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1.
A comparison of pasture and fodder crops for the production of slaughter lambs in the Pretoria‐Witwatersrand‐Vereeniging (PWV) area. A number of pasture and fodder species were evaluated for the production of mutton with weancr lambs. Animal performance and meat production under three stocking rates, which were classified as light, medium, and heavy, were obtained with the aim of identifying best pasture/fodder for every season. The pastures/fodders included were Lolium multiflorum cv. Midmar and Triticum X Secale pastures under irrigation, Avena sativa and Vicia dasycarpa pasture mixture and maize crop residues under rainfed conditions, and Medicago sativa and Digitaria eriantha hay for the winter months. The spring pastures were L. multiflorum cv. Midmar, Lolium perenne cv. Nui and Dactylis glomerata cv. Hera under irrigation, while the summer pastures included Digitaria eriantha var. eriantha and M. sativa cv. Cuf 101 pastures under rainfed conditions and Cynodon dactylon cv. NK37 under irrigation. Of these, the midmar pasture for the winter and spring, maize crop residues for the winter, Hera for the spring and Cuf 101 for the summer seemed to be the best pasture of those tested in their season of use, from an animal production point of view.  相似文献   

2.
Abstract

In a preliminary investigation four small grain species, oats (Avena sativa), rye (Secalae cereale), wheat (Triticum aestivum) and triticale (Triticum × secalae) were planted alone and in combination with Lolium multiflorum cv Midmar under irrigation. The dry matter (DM) yield of Midmar was also compared to that of four other annual ryegrass cultivars. All species combinations were harvested at either three‐ or six‐week cutting intervals and fertilized with either 200 or 400 kg N/ha.

As a group the pure ryegrasses had a greater yield potential than the small grain‐Midmar group which in turn out‐yielded the small grain group. Increasing cutting interval from three to six weeks had a far stronger positive influence on DM production than that of doubling the amount of nitrogen. Rye was the most successful small grain in being able to fill the winter gap in the fodderflow of Midmar ryegrass.

The small grains on average contributed about 25 % towards the total DM production in the small grain‐Midmar mixtures. Oats, although initially slow, had significantly (P≤0,05) higher yields than any of the small grains and had a longer, more evenly distributed growing season.  相似文献   

3.
Abstract

Four pasture legumes and seven grasses were subjected to a range of cutting frequencies during the 1980/81 season. A wide range of responses emerged, judged by both the dry matter and TDN yield responses of the different species. Whereas two cultivars of white clover and Ruanui ryegrass were most productive with frequent harvesting (every 2 to 4 weeks), kikuyu and Sirocco Phalaris responded well to a long interharvest interval (8 to 10 weeks). A number of pasture types, including lucerne, Currie cocksfoot, K31 fescue and Ariki ryegrass produced well at intermediate harvesting frequencies (6‐weekly) while in yet others (Kenland red clover and Seedmaster Phalaris) yield was not materially different over a wide range of cutting intervals in the range 6 to 10 weeks.  相似文献   

4.
Uittreksel

‘n Literatuuroorsig oor die gebruikswaarde van tropiese grassse as staande hooi, in die winter, word voorsien. Die invloed van klimaat op die keuse van spesies en bestuur van die grasse, gedurende die voorafgaande groeiseisoen, word bespreek. Meer onlangse gegewens oor die gebruik van Digitaria eriantha (Smutsvingergras) as staande hooi in die semi‐ariede gebied van Wes‐Transvaal word verskaf. Uit hierdie gegewens blyk dit dat Smutsvingergras ‘n belangrike rol kan speel in die oorwintering van diere.  相似文献   

5.
Abstract

N fertilizer was applied as a single dressing in spring at 0, 20, 40, 80, 160 and 320 kg N ha‐1 a‐1 to an established Digitaria eriantha pasture, previously used as a hay crop. The only significant increase in dry matter (DM) yield was obtained with 80 kg ha‐1 a‐1. The DM production per unit of nitrogen (N) applied also reached a maximum with 80 kg N ha‐1 a‐1. The distribution of rainfall also influenced DM yield.  相似文献   

