ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1971.tb00625.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

ABSTRACTAn experiment was conducted to measure the vertical distribution of LAI, sheath material and light in canopies of two contrasting perennial ryegrass varieties, S23 and Ba6280. In addition, the time course of DM production and LAI accumulation were measured over various periods of regrowth after defoliation. Considerable differences existed between these two varieties in canopy structure, light interception, LAI and crop growth‐rate over various periods of regrowth. The results offer explanations for intervarietal differences in productivity and differential responses to various cutting frequencies. A description is given of a technique for measuring the vertical distribution of herhage in a grass canop

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1971.tb00626.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1971.tb00627.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

ABSTRACTSingle spring dressings of N were compared with split applications over the first two growth periods of the year at ten sites in eastern England in the period 1964–67. None of the four spring periods was unusually dry and the single application of N in spring did not outyield a similar total N rate applied some before and some after the first cut. At nine out of ten sites split applications of N yielded considerably more in the second growth period than the single spring dressing. It is concluded that the split applications of N in the spring, already shown superior to single dressings under moist west country conditions, are correct for many seasons in the drier east of Englan

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1971.tb00628.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

ABSTRACTAn economic survey was carried out on sites in various regions of the Central Electricity Generating Board which had been restored with pulverized fuel ash. The ohject was to investigate the degree of success which could be achieved in restoring gravel pits and other ash disposal sites to agricultural use. Almost all of the sites had been incorporated into existing holdings and nearly all had the benefit of returned topsoil. The investigation showed that such land is as productive as land of a similar but undisturbed character when both are subject to similar conditions of good husbandry. Topsoil, where available, allows for greater flexibility in husbandry matters and particularly in cultivations.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1971.tb00629.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

ABSTRACTThe volatilization of ammonia which followed the application of urea to a pasture sod was determined over a period of 14 days. Significant ammonia losses were measured after foliar application of urea to sods in which the soil component had been previously isolated from the plant components by sealing the sods with an impermeable membrane. Losses of ammonia by volatilization over the experimental period were less from plant surfaces than from unsealed sods in which the soil contributed to losses. It is concluded that in addition to soil ureolytic activity, the plant and litter components of pastures may provide major pathways of loss in the N economy of grasslands.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1971.tb00630.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

ABSTRACTResults are presented to show the effect of white clover (Trifolium repens) and of applied N on the hotanical composition of swards sown with perennial ryegrass (Lolium perernne), timothy (Phleum pratense), meadow fescue (Festuca pratensis) and mixtures of two and three of these species. White clover had a more favourahle effect on the growth of perennial ryegrass than on either timothy or meadow fescue both in terms of yield and in terms of tiller numbers. Tiller numbers of rough‐stalked meadow grass (Poa trivialis) were increased and tiller numbers ofAgrostisspecies were reduced by application of N and by inclusion of clover. Possible reasons for these effects are considere

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1971.tb00631.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

ABSTRACTItalian ryegrass cv. Leda and perennial ryegrass cv. Presto were sown alone and in five mixtures containing different proportions of viable seed and compared with hybrid ryegrass cv. Manawa and Italian ryegrass cv. S22. Yields and herbage composition were measured five times in 1962 and 1963, with particular reference to the contribution from perennial ryegrass in the first year and the effects of Italian ryegrass on second‐year production.Italian ryegrass dominated first‐year production wbile perennial ryegrass dominated second‐year production. Manawa was the top yielder in the first year, but both Manawa and S22 bebaved as Italian ryegrasses and were badly frosted and weedy in the second year. The mixtures were generally intermediate in yield between the components and tended towards the yield of the more vigorous component. Since the more vigorous component changed from cut to cut or from season to season, the sums of harvests sbowed some advantage for certain mixtures. Certain pairs of herbage varieties can be sown togetber witb yield advantage. Furtber physiological investigations are warranted and the breeder has a part to play in a search for complementary vari

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1971.tb00632.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

ABSTRACTThe measurement of primary production and utilization of heather moors is a necessary part of studies aimed at understanding and ultimately improving secondary (animal) production.Heather is a woody perennial and presente many problems peculiar to itself. With management in mind a more precise method of classification and description of heather moors is suggested.The measurement of quantity of production in terms of standing crop, total edihie DM and annual DM production are described in detail. Chlorophyll extraction techniques are descrihed, these heing more rapid than hand separation and enabling many more samples to be handled.Digestibility and voluntary intake of heather as indices of quality are briefly discussed.A method for the calculation of grazing pressure or utilization is described. The method measures the percentage of available edible (photosynthetic) material which is consumed.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1971.tb00633.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

ABSTRACTSequential harvests of two tetraploid ryegrasses have shown that the commercially critical level of 90% germination was attained early in the ripening process. For the greater part of the maturation period the moisture level was maintained at 60% as in diploid grasses, but the rate of moisture loss during the latter part of ripening proved to be slower than in diploids. The large seeds are more susceptible to mecbanical damage at harvest and therefore require lower drum speed.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1971.tb00634.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY