THE DIGESTIBILITY AND PRODUCTIVITY OF SELECTED HERBAGE VARIETIES

Much of the published digestibility data refer to swards grown in the south of Britain. In order to study digestibility curves in a more northerly latitude, several pure swards were established in the west of Scotland in 1962 and 1963. Varieties included S22 and Tetila Italian ryegrass, S37 cocksfoot, S170 tall fescue, S215 meadow fescue, Scots timothy, English broad red clover, and SI00 white clover. In addition to primary growth in vitro digestibility, the effect of various cutting managements on digestibility and productivity was measured. Flowerhead emergence was delayed, with the result that the digestibility curve was later than is reported from southern Britain. Highest yields of digestible organic matter were obtained from the less frequent cutting regimes, but the mean digestibility of the herbage was lower. Pre-dictibility of herbage digestibility is desirable as the basis of a reliable and planned herbage utilization programme, particularly for conservation.     

INVESTIGATIONS ON LOCAL STRAINS (VARIETIES) OF HERBAGE PLANTS

Data are presented to show the effect on type of multiplying seed of wild white clover obtained from permanent pastures and of seed from old pastures in different localities. The variation in type in samples of commercial wild white clover is shown.
The cause of the change in type of certain stocks of Kersey white clover is demonstrated. The steps taken to maintain the original type are described.
The value of certain botanical characters in indicating the agronomic behaviour of varieties of white clover is discussed.     

西藏林芝地区大豆品比试验

为了筛选出适宜在西藏林芝地区及其它生态条件相似的地区推广和种植大豆品种,我们在前几年的大豆品种观察试验的基础上,于１９９７年进行了大豆品种比较试验,参试品种共有１０个。本文通过方差分析的基本原理,对大豆的产量和主要经济性状进行了初步探讨,结果表明：１０个品种在该地区的生态适应性较强,基本无病虫害发生,经济性状方面也表现较好,尤其是辽豆９号,鲁豆４号和东农８３６这三个品种表现最好,适宜在该地区推广示     

THE NORMAL-ACID FIBRE CONTENT OF SPFCIES AND VARIETIES OF HERBAGE GRASSES

Normal-acid fibre content has been suggested as a useful indication of the digestibility of herbage. The changes in fibre content were therefore recorded during the spring and early summer of 1957 and 1958 to see whether regular differences occurred between species and varieties of herbage grasses.
All species showed an increase in fibre content during spring and early summer, but considerable year-to-year fluctuations occurred: fibre content was also influenced by manuring and spacing. Regular differences between species and varieties have been detecled and, in perennial ryegrass, differences between individual genotypes. It should be possible to select breeding material for high or low fibre content if required.     

不同来源亚有限型大豆品种适应性的比较研究

采用地理纬度相似地区选育的、具有代表性的中、美大豆品种,在不同种植密度,施肥水平和种植地区条件下对大豆品种的适应性进行了比较研究.结果表明：在不同种植密度条件下美国俄亥俄州立大学选育的品种综合表现较好,都有较高的产量表现,对种植密度有较好的适应性;而辽宁省选育的品种大多产量较低,受种植密度影响较大,种植密度适应性较差.在磷酸二铵做种肥的条件下,美国俄亥俄州立大学选育的品种表现较好,对肥料的利用率较高;辽宁省选育的品种中,辽豆12号对施肥的反应较好,其它品种相对产量较低,肥力适应范围狭窄.美国俄亥俄州立大学选育的品种在不同地区种植平均产量均显著高于辽宁省选育的品种,两国品种对地区的适应性表现趋势一致,都是鞍山＞沈阳＞大连.     

COMPARISONS OF GRASS VARIETIES FOR SURFACE SEEDING UPLAND PASTURE TYPES

A study was made of the agronomic behaviour of 18 grass varieties, surface sown, after burning an upland heath community dominated by Calluna vulgaris . Complete exposure of the soil surface, the absence of competition and favourable moisture conditions provided excellent conditions for establishment. Despite this, sward development was slower than at any other site studied, and 18 months elapsed before satisfactory sward densities, and consequently a reasonable level of production, were achieved. In contrast, white clover developed vigorously from the outset. The red fescues, cocksfoots and S170 were the most promising, while the performance of most varieties was affected by one or more hazards such as frost-heaving and summer drought. The latter aggravated the tendency of some of the varieties to produce a profusion of flowering stems and, with few exceptions, considerably reduced the colour and vigour of the herbage.     

HERBAGE AND BEEF PRODUCTIVITY OF FERTILIZED PASTURES IN NORTHERN ONTARIO

The productivity of 2 fertilized sown pasture swards and of a 30-year-old pasture sod was evaluated under rotational and continuous grazing in 1956–62.The application of NP fertilizer (448 kg 11–48–0/ha every 3 years with 112 kg ammonium sulphate in the other years) gave the highest yields of DM and of beef, followed by the P treatment (1120 kg superphosphate/ha). Beef production showed only small responses to either the type of pasture sward, or the method of grazing. Seasonal distribution of beef production was slightly more even on the old sod. For the peak period of June-July, 68% of the gain was made on the old sod against 74% on the cultivated swards under rotational grazing and 79% under continuous grazing. DM/gain ratios were generally higher in wet summers than in dry ones. Conversely, estimated DM digestibility was lowest in wet summers.     

COMPARISONS OF GRASS VARIETIES FOR SURFACE SEEDING UPLAND PASTURE TYPES

A series of experiments was laid down in 1957 on different upland vegetation types in Scotland to provide a basis of critical information on the performance of 18 herbage varieties. The present paper deals with results on areas dominated originally by Molinia and Nardus at Sourhope farm, Roxburghshire. Data obtained between 1957 and 1954 are discussal in relation to sward development, competition with remnants of native herbage and seasonal productivity.     

COMPARISONS OF GRASS VARIETIES FOR SURFACE SEEDING UPLAND PASTURE TYPES

Two deep peal deposits, one in a high-rainfall area, were surface seeded with a number of grass varieties. Their sward development and general agronomy are described. Differences in performance are associated with moisture supply and severity of winter conditions. Tall fescue, red fescue and timothy gave good results at both centres.     

大豆叶片光合、蒸腾等生理特性的品种间比较研究

在25个大豆品种的鼓粒期,测定了植株主茎自上而下数第3片已完全展开叶的光合速率、暗呼吸速率、蒸腾速率、叶片对水分扩散导性、叶片对CO_2扩散导性、比叶重、叶绿素含量及水分利用效率。结果表明:所测性状在供试品种间均存在着极显著的差异性。在表型、遗传及环境相关分析的基础上,对有关性状间作偏相关分析的结果指出,椭园叶型品种的暗呼吸速率及叶CO_2扩散导性与其光合速率呈极显著偏正相关,并比叶重及叶水分扩散导性与其蒸腾速率呈显著或极显著偏正相关;披针叶型品种的比叶重、叶绿素含量及叶CO_2扩散导性均与其光合速率呈显著或极显著偏正相关,而且比叶重与其蒸腾强度的偏相关也达极显著水平。此外,在两种叶型品种中,光合速率均与蒸腾速率和水分利用效率呈极显著偏正相关,但蒸腾速率则与水分利用效率呈极显著偏负相关。本文还对大豆高光效生理育种及抗旱育种的目标进行了讨论。     

无限结荚习性与亚有限结荚习性大豆品种根系性状的比较研究

采用盆栽方法，对黑龙江省和吉林省的19份无限结英习性大豆品种和17份亚有限结荚习性大豆品种的根系性状进行了比较研究。结果表明：两种不同结荚习性大豆品种根系性状存在差异，与无限结荚习性大豆品种相比，亚有限结荚习性大豆品种根量多，根体积庞大，根表面积大，侧根发达。     

PRODUCTIVITY, PERSISTENCE AND RESPONSE TO NITROGEN OF ITALIAN RYEGRASS VARIETIES

The production of six varieties of Italian ryegrass was compared for three years by cutting 5 or 6 times during the growing season. All varieties showed falls in production of dry matter at high and low levels of N fertilization, but New Zealand HI and New Zealand Italian ryegrass showed significantly lower falls and gave top yields over the three years, in spite of severe frost damage in the first two. Crude protein and nitrogen absorption remained high at the lower level of fertilization (174–209 lb N/acre) and showed a fall only in the third year at the high level of N fertilization (348–418 lb N/acre).
The significance of the high response of the New Zealand varieties is discussed.     

COMPARATIVE PRODUCTIVITY OF 27 STRAINS OF GRASS IN THE WEST OF SCOTLAND

Seasonal productivity from plots of 27 strains of the principal grass species has been compared at Auchincruive over two seasons by a cutting technique. The following conclusions are reached:
Peak growth is limited to a short period before the first week in June. Extension at peak-growth level into the summer gap is not possible by the use of any of these grass strains grown alone.
The provision of grass for one cow per acre is possible for up to 142 days by the combination of strains.
Extension into the autumn can be achieved by conserving second-peak growth, which does not mature to the same extent as the first-peak growth.
In combining strains with advantageous growth periods due regard must be paid to their growth at other periods, which may be particularly low.
Combination of many strains is not likely to achieve as good a result as the use of 2, or at most 3, well chosen strains.