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911.
Journal of Plant Diseases and Protection - Comparative studies of different isolates of Neonectria ditissima obtained from canker lesions and rotten fruit showed that both five-septate macroconidia... 相似文献
912.
本试验旨在研究不同铜源(硫酸铜、碱式氯化铜和柠檬酸铜)和铜添加水平(20和30 mg/kg)对断奶仔猪生长性能、血清铜含量与含铜酶活性以及组织铜含量的影响,探讨断奶仔猪对不同铜源的相对生物学利用率。试验采用3×2双因子随机区组设计,选取平均体重为(8.98±0.48) kg的杜×长×大三元杂交断奶仔猪112头,随机分为7组,每组4个重复,每个重复4头猪。对照组饲喂玉米-豆粕型基础饲粮(铜含量为7.80 mg/kg),各试验组分别在基础饲粮中添加20或30 mg/kg硫酸铜、碱式氯化铜或柠檬酸铜(均以铜含量计)。试验预试期3 d,正试期28 d。结果表明:1)试验组与对照组断奶仔猪平均日增重、平均日采食量和料重比均无显著差异(P>0.05)。2)饲粮铜源和铜添加水平对断奶仔猪血清铜含量具有显著影响(P<0.05),但对血清铜蓝蛋白和铜锌超氧化物歧化酶活性均无显著影响(P>0.05)。3)饲粮铜源和铜添加水平对断奶仔猪肝脏铜含量具有显著影响(P<0.05),但对心脏、肾脏、胰脏和跖骨铜含量均无显著影响(P>0.05)。4)根据多元线性回归斜率比法计算,以血清铜... 相似文献
913.
This study was conducted to investigate the effects of compound p1ant nutrients (CPN) on rumen fermentation parameters, rumen microbiota and fatty acid composition of longissimus dorsi musc1e in finishing sma11 tai1 Han sheep. Sixteen 4-month-o1d finishing sma11 tai1 Han sheep with an initia1 body weight (BW) of (24.18±0.31) kg were random1y divided into two groups, name1y, with 8 rep1icates per group and 1 sheep per rep1icate. The sheep in the contro1 group were fed a basa1 diet, whereas the sheep of the contro1 group (CPN group) was fed the basa1 diet supp1ementation with 3‰ CPN. The experiment 1asted for 97 days after 7 days adaption. The resu1ts showed as fo11ows: compared with the contro1 group, 1) adding CPN decreased the concentration of ammonia nitrogen (NH3-N) (P<0.05); 2) CPN supp1ementation affected beta diversity of rumen microbiota; 3) the re1ative abundance of Acidobacteriota, Erysipe1otrichaceae_UCG-002, Lactobacillus, and Megasphaera were enhanced by adding CPN (P<0.05), whereas, the re1ative abundance of Bacteroidetes and Prevotella was 1ower (P<0.05); 4) the supp1ementation of CPN had no significant effect on fatty acid composition of longissimus dorsi musc1e of fattening sma11-tai1ed Han sheep (P>0.05); 5) the contents of tota1 MUFA, C18:1n9c, C14:1, C16:1, C18:2n6c, C18:3n3 and n-3PUFA in the longissimus dorsi musc1e were corre1ated with the re1ative abundance of Megasphaera, Erysipe1otrichaceae_UCG-002, Succiniclasticum and Ruminococcus (P<0.05). In conc1usion, CPN can regu1ate the rumen microbiota structure and reduce the rumen NH3-N concentration of fattening sma11-tai1ed Han sheep. In production practice, CPN can be used as a rumen eco1ogica1 regu1ator. © 2023 Authors. All rights reserved. 相似文献
914.
915.
916.
Effect of Timing and Nitrogen Fertilizer Application on Winter Oilseed Rape (Brassica napus L.). I. Growth Dynamics and Seed Yield 总被引:1,自引:0,他引:1
The field experiments conducted on the grey‐brown podzolic soil in the four growing seasons (1998–2001) at Krzeslice Farm, central‐western Poland comprised seven fertilization variants: 80NF + 80CAN; 80CAN + 80CAN; 80AN + 80AN; 80NF + 50CAN + 30CN; 80CAN + 50CAN +30CN; 80AN + 50AN + 30CN (where NF – nitrofos NPK; CAN – calcium‐ammonium nitrate; AN – ammonium nitrate; CN – calcium nitrate) and control (without N) applied in split rates at the beginning of spring regrowth (80 kg N ha?1), stem elongation (80 or 50) and flower buds visible stages (30). The yielding effect of tested fertilization variants was significant in comparison with the control (2.24 t ha?1). The highest mean seed yield (3.64 t ha?1) was collected from 80AN + 80AN and 80CAN + 80CAN variants. Mean values of 4 years indicate that the second N rate division (80 + 50 + 30) decreased yield, although not significantly in comparison with these two N treatments. Plants grown on these treatments have developed different patterns of growth to yield the seeds. These patterns were characterized by very high crop growth rate during flowering (above 21 g m?2 day?1) and negative at maturation (down to ?2.5 g m?2 day?1). Plants fertilized with ammonium nitrate (80AN + 80AN) reached maximum growth rate earlier (65 days), which lasted longer (20 days) than plants fertilized with calcium‐ammonium nitrate (71 days lasting 17.5 days). Plants grown on the control treatment reached the highest crop growth rate within 79 days (14.8 g m?2 day?1), which lasted 15 days. 相似文献
917.
