Multi-scale analysis of agricultural development: A modelling approach for Ilocos Norte,Philippines

Decisions and policies that have implications on allocation of resources are made at different levels. Goals at different scales may be conflicting and decisions at one scale have consequences for those at other scales. Performing analyses at more than one scale is, therefore necessary in analysing future options for resource use. This paper illustrates the use of a multi-scale method enabling assessment of multi-purpose natural resource management options. Three examples of analyses that it allows are presented for Ilocos Norte province in the Philippines, at the farm household, municipal (Batac municipality) and provincial levels. Results show that: (1) Differences in resource endowments of farm households strongly affect the potential adoption rates of five well-defined alternative technologies. (2) Limited markets, inadequate infrastructure and resource endowments of farm households have large effects on resource use and goal achievement in the municipality. Not including these factors in a resource use analysis results in a so-called aggregation bias. As these are significant, ignoring them may result in misleading simulation results and policy conclusions. The aggregation bias resulting from assuming spatially fixed input and output prices is significant for Batac, which has poor farm-to-market roads. This suggests large potential benefits from improving infrastructure. The factors investigated suggest that aggregate income in the municipality is most strongly affected by the size of the market for some vegetables. (3) The differences in resource allocations resulting from prioritizing objectives at different levels reveal potential conflicts. The municipal income was highest with crops which pose more risk to farmers; our farm household analysis shows that farmers tend not to select too much of these crops. Similarly, the provincial income is highest when resources in the province are allocated such that more of the staple crop rice and less of the highly profitable cash crops are cultivated in Batac, resulting in lower income for the municipality.     

Participatory integrated watershed management: Evolution of concepts and methods in an ecoregional program of the eastern African highlands

This paper focuses on the conceptual evolution of watershed management within the context of an action research program operating in the highlands of eastern Africa, as informed by both theory and practice. Following a review of the watershed management literature, and brief program and methodological overviews, the paper explores in detail the concepts of “participation” and “integration” in watershed management. Conceptual and methodological dimensions of the terms are discussed in the context of a watershed implementation process, clarifying how “watershed issues” are defined by local users, how “stakeholders” are defined with respect to those issues, and how participation and integration may be operationalized in practice. Data are selectively chosen from different pilot sites to illustrate how concepts underlying watershed management have been refined, and methods improved. It is clear that “participation” in problem diagnosis and program implementation must move beyond community-level fora to socially-disaggregated processes and explicit management of trade-offs to diverse groups. Secondly, integration does not come about through implementation of parallel interventions, but rather through an explicit analysis of potential trade-offs and synergies of interventions to diverse system components, and strategies to define and reach systems-level goals. Each approach requires attention to ways to optimize returns to diverse social groups and system components while minimizing negative spin-offs. The paper concludes with a discussion of implications for agricultural research and development in the eastern African region.     

An integrated modelling toolbox for water resources assessment and management in highland catchments: Model description

Water and land resource competition and environmental degradation pose difficult questions for resource managers. In particular, the ensuing trade-offs between economic, environmental, and social factors and their spatiotemporal variability must be considered when implementing management policies. This paper describes an integrated modelling toolbox that has been developed for highland catchments – specifically the Mae Chaem catchment in Northern Thailand. This toolbox contains models of crop growth, erosion and rainfall-runoff, as well as household decision and socioeconomic impact models. The approach described advances and complements previous approaches by: considering more complex interactions between land-use decisions and the hydrological cycle; modelling household decisions based on uncertain expectations; and assessing impacts of changes not only on flows and household income, but also on subsistence production and erosion. An example of the types of trade-offs and scenarios that can be assessed using the integrated modelling toolbox is also presented. This demonstrates that for the scenarios presented, the magnitude and direction of impacts simulated by the model is not dependent on climate. Further testing of the model is demonstrated in a companion paper. Overall, the plausibility of the model is shown.     

