Principles of veld management

Carrying Capacity potential of an area to support livestock through grazing and/or browsing and/or fodder production over an extended number of years without deterioration to the overall ecosystem. Assumption: Livestock daily DM intake equivalent (Demand) to 2.5-3.0 % bodyweight. To balance supply and demand correction for: Grazing (Harvest) efficiency Forage loss (fouling, trampling etc) Soil water holding capacity e.g clay versus sands Run-off and woody cover

Two major carrying capacity determination approaches Feed resources based Use by livestock pre-conditioned by proper use factors geared to prevent over exploitation and safeguard rangeland productivity Use empirical and or simulation models Uses rainfall records- 1mm produce 0.3kg DM???? Studies done in Matopos Uses livestock intake requirements Proper use- 30-50% of available biomass

Two major carrying capacity determination approaches Animal oriented approach Permissible amount of feed intake as in feed resource based approach but need to consider herbage quality and nutrient output thus lower estimates than plant based approach

Problems with carrying capacity estimates Scale or area of assessment Stock mobility Communal resources Several niches May include land units Kilometres apart Difficult to quantify Preference between animals species differ and assessing the fraction of edible feed becomes complicated (Especially with browse)- multi species systems Variability Time and space Climatic Production objectives/sytems Livestock mix

Factors to consider in CC estimation Topography Water distribution Wildlife influence Season Grazing management practice Non livestock demands

Carrying capacity concept General definition must encompass : elements of animal production goal, acceptable resource condition and time Optimum density (or carrying capacity)= carrying capacity in livestock oriented range management Economic carrying capacity. Subsistence density (Carrying capacity) = Population size at which an equilibrium between food demand and Supply is reached without external influence. Synonmous of carrying capacity= environmental carrying capacity, ecological carrying capacity, maximum carrying capacity, potential carrying capacity. Economic or optimum carrying capacity-equilibrium held in place by human intervation.  

Carrying capacity concept There are numerous managed equilibria depending on: production goals All are lower than subsistence In practise carrying capacity means different things to different people depending on production objectives. Carrying capacity has been applied to cattle mostly-graminoid herbage preferred by cattle have become the norm for assessment- hhrebs, dwarf shrubs and other woodies are classified as undesirable.

Carrying capacity concept In Sub-Saharan Africa Range production more a function of climate than stocking rate Climate and SR effects interacts and exert episodic rather than continuous impacts Livestock populations are more likely to be depressed by drought than overgrazing In the recovery wet years after a drought a, usually the regenerative capacity of the herds is often too low to keep with recovery of forage production

The use of carrying capacity concept Planning purpose Calculation of average productivity with respect to feed resources and expected livestock output Need to recognise spatio-temporal flu actions

Principles of range management Manipulation of vegetation and foraging animals to accomplish animal production objectives and rangeland sustainability Successful range management are based on the following principles: Control of animal numbers Spatial distribution of animals- (1) and (2) Stocking rate related Rest Period of use Top hamper control

Range management Control of animal numbers Perhaps most important factor in grazing management Done through the use of stocking rates Stocking rates- the must be based on the productivity of the area, animal needs and management objectives. Amount of land which the manager allocates to each livestock unit over the entire graze able period of the year (ha/Lu or Lu/ha). Function of the operator. Stocking rate must be based on the productivity of the area, animal needs and management objectives.

Two terms describing productivity of an area Grazing capacity—the area (in ha) of a particular type of vegetation required to support one livestock unit for the entire period that the land is grazed, without deterioration of the veld Carrying capacity STOCKING RATES affects: Forage production Individual animal performance Animal production per unit area Economic returns Ecosystem sustainability

Stocking effects on forage production Generally, as stocking rate increase, the quantity of the forage available declines because: An a short term basis, the rate of forage depletion exceeds the rate of forage accumulation On a long term basis, the interaction of biotic and abiotic factors on plant growth Heavy stocking rates- reduction in build up of carbohydrate reserves Quality of forage may be increased in the short term by high SR due to removal of low quality forage Long term changes in species composition under SR RESULTS IN LOW QUALITY FORAGE SR effects are also manifested by three stocking rate related factors namely- Stocking density, stocking intensity and stocking pressure.

