THE ENSILAGE OF AUTUMN-SOWN RYE

Autumn-sown rye was cut on five dates in spring and ensiled in laboratory silos. On two of the dates forage-harvested material was ensiled in PVC silos (containing about 1 t of fresh crop) as well as in laboratory silos. Ensiling was carried out with and without the addition of formic acid or glucose solution. After 96 days in laboratory silos, rye cut before ear-emergence and ensiled without additives gave silages of high pH value and high ammonia content. After ear-emergence satisfactory silage was produced without an additive, but the addition of formic acid always resulted in silages having lower pH values and lower ammonia contents. The addition of glucose resulted in silages with only slightly lower pH values and ammonia contents which were closely similar to those made without addition. Silages made in PVC silos were all well preserved, as indicated by low contents of acetic and butyric acids, but the addition of formic acid resulted in pH values and ammonia contents lower than those found in other treatments.     

A CORING TECHNIQUE FOR THE MEASUREMENT OF PASTURE OF LOW AVAILABILITY TO SHEEP

An account is given of a method for measuring short-grazed pastures. The procedure has particular value in studying the relationship of animal performance to pasture availability. A number of other pasture characteristics may be measured concurrently. These include species composition, tiller number and mean weight, stem-base material, roots, rhizomes and plant litter. The influence of core size and shape is studied and variance components reported.     

肉桂枝枯原因研究

肉桂泡盾盲蝽吸食肉桂枝条的汁液，造成微小伤口，并携带可可毛色二孢菌，使肉桂枝条容易被该菌侵染，造成皮层坏死，引发极严重的枝枯病。在某些林分，其它枝梢害虫如肉桂双瓣卷蛾、肉桂小峰、肉桂瘿蚊、肉桂木蛾、肉桂天牛，它们的为害也能不同程度地引起肉桂的枝梢枯死。     

THE USE OF PROPIONIC ACID AS AN ADDITIVE FOR MAIZE SILAGE

Two clamps of maize silage were prepared in mid-October, one with 0·33% propionic acid applied during harvesting and one without additive. The treated silage had a peak temperature 3°C below that of the untreated silage. The estimated loss of DM during ensiling was 8% greater in the untreated silage. The stability and acceptability of the silages were tested after exposure to air. The treated silage was slightly more stable than the untreated milage and the intakes by heifers were sligbtly greater. The digestibilities of the two silages estimated in wether sheep were similar, averaging 68·6% digestible OM in the DM at maintenance level and 63·5% at a high level of feeding. The intakes and growth rates of calves and beifers oifered the two silages were also similar.     

云南马铃薯贮存损失的调查和评价

调查了云南马铃薯主产区 17个农户家庭贮存马铃薯的现状和损失。作为商品薯贮存失去商品价值的损失率达到 4 7 4 % ,其中发芽薯占 35 4 % ,损失最大 ,贮存时间 12 0d块茎发芽率仅1 5 % ,但 15 0d迅速增加到 5 6 88% ;破损块茎占 7 2 % ;病害烂薯占 4 8%。马铃薯种薯与商品薯同仓混贮 ,在同样无光照的条件下 ,造成种薯过早发芽 ,而且芽细弱 ,降低了种薯的质量。马铃薯疮痂病 (S .scabies)发生普遍 ,在一些地方发病率高达 10 0 % ,应当引起重视。讨论了马铃薯贮存中存在的问题 ,提出了马铃薯贮存技术发展的意见。     

连作大豆化感作用研究

对连作大豆体系中化感物质的种类，来源途径，提取，分离，鉴定方法等进行了较详细的阐述，并介绍了有关于连作大豆化感作用的研究成果，以及今后研究应该注意的一些问题。     

黑龙江省北部高寒地区大豆重迎茬缓解剂筛选的研究

１９９５－１９９６两年在黑龙江省北部高寒地区的黑河农业科学研究所试验地，进行了大豆重迎茬缓解剂的筛选试验。结果表明，一些缓解剂对重迎茬大豆的根腐病或根蛇潜绳有较好的防治效果，大部分缓解剂能促进重迎茬大豆的生长发育，增加干物质积累和根瘤数量，增产幅度在３．６％～１７．４％，其中大豆微复药肥Ⅰ号最好。     

AN EVALUATION OF AN ELECTRONIC INSTRUMENT FOR PASTURE YIELD ESTIMATION

In situations where yield is variable but in which it is not desirable to take too large a cut sample, e.g. on grazed plots, the pasture-yield estimator can be used to improve the accuracy of yield estimation. An outline of the theory and examples of the use of the method are given.     

AN EVALUATION OF AN ELECTRONIC INSTRUMENT FOR PASTURE YIELD ESTIMATION

A model of the electronic instrument described by Campbell et al . (3) was built at the Grassland Research Institute and was found to behave in a very similar way to their New Zealand model. A considerable amount of field work was undertaken with it in 1964 and this demonstrated that no general relationship of acceptable accuracy had yet been found; nor could it be sufficiently improved by the inclusion of the meteorological and botanical factors recorded. This forces one to a consideration of double-sampling techniques, which appear worth while; they will be discussed in Part 2 of this paper.     

THE ELECTRONIC MEASUREMENT OF THE YIELD OF RAPE (Brassica napus)

The application of an electronic pasture probe to the measurement of rape is described. Measurements taken over two years demonstrated that good relationships could be established between probe readings and parameters of crop yield. Crop height, spatial distribution of crop profile, crop density and percentage DM were found to he significant factors in obtaining meaningful results.     

大豆成花诱导期间游离氨基酸含量与组分变化

在大豆品种早－１２短日成花诱导期间，初生叶及顶芽内游离氨基酸含量均比连续光照下的高。对初生叶及顶芽内各游离氨基酸组分的分析结果表明，多数氨基酸在ＳＤ诱导第２天含量均较高，作为重要中间代谢产物的谷氨酸和天冬氨酸，ＳＤ诱导第２天的含量明显比ＣＬ下的高，２ＳＤ下顶芽内精氨酸含量为２ＳＣＬ的２．５倍。     

A TEMPERATURE INDICATOR FOR USE DURING OVEN-DRYING OF HERBAGE

The drying of small herbage samples should be as rapid as possible so as to limit respiratory loss and enzymatic interconversions, especially if certain nonstnictnral carbohydrates are to be assayed. An inexpensive thermo-switch is described that indicates the time required to heat a mass of tissue in an oven to a given temperature. The time required to heat green herbage to a temperature (55°C) that will inactivate respiratory enzymes can be determined.     

大豆种子发育过程中脂肪酸积累模式研究

对夏大豆种子发育过程中脂肪酸的累积过程进行了研究.研究表明,大豆种子发育早期有6种脂肪酸,成熟期减少为5种.成熟期的种子亚油酸和油酸占全部脂肪酸的80%以上,棕榈油酸发育中途消失.大豆种子脂肪酸总量呈升-降-升的Z字型变化模式.此外,本文通过对脂肪酸组分的相关性及主成份分析,对大豆种子发育过程中脂肪酸的积累模式进行了探讨,发现大豆种子发育过程中油酸与亚油酸呈同步积累,高度正相关,在脂肪酸组成中具支配地位,推测SAD和FAD2两种酶在决定大豆含油量方面可能具有决定性作用.