Review and analysis of documented patterns of agricultural research impacts in Southeast Asia

Based on a comprehensive search and review of the literature, 42 studies are identified for in-depth review and analysis of documented impacts of agricultural research from 1959 to 2009. This body of evidence is subjected to a systematic, quantitative scrutiny for the coverage and type of impact to derive patterns, gaps and trends in documented impacts of research in the subregion. The analysis offers compelling evidence that past investments in agricultural research in the region have been productive. In so doing, the study also reveals some persistent patterns and identifies a number of gaps between investments and documented impacts. Strikingly, the benefits are principally derived from rice improvement research, which has generated 86% of total documented benefits in the Southeast Asia region over the past five decades. In comparison with rice improvement research, evidence of impacts in other areas such as natural resource management and other commodities is minor. This suggests that there is considerably more certainty about the ability of rice research, particularly genetic improvement, to generate impact than is the case for other research foci.However, even for rice, the evidence has been patchy across time and space. There has been no comprehensive and subregion-wide attempt to inventory trends in adoption of improved rice varieties and document historical net benefits generated by this research effort. Despite the large-scale, long-term and sustained adoption of research generated rice technologies for smallholder farmers in this subregion, an impressive story on the impacts of agricultural research on long-term developmental goals still remains undocumented. The paper also reveals a declining trend in total documented net benefits from agricultural research in recent years, which is probably attributable to research lag times and changes in the intensity of impact assessment over time.     

An economist's perspective on irrigation performance assessment: With examples from large scale irrigation in Morocco

This paper accepts that assessing the performance of irrigated agriculture is difficult because being multi-dimensional it requires a multi-disciplinary approach. Public irrigation schemes may have a number of often competing objectives and are assessed by interest groups with differing values and perspectives. A wide range of performance indicators are thus required. Some of these and the complex inter-relationships that may exist in the system are illustrated.     

The role and value of eastern star clover in managing herbicide-resistant crop weeds: A whole-farm analysis

In the broadacre dryland farming system of Western Australia herbicide resistance in major crop weeds is an increasingly serious problem. A new option to combat herbicide resistance involves growing eastern star clover (Trifolium dasyurum). This is a new pasture legume with a unique delayed germination that allows control of weeds using various chemical and non-chemical strategies, without unduly compromising the pasture’s subsequent production. This study assesses the role and value of eastern star clover in managing herbicide-resistant weeds on various farms. The study employs the farming system model known as MIDAS, a whole-farm, bioeconomic model. Key scenarios of different degrees of severity of herbicide resistance for three farm types are examined. The main findings of the analysis are that as the severity of herbicide resistance increases, eastern star clover becomes an increasingly attractive option. Although the introduction of eastern star clover does reduce a farm’s capacity to carry sheep, and thereby lessens profits generated by the sheep enterprise, it enables longer, more profitable sequences of crops to be grown with fewer weed problems. Sensitivity analysis suggests that reduced cost of eastern star clover seed, cheap supplementary feed, and higher grain prices will further increase the profitability of eastern star clover.     

Insecticide use impacts of Integrated Pest Management (IPM) Farmer Field Schools: Evidence from onion farmers in the Philippines

This article empirically examines the impact of Farmer Field Schools (FFS) on insecticide use by onion farmers in the Philippines. FFS is an intensive Integrated Pest Management (IPM) information dissemination method that encourages producers to lower their reliance on chemical insecticides for controlling pests and diseases in their farms. These FFS-IPM trainings have been conducted within vegetable-based production systems in the Philippines. The data used in the study are from a 2009 face-to-face farm-level survey of 200 onion growers in Nueva Ecija province. Using instrumental variable (IV) procedures to control for endogeneity and selection problems in the data, we find that FFS-trained onion farmers in the Philippines have significantly lower insecticide expenditures (∼PhP5,000) than non-FFS trained control farmers. When econometric problems due to endogeneity and selection are not controlled for, the FFS training did not show any statistically significant effect on insecticide use. The insecticide reducing effect of FFS has important environmental and health implications, and provides evidence about the effectiveness of the FFS training method in disseminating important IPM concepts in the country.     

Prospects for wheat production under changing climate in mountain areas of Pakistan – An econometric analysis

We assess potential future impacts of climate change on wheat yields in Swat and Chitral districts of Pakistan, mountainous areas with average altitudes of 960 and 1500 m above sea level, respectively. Using past climate data (1976–2000) to track temperature trends in both study districts, we find that increased temperatures correspond to an increase in Growing Degree Days (GDDs) and a decrease in Growing Season Length (GSL). Chitral district shows a stronger decline in season length than Swat district. Compared with the estimated optimum level of 157 days, the 25 year average GSL for the dominant varieties is estimated to be 156 days in Swat district and 195 days in Chitral district. Future increases in temperature of 1.5 and 3 °C are likely to cause wheat yields to decline (by 7% and 24% respectively) in Swat district and increase (by 14% and 23% respectively) in Chitral district. Future increases in precipitation of 5–15% during the growing season show a negligible impact on wheat yield.     