6.
Abstract

The objective of this study was to investigate the influence of different nitrogen fertiliser application levels in combination with different defoliation intervals on the dry matter (DM) production and water‐use efficiency of ryegrass (Lolium multiflorum,) cv. Midmar. In a field trial, four nitrogen levels (0, 150, 300 and 450 kg N ha?1) were combined with five defoliation intervals (every 2, 4, 6 and 8 weeks and twice a season). Soil moisture levels were measured with a neutron hydroprobe and were used to schedule irrigation. The dry matter production, nitrogen‐use efficiency (NUE), plant DM content and water‐use efficiency were influenced (P<0.01) by nitrogen level, defoliation interval, and the interaction between these factors. Total DM production varied from 64 to 20 922 kg DM ha?1. Dry matter production per unit of applied N decreased with an increase in N level within a defoliation interval. The plant DM content varied from 14.0% to 35.6%. The plant DM content decreased (P<0.05) with increasing N applications, while a lengthening of the defoliation interval resulted in an increase (P<0.05) in the DM content. No difference (P>0.05) was found in total water used when plants received N. Water‐use efficiency varied from 1.2 to 25.8 kg DM ha?1 mm?1 water received.  相似文献   

7.
Little work has been done in South Africa on the incidence of viruses in pasture grasses. The aim of this work was to carry out a survey of virus infections of some of the economically‐important pasture grasses in South Africa. Twelve winter and summer pasture grass species and one cereal forage crop species were collected from six different regions in early, mid‐ and late winter and summer. Plants were tested for virus(es) by means of symptomatology, transmission, dot‐blot immunoassays, Ouchterlony tests and electron microscopy. Serological tests indicate that Avena sativa from Roodeplaat and Bromus unioloides from Potchefstroom, Cedara and Nooitgedacht are positive for maize dwarf mosaic virus (MDMV). Lolium multiflorum from Cedara appears to be infected with two viruses, brome mosaic virus (BMV) and a potyvirus‐like agent, possibly ryegrass mosaic virus (RMV).  相似文献   

8.
Abstract

A number of grasses were ranked according to the order in which they wilted with diminishing moisture availability, and according to their ability to recover after water replenishment. Digitaria eriantha and Digitaria argyrograpta were the most sensitive to moisture stress, whereas Sporobolus fimbriatus and Panicum stapfianum were last to show signs of wilting. The latter two grass species were the first to recover from wilting during optimum soil water conditions. The leaf water potential and soil water content at which each grass species wilted were recorded.  相似文献   

9.
Uittreksel

Die produksie en kwaliteit van vyf spesies (Themeda triandra, Heteropogon contortus, Digitaria eriantha var. pentzii, Schmidtia pappophoroides en Eragrostis rigidior) is by verskillende frekwensies van ontblaring op ontbosde en onontbosde bosveld gemeet. In die daaropvolgende jaar is intensiteit bygebring met minder frekwensies en is die spesies na drie verminder (H. contortus, D. eriantha var. pentzii, en S. pappophoroides).

Ontbossing het by al die spesies, behalwe D. eriantha var. pentzii ’n hoogsbetekenisvolle verhoging in produksie tot gevolg gehad, sonder enige noemenswaardige invloed op kwaliteit.

Die spesies het verskil in hul reaksie op frekwensie van ontblaring, maar die 3‐ weeklikse en jaarlikse ontblarings het byna deurgaans swakker as die 6‐ en 9‐weeklikse onblarings presteer.

Alhoewel die spesies aanvanklik in twee groepe verdeel en aan verskillende stelle ontblaringsintensiteite onderwerp is, het die intensiteit wat 12 cm Stoppel laat, in alle gevalle die hoogste produksie gelewer.  相似文献   

10.
Abstract

Digltaria eriantha and Chloris gayana were grown under controlled conditions for three months and were treated with a nutrient solution containing 150 mMol NaCl and the following nitrogen sources: 25 or 200 mg/l NH4 +‐N or NO3 ?‐N or no nitrogen. The application of nitrogen was found to stimulate growth, i.e. leaf area and dry mass in both grasses, with a greatest growth response to both NH4 +—N treatments in D. eriantha, and NH4 +‐N and NO3 ?—N treatments in C. gayana. Proline accumulated in both grasses, but this accumulation followed different trends in the two grasses. Soluble sugars (non‐structural) accumulated in the above ground component in D. eriantha, while in C. gayana soluble sugars accumulated predominantly in the roots, possibly as osmotica, or for storage and may thus have been available for regrowth.  相似文献   

11.
ABSTRACT

1. The aim of this study was to determine the nutritional status of backyard chickens reared under 4 different agro-climatic conditions (tropical, humid subtropical, cool-temperate and semi-arid) of India during different seasons of the year and to compare their nutritional status with those reared under confined feeding system (CFS). In each season, 15 adult and 15 grower chickens were slaughtered for collecting content of crop and gizzard to assess the nutritional status from different agro-climatic conditions.

2. The dry matter content of crop and gizzard was higher (P < 0.01) in chickens reared under backyard conditions compared to those reared under CFS.

