ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1980.tb01508.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractSeveral different techniques for the non‐destructive estimation of pasture or range biomass are critically reviewed and compared to remote sensing methods. Similarities and differences between the visual estimation procedure, β‐attentuation, capacitance meters, weighted disc, and spectral methods are discussed in terms of accuracy, time, ease of operation, operational constraints and calibration procedures. No one technique has been shown to be superior across the board to the other techniques reviewed for ground‐based biomass estimation. A discussion of the strengths and weaknesses of each non‐destructive method allows for the selection of the technique most suited to a particular app

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1980.tb01509.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractDactylis glomerataandHolcus lanatuswere grown together in boxes with either full competition, root competition only, shoot competition only or no competition between them. The boxes were either fertilized (150 kg ha‐1N, 100 kg ha‐1K, 80 kg ha‐1P) or not fertilized. The experiment was continued for 13 months, and a total of six cuts were taken.H. lanatuswas more competitive thanD. glomeratathroughout the experiment, though the effect declined after flowering during the second growing season. The effects of root competition were generally much greater than those of shoot competition and tended to increase during the first year. However, the effects of root competition declined, relative to shoot competition, after flowering in the second growing season.Fertilizer applications slightly increased the root competitive ability ofH. lanatusrelative toD. glomeratabut slightly reduced its shoot competitive ab

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1980.tb01510.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractCalibration of an earth‐plate forage capacitance meter was conducted on pure stands ofFestuca arundinaceaSchreb.,Medicago sativaL.,Cynodon dactylon(L.) Pers. andTrifolium repensL. and a mixture ofTrifolium repensandDactylis glomerataL. Dry weight (DW) prediction equations were developed using the instrument capacitance reading modified by visual estimates of height, stand density and species percentage. In general, meter readings (MR) correlated better with DW than with fresh weight or weight of water and especially when the area harvested exceeded 0·537 m2. Correlation between MR and DW improved with increasing top plate area and with decreasing distance between the top plate (suspended sheet of aluminium) and the earth‐plate ground. The use of a plastic shield to suppress the forage to a uniform height caused a reduction in the correlation between MR and DW.The use of MR to predict DW from selected settings, their linear and curvilinear relationships and several auxiliary observations gave results withR2values ranging from 0·94 to 0·99, depending on species and m

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1980.tb01511.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractA comparison was made of the effect of a cereal supplement during early lactation on the performance and intake of ewes suckling two lambs while rotationally grazing pasture at stocking rates of 20, 17 or 14 ewes per ha. Supplement (S) at the high (H) and medium (M) stocking rates resulted in higher organic matter (OM) intakes (grass + supplement) of 2040 and 2500 g d‐1respectively, compared with the herbage OM intakes of unsupplemented (U) ewes of 1750 and 2040 g d‐1respectively. At the low (L) stocking rate the total OM intake of supplemented ewes and the herbage OM intake of unsupplemented ewes was similar at 2250 and 2210 g d‐1respectively.Lamb growth rate (g d‐1) to 12 weeks of age was significantly lower on treatment UH (229) compared with those on UM (253) and UL (262). Growth rates on S treatments were similar (SH 248; SM 261; SL 272) and there were no significant differences between S and U within stocking rates. Unsupplemented ewes lost significantly more weight during the period of intake measurement than those receiving supplement. The speed of rotation was faster where supplement was not fed at the medium and high stocking rates and herbage accumulation under UH was less than under SH. Only at the high stocking rate did feeding a supplement give a higher financial

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1980.tb01512.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractThe effects of fertilizer treatment were studied over two seasons on a 2 × 2 factorial arrangement of altitude and major soil group. The soil groups were brown earths and podzols and the altitudinal zones were 260–320 m and 380–440 m. Major responses were found to N only and these were generally linear in terms of overall dry matter yield up to the highest treatment level of 176 kg ha‐1. Productivity on brown earths was significantly higher than on podzols and differences between soil groups were not removed by increasing fertilizer input. In most instances 88–132 kg ha‐1N would have to be added to podzols to achieve the same yields as on brown earths with no N input. Apparent fertilizer recoveries and responses per unit of fertilizer input did not, however, differ markedly between soil groups. Overall yields were comparable with those from lowland situations at similar levels of N input, but the growing season was short and 60–80% of production was obtained b

