Management Controls on Productivity

Abstract

Abstract: Replacement of the native perennial flora of California grasslands by alien annual plants has had a major impact on management options available to stewards of the grassland. The tenacity of highly competitive annual species has made it difficult to control productivity for the purpose of improving performance of domestic livestock. On the other hand, the resilience of the annual vegetation forgives abusive practices time and time again. Availability of small-seeded annual legumes from other Mediterranean-climate regions of the world has provided a technology that alleviates one of the primary factors limiting productivity, nitrogen. This technology is well developed and available to the rancher. Poor returns from ranching in general, due to national agricultural policies, seem to be the only obstacle to greater adoption of annual legume pasture improvement programs. Eight number of vegetation management technologies have been used to increase grassland productivity. Prescribed fire is used to reduce litter accumulation of undesirable weed species and to remove competing shrubs and trees of low forage value. Annual legumes and perennial grasses are seeded to increase availability of high quality forages. Fertilizers are used alone or as part of a legume-based pasture improvement program. Irrigation has been used to lengthen the growing season of annual species. Some annual grasslands subject to soil compaction problems and also suitable for farming are used in a dual fashion for dryland grain farming and livestock grazing on a rotational basis. Until recently, herbicides were used in an array of different ways to make other improvements possible. Lack of response of the annual plants to season and intensity of grazing has resulted in little application of grazing systems, but new systems are now being investigated. Need for fire control, wildlife habitat improvement, and increased watershed production can fit into range improvement programs for multiple use benefits. Serious questions remain about the sustainability and cumulative effects of our grassland management activities. Clearly the demand for cordwood can and does exceed the supply, given the large and rapidly growing population of California. Grassland weed problems and lack of regeneration of deciduous savanna and woodland communities are problems needing greater attention. Educators and extension persons alike must take the long view in teaching the public about the long-term value of its natural resources.