W. Richard Teague

Long-Term Water Balance in a Semiarid Shrubland

Abstract Baseline information on the water balance is essential for adequately understanding ecohydrological relationships on rangelands. Unfortunately, such information is not always available, because insufficient data have been collected and/or the data do not represent relevant temporal or spatial scales. In particular, for many rangelands long-term records of runoff at the small catchment or larger scales are relatively rare. In this study, we used catchment-scale data, collected over nearly a decade, to estimate the long-term water balance for mesquite–juniper rangelands in the Rolling Plains of Texas. The data include precipitation, surface runoff, soil water, and vegetation cover; these were measured on 9 microcatchments, each about 1.4 ha in size. Soil water was determined by neutron-probe measurements to a depth of 120 cm. Surface runoff was, surprisingly, a very small component (< 1%) of the water budget and occurred only during extraordinary precipitation events. Soil-water recharge resulted mainly from winter precipitation. Evapotranspiration, which took place during the entire year, ranged from less than 1 mm·day−1 during the winter to almost 8 mm·day−1 during the summer. This study is important because it clearly documents how water is allocated on these rangelands at spatial and temporal scales that are relevant to management. The results from this study, in conjunction with other work in the Rolling Plains, suggests that there is little potential for increasing water yield via brush control in these landscapes.

Evaluation of Continuous and Multipaddock Grazing on Vegetation and Livestock Performance—a Modeling Approach☆

ABSTRACT Although the impact of optimal stocking rate on rangeland health and ranch profitability has been extensively studied, grazing management practice has received far less attention in mathematical modeling analyses. This paper uses a mathematical model to examine the impacts of continuous grazing and multipaddock (MP) grazing on vegetation and livestock forage consumption. Simulations are carried out using parameters applicable to the southern tallgrass prairie of North America. On small areas of land with no difference between defoliation rates across different grazing methods, the performance of MP grazing is no better than continuous grazing. At the scale of commercial ranches, MP grazing with improved defoliation management improves grass composition and productivity, as well as livestock consumption relative to continuous grazing, especially with heavier stocking rates and unfavorable initial biomass composition. The advantages of MP grazing, however, are reduced with favorable rainfall conditions, light stocking, low levels of undesirable plants, and inadequate recovery periods.

Bridging the Research Management Gap to Restore Ecosystem Function and Social Resilience

Modern technology, knowledge, and organization have greatly increased agricultural productivity, but management has prioritized short-term benefits from the production of food, fiber, and fuel. By not accounting for environmental and social costs, we have compromised the integrity of global ecosystems and caused negative impacts on our social environment. For humans to live sustainably, we must prevent depletion of natural resources and protect their potential for self-replenishment. To continue receiving ecosystem goods and services, we must stop counting the consumption of natural capital as income. Regenerative agriculture could help reverse these negative trends, but a different research approach is needed to understand the impacts of regenerative management. Much component research does not translate into producing sustainable results on managed landscapes. It is important to understand how cropping and grazing management can best regenerate soil and ecosystem function, while producing long-term economic returns. To this end, a framework is outlined that combines small-scale component research and whole-systems research, working in collaboration with farmers who improve the environment and excel financially. This approach addresses questions at commercial scale, and by integrating component science into whole-system responses, it identifies emergent properties that may result in synergistic positive outcomes and avoid unintended consequences.

Herbaceous diversity and composition in mixed Juniperus Pinchotii-Prosopis Glandulosa communities in Southern mixed-grass prairie

ABSTRACT Herbaceous biomass and composition were measured across a continuum of increasing cover of mixed Prosopis glandulosa and Juniperus pinchotii woody plant from 1996 to 2003. The study site in northwest Texas had no history of woody plants treatment and comprised trees up to 6 m tall with cover averaging 65%. A strong, negative, linear relationship between woody plant cover and herbaceous biomass was measured (p = 0.0001). Precipitation differences resulted in 2.7 fold variation in herbaceous biomass between years (p = 0.003) and affected the slope of the decline of herbaceous biomass associated with increasing woody plant cover (p = 0.034). Within any year the slope of decline of herb biomass was parallel for Prosopis and Juniperus cover (p = 0.843). Relative to zero woody cover, 100% Prosopis cover reduced herbaceous biomass by 56% (p = 0.0001) while 100% Juniperus cover reduced herbaceous biomass 73% (p = 0.0001). At 100% cover Prosopis had twice the herbaceous biomass compared to Juniperus (p = 0.0021) but both species reduced herbaceous biomass by ± 1300 kg ha−1. Warm season herb biomass decreased with increasing Prosopis or Juniperus cover while cool season herbaceous biomass was minimally influenced by increases of either species. Multivariate analysis indicated vegetation associations differed between tree species. Vegetation differed (p = 0.001) between low (<25%) and high (>75%) Prosopis cover (dissimilarity R = 0.98), between low and high Juniperus cover (R = 0.81). Ten herbaceous species consistently decreased and 2 consistently increased with increasing woody plant cover.