Economic analysis of drought risk: An application for irrigated agriculture in Spain

This paper describes a two-part methodology for managing the risk posed by water supply variability to irrigated agriculture. First, an econometric model is used to explain the variation in the production value of irrigated agriculture. The explanatory variables include an index of irrigation water availability (surface storage levels), a price index representative of the crops grown in each geographical unit, and a time variable. The model corrects for autocorrelation and it is applied to 16 representative Spanish provinces in terms of irrigated agriculture. In the second part, the fitted models are used for the economic evaluation of drought risk. Inflow variability in the hydrological system servicing each province is used to perform ex-ante evaluations of economic output for the upcoming irrigation season. The model's error and the probability distribution functions (PDFs) of the reservoirs’ storage variations are used to generate Monte Carlo (Latin Hypercube) simulations of agricultural output 7 and 3 months prior to the irrigation season. The results of these simulations illustrate the different risk profiles of each management unit, which depend on farm productivity and on the probability distribution function of water inflow to reservoirs. The potential for ex-ante drought impact assessments is demonstrated. By complementing hydrological models, this method can assist water managers and decision makers in managing reservoirs.     

Individual-based models in the analysis of disease transmission in plant production chains: An application to potato brown rot

Spread of plant disease in production chains of planting material is a process of great economic importance, but has received little attention from plant disease epidemiologists. Disease control in production chains is therefore often based on rules of thumb and expert judgement by regulatory bodies, rather than on an explicit analysis and evaluation of the epidemiological and economic consequences of alternative strategies. This paper puts forward the idea that individual-based models may be used as a framework to simulate the spread of disease-causing organisms in plant production chains. The “individuals” in this context are the trading units (e.g., batches, lots) of a production chain. The quarantine disease “potato brown rot”, caused by the bacterium Ralstonia solanacearum, is used as an illustrative example. The model simulates the spread of potato brown rot over all potato growing farms and fields in the Netherlands over a chosen time frame. It addresses the relevant infection pathways for this disease in potato production and is spatially explicit.

Model outputs of simulations based on the control strategy as applied in the Netherlands until 2004 are presented. The effects of minor adjustments to this strategy are investigated. The simulations show an irregular pattern of brown rot dynamics in the potato production chain, as is observed in practice. Simulations quantify the relative importance of different infection pathways, and elucidate the effect of testing frequency on these pathways and on the over-all brown rot incidence. The study shows that individual-based modelling (IBM) provides a powerful platform for modelling the epidemiology and impact of diseases in plant production chains. IBM can be effectively used for the analysis, evaluation and design of cost-effective disease management policies.     

Uncertain water supply in an irrigated Mediterranean area: An analysis of the possible economic impact of climate change on the farm sector

Analysis of the possible economic impact of climate change at the local level is becoming increasingly relevant to agricultural policy, in terms of the definition of new measures to sustain adaptation of the farm sector. This study focuses on a Mediterranean agricultural zone to evaluate the economic impact of rainfall regime changes that modify the accumulation of irrigation water in a dam. The objective is to identify farm typologies that suffer more from rainfall changes, in order to target policy measures that increase farm sector capability to adapt to climate change. First, an analysis of historical series is conducted for precipitation. The decreasing trend in annual precipitation, as well as an increase in monthly rainfall variability, is shown to have a statistically significant influence on the regime of water accumulation in the dam. Density functions representing this regime are estimated for several periods, including the 1960s-1970s, the current time and a time interval that extends to 2015. A comparison of these functions reveals an increase in variability of water accumulation in the dam through time. Parameters of these functions are used in three models of Discrete Stochastic Programming to represent different expectations of irrigation water availability and to simulate the possible reaction of the farm sector in the study area to the different scenarios. The simulation results show that both income and employment are noticeably reduced in some farm typologies when scenarios with higher variability levels for water accumulation in the dam are considered. In addition, changes in the use of soil are seen, the use of inputs declines and the quantity of extracted groundwater increases.