高寒牧区藏系绵羊(1岁)冬季暖棚育肥试验

试验结果表明:藏系羔羊日粮中精料比例越高,个体增重、饲料转化率达到最大的时间就越长,曲线的峰值就出现的越晚。各育肥期羔羊个体增重在育肥组之间差异不显著,但同一育肥组羔羊的个体增重在不同育肥期之间差异显著(P<0.05)。3个育肥组和对照组羔羊个体总增重的顺序为:第1组>第3组>第2组>对照,且它们的增重率分别为51.27％、50.08％、48.75％和-8.25％,且3个育肥组羔羊个体增重极显著地高于对照组(P<0.01)。不论从羔羊个体增重,还是从饲料转化率的角度考虑,利用相应的日粮组成育肥1岁羔羊时,第1组、第2组和第3组分别不能少于50d、40d和40d。3个育肥组羔羊个体增重与实际采食量之间均呈显著的正相关关系,且第1、第2和第3组的线性回归方程依次为:Y=0.5951X-4.7596(r=0.8037,P<0.05);Y=0.5456X-6.2214(r=0.8587,P<0.05);Y=0.2418X-6.408(r=0.8474,P<0.05)。当X=7.998kg/10d·只,11.403kg/10d·只和26.502k/10d·只时,第1组、第2组和第3组羔羊的个体增重均为零,即在这种采食量水平下,只能够维持各组羔羊的基础代谢,只有采食量大于这种水平时,羔羊才能进行净生产。     

湟源地区草场封育对牧草结构及产草量影响的研究

对寺寨牧场1997－2000年3年牧草结构及产草量进行了测定分析，结果表明，天然草场通过围栏封育比未封育草场牧草种类，高度，盖度，明显增加，产草量提高68．4％。     

农牧交错区不同牧草时期放牧奶牛采食量与食性的研究

用饱和烷烃法对不同牧草时期放牧奶牛的采食量进行了测定.结果表明:放牧奶牛在牧草幼嫩期、旺盛期、枯黄期3期的采食量结果分别为:绝对采食量(kg/d)为11.54±0.66、13.83±0.55、5.75±0.32,采食量在牧草旺盛期时达到最高.采食组成幼嫩期以苔草为主、旺盛期以隐子草为主、枯黄期以赖草为主,这与草场植物的生长和奶牛的喜好有关.     

Identification of cultivars of pasture legumes (Centrosema macrocarpum,C. pubescens and C. sp.n.) by acid polyacrylamide gel electrophoresis of cotyledons storage proteins

Summary An electrophoretic procedure was developed for storage proteins which can discriminate cultivars of forage legumes, Centrosema macrocarpum, C. pubescens and C. sp.n. Proteins extracted from cotyledons were separated in 10% polyacrylamide gel containing 10% sucrose. Electrophoretic patterns are presented to illustrate the results that can be obtained with the procedure described. Cultivars of all three species were distinguishable based upon the variation in their acid soluble seed proteins.Joint publiccation of the Department of Food Science, University of Manitoba (No 101) and Centro Internacional de Agricultura Tropical-CIAT.     

黄土高原沟壑区人工草地生产力研究—以长武王东沟试验区苜蓿地为例

该以长武王东试区苜蓿为例，根据草地生产力形成机制，结合一系列试验数据，探讨了人工草地生产潜力及其载畜量的估算方法。析人工草地生产力形成过程，量化了各种生态因子的产量效应，指明了提高草地生产力及其载畜量的有效途径。     

基于Landsat TM影像的半干旱牧区天然打草场面积的遥感监测

天然打草场是中国草地畜牧业的物质基础,也是中国内陆的生态屏障。目前中国打草场分布状况、分布面积、产量高低等信息十分缺乏,严重制约饲草储备和救灾应急功能发挥。为解决这些问题,该文基于2009－2011年的Landsat TM5影像数据,并借助野外调查点和目视解译方法对中国半干旱牧区天然打草场状况进行监测分析。结果表明,中国半干旱牧区天然打草场面积达800.35万hm2,目视解译结果的平均解译精度达到76.78%。其中,内蒙古天然打草场面积居首位,面积为688.04万hm2,其次是松嫩平原草原区,打草场面积为91.80万hm2,河北半干旱农牧交错区的打草场面积最小,为20.51万hm2。在内蒙古,呼伦贝尔草甸草原天然打草场约为180.89万hm2,科尔沁沙化草原天然打草场约为96.44万hm2,锡林郭勒典型草原天然打草场面积约为395.40万hm2。研究区天然打草场的植被类型以温性草原类、温性草甸类、低地草甸类为主,少量分布在山地草甸类和温性荒漠草原类。该研究结果可为进一步分析全国半干旱区域打草场变化提供数据支撑。     

