Agricultural Land Retirement Research Articles

Sustainable groundwater management and its implications for agricultural land repurposing

In this paper, we examine the implications of groundwater sustainability policies on agricultural land retirement and how retired land can be repurposed to minimize social, economic, and environmental harms, while maximizing potential benefits. Globally, as water resources are strained by increasing agricultural demand and biophysical factors, policies are enacted to restrict groundwater pumping for irrigated agriculture in order to stem social, economic, and environmental harm. However, little is known about the implications of land retirement on ecosystems and people, and how this land can be best repurposed. Using Kern County, CA, as a case study, we draw from 23 qualitative interviews with stakeholders in the agricultural, water, and conservation sectors to understand the impacts of sustainable groundwater management policy and options for land repurposing. Stakeholders in our study outlined both positive and negative impacts of such policies across the region, including increased financial costs of agricultural production, crop type switches to perennial crops such as trees and vines, and improved communication and collaboration among stakeholders. Stakeholders discussed options for land repurposing to maximize ecological, social, and economic benefits, including habitat restoration, installation of solar farms, grazing, groundwater recharge, temporary fallowing, and recreation and parks. Finally, we propose recommendations to maximize the benefits and minimize the harms from the retirement and repurposing of agricultural land: (1) increasing regional planning and cross-stakeholder communication for strategic land repurposing, (2) minimizing the burden of policies that may restrict land repurposing options, and (3) ensuring financial incentives exist for landowners to repurpose their land.

Land use impacts of the Conservation Reserve Program: An analysis of rejected offers

AbstractThe Conservation Reserve Program is the largest agricultural land retirement program in the United States, with more enrolled acreage entering the program through a competitive auction called the General Signup than any other component. In this study, we assess the land use impacts of the Conservation Reserve Program by observing the land use decisions of parcels following the 2016 General Signup. We estimate land use impacts using a regression discontinuity design based on the Environmental Benefits Index, the program's selection and ranking mechanism. Our estimates largely rely on the auction design of the General Signup, such that we observe the land use decisions of rejected offers. We also use information on the rental rates of these offers to understand what the program pays to retire land in different uses. We estimate that a marginal acre of land enrolled in the Conservation Reserve Program replaces 0.30 acres in cropland, 0.25 acres in mixed forage, 0.32 acres in grassland, 0.12 acres in idle or fallow land, and 0.01 acres in timberland. We also find that enrollments from newly offered fields are more likely to displace cropland and less likely to displace grassland than returning fields. Consequently, we estimate that new enrollments lead to 47% greater reductions in water‐driven erosion and 12% greater reductions in wind‐driven erosion, compared to fields with prior enrollment.

The effect of agricultural land retirement on pesticide use

Agricultural land retirement generates risks and opportunities for ecological communities and ecosystem services. Of particular interest is the influence of retired cropland on agricultural pests and pesticides, as these uncultivated lands may directly shift the distribution of pesticide use and may serve as a source of pests and/or natural enemies for remaining active croplands. Few studies have investigated how agricultural pesticide use is impacted by land retirement. Here we couple field-level crop and pesticide data from over 200,000 field-year observations and 15 years of production in Kern County, CA, USA to investigate: 1) how much pesticide use and applied toxicity are avoided annually due to the direct effects of retirement, 2) whether surrounding retirement drives pesticide use on active cropland and what types of pesticides are most influenced, and 3) whether the effect of surrounding retirement on pesticide use is dependent on the age or revegetation cover on retired parcels. Our results suggest about 100 kha are idle in any given year, which equates to about 1.3-3 M kg of pesticide active ingredients foregone. We also find retired lands lead to a small increase in total pesticide use on nearby active lands even after controlling for a combination of crop-, farmer-, region- and year-specific heterogeneity. More specifically, the results suggest a 10 % increase in retired lands nearby results in about a 0.6 % increase in pesticides, with the effect sizes increasing as a function of the duration of continuous fallowing, but decreasing or even reversing sign at high levels of revegetation cover. Our results suggest increasingly prevalent agricultural land retirement can shift the distribution of pesticides based on what crops are retired and what active crops remain nearby.

A meta-analysis contrasting active versus passive restoration practices in dryland agricultural ecosystems.

