Phosphorus or sulphur applied alone to a soil deficient in P and S did not increase subterranean clover (Trifolium subterraneum) yields; but when the two elements were applied together, a five-fold ,increase was obtained. The nutritive value of the clover was evaluated by measuring sheep rumen microbial activity using an anaerobic manometric technique. Subterranean clover fertilized with P alone increased the microbial activity about 6%. In contrast, the clover fertilized with S alone decreased activity about 5%. When P and S were applied together, microbial activity was increased 20 to 30%, depending on the rates applied. There was a positive correlation between the level of reducing sugars in the clover and the degree of rumen microbial activity.
AREAS in which white clover grows reasonably well have the potential of carrying a certain stocking rate without using fertilizer nitrogen. The development of dairying in such areas will logically use the best available legumes to increase stock carrying capacity to its economic optimum. Evaluating the place of fertilizer nitrogen in these areas will therefore be concerned with the establishment of the maximum economic production from legume-based pastures, and secondly with the increase in production per unit area possible using a range of nitrogen levels. Where the research objective is to provide guidance to a developing. industry, the optimum production from both nitrogen’ sources must be defined using available information on the best management systems, most suitable .legumes, most effective rhizobium, etc. This approach accepts that new information on any of the factors involved could increase the stocking rate which gives optimum production from either nitrogen source and would advocate that some of the research resources should be used to examine such management factors. If this guidance is not available, decisions will still have to be made by the industry but at greater risk (Morley and Spedding, 1968).
Pasture quality has been defined as a function of both intake and nutritive value. Results of New Zealand work on the quality of individual pasture species is collated. All grasses studied were of higher quality than perennial ryegrass and the legumes were higher again than the grasses. Possible reasons for these differences are considered. The role of digestibility in defining pasture quality has been examined and ‘it was concluded that digestibility is a useful index for low and medium quality herbage, but is of limited use for high quality herbage. Consideration is given to the choice of a suitable index for high quality herbages.
IN New Zealand, as in a number of other pastoral areas (A the world, controversy has surrounded the value of pasture management studies using indices such as dry matter production as an aid to predicting possible animal production levels per unit area. This stems from the fact that investigators studying the significance of different frequencies and intensities of grazing on pasture production and species productivity have been able to demonstrate very large differences in herbage production levels, whereas animal production studies using parameters of animal production as indices in these same environments have frequently failed to reflect such large differences. This is in spite of the fact that the extra production obtained in the pasture studies is frequently of high quality and is a very desirable feed for livestock.
In a simulated sward of Wairau lucerne cut at an immature stage of growth to leave a stubble of 10-11 cm, removal of all or one half the residual leaf area resulted in an initial decline of root weight and low or negative crop growth rates.
ON SOILS with good moisture retention, lucerne pastures at Lincoln have been demonstrated to yield more herbage more reliably than clover-based pastures (O’Connor et aZ., 1968). On light lands lucerne-based pastures are superior to clover-based pastures (Iversen and Calder, 1956; Flay, 1965; Iversen, 1965) . Iversen (1965) demonstrated the beneficial effects to lucerne yield and persistence on light land of “lenient” treatment (involving long spelling duration with short grazing duration) in contrast to “severe” treatment (involving semi-continuous grazing). Iversen (1967) reported similar benefits on a deep soil from such “lenient” treatment in contrast to continuous grazing over the same period from September to May. The work of Vartha (1970) on Wakanui soil at Lincoln has demonstrated that longer spelling duration is beneficial to lucerne in association with grasses where grazing duration was kept short.
An experiment is described in which the comparative productivity per acre has been measured using three classes of stockbreeding ewes, webhers and dairy beef cattle. Results have been expressed in terms of pasture production, feed Intakes, feed conversion efficiency, and output of meat and wool Per acre. These results ,have been discussed with particular reference to the potential production levels of various classes of livestock on a per-acre basis.
Details are given of intensive sheep farming on improved pastures in the #higher rainfall areas of Otago and Southland. The main features of pasture a,nd stock management used to achieve high levels of meat and wool production are described, and an outline is given of an all-grass, heavy stocking, farmlet study
COMMERCIAL, non-pedigree, livestock farmers in New Zeal. and find their economic future limited by the volume of animal products which they can sell from their farms. Inexpensive fodders and grains are not available in sufficient quantity to permit anything approaching the “feedlot” farming of other countries. Increased volume of output must, therefore, come substantially from those crops the farm can grow, and grow most efficiently. Climate, topography and experience currently dictate that this is the grass crop. The development of new skills and new technology may change this on those limited areas of New Zealand on which topography permits arable farming, but any widespread modification to the traditional pattern is a long way off.
In the genera Phalaris and Lolium, annual species have higher herbage nutritive value than perennials, and hybrids between annuals and perennials are intermediate. It is not yet known whether plant breeders will be able to improve the herbage quality of the perennial species without sacrificing some perenniality. Information needed to resolve this question could be obtained in various ways, some of which are discussed. Plant survival is of special importance in P. tuberosa, but in the ryegrasses some loss of perenniality has been tolerated by New Zealand farmers.
PASTURE PRODUCTION is logically measured in terms of grazing animals supported by that pasture. A simple calculation based on stock numbers and area in grassland in New Zealand shows that over the last forty years carrying capacity has increased from 1.4 to 3.2 “sheep units” per acre, or 130% (N.Z. Official Year Book).
WHEN your chairman asked for a description of grassland research in the United States, present and future, the mere thought of the task brought me a picture of a flea contemplating an elephant. Grassland agriculture is so large and varied in its entirety, is spread over so many disciplines, and is so complex in the interrelationships of the biological, social and economic communities that I can only hope to comment on how this flea views the rapidly changing giant.
Carbohydrate fractions and total nitrogen were measured in leaves and stems of Wairau lucerne grown in Canterbury. Leaves had lower levels of total soluble carbohydrate (3-5%), cellulose (S-10%) and lignin (a-4(%), and higher levels of total N (3.5-5%) than stems (total soluble carbohydrates l&22%, cellulose 2535%, lignin 4-11% and total N 1.5-4%). During the season, leaves did not change much in composition, whereas stems gradually increased in cellulose and lignin. Wintergrowing lucerne stems contained high total N (up to 4%), low, cellulose (13%) and lignin (4%). Irrigation increased soluble carbohydrate in stems, but not leaves ‘in immature luceme. Defoliation of luceme led to a fall in soluble carbohydrate in the standing stems. About 50% of the lucerne total N was easily extracted from the plant as protein. .On a kg/ha basis, a yield of 15, 232 kg of DM (non-irrigated) contained 480 kg of total N, 1,385 kg total soluble carbohydrate and 2,563 kg of cellulose. Over a 70-day summer period, a protein yield of over a metric ton/ha was extracted from irrigated lucerne.
IN Canterbury lucerne is generally established in 7 in. rows, without companion species, by drilling inoculated lucerne seed with matured lime-reverted superphosphate into an adequately cultivated and limed seedbed (Anon, 1958). As the crop ages, other species establish voluntarily so that eventually a mixed association of lucerne and variable proportions of grasses, clovers and other herbs results (Blair, 1965). The point at which volunteer species establish in the lucerne crop varies, and, although many crops remain free from other species for several years, some become infested during their establishment phase (Allen, 1967). The establishment and persistence of volunteers in the lucerne crop are affected by a wide range of factors such as the occurrence of lucerne diseases and pests (Blair, 1968), the variety of lucerne sown (Lobb, 1969), harvest and grazing management (Keoghan, 1967; O’Connor and Vartha, 1968), and applications of fertilizers (Sewell, 1960; Stephen, 1964; Harris, et al., 1966).
THE NEED for greater efficiency in pasture utilization is becoming more marked as stock numbers rise. In Southland, much of the increase is arising from higher stock concentrations and rates of almost 10 sheep per acre are known (Lawlor, 1970), although the average is considerably lower.
IT IS ESTIMATED that there are three-quarters of a million acres on the Canterbury Plains which can be classified “light land”, a classification which is a little vague, but sufficiently understood for there to be no need to attempt to define it here.
DURING the past few years, increasing emphasis has been placed on the use of nitrogen fertilized grass species, rather than grass-legume mixtures, in the North-eastern United States. According to Washko et al. (1967)) factors contributing to this trend have been the spread of the alfalfa weevil, development of improved, high yielding grass varieties, the availability of nitrogen fertilizer at economical prices, better harvesting and storage techniques, and the demonstration that grasses fertilized adequately and cut early are equivalent to legumes in nutritive quality. Of the different grass species examined, cocksfoot (Dactylis glomerata) has been shown to respond well to nitrogen fertilization, to be highly competitive, and to recover well under severe cutting managements. It has been claimed that cocksfoot is inferior nutritionally to other grasses. This was not substantiated in sheep feeding trials with herbage cut at different growth stages (Reid et al., 1962; Reid and Jung, 1965, or in subsequent grazing trials (Reid, Jung and Kinsey, 1967).
It was my original intention to present a review of past and present pasture research in South Africa and to speculate on future developments in pasture production and research.
MIDWESTERN United States has a temperate climate, more specifically d.escribed as subhumid and microthermal. Pasturing systems in this area have developed to take advantage of the normal seasonal growth pattern of perennial legumes and grasses. Thus, pasturing is practised extensively from May through September (5 months). Limited grazing is available in April, October, and November.
GRASS still occupies about 65% of the agricultural land of the islands that make up the United Kingdom. The research effort devoted to all aspects of its growth and utilization is considerable and is carried out by many official organizations, by large commercial firms, and by a few farmers. A review of the progress during the last decade, if confined to the limits of a single paper, is in consequence likely to be biased- in the direction of the writer’s own interests. I confess at the start that this review is based largely on my experiences at the Grassland Research Institute at Hurley during the last five years and draws freely on the thoughts and recollections of several of my senior colleagues.
NZ Grassland Association Inc.
11 Montrose Street, Mosgiel, Dunedin 9024 New Zealand | P: +64 3 477 0712 | F: +64 3 473 6495 | E: nzgrassland@gmail.com
© Copyright NZ Grassland Association Inc. 2011. All rights reserved
Refund Policy | Disclaimer | Privacy Policy | Terms & Conditions