An investigation into the validity of some of the pasture and veld norms used in budget feed programmes in the Underberg district

[摘要] Underberg lies immediately to the east of and below theDrakensberg, which is a mountain range in the province ofNatal of the Republic of South Africa.The agriculture extension area is comprised of 200farms, which on an average are 800 hectares in extent.As a result of an active study group, which for theyears 1953 to 1970 kept accurate economic figures, the maincost items on the farm were found to be fertilizer, boughtfeed, repairs, labour and fuel cost. The extension workersdecided to help the farmers by trying to cut the bought feedcosts. To this end the idea of budget feeding was introducedand put into practice by the extension workers. Budgetfeeding was the name given to the plan, which assisted thefarmer in calculating the necessary feed required to feed hisanimals for the 355 days of the year. Knowing the amount offeed required, norms of quantity and quality were applied tothe budget feed exercise, leading to the number of hectaresof each crop that should be grown.Over a five year period budget feeding was carried outin the Underberg district. The plan was moderately successful.However, there were a number of farmers that were disappointedwith the plan, in that they apparently carried out the budgetfeed plan, but still ran short of feed towards the end ofwinter.A check was made on the factors that could lead to abudget feed shortcoming. An evaluation on the check pointsshowed that there were some limiting factors, which possiblycould hamper the success of an Underberg budget feed plan.2. It was decided to investigate the limiting factors inmore detail, and to this effect the following trials wereundertaken.A comparison of the productivity of eight existing farmpastures was undertaken under topland irrigated, topland non-irrigatedand lowland non-irrigated conditions.The dry matter yields of the eight types of pasture variedenormously from the dry matter yield norms used in thebudget feed exercise. The actual yield of fescue wasapproximately thirty percent less than the fescue norm used forbudget feeding.The trial established that straight clover was a highyielder of crude protein and a low yielder of fibre. Aryegrass and clover mixture, from a feed quantity and qualitypoint of view, performed well.Cocksfoot in general supplied the lowest yield of drymatter per hectare and the fescue was found to be the highestcontainer of fibre and thus the lowest T D N supplier.Kikuyu, although having a shorter growing season for thearea, gave the highest overall dry matter yield. The non-irrigatedkikuyu out yielded the irrigated kikuyu, a phenomenonwhich needed investigation.The addition of clover to the grass in the sward wasdefinitely advantageous.Irrigation on average increased the air dry matter yieldby 2,81 ton per hectare. Due to irrigation, this extra drymatter yield at 3 cents per kilogram dry matter meant anextra gross amount of R76 per hectare.Non-irrigated lowland pastures, with the exception ofstraight clover, outyielded their counterparts under non-irrigatedtopland conditions, the reason apparently beingthat the lowland conditions have much cooler temperatures overthe year.On the average, non-irrigated topland pastures yielded0,12 ton of air dry matter per hectare more than the non-irrigatedlowland pastures. Clover pastures under non-irrigatedtopland conditions out yielded the clover under non-irrigatedlowland conditions by 1 ton of air dry matter (A D M) /ha.3. A comparison of the dry matter yields of topland irrigatedAriki ryegrass, Danish cocksfoot and Kentucky fescue pasturesgrown under farm conditions and under plot conditions showedthat plot yields on the average yielded 30 percent more thanthe equivalent pastures on the farm (15,83 air dry matter/haversus 11,91 A DM/ha).4. A comparison of Lolium multiflorum cultivars in theUnderberg area showed that over the six month winter period,Tetila, Tetrane, Midmar, Local Hipkin and Local Hulleys weresignificantly superior to the other cultivars under test.Tetila, cultivar, a tetraploid type, gave the highest D M yieldof 9,77 ton per hectare. During the critical July and Augustwinter feeding period the cultivar Midmar out yielded all theother cultivars by providing ,2,93 ton of dry matter per hectare.Further, it was found that the diploid cultivars out yielded thetetraploid cultivars during the mid winter period. It isimportant to note that certain cultivars out yielded others, andhence a specific cultivar should always be stated when applyinga norm for budget feeding exercises in the Underberg area.A variation in the quantity and quality of the material onannual ryegrass pastures over the May to mid September periodwas very apparent. The average quadrat yield dropped from 2,71kg wet material/m2 in mid May to 0,55 kg wet material/m2 at the endof July. It is thought that heavy frosts dried the foggage outand then heavy berg winds blew much of the conserved foggage away.Over the test period the crude fibre of the ryegrass foggage variedbetween 17,8% and 33,7%, while crude protein varied between 21,4%and 11,9%. For budget feeding purposes no specific norm of yieldand quality of ryegrass foggage can be used over the winter period.It appears to be impractical to apply an accurate ryegrass foggagequantity and quality norm to an Underberg budget feed exercise.An evaluation of a trial on the productivity of Underbergveld with the aim of determining whether the budget feed norm of0,5 M L U/ha/season carrying capacity was correct was undertaken.All the results showed that 0,5 M L U/ha/season was not too highand thus should the Underberg budget feed farmer be short of feed,the fault would not lie in the fact that an incorrect veld carryingcapacity norm had been applied to his budget feed plan.The assessment of the non-utilization of pastures by thegrazing animals on seven Underberg farms showed that on average26,6% of the pasture was not utilized after one grazing. Onefarmer utilized only 48,6% of the pasture available to him.It appears that the non-utilization of pastures by the farmerwas one of the reasons why some Underberg farmers were shortof feed after attempting to carry out their budget feed plan.8. Due to the high non-utilization figure of pasture bygrazing animals shown up in Chapter 4.1, a further similarinvestigation on another twelve farms was undertaken. Thistrial verified the Chapter 4.1 results by producing an averagenon-utilization of pasture figure of 39,5%. One farmer inthis trial utilized only 40% of the available pasture at onegrazing. On nine of the twelve farms there was no apparentadvantage to be gained by such poor utilization since thepastures were not subsequently regrazed.By calculation from the protein and fibre figures thehighest T D N figure was obtained from the pure clover trialin the pasture productivity study (Chapter 3). The cloverfed to an arbitrary 275 kg beef animal would provide the bestpasture for obtaining a 1 kg/day gain. Should bloat be aproblem the next best pasture, from the point of view of averagedaily gain, would be kikuyu, which would supply enough nutrientsto allow a 275 kg animal to gain 0,85 kg/day.The addition of clover to the grass sward improved thequality of the pasture and appeared to have an economic effecton both pasture and animal production.It is apparent that the correct pasture type should begrown by the Underberg budget feed farmer, as is shown bythe difference of 4,4 ton of D M in yield per hectare infavour of kikuyu over cocksfoot when grown under non-irrigatedtopland conditions.10. It is important to use an accurate norm in a budget feedplan. The current inaccuracy of as much as 39,1% in the budgetfeed plan is unsatisfactory.The validity of pasture productivity studies are discussedin paragraph 5.7.1. Certain of the results were verified bytrials in an ensuing year.The weaker links in the budget feed scheme formed themain focus of this work. Certain variations in accepted normsand principals in budget feeding are shown up, as summarizedbelow:-pasture productivity studies, up to 39,1% variation fromnorm used;up to 24,2%;up to 31,8%;up to 26,7%; andup to 39,2%.plot versus farm pasture yield,ryegrass cultivar trial,non-utilization of pasturetrial,non-utilization of pasturetrial II,The above percentage figures averaged out at 32,3%.A safety factor of 32% extra feed necessary for feedinganimals was built into eleven new Underberg budget feed schemes,and the result was that no farmer who carried out his budget feedplan complained of being short of feed.

[发布机构] University of the Free State