ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1964.tb01132.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

A survey was made of the flowering responses of 47 annual, biennial and perennial grasses, to measure the extent of any winter requirement for floral induction, and to see how far this could be provided by controlled cold or short‐day treatment.The annual species showed little or no inductive requirement, nor did the perennialsArrheuatherum elatius, Ceratochloa unioloides, Phleum pratenseandPoa nemoralis. Most perennials possessed a definite inductive requircinent. A few species, such asLolium perenne, responded to both cold and short‐day given to the young seedling, while others, such asPhleum nodosum, Agrostis alba, A. canina, A. stoloniferaandA. tenuis, responded to short‐day induction but not to cold.Many temperate perennials, however, includingCynosurus cn'status, Dactylis glomerata, Festuca pratensis, F. rubra, Poa pratensisandP. trivialisdid not respond to seedling induction and possibly have a juvenile stage before they are able to respond to inductive conditions.The sequence of flowering responses in the temperate perennial grasses is evidently more complex than was previously thought, and the perennial habit can be achieved by many different developmental pat

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1964.tb01133.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

The effects of three stocking rates on fat‐lamb production were examined. These stocking rates were imposed upon four grazing systems. The grazing managements had no significant1effects upon the rate of liveweight gain or the total liveweight of lamb produced per acre, nor were the ewes’ liveweights significantly affected. Reasons are suggested. The lambs’ rate of liveweight gain was related negatively and the total liveweight of lamb produced per acre was related positively to stocking rate. The ewes’ liveweights were similarly affected, there being the highest losses of liveweight under the high stocking rate. In all cases significant differences existed between the stocking rates and there was a significant linear relationship between them. It is concluded that high stocking rates are essential to obtain the maximum fat‐lamb production on a ‘per

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1964.tb01134.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1964.tb01135.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Perennial ryegrass and meadow fescue were grown alone and in association in field plots, to gain an idea of the nature and importance of the competitive interactions between them, and their relative contributions to the yield of the newly‐established sward.Experiments over 10 weeks and 9 months both showed that the contribution by fescue to the overall dry‐matter yield was severely restricted by perennial ryegrass. There were no deaths of fescue plants during the experimental period (which included an overwintered treatment). The depression in yield was rather a result of a marked decrease in size and weight of the individual plants, brought about by competition for light and nutrients from the faster‐growing rye

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1964.tb01136.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Using ryegrass and lucerne silages, investigations were made into the relationship between plant‐cell breakdown, as evidenced by a collapse of the silage mass and by an increase in its electrical conductivity, and the initiation of lactic‐acid production. Changes in the water activity of the juices available as a medium for the silage bacteria were also examined. It has been shown that cell breakdown and the resultant release of the plant juices Is a necessary pre‐requisite for the production of significant amounts of lactic acid during ensilage. The investigation also confirms that the complete exclusion of fresh air from the silage mass can usually be expected to result in cell breakdown within a few

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1964.tb01137.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

A small‐scale conservation experiment is described in which molasses, zinc bacitracin and dried sugar‐cane juice were compared as additives to grass silage. The results indicate that all these additives improved the quality of the silage, but do not suggest any significant decrease in dry‐matter loss due to the use of preserva

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1964.tb01138.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

Two levels of nitrogen application (70 and 180 lb per acre per annum) were compared on 6 long‐duration leys. The treatments were repeated for periods of up to 4 years on tiie same swards. The higher N dressing produced 2230 lb more dry matter per acre than the low rate, an increase of 28%, and the yield was also more evenly spread throughout the season. There was virtually no clover on the high‐N swards. The proportion of clover varied under low N but tended to increase as the season progressed. The sown grasses remained the dominant sward constituents throughout the experiment, and there was no sign of loss of vigour on the high‐N swards. Utilized‐starch‐equivalent outputs were calculated from 3 different swards for 1956–8 and there was a significant positive correlation between the dry‐matter yields and utilized‐starch‐equivalent

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1964.tb01139.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1964.tb01140.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

The productivity and persistence of 27 varieties of herbage plants were compared, following sowing on a blanket peat after ploughing. Yields were estimated from 3–5 cuts per year for 5 growing seasons. The top yields in each year ranged from 2510 lb/ac. in the 5th year when no nitrogenous fertilizer was applied up to 4700 lb/ac. in the 3rd year when given 174 lb N/ac. Such levels are slightly less than half the level expected on lowland, but livestock output on hill land is far lower than on lowland. Varietal differences were significant, with red fescues, especially S59 smooth‐stalked meadow grass, S170 tall fescue, S143 cocksfoot, Yorkshire fog and S53 meadow fescue giving top yields and persistence. Aberystwyth varieties were in all cases superior to other varieties. S50 timothy and S23 perennial ryegrass were persistent but production was low. The conclusions are compared with those of other investigat

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1964.tb01141.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY