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1.
The effect of feeding forage legumes, Cowpea, Silverleaf desmodium and Oxley fine stem stylo, as protein supplements to natural pasture (veld) hay on intake, growth rate and nitrogen metabolism in growing lambs was evaluated. Thirty growing lambs were stratified according to body weight and randomly assigned, within a stratum, to five diets in a completely randomised design. The diets were veld hay alone (V), veld hay supplemented with either 10 g/kg of urea (VU), veld hay supplemented with 250 g/kg Cowpea (VC), 250 g/kg Silverleaf desmodium (VS) or 250 g/kg Oxley fine stem stylo (VF) forage legume hays. The V and the VU groups were used as control diets. Animals supplemented with either urea or the forage legume had higher (P < 0.01) total dry matter intake compared with the animals on V. The animals supplemented with the forage legumes had higher (P < 0.01) nitrogen intake and faecal nitrogen output than the non-supplemented group. All animals, across the treatments, lost body weight; lambs on V had higher (P < 0.01) body weight losses than those in the other treatments. The forage legume supplemented groups lost less (P < 0.01) body weight than those on the V and VU diets. Although supplementation with forage legumes enhanced feed intake and reduced weight losses it did not maintain body weights of lambs fed a basal diet of poor quality roughages.  相似文献   

2.
A comparative study was undertaken of the grass component of the three main veld types of the Vryburg district; namely Sand veld, Dolomite veld and Lime veld. Results indicate that different species within the same veld type and the same species in different veld types differ in their dry matter production, digestibility and digestible organic matter production. Botanical composition and basal cover also varied between veld types. Veld types also differ in DM yields, digestibility and DOM yield.

The average digestibility of all species at three growth stages (leafy, flowering and mature) was 48,7% in sand veld, 54,8% in dolomite veld and 54,7% in lime veld. The average dry matter production and digestible organic matter production per m2 at three growth stages were 2 083,9 g and 844,5 g in Sand veld, 2 108,6 g and 952,5 g Dolomite veld, and 1 776,0 g and 808,8 g in Lime veld, respectively. The possibility of deficiencies of Zn, Cu and P is indicated in all three veld types.

The percentage basal covers of sand veld, Dolomite veld and Lime veld were 4,3%, 2,1% and 5,0% respectively. The average DM yield and DOM yield of the veld types were 786,4 and 301,1 kg/ha in Sand veld, 403,9 and 189,2 kg/ha in Dolomite veld, and and 365,7 kg/ha in Lime veld respectively. The average digestibility of the veld types were 44,0%in Sand veld, 56,3% in Dolomite veld and 52,3% in Lime veld.  相似文献   

3.
Abstract

The long term effects of a 5N x 3P factorial fertilizer application trial on hay yields, botanical composition and soil properties of veld are presented. Significant increases in hay yields were recorded during most years. There was a strong correlation (r = 0,757) between mean (over all 15 treatment combinations) annual hay yields and annual rainfall.

N and N + P fertilizer lowered the percentage basal cover of the tribe Andropogoneae. A notable exception of this tribe was Heteropogon contortus which increased significantly at the lower fertilizer levels. The basal cover of the tribe Paniceae generally increased with N and P fertilizer application. The reaction of the basal cover of the tribe Eragrosteae showed little by way of definite tendencies.

Increasing N and P levels generally resulted in decreases in soil pH, Ca, Mg, K and an increase in compaction of the soil surface layer. However, higher levels of N x P resulted in higher water infiltration rates than occurred in control plots, although initial infiltration rates were greatest in control plots. Despite certain undesirable effects of fertilizers on basal cover and certain chemical and physical properties of the soil, the fertilized plots maintained a high level of production.  相似文献   

4.
Annual herbage yields of grasses grown on sandy soils on Henderson Research Station seldom exccecîf 10 000 kg/ha dry matter, while on heavy clay soils yields of 18 000 kg/ha are consistently obtained with similar amounts of applied fertilizers.

Eight grass species were established in sandy soil that had either not been fumigated or been fumigated with methyl bromide against soil nematodes. In the following season herbage dry matter yields increased from 13 280 kg/ha to 15 690 kg/ha due to fumigation, ou the average, while increases of 50% or more were obtained for three grasses. Yield reductions in two species may have been due to phytoloxic residues.

Fumigation reduced the number of nematodes in the soil and in the grass roots.  相似文献   

5.
This article on the short‐term effects of veld fertilization in the Bankenveld, deals with the effects of nitrogenous, phosphatic and potassic fertilization, and stocking rates on beef, mutton and wool production. Increased beef production was obtained by applying nitrogenous (linear to 80 kg N/ha) and phosphatic fertilizer to the veld. Fertilization influenced the production of merino sheep less than that of cattle.

Production per animal decreased and that per unit area increased (to a certain point) as a result of increased stocking rates. The expression of these results as MLU/ha or as ha/MLU influenced the form of the response obtained.

Problems were encountered in utilizing fertilized veld, which influenced the economics of the practice. In spite of poor utilization, on some treatments, it appears that veld fertilization can be profitable in its initial stages.  相似文献   

6.
Abstract

In a preliminary investigation seven legumes were planted alone and in combination with Lolium multiflorum cv. Midmar. The pure stands of legumes were harvested at either four, five or six week cutting intervals, while the pure stands of Lolium multiflorum and the ryegrass/legume mixtures received in addition to the cutting treatments 0, 200 or 400 kg N/ha in four equal applications. The ryegrass and legume components were harvested separately for dry matter yield (DM) and crude protein (CP) determinations.

Trifolium repens and T. pratense were the most suited companion legumes in terms of DM yield, CP content and the ability to extend the growing season. Ornithopus sativus and T. vesiculosum were the most suited annual legumes to grow in combination with L. multiflorum. Nitrogen had a far stronger positive effect on the DM yields and CP content than cutting interval, with the pure stands of L. multiflorum responding the most to nitrogen. The legume DM yields were adversely affected by the addition of nitrogen and by lengthening of the cutting interval. The incorporation of legumes into a ryegrass sward had the greatest positive effect on DM yields and CP content and yield when no nitrogen was applied and when harvested at six week intervals. Dry matter yields of the mixtures were only slightly reduced when half the maximum amount of nitrogen was applied.  相似文献   

7.
A programme of radical veld improvement applied on a farm in a cool, high rainfall area of East Griqualand is described. The veld was burnt in spring and fertilized with 300 kg/ha superphosphate and 45 to 60 kg/ha N. It was then heavily grazed with cattle and sheep during summer, using an eight‐camp rotational system, and in February it was oversown with cocksfoot and given a further 45 kg/N/ha. Grazing, with cattle only, continued into autumn. In the second year clover was sod‐seeded into part of the area.

With the eight‐camp grazing system, the number of MLU grazing days per ha increased from 161 on unimproved veld to 411 in the third year after improvement. In addition, the conception rate of cows increased from 85% to 97% and lambs could be run on the area which previously would support only mature, dry sheep.  相似文献   

8.
Abstract

Beef production from veld, in the short term, was found to be greater under a continuous grazing system than under a rotational grazing system. Average daily gains decreased from a maximum in late‐spring and the highest three‐year mean value was 0,5 kg/animal/day. Livemass gains/ha were highest at a stocking rate of 2,2 animals/ha and were 131,4 kg/ha under continuous grazing and 88,6 kg/ha under rotational grazing. Estimated mean maximum gains/ha were 0,78 kg/ha/day at a stocking rate of 2,5 animals/ha under continuous grazing and 0,55 kg/ha/day at a stocking rate of 1,7 animals/ha under rotational grazing. However, optimum economic stocking rates were estimated to occur below those where beef production/ha was maximum.  相似文献   

9.
Abstract

Run‐off and soil loss were monitored from a climax, subclimax and pioneer veld, each on a 5,9%, 4,1% and 2,1% slope, by means of a rainfall simulator on a Valsrivier soil form. With rainfall intensity, soil moisture content at the beginning of each rain storm, and soil texture the same for each treatment, plant cover and composition had a significant (positive) (P≤0,05) influence on the amount of soil loss and run‐off that occurred, as against the insignificant influence of the slope.

An average of 6,2 t/ha soil loss and 80,6% run‐off of the amount of water applied occurred from the pioneer veld (0,7% basal cover) on the steepest slope. In all the successional stages more run‐off and less soil loss occurred from wet soil than from dry soil. Significant (P≤0,01) relationships between basal and canopy cover were obtained with run‐off and soil loss.

The climax, subclimax and pioneer veld produced on average 0,57 g, 0,23 g and 0,07 g aboveground phytomass for each litre of water evapotranspirated.  相似文献   

10.
Campesino systems on hill slopes in Central Mexico rely on equids for multiple activities and have a problem in adequately feeding them. A participatory trial was conducted to evaluate the inclusion of common vetch in the traditional forage oat crop to improve its feeding value. An agronomic evaluation was undertaken by intersowing common vetch at 40 kg seed/ha with oats at 80–100 kg/ha in small plots, recording the yield and the chemical composition of the fresh forage in ten plots at harvest. The data were analysed as a completely random design, taking each farmer/plot as a treatment. A feeding trial compared the live weight of 7 donkeys fed oats and vetch against 17 donkeys fed traditional forage. There were differences between farmers in forage yields (p<0.01) that could not be explained as due to soil types or management. The mean yield of 31.0 t/ha of fresh forage of oats–vetch was 20.5% higher than that from monoculture, and had a higher crude protein content. Donkeys fed the oats–vetch were heavier (p<0.001). The farmers evaluated the oats–vetch association positively, appreciating the higher yields and good condition of their equids. The combination is an appropriate technology for these campesino farming systems.  相似文献   

11.
Abstract

The effect of four seeding rates (3; 6; 12 and 24 kg/ha), four methods of weed control (nil, mowing, 4 l/ha of 2,4‐D amine and hand weeding) and two times of cutting (late boot stage and end of season) on the establishment and yield of a Rhodes grass pasture was investigated. The experiment was first sown in 1980 and repeated in the same form in 1982.

Mother and daughter plants were counted and the canopy cover of Rhodes grass was estimated a year after seeding. Subsequently, the experiments were harvested a number of times.

Seeding rate, weed control and cutting affected the density of plants. The higher densities affected the yield of the pasture initially only. The value of using more than 3 kg/ha of commercial certified seed is doubtful. The use of adequate measures to control weeds does seem to be economically justified.  相似文献   

12.
Stylosanthes guyanensis was successfully sod‐sown in natural grassland in Swaziland's subtropical Middle‐veld. Introduction of the legume considerably improved yields and protein‐content of the herbage. A new strain of Stylosanthes has recently been obtained which is better adapted to heavy grazing and trampling than the common type.  相似文献   

13.
An autecological study of Cassia mimosoides L., which invades mismanaged Dohne Sourveld, was initiated at the Agricultural Research Institute, Dohne. A study of the growth characteristics revealed that the nature of the root distribution enabled the plant to take up moisture from superficial as well as deeper soil layers, while the position of the crown buds at or below soil level offered protection from fire damage. These characteristics plus the unpalatability of the plant to sheep and cattle placed it in a favourable position in competition with grasses. However, the relatively low‐growing C. mimosoides plants appeared to be at a disadvantage in rested veld. Although seeds were dormant when released, germination took place and seeds retained their viability over a long period. Under natural conditions the germination of non‐dormant seeds was controlled largely by temperature and moisture. Few seedlings established themselves in rested veld. It was suggested that a long rest period for the veld, followed by a spring burn, would be most effective in controlling the establishment of seedlings.  相似文献   

14.
Samples of the tropical forage legumes Vigna unguiculata (L.) Walp (cowpea), Desmodium uncinatum (silverleaf desmodium), Stylosanthes guianensis (oxley fine stem stylo) and Stylosanthes scabra (fitzroy) and of natural pasture (veld) hay were analysed and ranked according to their proanthocyanidin (PA) and saponin content. Silverleaf desmodium and fitzroy leaf and stem samples of different ages were also separately analysed for the PA contents. All the samples analysed contained some PA but no saponins. High levels of PA were detected in silverleaf desmodium and very low levels in veld hay and cowpea. In all samples, more of the tannins were bound to protein or neutral detergent fibre (NDF) than were extractable, most being bound to proteins. The proportion of the unextractable PA was greater in younger than in mature materials.  相似文献   

15.
Abstract

The influence of rotational and continuous grazing systems, each applied with four stocking rates, on the above‐ground phytomass of veld was determined over four years.

Grazing systems showed a significant influence on available herbage during one year only. Increased stocking rates brought a progressive decline in above‐ground phytomass. During the fourth season (1980/81) the average grazing pressures at stocking rates of 10 ha, 7 ha, 5,5 ha and 4 ha/Large stock unit were 5 984 kg, 3 417 kg, 2 390 kg and 1 238 kg and 1 238 kg phytomass/Large stock unit, respectively. At the end of the fourth season (July, 1981) there was reserve grazing available on the various stocking rates for approximately 579 days, 337 days, 202 days and 76 days, respectively. The risk of high stocking rates in the marginal rainfall regions, is emphasised.  相似文献   

16.
Abstract

The reaction of Anthephora pubescens to N, P and K fertilization was evaluated from 1976 to 1983. Dry matter production at N levels of 0; 75 and 150 kg/ha were 1,9; 2,2 and 2,3 ton/ha respectively. This relative poor reaction to N was related to rainfall variations and the initial low soil P status. A significant N × P interaction was recorded. Dry matter production increased from 1,6 ton/ha at the NO × PO treatment to 2,8 ton/ha at the 150 kg N/ha × 20 kg P/ha treatment. Anthephora responded poorly to K fertilization and the mean dry matter production was 2,1; 2,2 and 2,2 ton/ha with 0; 75 and 150 kg K/ha respectively.