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1980.tb01513.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractThe response of marsh birdsfoot trefoil (Lotus uliginosus) to inoculation with appropriateRhizobiumspp. was compared over 2 years. Inoculated and uninoculated seed was sown at 5 kg ha‐1on three soil types, brown earth, peaty podsol and deep peat. Perennial ryegrass cv. Perma was sown at 20 kg ha‐1as a companion species. Plots received either no N or a light starter dressing of 30 kg ha‐1N. Significant benefits from inoculation were recorded forLotusgermination and nodulation,Lotusand non‐Lotusherbage DM harvested andLotuscover on the deep peat, and to a lesser extent on the other soil‐types. Due to particularly uneven early establishment, work on the peaty‐podsol site was discontinued at an early stage. There was a trend towards depression ofLotuswhere N had been applied to inocu

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1980.tb01514.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractThree first‐harvest grass silages made from S23 perennial ryegrass cut on 25 May, 13 June and 25 June, and termed early, medium and late silages respectively, were compared in a 16‐week feeding experiment with fourteen Ayrshire cows. The early, medium and late silages had D‐values of 71·2, 65·0 and 62·5 respectively. The early silage was offered alone, whereas the medium and late silages were supplemented with a concentrate containing 208 g crude protein per kg DM at rates of 2, 3 and 4 kg per 10 kg milk. Silage DM intake was 12·8 kg per cow per d on the early silage treatment, and decreased progressively as concentrate intake increased on the other silage treatments. The mean daily milk yields were 16·0 kg per cow in the early silage treatment, 17·0, 18·4 and 20·4 kg per cow in the medium silage treatments, and 16·8, 18·1 and 20·2 kg per cow in the late silage treatments on the 2‐, 3‐ and 4‐kg concentrate treatments respectively. Fat concentration in the milk was not affected significantly by treatment, whereas the CP and SNF concentrations increased progressively and significantly as supplementary feeding increased. From the relationship between milk yield and concentrate intake it was calculated that the medium and late silages required a daily concentrate supplement of 2·1 kg DM per cow to give the same daily milk yie

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1980.tb01515.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractPlantsof Holcus lanatusL. andLolium perenneL. were grown in monocultures and in 50:50 mixtures and cut at three heights and at three frequencies during 24 weeks. The higher theH. lanatusplants were cut the greater was their harvested yield but height of cutting did not affect the yield ofL. perenne.Reduction in the frequency of cutting increased the total harvested yield of both species in monoculture. In mixture,H. lanatusdominatedL. perenne, especially with high and infrequent cutting. Stubble yields generally followed harvested yields.In a second experiment,H. lanatusplants were cut sequentially in spring; plants cut in early June produced very few panicles in the regrowth.In a third experiment the growth of decumbent tillers in late summer on spaced plants ofH. lanatusproduced a stoloniferous growth habit. The production of lateral shoots and roots on these stolons was measured in spring on plants undergoing various types of defoliation. Regular cutting of the parent plant increased the production of lateral shoots on stolons but did not affect the production of lateral roots.The significance of these results is discussed in relation to the manipulation of swards containing these two species.

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1980.tb01516.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractItalian ryegrass,Lolium multiflorumLam., cv. RvP., was broadcast in spring on to fine and coarse seedbeds at seed rates of either 2 or 20 kg ha‐1. Each of the four combinations of sowing condition was either left untreated or treated with fungicide or insecticide. The establishment of the sown species and of weeds under each regime was measured and their relative contribution to dry matter assessed in four cuts during the sowing year. Seed rate affected weed invasion and yield more than seedbed condition. Insecticide treatment increased the establishment and yield of ryegrass and its contribution to total herbage yield under all four sowing conditions. The fungicide treatment had no effect. The improvements caused by insecticide treatment were associated with a reduction in the level of infestation by shoot flies,Oscinellaspp. (Diptera: Chloropidae): the effect of a single treatment in April was still detectable in Octobe

ISSN:0142-5242    

DOI:10.1111/j.1365-2494.1980.tb01517.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY