04394nam a2200709 a 450000100080000000500110000800800410001902000150006010000210007524500610009626000250015730000100018252026620019265300280285465300160288265300170289865300220291565300170293765300210295465300230297565300150299865300170301365300110303065300120304165300200305365300150307365300160308865300140310465300260311865300180314465300140316265300180317665300140319465300150320865300110322365300190323465300220325365300130327565300140328865300120330265300130331465300130332765300130334065300210335365300220337465300200339665300230341665300210343965300200346065300130348065300240349365300130351765300230353065300100355365300090356365300190357265300280359165300210361965300190364065300130365965300120367210101582016-03-11       1994    bl uuuu      00u1 u    #d  a05820786871 aHUMPHREYS, L. R.  aTropical foragesbtheir role in sustainable agriculture.  aEssex: Longmanc1994  a414p.  aPressure on the land resources of the tropics and subtropics has increased as the numbers of people supported by the land have risen. The cultivation of uplands which are marginally suited to annual cropping has led to decreasing soil fertility and declining crop yields. Increased run-off from these lands has altered the hydrological characteristics of the watersheds, and the soil eroded represents the loss of irreplaceable resources. Continous monocropping leads to the development of intransigent problems of disease, pest or weed infestation. In the humid tropics plantation agriculture is vulnerable to world price fluctuations, and farmers dependent upon a single export commodity seek to diversify their operations. Tropical forages are playing an increasing role in the development of sustainable cropping systems, and a new technology of forage improvement has arisen. This book begins by outlining the objectives of the interaction between crops, pastures and animals. These may be directed primarily to the maintenance or repair of soil fertility, as reflected by the nitrogen accretion due to forage legumes, the organic matter status, attributes of soil structure, the control of erosion and the spatial transfer of nutrients. The integration of forages in cropping systems may also lead to more efficient utilization of environmental resources, as represented by energy flows, moisture conservation and crop protection, whilst the added flexibility of production can lead to diversification and stabilization of farm income. Principles for the management of various types of crop/forage systems are described. Pasture with tree crops may involve coconut, rubber, oil palm and fruit crops, representing developed land whose use may be intensified; or agroforestry in which timber and animal products are the outputs. Alley farming, in which shrub legumes are grown in conjunction with annual crops and are fed to livestock, has gained favour in some tropical regions as an innovative technology. The concept of ley pastures in rotation with annual crops requires revaluation, whilst the planting or regeneration of pastures after an annual cropping phase is widely practised. The integration of animals in annual cropping systems is favoured by companion or relay cropping with forage crop legumes, whilst the complementary use of crop and pasture lands is a feature of some systems where ruminants are used for draught as well as meat or milk. Environmental protection and the maintenance of agriculture require the wide adoption of forages in tropical cropping systems. This book outlines the science upon which this adoption may be based.  aAgricultura sustentavel  aAgriculture  aAgroforestry  aAgrossilvicultura  aConsorciacao  aCropping systems  aCulturas tropicais  aDegradacao  aDeterioracao  aErosao  aErosion  aFarming systems  aFeed crops  aFertilidade  aFertility  aFixacao de nitrogenio  aForage plants  aHusbancry  aLand resource  aLForragem  aManagement  aManejo  aMixed cropping  aNitrogen fixation  aPastagem  aPastagens  aPasture  aPastures  aPecuaria  aPesquisa  aPlant protection  aPlanta forrageira  aProducao animal  aProtecao de planta  aRecurco da terra  aRegiao tropical  aResearch  aSistema de producao  aSistemas  aSoil deterioration  aSoils  aSolo  aSustainability  aSustainable agriculture  aSustentabilidade  aTropical crops  aTropicos  aTropics