Restoring grazing values
Managing perennial grasses and ensuring re-seeding, whether naturally or with commercial seed, is critical for farmers.
08 May 2019 | Agriculture
The abundance of the most valuable grass species in many parts of the country has decreased, resulting in loss of grazing value especially in communal areas, and the carrying capacity has drastically decreased over the years.
The grasses that are now dominating are the opportunistic ones with little grazing value such as Aristida stipitata, amongst others.
This has significantly compromised livestock productivity and the potential income of farms.
The underlying reasons are the poor grazing regimes which led to overgrazing, in turn resulting in rangeland degradation in the form of bush encroachment and soil erosion, amongst others, and this is further exacerbated by the erratic rainfall.
When there is no grass there will be no money. The grazing value of an area is determined by the grass growth/life cycle, species composition and nutritional value.
There are two types of grasses in terms of life cycles; these are annual and perennial grasses.
An annual grass (e.g. Eragrostis porosa, Chloris virgata, etc.) is mainly the first grass type to emerge in abundance after the first rainfall, and thus, the first green food for grazing animals after the dry season.
Annual grasses have a shallow root system and few leaf materials; and only need a minute amount of moisture, nutrient and sunlight.
These types of grasses grow and produce seeds fast, but survive only during the rainy season and die (disappear as winter season starts).
The next annual grass will only grow from the seed. In contrast, perennial grasses such as the common Cenchrus ciliaris (blue buffalo grass) Schmidtia pappophoroide (Kalahari sand quick), or Anthephora pubescens (wool grass) have deep root systems and massive leaf materials, and require enough investment in terms of moisture, nutrients, and sunlight, and thus take longer (about 2-3 months) to grow to maturity. They are the bulk of the grazing animal's diet throughout the year.
At the end of the rainy season, they do not die but go into dormancy for the dry season. They shed seeds and withdraw all nutrients (from leaves and stems) back underground in their stump as food reserves for the next season's growth.
The same dormant grass stump will produce fresh/new stems and leaves, and also, the seeds will germinate into new grasses.
These grasses shed seeds as they start to dry in the dry season, from May.
These seeds may be found collected together in ditches on the soil. In August, the wind distributes and sows them, and when the rainfall starts, the germination process begins.
In an effort to restore grazing lands and produce their own fodder, farmers need to reintroduce these perennial grasses by re-seeding. These grasses can be cultivated and protected like food crops in gardens or crop fields, and can also be planted in grazing areas.
The seeds can be harvested from standing grass or purchased from common agricultural input shops.
It is very important that cultivated grasses are protected from disturbance (grazing), and are allowed to grow to maturity until they produce seeds and are able to regenerate themselves.
Once harvested, it can be processed into hay or milled and mixed with other feedstuffs and used or stored for the period of fodder scarcity.
*Erastus Ngaruka is the technical officer of livestock at Agribank