The mean crude protein content of A. pubescens increased from 6,5 % at the NO level to 8,8 % with 150 kg N/ha. The P content of plant material increased from 0,13 % at the PO level to 0,20 % with 20 kg P/ha. The Zn content of plant material dropped to sub‐optimal levels during the trial.  相似文献   

17.
Abstract

Yield response of crownvetch (Coronilla varia) cv. Penngift, lucerne (Medicago sativa) cv. CUF 101, white clover (Trifolium repens) Dusi type and Kenya white clover (T. semipilosum) cv. Safari to differential application of lime and superphosphate were determined in a 5 × 4 factorial experiment on a virgin soil of the Griffin form. Lime rates varied from 0 to 7t/ha and phosphate rates from 0 to 150 kg P/ha. Patterns of response differed markedly between legumes. Clover yields were high even in the absence of lime and responses to differential lime rates were negligible. By contrast, yields of crownvetch and lucerne where no lime was applied were very low and yields increased markedly with successive increments of lime, the response of lucerne being greater than that of crownvetch. All the legumes responded to the application of phosphate, but yield increases decreased progressively with increasing phosphate level. Effects of the treatments on soil acidity and extractable nutrient elements were determined. A notable feature was an interactive effect between lime and phosphate on extractable phosphorus (0,25M NaHCO3, pH 8,5). Values increased progressively with successive increments of phosphate application, but decreased with increasing lime application. Depressive effects of lime were greater than at the lower levels of phosphate.  相似文献   

18.
This study examined the effects of adding forage legumes as protein supplements to poor-quality natural pasture (veld) hay offered to goats on microbial protein yield and nitrogen metabolism. Four indigenous Nguni-type goats were used in a 4×4 Latin cross-over design experiment. Goats were randomly allocated to four dietary treatments comprising commercial goat feed (GF), veld hay supplemented with cowpea (CW), velvetbean (VB) or silverleaf desmodium (SD). Microbial protein yields were determined using the purine derivatives technique and nitrogen retention was calculated from the digestible organic matter intake. Total nitrogen intake was significantly higher in the GF followed by CW, SD and VB, respectively. Microbial protein supply, calculated microbial true protein and digestible microbial true protein were affected (P<0.05) by legume supplementation. Animals on poor-quality forages had the most efficient microbial protein synthesis. However, supplementation of hay failed to meet the maintenance requirements of animals as evidenced by negative nitrogen balances in VB and SD. The efficiency of utilisation of nitrogen in the supplements could have been limited by unavailable fermentable metabolisable energy in the diets. Supplementation of poor-quality veld hay with legume forages could improve utilisation, especially in the dry season.  相似文献   

19.
Abstract

The Highland Sourveld of Natal is an important beef producing area. Although it covers only 13% of the total area of the province, it supports 18% of the beef cattle population.

The performance of cows and their calves stocked at four stocking rates on Highland Sourveld was studied. Two stocking rates were duplicated to test the benefit of an energy lick against a mineral lick. The effect of stocking rate on the veld was monitored in terms of compositional change.

Stocking rate significantly affected cow performance and consequently calf performance. An energy lick supplement, as opposed to a mineral lick supplement, was beneficial at the 1,0 LSU/ha stocking rate, but not at the 1,67 LSU/ha stocking rate.

The composition of the veld in the low to moderately stocked treatments changed relatively little, over the recording period, whilst the very high stocking rate treatments showed a rapid delcine in veld composition score.  相似文献   

20.
Abstract

Knowledge of the germination behaviour of desirable plants to be sown in the veld for veld improvement is still inadequate. To gain this knowledge, seed of different species of Karoo bushes and grasses were planted on two soil types at different planting depths.

Germination percentage of all species tested were significantly lower when planted on the surface in sand as compared with depths of 10 and 20 mm. Germination percentages were also lower at the 0 to 2 mm planting depth than the 10 mm and 20 mm planting depths when planted in a sandy loam soil.  相似文献   

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