二次制粒加工断奶过渡料对仔猪小肠功能的影响

选用360头21日龄断奶仔猪,按饲粮的制粒工艺、原料预处理不同,分成4个处理组,研究二次制粒加工断奶过渡料对仔猪小肠功能的影响.处理组1饲粮普通一次制粒并使用未膨化玉米及豆粕;处理组2饲粮一次制粒、使用膨化玉米及豆粕;处理组3采用二次制粒工艺、使用未膨化玉米及豆粕;处理组4二次制粒、使用膨化玉米及豆粕.结果表明,处理组...     

酸性土壤施石灰对土壤理化性质、微生物数量及烟叶产质量的影响

[目的]研究酸性土壤施石灰对土壤理化性质、微生物数量及烟叶产质量的影响,以期为宜宾市酸性土壤改良提供科学依据。[方法]以K326为供试烤烟品种,结合大田试验与室内试验,研究石灰对土壤p H、有机质、微生物数量及烟草化学成分等的影响。[结果]与不施石灰处理相比,施石灰处理土壤p H、碱解氮、速效磷、速效钾含量均增加,土壤有机质含量降低,土壤细菌、放线菌数量分别提高32.7%~115.8%和32.9%~73.3%,真菌数量降低25.0%~51.9%,烟株生长发育增强,烟叶产质量、可用性提高。[结论]在宜宾烟区p H 5.06左右的土壤,石灰施用量以1 500 kg/hm2为宜。     

Field crop responses to lime in the mid-north region of South Australia

In the cropping regions of South Australia there is little information on whether acidity and acidification associated with high-input agriculture is affecting crop production and profitability. In much of the mid-north of South Australia, where thermic Calcic Palexeralf soils predominate, the levels of Al are low compared with other acid-soil types reported in comparable studies in Australia. In this study lime requirement curves have been used to predict the lime rate that achieves 80–90% maximum yield for different crop species on 3 sites on the red-brown earth soil type in the mid-north of South Australia. The results given demonstrate that the approach used for predicting lime responsiveness, with lime requirement calculated using the model of [Hochman, Z., Godyn, D.L., Scott, B.J., 1989. The integration of data on lime use by modelling. In: Robson, A.D. (Ed.). Soil Acidity and Plant Growth. Academic Press, Sydney, Australia, pp. 265–301], has provided good estimates of final pH changes. Yield response curves show that the largest yield gains mostly occurred in the second season of the experiment when lime at about 2.0 t/ha increased pH_Ca to 5.5–6.0. With the lime treatments calculated, yield of wheat, barley and faba beans were increased by about 70%, and durum by 30% compared with the control. It would appear that liming to achieve a pH_Ca of 5.2 has removed Al toxicity, and further liming to achieve pH_Ca 5.5–6.0 may have improved other soil properties to realise further yield gains. With cropping in this region commonly using practices that include high fertiliser nitrogen input and retention of crop residues, acidification is likely to be an on-going issue with these red-brown earth soils. Thus it is appropriate that soil testing and, where required, liming at the rate of 1.5 t/ha is used by farmers to both improve cropping profitability and also offset acid input associated with the farming practice.     

胡麻种子丸粒化技术的探讨

为改善胡麻的播种质量,提高田间出苗率和保苗率,选用吸水保水能力强的活性炭、凹凸棒和膨润土为主要原料,以不同配比对胡麻种子进行丸化处理,研究了丸化种子发芽指标和质量指标.结果表明:丸化种子的发芽指标较对照均有所降低,其中活性炭处理与对照无显著差异,达到对照的95.12%~99.51%,材料配施处理均高于其他丸化处理;除单用活性炭的处理外,含活性炭、膨润土的处理种子发芽势较其他丸化处理高出2.04%~39.41%,含活性炭、凹凸棒的处理种子发芽率较其他丸化处理高出2.66%~27.48%;除活性炭∶膨润土=1∶2、活性炭∶凹凸棒=1∶2的处理外,其他处理种子各发芽指标与裂解率变化趋同;活性炭处理的种子丸粒大小(6.76mm)、净度(83.6%)、均匀度(71.4%)、包籽效果(单籽率43.7%、含籽率208.7%)等质量指标较差,但其发芽指标高,可以通过与其他材料配施,既可改善种子的质量指标,又可保证高的发芽指标,因此,它是胡麻种子丸化处理较为理想的材料之一.     

