Variable Input Allocation: Why Heterogeneity Matters?

The allocation of variable inputs among crops is a common problem in applied studies that use farm accountancy data. Standard farm accounting information is typically restricted to aggregate or whole-farm input expenditures; there are usually no details on how these expenditures are split among crops. Most studies employing multi-crop econometric models with land as an allocable fixed input consider generally variable input uses at the farm level (Moore and Negri, 1992). However, the allocation of variable inputs among crops appears to be useful for several objectives, such as to analyze the evolution of gross margins at the crop level, to investigate the empirical validity of a multi-crop econometric model and to provide important information for extension agents or farmer advisors.Variable Input Allocation, heterogeneity, Agricultural and Food Policy, Agricultural Finance, Crop Production/Industries, Farm Management, Research Methods/ Statistical Methods,

Simple econometric models for short term production choices in cropping systems

The aim of this article is to present new models of acreage choices to describe short term production choices. Its construction combines concepts developed in the Positive Mathematical Programming and Multicrop Econometric literatures. They consider land as an allocable fixed input and motivate crop diversification by decreasing returns to crop area and/or implicit costs generated by constraints on acreage choices and by limiting quantities of quasi-fixed factors. Attractive re-parametrization of the standard quadratic production function and different functional forms for cost function are proposed to have parameters easily interpretable and to define econometric models in a very simple way.Acreage share; Production function; Multicrop econometric model; Positive Mathematical Programming

Endogeneity of acreage choices in input allocation equations: implied problems and a solution

Replaced with revised version of paper 07/10/09.input allocation, multi-output econometric model, control function approach, Crop Production/Industries, Production Economics,

WILLINGNESS TO PAY FOR AN INCREASE IN THE QUALITY OF DRINKING WATER: AN APPLICATION TO FRANCE

In this paper a method to infer the value for consumers of the quality of supplied water is presented and applied. It uses concepts developed in the literature of environmental good valuation and the literature of equivalence scale measurement. It is applied to French data.willingness to pay, drinking water, indirect observed method, Environmental Economics and Policy,

Accounting for agronomic rotations in crop production: A theoretical investigation and an empirical modeling framework

As far as crop acreage choices are concerned, a consensus seems to exist among agricultural scientists and extension agents: crop rotation effects and the related constraints are major determinants of farmers’ crop choices. Crop rotation effects are inherently dynamic. They are generally ignored in multicrop models with land as an allocable input found in the literature since most of these models are developed within a static framework. The aim of this paper is twofold (i) to propose a new approach and tools for investigating dynamic crop acreage choices accounting for crop rotation benefits and constraints and (ii) to illustrate the impacts of crop rotation effects and constraints on farmers’ acreage choices through simulation examples. The models proposed in this paper are sufficiently simple for being empirically tractable either in simulation studies or in econometric and mathematical programming analyses. Our simulation results tend to show responses of the optimal dynamic acreages to simple price shocks which are much more complex than those implied by static models. They also demonstrate that farmers’ perceptions of the future economic context are crucial determinants of their acreage choices. In fact current acreage choices may appear suboptimal in a static sense but are fully consistent when dynamic effects of crop rotations are specified.Crop rotation, Dynamic programming, Acreage choice, Crop Production/Industries, Land Economics/Use, Q12, D21, D24, D92,

Measuring farmers’ risk aversion: the unknown properties of the value function

We argue in this paper that available econometric estimates of farmers’ risk aversion do not measure true farmers’ preferences towards risky outcomes. Available analyses are mostly of static nature and indeed measure the parameters of the synthetic optimal value function rather than the deep parameters of the utility functions. We derive analytical and empirical results in a simple dynamic and stochastic framework showing that that there is not a simple relationship between utility functions and value functions when agents have many decision variables. In particular we find that the value function does not necessarily exhibit DARA when the instantaneous utility function satisfies DARA and conversely. We recommend performing dynamic econometric estimation with at least farm production and consumption data.Risk and Uncertainty,

