：1
物种多样性对生态系统功能的影响是生态学领域的核心问题之一。本研究利用内蒙古荒漠草原80个野外植被、土壤调查样地资料,结合气候数据,探讨物种多样性、生产力与气候因子和土壤养分的关系,为进一步认识多样性-生产力关系提供参考。结果表明,1)物种多样性、生物量与年平均降水量均呈线性正相关,与年平均温度均呈线性负相关,与干燥指数均呈线性正相关。2)物种丰富度与土壤全磷含量呈线性负相关(R2=0.072, P<0.05),与速效氮含量呈线性正相关(R2=0.183, P<0.01),Shannon-Wiener指数与速效氮也呈线性正相关(R2=0.061, P<0.05);生物量与土壤全氮、速效氮和有机碳含量都呈线性正相关,相关系数分别为0.150,0.177,0.089(P<0.01)。3)群落生物量与物种多样性呈线性正相关关系。4)干燥指数是影响多样性和生物量的主要环境因子。 相似文献
20.
云南湿热地区距瓣豆的铜、锌和锰营养 总被引：2，自引：1，他引：1
在云南省亚热带湿热地区为了探讨微量元素铜、锌和锰施用对引进优良豆科牧草距瓣豆生长的影响,开展铜、锌和锰的不同施量对距瓣豆干物质产量、种子产量影响的单因子完全随机区组试验.结果表明,施用铜1.2～2.4 kg/hm2和锰3. kg,/hm2的处理比对照距瓣豆干物质产量分别提高58.4%～88.4%和48.1%(P<0.05),种子产量分别提高295.5%～272.7%和80.4%(P<0.01);施铜还可提高距瓣豆氮、钙、硫、铜、锌和锰含量,显著增加单位面积距瓣豆对氮的需求量(P<0.01),其次是磷、钾、钙、硫、铜、镁、锌和锰的营养需求量(P＜0.05);施适量锰可增加距瓣豆的钙、锌和锰含量,显著增加单位面积距瓣豆的钙和锌产量(P＜0.01),其次是氮、磷、钾、镁、铜和锰的产量(P＜0.05).施用锌虽然对距瓣豆干物质产量和种子产量提高没有显著效果,但是可以提高距瓣豆的钙、锌和锰含量,显著提高单位面积距瓣豆的锌产量(P＜0.01),其次是氮、钾和锰的产量(P＞0.05),显著的降低距瓣豆对钙(P<0.01)和磷(P<0.05)的吸收量.综合分析,在施磷肥和其他元素肥的基础上,加施铜1.2 kg/hm2或锰3.9 kg/hm2,可获得高产、收益好的距瓣豆优质饲草,同时满足饲养牲畜生产的营养需要. 相似文献