Principles of Intensive Range Improvements

Our expanding population is demanding more productivity and other contributions from our rangelands. Range science is concerned with the plants, animals, soils, and waters on rangelands, particularly the interaction of these factors. Native plant communities should only be used as guides to determine site potential. Extensive practices on rangelands include manipulation of animals and burning. Intensive practices include control of unwanted plants, revegetation, and fertilization. When properly conducted, intensive manipulation practices often result in much higher production than before treatment. Each land manager determines the desired level of productivity based on economic, cultural, political, and social factors, and the availability of technology. The most effective method for control of unwanted plants varies with the sites, the species, and the degree of infestation. Revegetation may be required where desirable vegetation has been depleted by past grazing abuses, droughts, and encroachment of unwanted plants. Water is generally the primary factor limiting plant growth but when that need has been satisfied, additional plant nutrients such as nitrogen and phosphorus may be useful. The more costly practices are riskier and require higher management inputs, but the potential benefits are great. With changing technology or favorable economic conditions, the range manager may decide to intensify his range improvement efforts. Man is making tremendous advances in many fields of science. Our expanding population is demanding increasing productivity from all of our agricultural lands, including rangelands. The rise of our present civilization has been made possible by the advances in agricultural production. The development occurred because people were able to influence their environment. A primary principle of range science has been that the natural plant communities provide a guide to potential herbage cover and production. We must remember that the native plant communities are only guides to site potential. Some plant species may be introduced to an area with some of the manipulative treatments that may be superior in some, if not all, aspects of rangeland management (Love 1961). An example of this is the introduction of crested wheatgrass (Agropyron desertorum) in the western areas of Canada and the United States. These manipulative treatments require the application of a number of principles. This paper is an attempt to establish a concept of range science and discuss some of the major principles that the resource manager should consider when conducting manipulative treatments on rangelands. It is useful to conceptualize the practices used in range science in a diagram (Fig. 1). Each land manager determines the desired level of productivity based on economic, political, cultural, and social factors, and the availability of technology. Examples of extensive practices for rangelands are manipulation of grazing, as in various systems, and the use of fire. These practices may require some fencing, water developments, and/ or fire lines, but they generally do not risk the loss of the present vegetation cover as do some of the more intensive manipulative practices. These extensive practices are less costly but the opportunities to dramatically increase pro