不同大豆品种在养分吸收及产量上的比较

采用盆栽试验方法对红丰11等四个大豆品种吸收利用氮、磷、钾养分的能力进行了比较研究。结果表明,在施肥一致的条件下,不同大豆品种对养分的吸收利用能力不同,养分利用率也不同,导致产量的差异。以红丰11养分吸收量最多,表现产量最高。     

Invertebrate grazing determines enzyme production by basidiomycete fungi

Extracellular enzymes produced by heterotrophic microorganisms in the soil are responsible for the decomposition of organic compounds. Basidiomycete fungi are the primary decomposer agents in temperate wooded ecosystems and contribute extensively to extracellular enzyme activity and nutrient mineralisation within soils. Growth and development of basidiomycete mycelia is influenced by soil-dwelling invertebrate grazers with potential implications for fungal activity and ecosystem functioning. The impacts of four invertebrate taxa belonging to Isopoda, Myriapoda, Collembola and Nematoda on the production of eight hydrolytic enzymes by four saprotrophic basidiomycetes (Phanerochaete velutina, Resinicium bicolor and two strains of Hypholoma fasciculare) were compared in a factorial microcosm study. Grazing generally increased enzyme production but invertebrates had species-specific impacts on enzyme activity. The magnitude of grazing influenced enzyme activity; macrofauna (woodlice and millipedes) induced the greatest responses. Enzymatic responses varied markedly between fungi. Grazing enhanced enzyme activity in the exploitative mycelial networks of P. velutina and H. fasciculare, while the opposite effects were observed in the explorative R. bicolor networks. The impacts of soil fauna on nutrient mineralisation depend on fungal community composition. β-glucosidase, cellobiohydrolase, N-acetylglucosaminidase, acid phosphatase and phosphodiesterase activities were affected most frequently by grazing and invertebrate activity, and thus had direct consequences for carbon, nitrogen and phosphorous cycling. The results indicate that invertebrate diversity and community composition may influence the spatial distribution and activity of extracellular enzymes with direct implications for nutrient mineralisation and trunover in woodland soils.     

番茄营养液深液流无限生长型栽培营养液的管理与调控

根据北京地区的水质特点和非常规栽培的特殊性,制定了在营养液深液流无限生长型栽培条件下使用的营养液配方。并根据番茄生长发育的不同时期和养分吸收特性,及时调整营养液的组成成分、浓度、酸碱度等,对营养液实行动态管理。栽培试验结果表明,该配方中的各种营养成分（N、P、K、Ca、Mg等）基本可以被番茄均衡地吸收,属于营养均衡的配方。     

膨化全脂大豆对仔猪生产性能和养分消化率的影响

根据遗传、性别、体重等相一致的原则,将30头35日龄断奶的杜洛克仔猪随机分为3个组,每组设2个重复,研究膨化全脂大豆对仔猪生产性能和饲粮养分消化率的影响。对照组以玉米豆粕等配制饲粮,试验1组以膨化全脂大豆替代50%的豆粕,试验2组以膨化全脂大豆替代全部豆粕,其他饲粮组成保持不变,进行40 d的饲养试验。在试验第20 d开始,连续收集粪便3 d,测定饲粮养分消化率。结果表明,试验1组日增重比对照组提高了17.6%,差异显著(P<0.05),试验2组比对照组提高了7.4%(P>0.05);试验1组和试验2组饲料利用率分别比对照组提高11.7%和7.6%。试验2组干物质消化率显著高于对照组(P<0.05),蛋白质的消化率三个组基本接近,但含有膨化大豆的试验1组和试验2组的粗脂肪和粗灰分的消化率均比对照组有提高趋势。     

Effects of supplementation with narasin,salinomycin, or flavomycin on performance and ruminal fermentation characteristics of Bos indicus Nellore cattle fed with forage-based diets

The aim of the present study was to evaluate the inclusion of narasin, salinomycin, or flavomycin for 140 d on ruminal fermentation parameters, apparent nutrient digestibility, and performance of Nellore cattle offered a forage-based diet. In experiment 1, 32 rumen-cannulated Bos indicus Nellore steers [initial body weight (BW) = 220 ± 12.6 kg] were assigned to individual pens in a randomized complete block design according to their initial shrunk BW. Within block, animals were randomly assigned to 1 of 4 treatments: (1) forage-based diet without feed additives (CON; n = 8), (2) CON diet plus 13 ppm of narasin (NAR; n = 8), (3) CON diet plus 20 ppm of salinomycin (SAL; n = 8), or (4) CON diet plus 3 ppm of flavomycin (FLA; n = 8). The experimental period lasted 140 d and was divided into 5 periods of 28 d each. The inclusion of feed additives did not impact (P ≥ 0.17) dry matter intake (DMI), nutrient intake, and apparent total tract digestibility of nutrients. Nonetheless, steers fed NAR had lower (P < 0.01) molar proportion of acetate compared with CON, SAL, and FLA steers, whereas ruminal acetate tended to be greater (P < 0.09) for SAL vs. CON and FLA, but did not differ (P = 0.68) between CON vs. FLA steers. Ruminal propionate was the highest (P < 0.01) for steers fed NAR and did not differ (P > 0.20) between CON, SAL, and FLA. Consequently, NAR steers had the lowest (P < 0.01) Ac:Pr ratio, whereas Ac:Pr did not differ (P > 0.18) among CON, SAL, and FLA. Total volatile fatty acids were greater (P < 0.04) for NAR and CON vs. SAL and FLA, but did not differ (P > 0.67) among NAR vs. CON and SAL vs. FLA. In experiment 2, 164 Nellore bulls (initial shrunk BW = 299 ± 2.5 kg) were assigned to feedlot pens for 140 d in a randomized complete block design. Within block (n = 10), animals were randomly assigned to the same treatments used in experiment 1. Average daily gain was greater (P < 0.01) in NAR vs. CON, SAL, and FLA bulls, and did not differ (P > 0.12) between CON, SAL, and FLA bulls. Bulls fed NAR had greater (P < 0.02) DMI (as kg/d or % BW) and final shrunk BW compared with CON, SAL, and FLA bulls, whereas DMI and final shrunk BW did not differ (P > 0.26) between CON, SAL, and FLA bulls. Feed efficiency, however, was not impacted (P = 0.51) by any feed additives used herein. Collectively, narasin was the only feed additive that benefited performance and ruminal fermentation of Nellore animals fed a forage-based diet.     

