INFLUENCE OF CLIPPING AND GRAZING ON
GROWTH, QUALITY, MINERAL CYCLING, SOIL CHARACTERISTICS, AND PROFITABILITY OF
WW-B. DAHL OLD WORLD BLUESTEM IN SUSTAINABLE SYSTEMS
TERESA DUCH
In
order to find a sustainable production system there are many factors to keep in
mind. First of all, sustainability must be defined in terms of ecology and
economy. Ecology involves natural aspects of production including vegetation
and animal species, type of soil, climate, water availability, nutrient cycle
and other factors. Economy addresses the purpose of the production, the
profitability of the system, and the farmer’s willingness to change the
traditional system into a “new” system. To fully address sustainability, it is
necessary to develop relationships between ecology and economics. Thus,
forage-livestock systems could be defined as “… the integrated combination of
animal, plant, soil and other environmental components managed to achieve a
productive agro ecosystem (FGTC, 1992). These systems, if managed correctly,
are an alternative in areas where traditional systems are no longer efficient.
Initially, it is important to know all the aspects individually and deeply,
although to define the system these factors must be playing together. The
starting point is to know the productive framework of the system; the soil type
and climate could be the most important factors of it and cannot be changed.
The second point is to know what plant species could be produced in this
framework. The next point is to know what kind of livestock can graze this
plant successfully; at this time is when the management strategies are defined.
The last point, but no less important, is to realize the economic profitability
of the system and the effectiveness of it in the chosen place.
This research is intended to define a forage-livestock system in the Southern Plains, using ‘WW-B. Dahl’ (Bothriochloa bladii) as the forage component because of its recognized value as forage and its extremely important seed production and commercialization.
WW-B. Dahl is one of the species known as Old World Bluestem. WW-B. Dahl has been introduced in the United States over the last 40 years. The seed was collected near Manali, India, and forwarded to the Oklahoma Agricultural Experiment Station at Stillwater, in 1960. Beginning in 1976, it was evaluated by the Southern Plains Range Research Station at Woodward Oklahoma. Finally, and after 15 years of adaptation and production testing, the USDA-ARS, USDA-SCS, TEXAS Tech University, and the Texas Agricultural Experiment Station released it jointly, in March 1994 (Dewald et al., 1995).
The Overall objective of this study can be divided in two parts:
First, determine effects of defoliation strategies on growth, chemical composition, and economic profitability of WW-B. Dahl within a sequence grazed system with Rye and Wheat in the Southern High Plains.
Second, determine effects of grazing on nutrient cycling and soil compaction on the crop-forage-livestock system compared with a cotton monoculture.
The specific objectives are:
1. Determine effects of grazing steers on soil properties (compaction, pH and fertility), forage production (growth, regrowth, percentage of ground cover, seed production, and quality) and the pasture (botanical composition) when grazing WW-B. Dahl continuously until June or July compared with no grazing.
2. Determine the effects of grazing vs. no grazing of Rye and Wheat on soil compaction, pH and fertility.
3. Determine effects of defoliation time on WW-B. Dahl growth, regrowth, percentage of ground cover, seed production, quality and botanical composition.
4. Estimate the economic profitability of WW-B. Dahl grazed by steers or harvested for hay and seed production.
Results to date are summarized in the following figures:
Fig. 1. Fresh biomass yield at different clipping times
Fig. 2 and 3. Flowering stages