The decoupling of farm programs: Revisiting the wealth effect

Recent reforms of agricultural policies in developed countries introduced direct payments to the detriment of traditional production enhancing instruments. Whereas these new instruments can influence production through several effects, current empirical studies do not show any significant impact on production; direct payments mainly increase land values. In this article, we revisit the evaluation of the coupling effects passing through the wealth of agricultural households. The initial wealth of these agents, while being mainly in form of land asset holding, is always assumed to be fixed. On the contrary we show theoretically and empirically that, once the impact of farm programs on initial wealth is properly accounted for, the measure of the coupling effects is considerably increased for direct payments and more much marginally for traditional policy instruments. We illustrate the impact of this initial wealth actualisation through a simulation of the suppression of the US corn policy. The impact of this policy was underestimated by two thirds.agricultural policy, decoupling, wealth effect,

Metabolic regulation during sport events: factual interpretations and inadequate allegations

.Different fuels are available to generate ATP for muscle activities during sport events. Glycogen from striated muscles and liver stores may be converted to lactic acid or almost completely oxidized to carbon dioxide (CO2), triacylglycerol within the muscle itself and fatty acids from adipose tissue could be converted to CO2 in acting muscles, some free amino acids can be released within the muscle itself and from intestinal stores to sustain the amount of ATP generation indispensable for muscle contraction. All single biochemical reactions, but one, need one or several enzymes to activate the conversion of a substrate into a product. The energy transformation in biochemical reactions is led by application of so-called free energy. Reversible and non-reversible reactions within a metabolic pathway are dependent on specific enzymes near or far from equilibrium. Allosteric enzymes are regulatory enzymes that provide the direction in the pathway. A regulatory enzyme is either activated or inhibited by small regulators (ligands). A reversible substrate cycle between A and B is catalyzed by two enzymes with different fluxes. The need of ATP production for muscle contraction is under the leadership of regulatory enzymes and available substrate stores. The improvement of adapted metabolic reactions under sport training depends on the appropriate increase of regulatory enzymes within the glycolytic and oxidative pathways. The amount of some specific enzymes is increased by training in order to improve the maximum activity of the metabolic pathway. Unfortunately, several publications do not precisely implicate the appropriate enzyme(s) to explain or reject the adaptation induced by the training schedule. A few examples will illustrate the factual interpretation and the inadequate allegation

Metabolic regulation during sport events: factual interpretations and inadequate allegations

.Different fuels are available to generate ATP for muscle activities during sport events. Glycogen from striated muscles and liver stores may be converted to lactic acid or almost completely oxidized to carbon dioxide (CO2), triacylglycerol within the muscle itself and fatty acids from adipose tissue could be converted to CO2 in acting muscles, some free amino acids can be released within the muscle itself and from intestinal stores to sustain the amount of ATP generation indispensable for muscle contraction. All single biochemical reactions, but one, need one or several enzymes to activate the conversion of a substrate into a product. The energy transformation in biochemical reactions is led by application of so-called free energy. Reversible and non-reversible reactions within a metabolic pathway are dependent on specific enzymes near or far from equilibrium. Allosteric enzymes are regulatory enzymes that provide the direction in the pathway. A regulatory enzyme is either activated or inhibited by small regulators (ligands). A reversible substrate cycle between A and B is catalyzed by two enzymes with different fluxes. The need of ATP production for muscle contraction is under the leadership of regulatory enzymes and available substrate stores. The improvement of adapted metabolic reactions under sport training depends on the appropriate increase of regulatory enzymes within the glycolytic and oxidative pathways. The amount of some specific enzymes is increased by training in order to improve the maximum activity of the metabolic pathway. Unfortunately, several publications do not precisely implicate the appropriate enzyme(s) to explain or reject the adaptation induced by the training schedule. A few examples will illustrate the factual interpretation and the inadequate allegation