3. Higher (P < 0.01) crop and gizzard contents were recorded during winter compared to the rainy season. The proportion of grains in the crop during summer and winter season was higher compared to rainy season. Further, there were more insects present in the crop during the rainy season and winter compared to summer.

4. The proportion of insects was higher in chickens reared in humid, subtropical and cool temperate regions compared to semi-arid conditions. The consumption of grasses was higher in cool-temperate regions as compared to those reared under other areas.

5. Crude protein (CP), Ca, P and gross energy (GE) content of the crop were higher in chickens reared under CFS compared to those reared in backyard systems and CP in the crop contents was lower in backyard chickens reared in humid subtropical and semi-arid regions compared to other areas. Similarly, lower (P < 0.01) Ca levels were seen in crop and gizzard contents from birds reared in semi-arid Rajasthan, and P and GE were lower in tropical wet and dry Telangana (TWT) compared to the chickens reared in the backyard conditions in other regions.

6. Based on the results, the nutrient intake for birds utilising the scavenging feed resource base (SFRB) in the TWT region was below the requirements of backyard chickens from the other regions selected in the present study. GE and CP were critically deficient in the SFRB of the TWT region. Therefore, evolving location-specific supplementary diets using locally available feed resources to meet nutrient requirement of backyard chickens is required for optimising production potential.  相似文献   

12.
Abstract

A two‐year study was conducted in lightly grazed areas of Matopos Research Station, Zimbabwe, to evaluate the impact of widely spaced trees on understorey grass composition, yield and quality. The study trees were Terminalia sericea and Acacia karroo. Ordination techniques using grass density and biomass as indices separated quadrats according to soil type but not grass species according to understorey or open areas or according to tree species. Grass yield under tree crowns was similar to open areas, in contrast with most reports where understorey areas had higher yields. The high understorey grass quality that has been reported from savanna areas exhibiting grass composition differences was not expressed. Selective grazing of palatable perennial grasses growing in association with tree crowns and their eventual replacement by low‐yielding and less‐palatable grasses that normally grow in open areas is proposed as an explanation of the unique tree‐grass interaction scenario of this study. In areas where this replacement has occurred, recovery may require management interventions.  相似文献   

13.
Abstract

A fodder flow/animal experiment 40,8 ha in extent (7,5 ha irrigated), with 19 paddocks, was carried out over a two and a half year period.

The aims were: firstly, to compare fodder crops within seasons, and fodder flows over three seasons (winter‐spring‐summer), by means of pasture and animal parameters; secondly, to make economic comparisons between different fodder flows, for growing out beef steers.

The conclusions were that: Digitaria eriantha ssp. eriantha is superior to Eragrostis curvula cv. Ermelo for animal production; maize residue gives economically favourable results due to low costs and compensatory growth of cattle; an irrigated pasture providing fodder in more than one season of a flow, for example, Festuca foggage — Festuca pasture — Digitaria pasture, gives a very profitable fodder flow, because the costs of production are divided between two seasons; dryland fodder flows with the sequence maize residue — silage or hay — Digitaria or, with silage or hay replacing the maize residue, were also very profitable; and, the fodder flow giving the highest livemass gain per steer, is not necessarily the most economic. Different kinds and classes of livestock require different fodder flows.  相似文献   

14.
Abstract

Digitaria eriantha plants were grown under controlled conditions for a period of three months, during which time they were supplied with the following forms and concentrations of nitrogen: 50 mg/1 NO3 ?‐N, 200 mg/1 NO3 ?‐N, 200 mg/1 NH4 +‐N and a combined form containing both NO3 ?‐N and NH4 +‐N with a nitrogen concentration of 200 mg/1. Control plants received no nitrogen.

At monthly intervals both above and below ground components were assayed for soluble and insoluble carbohydrate contents. Dry mass and leaf areas were also measured.

The nitrogen treatments were found to influence the allocation of photosynthates into either soluble or insoluble carbohydrates. In above ground tissue, the soluble carbohydrate component decreased with time, while the insoluble component increased with time. In root tissue the reverse trends were observed. Both dry mass and leaf area development were enhanced in plants supplied with nitrogen in any form. It was suggested that growth of D. eriantha was influenced by carbohydrate fluctuations.  相似文献   