Sulphur in soil and light fraction organic matter as influenced by long-term application of superphosphate

Numerous studies have examined the role of light fraction (LF) organic matter in soil C and N cycling, but there is no published information on the amounts and nature of S in LF. The objective of this work was to characterize the S composition of LF in soils receiving different inputs of fertilizer S. Soils (0-7.5 cm) were taken from a long-term experiment (1952-1999) set up to examine the effects of single superphosphate (SP) (applied at 0, 188, or 376 kg ha⁻¹ yr⁻¹, which equates to 0, 21, and 42 kg SO₄-S ha⁻¹ yr⁻¹) on the productivity of an irrigated, grass-clover pasture grazed by sheep. The S content of LF (separated by flotation on NaI solution with specific gravity 1.7) increased by ∼20-30% in response to SP. The LF was enriched in organic S compared with whole soil (S concentration in LF was ∼1000-1400 mg kg⁻¹ vs ∼400-500 mg kg⁻¹ in whole soil), but LF-S represented only 1.3-4.7% of soil S. Most (∼88%) of the S in LF was C-bonded, reflecting the dominance of this form of S in organic matter returned to the soil in dung and plant residues. Hydriodic acid (HI) reducible-S accounted for only ∼12% of LF-S, compared with 28-35% of whole soil organic S. Superphosphate tended to increase total soil N, due to improved clover growth. There was a strong positive relationship between total N and C-bonded S in whole soil and LF, whereas soil HI-S and N were not associated. Increases in C-bonded S where SP was applied appeared to be driven mainly by increases in soil N, which in turn were due to improved clover growth in response to phosphate supplied by SP. Increases in HI-S due to SP application were probably a direct response to inputs of S. As LF is a small pool of S, with a relatively wide C:S ratio (∼200:1), we concluded that it is unlikely to contribute a significant amount of plant-available S.     

Crop responses to applied soil compaction and to compaction repair treatments

Crop responses to annual compaction treatments (applied to whole plots) and management treatments to ameliorate compacted soil were determined in a field experiment on a Vertisol. Initially, all treatments except a control were compacted with a 10 Mg axle load on wet soil (26% gravimetric water content compared with a plastic limit of 22%). Annually applied axle loads of 10 and 6 Mg on wet soil (25–32% soil water) tended to reduce seedling emergence, grain yield (wheat, sorghum and maize), soil water storage and crop water use efficiency (WUE). Annual applications of an axle load of 6 Mg on dry soil (<22% soil water) had little effect on crop performance. Mean reductions in the yield of five crops (three wheat, one sorghum and one maize) in comparison with the uncompacted control were 23% or 0.79 Mg ha⁻¹ (10 Mg on wet soil), 13% or 0.44 Mg ha⁻¹ (6 Mg on wet soil) and 1% or 0.03 Mg ha⁻¹ (6 Mg on dry soil). Maize grown in the fifth year of treatment application was most affected by compaction of wet soil, its WUE being reduced from 14.3 to 9.7 kg ha⁻¹ mm⁻¹ in response to an axle load of 10 Mg. Reduced WUE was associated with delayed soil water extraction at depth. A 3-year pasture ley was the most successful amelioration treatment. A wheat and a maize crop grown after the ley outyielded the control by 0.33 and 0.90 Mg ha⁻¹, respectively. So the pasture not only ameliorated the initial compaction damage, with respect to crop performance, but resulted in improvements in two subsequent crops.     

刚果12号桉人工林下土壤微生物与土壤养分研究初报

以海南省儋州林场刚果12号桉(Eucalyptus ABL12)人工林土壤为对象,研究了刚果12号桉人工林地土壤微生物类群的分布规律及土壤养分的变化。结果表明:在土壤剖面上,土壤微生物具有一定的垂直变化,并随着土层深度的增加而减少,主要集中在0～20 cm的土层中;土壤微生物3大类菌中,细菌所占比例最大,其次为放线菌、真菌;土壤微生物数量还具有一定的季节变化,最大值一般出现在9、10月份;各样地中土壤微生物类群及土壤养分总体表现为:桉-豆科牧草>桉-禾本科牧草>纯桉林,且土壤微生物类群与土壤养分之间存在一定的相关性。本研究结果也表明,经过桉树-牧草间种后,桉树人工林土壤的微生物性质得到了很大改善。     

我国农业科技园区的建设与发展

农业科技园区的基本特征是“三高一新”,具有示范、带动和龙头作用。开发农业科技园区应明确发展思路,完善管理机制,建立人才流动和激励机制。