The short-term effects of cessation of fertiliser applications,liming, and grazing on microbial biomass and activity in a reseeded upland grassland soil

A field study was conducted to determine the influence of a short-term (2 year) cessation of fertiliser applications, liming, and sheep-grazing on microbial biomass and activity in a reseeded upland grassland soil. The cessation of fertiliser applications (N and NPK) on a limed and grazed grassland had no effect on microbial biomass measurements, enzyme activities, or respiration. Withholding fertiliser and lime from a grazed grassland resulted in significant reductions in both microbial biomass C (P<0.05) and dehydrogenase activity (P<0.05) by approximately 18 and 21%, respectively. The removal of fertiliser applications, liming, and grazing resulted in even greater reductions in microbial biomass C (44%, P<0.001) and dehydrogenase activity (31%, P<0.001), and significant reductions in microbial biomass N (P<0.005), urease activity (P<0.05), phosphatase activity (P<0.001), and basal respiration (P<0.05). The abundance of culturable bacteria and fungi and the soil ATP content were unaffected by changes in grassland managements. With the cessation of liming soil pH fell from 5.4 to 4.7, and the removal of grazing resulted in a further reduction to pH 4.5. A significant negative linear relationship (r ²=0.97; P<0.01) was found between increasing soil acidity and dehydrogenase activity. Possible mechanisms influencing these changes are discussed.     

不同土壤环境对温郁金栽培的影响研究

试验研究不同土壤环境对温郁金栽培的影响结果表明,在石灰土上栽培的温郁金具有较长的生长期和较高的生物量,莪术中莪术油含量也比栽培在酸性红壤上的高,石灰土比红壤更能忍受施加铵态氮肥带来的负面效应。     

Detection of nitrification in a stagnohumic-gley soil

Summary Three different nitrification assays (short-term nitrifier activity, assimilatory nitrate reductase activity of Lolium perenne, and nitrate accumulation in the absence of plants) were performed either on soil from a naturally acidic stagnohumic-gley or on leaves from L. perenne grown in this soil. Before the investigation the soil was limed and fertilised in a manner consistent with established agricultural pasture improvement strategies. Short-term nitrifier activity was only detected in soils above pH 5.6. However, nitrate reductase activity and nitrate accumulation both showed a near linear increase between soil pH 3.8 and 6.8. These findings are attributed to the nature of the assays, each of which considers a different component of the soil nitrifier population.     

Effects of mesofauna exclusion on the microbial biomass in two moder profiles

Summary In December 1988, litterbags (mesh size 45 or 1000 m) were exposed in the organic layer of a limed and unlimed moder soil under beech forest in the Solling area (Germany). At both sites, substrata from the L1, L2, F1, F2 and from the H Layer were sampled shortly before the beginning of the experiment, defaunated, filled separately into litterbags and replaced in the respective horizons in the field. Litterbags were retrieved on three sampling dates (May, September, and November 1989). The soil microbial biomass was estimated by means of the fumigation extraction method. The results show that the effects of excluding mesofauna from the 45-m litterbags were different in different horizons, on different sampling dates and in different study sites. Calculation of the average effect from the three sampling dates revealed that mesofauna exclusion reduced the microbial biomass C at both sites. It was concluded from horizon- and season-specific differences between the two litterbag treatments that a depression in microbial biomass C in the organic layer of a moder soil by mesofaunal grazers is confined to situations where environmental conditions cause strong feeding pressure and when the microflora is exposed to environmental stress.     

直播稻丸化种衣剂应用效果初报

2005年采用自行研制的水稻丸化种衣剂包衣直播稻种子，在汉寿和浏阳进行了试验研究。结果表明。相比对照，丸化剂能加快直播稻出苗、促进分蘖、增加干物质积累，最终明显提高了秧苗综合素质；同时农药成分能有效防治秧苗期稻蓟马危害，防效达70.89％。最终产量平均增幅5．83％～8．59％，单位面积有效穗数明显增多是增产的主要原因。     

Lime pelleting inoculated serradella (Ornithopus spp.) increases nodulation and yield

Lime pelleting of the inoculated seed is recommended for most pasture legume species to improve survival of the rhizobia on the seed and to counter deleterious effects of soil or fertiliser acidity on rhizobial numbers. Except for New South Wales, lime pelleting is specifically not recommended for serradella (Ornithopus spp.). Our objectives were to evaluate effects of lime pelleting on bradyrhizobial numbers on seed, and nodulation and growth of the serradella plants. Three experiments are reported at two acid-soil sites in northern New South Wales involving four cultivars of yellow serradella (Ornithopus compressus) and Bradyrhizobium sp. (Lupinus) strains WSM471 (current inoculant strain) and WU425 and WSM480. Lime pelleting increased bradyrhizobial numbers on seed, 24 h after inoculation, by an average of 90%. Similarly, lime pelleting increased nodulation and shoot dry matter of the inoculated plants by an average of 57 and 28%, respectively. The three strains were similar in effects on plant growth. Relative values for shoot dry weight, averaged over sites, were 100 for WSM471 and 98 for both WU425 and WSM480. Our results confirmed previous research that lime pelleting inoculated serradella seed was not deleterious to survival of the bradyrhizobial inoculum, and showed that it could result in enhanced symbiotic activity of the inoculum in some instances. We recommend lime pelleting of serradella and that WSM471 remain the inoculant strain.