Two commonly used forms for crop response to inputs are a smooth, differentiable production function and a linear response and plateau (LRP) model. This paper reconciles these two views by showing that smooth functions can be derived by aggregating the effects of heterogenous inputs on LRP functions. Data on com growth are used to test two specific aggregations.

Because of difficulties in measuring effluent from nonpoint pollution, proposals for regulating agricultural runoff often suggest instruments applied to inputs or management practices. When pollution functions vary across sources, uniform input instruments cannot achieve a least-cost pollution reduction, but efficient instruments may be difficult to administer. In this paper we analyze lettuce production on two soils in California's Salinas Valley to consider empirical costs associated with uniform input taxes and regulations. The results suggest that uniform instruments may not be costly relative to an efficient baseline. Though taxes are more efficient, farmers have higher profits with regulations.

Yard-scale landscape designs can influence environmental quality through effects on habitat, stormwater runoff, and water quality. Native plant gardens may have ecological benefits, and previous research has shown that yards using these plants can be designed in ways that people find attractive. This study examines whether people are willing to pay more for more ecologically benign designs than for a lawn. A contingent choice survey was conducted in southeast Michigan in which people were presented with four different yard designs (three of which included native plants) in three different settings, with different monthly maintenance costs for each design. Respondents were asked to rank their choices of the yards while considering the maintenance costs they were presented. Results suggest that people are willing to pay more for well-designed yards including native plants than for lawns, and that their increased willingness to pay exceeds any increase in costs associated with the native plantings. These results should encourage homeowners, landscape designers, and the landscape plant industry to work with native plants. In this study, people were willing to pay more for designs that present gains for the environment, without government intervention and without social cost.

Control of nonpoint source pollution often requires regulation of inputs, but first-best solutions are unattainable. Because inputs are monitored by different agencies and regulatory coordination can be costly, it may be more practical to regulate single inputs. A cost-effectiveness approach to determining the best single-input tax policy is developed and applied to the question of reducing nitrate leaching from lettuce production in California. Water is the best single input to regulate, and efficiency losses from this second-best approach appear not to be great. Conditions for the welfare ranking of policies to be invariant to heterogeneity in production or leaching are identified. Copyright 1996, Oxford University Press.