The use of overhead trellis systems for the production of dry-on-vine (DOV) raisins and table grapes in California is expanding. Studies were conducted from 2006 to 2009 using Thompson Seedless grapevines grown in a weighing lysimeter trained to an overhead arbor trellis and farmed as DOV raisins for the first two years and for use as table grapes thereafter. Maximum canopy coverage for the two lysimeter vines across years was in excess of 80 %. Seasonal (15 March–31 October) evapotranspiration for the lysimeter vines (ETLys) was 952 mm in 2007 (farmed as DOV raisins) and 943 and 952 mm (when farmed as table grapes). The maximum crop coefficient (K cLys) across all 4 years ranged from 1.3 to 1.4. These maximum values were similar to those estimated using the relationship where K c is a function of the amount of shaded area measured beneath the canopy at solar noon (K c = 0.017 × percent shaded area). Covering the lysimeter’s soil surface with plastic (and then removing it) numerous times during the 2009 growing season (1 June–14 September) reduced ETLys from an average of 6.4 to 5.6 mm day?1 and the K c from 1.07 to 0.93. A seasonal basal K c (K cb) was calculated for grapevines using an overhead trellis system with a 13 % reduction in the K cLys across the growing season. 相似文献
918.
Irrigation systems aim to meet multiple objectives and performance must therefore be assessed using quantifiable measures for each. It therefore becomes an extremely difficult task to capture the valuation of all of them simultaneously and to mentally process the trade-offs between them in order to arrive at an overall impression of system performance. There is a need for a methodology which provides a systematic approach to comparing and combining the components of overall performance.Multi-Attribute Utility Theory offers an attractive approach to assessing performance of irrigation systems in the form of a utility function which reflects the strength of preferences and trade-offs between individual performance criteria. The method is described and demonstrated on the basis of a case study of irrigation in Sudan. 相似文献
919.
Summary Traffic during alfalfa harvest operations can cause soil compaction and damage to newly growing stems. Root exploration for soil water and nutrients, forage growth dynamics, and final yield can all be affected. The objectives of this study were to determine the long-term effects of harvest traffic and soil compaction on water-use efficiency (WUE) of alfalfa grown in a Wasco sandy loam (coarse-loamy, mixed, nonacid, thermic Typic Torriorthents). Alfalfa was planted into tilled soil and managed with or without harvest traffic. Plants subjected to traffic during harvest had a significantly lower WUE two out of the three years studied compared to plants that were never subject to traffic. The second experiment examined whether planting alfalfa into compacted soil and managed with or without harvest traffic altered WUE. Soil compaction had no affect on alfalfa WUE. It was significantly lower when grown in compacted soil and subjected to harvest traffic. It is suggested that the decrease in WUE caused by harvest traffic may be explained by plants allocating carbohydrates to damaged shoots and crowns instead of to above ground forage production. The area of the field affected by harvest traffic, which damages newly growing stems, should be minimized to increase crop water use efficiency. 相似文献
920.
Summary Knowledge of the flux of water flowing through macropores in soils is required to devise management strategies for efficient fertiliser use and to prevent fast movement of solutes and pollutants to groundwaters. Water and solute balances in soil profiles were used to develop a simple model for assessing the magnitude of macropore flow. Fluxes of water bypassing the soil matrix were calculated at 35 sites to be between 0 and 415 mm y–1, with the flux being < 200 mm y–1 at most sites. The maximum flux was three times the flux flowing through the soil matrix but only one third of that infiltrating the soil. The flux of macropore flow was not simply related to soil types or soil properties, although the highest fluxes did occur in cracking soils. A qualitative method of using soil chloride profiles to indicate the occurrence (but not magnitude) of bypass flux was also demonstrated. Both these quantitative and qualitative assessments of bypass flow should assist in interpreting root-zone hydrology in soils. 相似文献