The potential of some neotropical Albizia species and close relatives as fodder resources

Six neotropical woody Mimosoid legume species, in the genera Albizia, Hesperalbizia, Pseudosamanea and Samanea, were evaluated for potential as animal fodder, using a combination of analytical techniques, in vitro digestibility, and assessment of relative palatability to sheep in a preference test in Honduras. Leaf chemical composition was evaluated in terms of content of crude protein, acid detergent fibre, neutral detergent fibre, condensed tannins (acid butanol assay) and total tannins (protein precipitation: radial diffusion assay). Crude protein and digestibility data were combined into an ‘index’ by which the species could be ranked; according to this criterion the most promising species were Pseudosamanea guachapele, Albizia adinocephala and Hesperalbizia occidentalis. In the preference test, however, Pseudosamanea guachapele and Albizia niopoides appeared much more palatable to sheep than any of the other species. A small amount of H. occidentalis was also eaten, but the other species were completely refused throughout the 16 day experiment. H. occidentalis was the fastest-growing species on this site. Using a combination of these evaluation criteria, H. occidentalis and P. guachapele appear to be the species with the greatest potential for fodder use. This revised version was published online in June 2006 with corrections to the Cover Date.     

高粱遗传资源的耐瘠性鉴定研究

人工设置瘠薄地块，对高粱进行耐瘠性鉴定，应用耐瘠指数和出苗至开花延迟天数两个分级指标，结合田间目测评级，对养分胁迫下高粱受害程度、产量降低水平和植株死亡等与对照区品种比较，划分品种的抗性等级，从高粱种质资源中筛选出一级耐瘠品种77份。     

麦麸猪消化能与能量消化率预测方程的建立

本试验旨在测定麦麸的猪消化能(DE)及麦麸各化学成分对DE与能量消化率(DCE)的影响,分析用麦麸化学成分建立其DE与DCE的预测方程。试验选用12头三元杂交(杜×大×长)去势公猪[初始体重为(36.6±2.9)kg],采用2个6×6拉丁方试验设计(6期,11种饲粮),应用全收粪法测定10种不同产地和批次麦麸的DE,通过分析麦麸原料中的粗蛋白质(CP)、粗纤维(CF)、酸性洗涤纤维、中性洗涤纤维、淀粉(St)、粗脂肪、粗灰分、总能与DE及DCE之间的相关关系,筛选出最佳的预测因子并建立预测方程。结果表明:10种麦麸的平均DE为11.72 MJ/kg(干物质基础),平均DCE为61.31%,St为DE和DCE的最佳预测因子。推荐DE预测方程:DE=0.31×St+3.71(R2=0.76,RSD=0.42,P<0.01)、DE=-0.91×CF-0.71×CP+33.80(R2=0.76,RSD=0.35,P<0.01)。推荐DCE预测方程:DCE=1.70×St+22.28(R2=0.76,RSD=2.89,P<0.01),DCE=-5.02×CF-3.65×CP+182.81(R2=0.80,RSD=1.79,P<0.01)。由此可知,本试验利用麦麸原料营养成分建立的DE及DCE的预测方程相关指数较高,且由本试验结果预测的DE值比较准确。     

不同菌制剂对育成期梅花鹿采食量及营养物质消化率的影响

为了确定不同菌制剂对育成期梅花鹿采食量及营养物质消化率的影响,选择健康、年龄一致、体重相近雌性育成期梅花鹿36头,随机分成4组,每组9头,精饲料饲喂量相同,分别在秸秆饲料中添加白腐菌、枯草芽孢杆菌、乳酸菌和复合菌(白腐菌、枯草芽孢杆菌、乳酸菌按1∶1∶1复合)各0.25 g/kg秸秆.结果表明:在梅花鹿饲料中添加白腐菌...     

Effects of different nutrient solution formulations on morphological and biochemical characteristics of nursery fig trees grown in substrate culture

This research was carried out to determine the effects of different nutrient solution formulations on the growth of nursery fig trees in substrate culture, which is one of the soil-less culture techniques. The hardwood cuttings of Ficus carica L. cv. “Sar?lop” (Calimyrna) were planted into pots filled with 13 L of perlite. Five different nutrient solution formulations were tested on the quality and growth progress of nursery fig trees. The trials were conducted in two different growing conditions, namely, high-tunnel and open-field conditions in substrate culture. To observe the effect of different nutrient solution formulations on nursery fig trees, some morphological and biochemical characteristics were determined. It was concluded that the use of Hewitt's and Hoagland's nutrient solution formulations led to increased growth of nursery fig trees in high-tunnel and open-field conditions, respectively.