Stocking effects on forage production Stocking Density- relationship between the number of livestock units and areas of land at any given instant in time. I f an operator divides 100 ha of pasture, veld etc into four paddocks, each of 25 ha and places 50 LU of cattle on the area and practice rotational grazing, the stocking rate would be 0.5 LU/ha (50÷100), whilst the stocking density of the paddock being grazed would be 2LU/ha (50÷25). Stocking pressure-The mass of available forage the operator has allowed per livestock for a relatively short period of time. Stocking Intensity- An expression reflecting simultaneously both the degree of stock concentration (stock density) and length of grazing period. found by multiplying the stocking density by the period of grazing to give the number of LU day/ha. expression of the degree of utilization of an area, and generally only has a meaning in relation to relatively short grazing periods. (often expressed in cattle days per ha (CDH)). Forage availibility- The mass of available forage per hectare at any instant in time

Grazing systems A grazing system is a specialized management which defines periods of grazing and no grazing for two or more paddocks or management units The objectives of utilizing grazing systems are: Improve range condition Achieve spatial distribution of animals through paddock size and shape Promote uniform forage utilization by reducing selective grazing Increases animal performance Increase flexibility of range management Improve forage quality and quantity

Grazing systems The choice of a grazing system is affected by: Climate, topography, type of vegetation, type of live stock, water availability and management capacity

Grazing systems Continuous grazing- Management in which animals are kept in a single enclosure for the entire grazeable period of each year. The number of animals in the enclosure may be varied according to the grazing, but at least some animals are present at all times during the grazeable period; Deferred grazing/Rotational resting- management which requires the grazing allocated to a group or groups of animals for the entire grazeable period, to be subdivided into at least one enclosure more than the number of herds involves the successive resting of the enclosure from grazing for specific purposes such as seeding and translocation aimed at restoration of vigour and productivity, rather than merely to allow regrowth of vegetative material for grazing

Grazing systems Rotational grazing- management which requires the grazing allocated to a group or groups of animals for the entire grazeable period, to be subdivided into at least one enclosure more than the number of herds in a rotation, so that at any time the animals are concentrated on as small part of the grazing available to them as paddocking permits and involves the succcesuve grazing of the enclosures in a rotation. Rotational resting and grazing- Management which incorporates both concepts of above types of grazing management. See Tainton, beef production management

Calculations A farmer from the Middleveld asks for help. He tells you he has one herd of 375 steers weighing 360 kg each in 1200 ha divided into six camps. Each camp has 54t of forage dry matter. After inspecting his veld with him you decide that he should be using a mid- season grazing cycle of 54 days, and estimates his current grazing capacity as 1LU:4ha (where, in this case, 1LU is the same as 450kg). He now wants to know: Stocking rate Current carrying capacity Stocking density Grazing period Rest period Stocking intensity Stocking pressure

Calculation Forage availability Stocking intensity in the early season Give appropriate units for each answer ANSWERS Stocking rate= 375×360 × 1 = 0.25 LU/ha or 1 LU:4 ha 450 (6× 200) ii) Current carrying capacity = 6×200×1= 300LU 4 iii) Stocking density = 375 × 360 × 1 = 1.5LU/ha or 1LU:0.67 ha 450 200

Grazing period = 54 =9 days 6   v) Rest period =54 × 5 = 45 days (54-9=45 days) vi) Stocking intensity (=stocking density × grazing period) = 1.5 × 9= 13.5 LU.days/ha

Stocking pressure 54 × 450 × 1 = 0.18 t DM/LU 360 375 360 375   viii)Forage availibility = 54 = 0.27t DM/ha 200 ix) Stocking intensity in the early season =1.5 × 5 = 7.5 LU.days/ha Note the shorter grazing period

Assignment You visit a successful rancher in Kadoma (Natural Region 111, in the higher rainfall area part of the middle veld) and find in one area of his ranch he has 500 steers of 300kg mean body mass rotating through six paddocks. Each paddock is 250 ha in size with, in mid- summer s a standing herbage of 54 toonnes of dry matter before grazing. The current grazing capacity is 1LU:4 ha. The farmer is uses a grazing cycle of 54 days in mid-summer, and imposes the same stocking intensity on each of the paddocks at any particular time of the year. Calculate the following for the ranch, giving appropriate units:

Current carrying capacity Stocking rate Stocking density Grazing period Rest period Mid –summer stocking intensity Forage availability in mid-summer Stocking pressure in mid summer The appropriate stocking intensity in early summer

The grazing cycle in early summer The rest period in early summer The grazing period in early summer (12) (b) Discuss what options the farmer has for increasing his overall carrying capacity of that section (8)