Predicting the long-term productivity, economic feasibility and sustainability of smallholder hedgerow agroforestry systems using the WaNuLCAS model

The long-term productivity, economic feasibility and sustainability of Eucalyptus-maize hedgerow agroforestry system were simulated and predicted using the WaNuLCAS model. WaNuLCAS is a process-based model of water, nutrient and light capture in agroforestry systems. It is the most flexible model currently available for evaluation of management options in agroforestry systems based on site-specific information and farmer management objectives. The results of this simulation were compared with the results of the simulation of a continuous maize monocropping system. The model was calibrated using experimental data and survey results in a study conducted at Claveria, Southern Philippines. Simulation revealed that more than half of the total nitrogen in the two systems is tied up in the soil organic matter (SOM). Leaching and lateral flow are the main avenues of nitrogen loss in both systems. Modelling the water balance of the two systems showed that a eucalypt-maize hedgerow system had higher subsurface flow and surface run-off. Maize yield was initially higher in the continuous annual cropping system (2.4 t/ha) than under the eucalypt-maize hedgerow system (1.8 t/ha). The benefit obtained from the maize cropping system is the grain produced while those from the eucalypt-maize hedgerow system are maize grain and timber. Financial analysis showed that the eucalypt-maize hedgerow system had a higher NPV after nine years of simulation (PhP306,536), compared with the continuous maize (PhP16,998). Results of this study have shown that the eucalypt-maize hedgerow system provides substantial improvements to a range of biophysical and economic measures of productivity and sustainability

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

Patterns and Processes in Population Divergence of 'Microlaena stipoides' (Labill.) R. Br.

The distribution of 'Microlaena stipoides' (Labill.) R. Br. on the Northern Tablelands of New South Wales was examined by surveying 101 paddocks on 33 commercial properties. Greater abundance of 'M. stipoides' was observed on the eastern side and the southern half of the Northern Tablelands where rainfall and altitude were higher. Pasture management correlates that were significantly associated with abundant 'M. stipoides' were high tree density, minimum soil disturbance and long period since last cultivation. Greater abundance of 'M. stipoides' was observed in paddocks containing other year-long green perennials, cool season annuals and exotic sown species in addition to warm season perennials and annuals. 'Microlaena stipoides' grew well in association with other perennial grasses found in permanent pastures, such as 'Lolium perenne', 'Damlis glomerata', 'Poa pratensis' and 'Phalaris aquatica', which may indicate the permanency of these species associations

Modelling the dynamics of agroforestry adoption in the uplands of Southern Philippines using companion modelling approach

A model was developed following an iterative process based on repetitive back-and-forth steps between the model and field activities. A Multi Agent System (MAS) was integrated with a Role-Playing Game (RPG) to understand the dynamics of agroforestry adoption in Claveria, Misamis Oriental. The model simulated and observed different scenarios: cumulative income of agroforestry adopters and non-adopters, impact of market information on farm income, and neighbour effects on the spread of agroforestry adoption. Results of the computer simulations were verified using farmer games and focus group discussions. Agroforestry and non-agroforestry farmers were invited to participate in the role-playing game in order to understand more precisely and validate the model. During the conduct of the role-playing game, the individual behaviour of agents under a number of scenarios and the properties of the system emerging from their interactions were examined and discussed among the players. The model scenarios and role-playing game can serve as a decision support for policymakers, farmers and other stakeholders towards sustainable management of resources. It is envisioned to produce information useful for understanding the decision-making strategies of farmers with regard to agroforestry adoption that can be essential to the success of efforts to address the sustainability of upland areas in the Philippines and elsewhere in south-east Asia

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

Food security outcomes in agricultural systems models: Current status and recommended improvements

Improvement of food security is a common objective for many agricultural systems analyses, but how food security has been conceptualized and evaluated within agricultural systems has not been systematically evaluated. We reviewed the literature on agricultural systems analyses of food security at the household- and regionallevels, finding that the primary focus is on only one dimension of food security-agricultural output as a proxy for food availability. Given that food security comprises availability, access, utilization and stability dimensions, improved practice would involve more effort to incorporate food access and stability indicators into agricultural systems models. The empirical evidence base for including food access indicators and their determinants within agricultural systems models requires further development through appropriate short and longterm investments in data collection and analysis. Assessment of the stability dimension of food security (through time) is also particularly under-represented in previous work and requires the development and application of appropriate dynamic models of agricultural systems that include food security indicators, coupled with more formalized treatment of robustness and adaptability at both the regional and household levels. We find that agricultural systems models often conflate analysis of food security covariates that have the potential to improve food security (like agricultural yields) with an assessment of food security itself. Agricultural systems modelers should exercise greater caution in referring to analyses of agricultural output and food availability as representing food security more generally