Alternative Land Use Options for Philippine Grasslands: A Bioeconomic Modeling Approach Using the WaNuLCAS Model

In the Philippines, pure grasslands occupy 1.8 million ha and another 10.8 million ha (33% of the country\u27s total land area) is under extensive cultivation mixed with grasslands and scrub. Most of these grasslands are under-utilised and dominated by Imperata cylindrica. Imperata grasslands generally represent areas of degraded soils that are acidic, low in organic matter and susceptible to erosion. However, conversion of these grassland areas into upland farms planted to annual crops and perennial trees is proliferating at a fast rate. This is triggered by the interacting factors of rapidly increasing population, the system of landholding, scarcity of jobs and the declining arable area in the lowlands

Alternative Land Use Options for Philippine Grasslands: A Bioeconomic Modeling Approach Using the WaNuLCAS Model

In the Philippines, pure grasslands occupy 1.8 million ha and another 10.8 million ha (33% of the country’s total land area) is under extensive cultivation mixed with grasslands and scrub. Most of these grasslands are under-utilised and dominated by Imperata cylindrica. Imperata grasslands generally represent areas of degraded soils that are acidic, low in organic matter and susceptible to erosion. However, conversion of these grassland areas into upland farms planted to annual crops and perennial trees is proliferating at a fast rate. This is triggered by the interacting factors of rapidly increasing population, the system of landholding, scarcity of jobs and the declining arable area in the lowlands

Hedgerow Systems and Livestock in Philippine Grasslands: GHG Emissions

Hedgerow systems are widely adopted in the smallholder farms in the sloping grassland areas of Claveria, Mindanao, Philippines. The system is effective in addressing soil erosion problems and in conserving the topsoil. Gmelina arborea and Eucalyptus deglupta are two fast-growing timber species that are planted in hedgerow systems while maize is planted in the alley areas in between the hedgerows. Livestock holdings are widespread in Claveria, with 74% of the households having livestock. Cattle and carabao are the most common livestock in smallholder farms providing draught power for land preparation and transportation. In hedgerow systems, fodder tree leaves and crop residues are fed to livestock, while animal manure is added to the soil. Thus, these systems may serve as both a source and sink of methane and nitrogen oxides, depending on the management practices and component trees and crops of the system. This study aims to estimate methane emissions from livestock holdings and nitrogen oxide emissions through fertilization, tree litterfall and decomposition, maize residue incorporation and livestock manure from G. arborea and E. deglupta hedgerow systems

Natural vegetation strips (NVS) and Gmelina cropping systems

Recent rising demand for timber in Northern Mindanao, Philippines has driven smallholder farmers to plant fast-growing timber species, mostly Gmelina arborea, within their farms. The trees are commonly planted in portions of farms as block planting, along farm boundaries, or established along contour strips. Both natural vegetation strips (NVS) and tree cropping systems are examined here from biophysical and economic perspectives. In this paper, farmer surveys are reported with the aim of determining how livestock are raised in relation to the agricutural and tree components in both NVS and Gmelina block planting systems. The contribution of the animals to the productivity of each cropping system is established. Following the survey, the computer model, Soil Changes Under Agroforestry, is used to predict crop and tree yields for a number of years. These yields, in combination with the economic data collected, are input to a benefit-cost analysis that determines the long-term economic productivity of the cropping systems, with and without the animal component. The integration of livestock within both cropping systems was found to enhance economic productivity. The Gmelina system was the more profitable of the two systems but required a greater investment

Competitive abilities and divergence of 'Microlaena stipoides' populations with associated perennial grass species in New South Wales, Australia

Plant-plant interactions play an important role in the structuring of communities and in maintaining genetic diversity in populations. The reciprocal transplant technique is a powerful tool of testing fitness of populations and Connell (1980) suggested field experiments to demonstrate coevolutionary divergence of competitor plant species. This study followed Connell's (1980) proposed experimental design with the aim of determining the occurrence of microevolution among 'Microlaena stipoides' populations with four associated grass species in permanent pastures, namely 'Lolium perenne', 'Poa pratensis' (Ppr), 'Dactylis glomerata' and 'Phalaris aquatica'

Improving smallholder farming systems in Imperata areas of Southeast Asia: alternatives to shifting cultivation

This is a report of a collaborative research project, 'Improving smallholder farming systems in Imperata areas of Southeast Asia: a bioeconomic modelling approach' sponsored by the Center for international Forestry Research and the Australian Centre for International Research. The nature of the Imperata problem and the methodology is outlined. Imperata is essentially restricted to upland areas, since it does not coexist with lowland rice farming. There is a section on bioeconomic analysis of traditional smallholder 'shifting cultivation' farming systems where the fallow is Imperata and another contains a series of case study descriptions of successful tree growing by smallholders on Imperata grasslands. The core modelling work of the project is reported. Various tree-based interventions are modelled with and without an animal component. Some of these modelled farming systems are already in place in farmers' fields. In these cases, possible management or policy interventions analysed with the models can point the way to productive and economic improvements. In other cases, the farming systems modelled are 'experimental' in nature. Imperata grows on uplands of various slopes, but some special attention is given to Imperata on steeply sloping land where soil erosion is a particular problem. Finally, two key issues in relation to tree growing on Imperata grassland, fire control and carbon sequestration, are addressed. These are viewed both from the viewpoints of the individual smallholder and of the broader society. This is an overview and compilation of studies, many of which were previously reported in a series of project papers published by Centre for Resource and Environmental Studies, Australian National University between 1995 and 1998