15.
Abstract

The productivity of Trifolium repens L. cv. Ladino, under irrigation in the subtropical region of Gauteng, South Africa, is unknown. The performance of T. repens was determined over five years (1981/1982 to 1985/1986), at two defoliation frequencies, four levels of nitrogen (0, 400, 800 and 1 600 kg N ha?1 ‐ total applied over five years), and either the removal or recycling of harvested material. Frequent, compared to infrequent defoliation, resulted in higher dry matter (DM) yields from the second year onwards. Dry matter yields were positively affected by the recycling of material, compared to no recycling. A mean DM yield of 191 ha?1 in the first year and 12 t ha?1 in the final year, was obtained. The highest DM yields occurred during October for all years and lowest DM yields from January to March. The first and final year showed similar peaks (late October) and troughs (March till April). Crude protein (CP) content of the herbage was influenced more by frequency of defoliation than recycling of material, where the highest CP content in any year was obtained from frequent defoliation. Nitrogen fertiliser applied up to a total of 1 600 kg N ha?1 over five years had no effect on either DM yield or crude protein content. This study has shown that T. repens could be a productive pasture for at least five years in the subtropical region of Gauteng, South Africa. Productivity and quality of T. repens were enhanced by a defoliation interval of less than five weeks and when soil high fertility was maintained by recycled plant material.  相似文献   

16.
Abstract

Marked populations of Themeda triandra and Sporobolus fimbriatus tillers were sequentially harvested at fortnightly intervals both under irrigation and under unamended moisture conditions. Sampling covered a period from tiller initiation through to senescence after flowering.

Tiller masses and green leaf areas were used to derive absolute growth rates, relative growth rates, net assimilation rates and leaf area ratios respectively. Growth rates of Themeda triandra were higher, or were maintained at high levels for longer than those of Sporobolus fimbriatus. Moisture stress resulted in considerably depressed growth rates. Photosynthetic efficiency of spring emerging tillers was potentially greatest in midsummer, but this seasonal influence was masked by moisture stress on non‐irrigated treatments.  相似文献   

17.
Abstract

The grazing value of the seven most prominent grass species in Tarchonanthus‐limeveld was investigated from 1977 to 1981.

The frequency of utilization of Chrysopogon serrulatus was exceptionally high (93%), while Sporobolus fimbriatus, Themeda triandra and Digitaria seriata were intermediate (50–60%) followed by Cymbopogon plurinodis (34%). Eragrotis lehmanniana and Fingerhuthia africana were poorly grazed (12 to 16%). The utilization of species was influenced by stocking rate. Statistical differences between species indicated a relatively high biomass production (600 to 740 g DM/m2 per year) for E. lehmanniana, C. plurinodis and T. triandra, while F. africana, S. fimbriatus and D. seriata were intermediate (320 to 420 g DM/m2 per year). E. lehmanniana, C. plurinodis and T. triandra produced the highest above‐ground phytomass, but had a lower crude protein content (2,9 to 7,4%) and digestibility (46,1 to 61,3%) than the other four species (3,8 to 9,7% crude protein and 50,5 to 68,4% digestibility).  相似文献   

18.
Abstract

Marked populations of Sporobolus fimbriatus tillers were sequentially sampled at fortnightly intervals under normal rainfall conditions and under irrigation respectively, covering a period from tiller initiation through to senescence after flowering. Parameters recorded included shoot apex elevation, tiller mass and leaf development.

Surviving tillers consisted of two sub‐populations, those that flowered in autumn and those that remained vegetative. Flowering of individual apices was rapid, but was spread over a number of months for the whole population. Moisture played an important role in determining tiller size, and at least some forage was lost through leaf drop on tillers rested for a whole season.  相似文献   

19.
Abstract

The study was conducted on smallholder dairy farmers in Tanzania. A number of forage species and feed supplements were collected and analysed. Panicum maximum and P. purpureum constituted the bulky forage in about 20 and 11 households, respectively. The crude protein (CP) content of P. maximum and P. purpureum ranged from 6.5 to 8.5% and 7.8 to 10.2% while in vitro dry matter digestibility ranged from 44 to 50 and 48 to 51%, respectively. The mineral content of these two grasses were adequate for Ca but 95% of the forages were deficient in Cu and Zn and 84% in P. The CP content of multipurpose tree leaf was 3–4 times higher than that of grasses. In conclusion, the study revealed that dairy farmers depended solely on natural grasses and crop residues, which are low in CP, digestibility and mineral content.  相似文献   

20.
Abstract

Embryogenic callus was obtained from immature regions of the leaf of Digitaria eriantha when grown in the dark on a MS medium supplemented with 1,0 or 2,0mg/dm3, 2,4‐D and 3–9 % sucrose. Plantlet regeneration occurred when the calli were transferred to MS medium containing 0,1 mg/dm3, 2,4‐D and 7–8 % sucrose, and placed under 16 hour photoperiod. The regenerated plantlets were successfully planted out into a mixture of sand and potting soil.  相似文献   

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