Restoration of agricultural drylands globally, here farmlands and grazing lands, is a priority for ecosystem function and biodiversity preservation. Natural areas in drylands are recognized as biodiversity hotspots and face continued human impacts. Global water shortages are driving increased agricultural land retirement providing the opportunity to reclaim some of these lands for natural habitat. We used meta-analysis to contrast different classes of dryland restoration practices. All interventions were categorized as active and passive for the analyses of efficacy in dryland agricultural ecosystems. We evaluated the impact of 19 specific restoration practices from 42 studies on soil, plant, animal, and general habitat targets across 16 countries, for a total of 1,427 independent observations. Passive vegetation restoration and grazing exclusion led to net positive restoration outcomes. Passive restoration practices were more variable and less effective than active restoration practices. Furthermore, passive soil restoration led to net negative restoration outcomes. Active restoration practices consistently led to positive outcomes for soil, plant, and habitat targets. Water supplementation was the most effective restoration practice. These findings suggest that active interventions are necessary and critical in most instances for dryland agricultural ecosystems likely because of severe anthropogenic pressures and concurrent environmental stressors—both past and present.

Assessing soil resilience across an agricultural land retirement chronosequence

Reestablishment of perennial vegetation can improve soil conditions on intensively cultivated lands, but the timeframe required to recover uncultivated soil quality is not well understood. This study aimed to measure the recovery of soil physical (bulk density, aggregate stability, and water infiltration rate), biological (total microbial biomass and soil respiration), and chemical (surface soil organic carbon [SOC]) parameters across a 30-year land retirement chronosequence. Soil parameters on lands retired under long- and short-term Conservation Reserve Program (CRP) enrollment periods were compared to undisturbed and actively cropped lands, and chronofunctions were utilized to estimate the time required to achieve uncultivated soil quality. Results showed that short-term enrollment was not sufficient to restore any parameters to uncultivated quality, although bulk density, water infiltration, soil respiration, and total organic carbon (C) levels generally trended toward the undisturbed condition. No significant differences between the uncultivated and 30-year CRP enrollment for aggregate stability and total microbial biomass suggests uncultivated soil quality was restored within 30 years of land retirement. Based on chronofunction analysis, an estimated period of 53 years would be necessary to return bulk density and soil respiration to undisturbed quality on retired land. Water infiltration and SOC had the longest predicted recovery time of 75 and 128 years, respectively. These results suggest soil properties recover at varying rates once retired into perennial grassland systems, and long-term land retirement is necessary to restore soil properties to precultivation condition and maintain high quality soils capable of providing key ecosystem services.

Assessing the Efficiency of Alternative Best Management Practices to Reduce Nonpoint Source Pollution in a Rural Watershed Located in Louisiana, USA

We conducted biophysical simulations using MapShed to determine the effects of adopting best management practices (BMPs) to reduce nutrients and sediment pollution in a watershed dominated by poultry production in the Saline Bayou Watershed, Louisiana, USA. The reduction of three water pollutants, nitrogen, phosphorus, and sediment from adopting different BMPs were assessed using a linear programming model with the cost minimization objective. We considered three weather scenarios (dry, normal, and wet) and BMP parameter efficiencies obtained from linear regression models. Optimization results showed that nutrient management and agricultural land retirement reduced most of the phosphorus runoff in the watershed at the lowest cost. Results were robust to alternative weather (dry, normal, and wet) scenarios.

Land conservation can mitigate freshwater ecosystem services degradation due to climate change in a semiarid catchment: The case of the Portneuf River catchment, Idaho, USA

There is increasing evidence of environmental change impacts on freshwater ecosystem services especially through land use and climate change. However, little is known about how land conservation could help mitigate adverse water-sustainability impacts. In this paper, we utilized the InVEST tool and the Residual Trends method to assess the joint effects and relative contributions of climate change and land conservation on freshwater ecosystem services in the Portneuf River catchment in Idaho, USA. We developed five hypothesized scenarios regarding gain and loss in the enrollment of Conservation Reserve Program (CRP), the largest agricultural land-retirement program in the U.S., plus riparian buffer and assessed their interactions with climate change. Results suggest that the realized water yield in the Portneuf River catchment would possibly be 56% less due to climate change and 24% less due to the decline of CRP enrollment. On the contrary, if CRP enrollment is promoted by ~30% and riparian buffer protection is implemented, the water supply reduction in the year 2050 could be changed from 56% to 26%, the total phosphorus (TP) and total nitrogen (TN) export would be reduced by 10% and 11%, and the total suspended sediment (TSS) reduced by 17%. This study suggests that increasing implementation of the CRP would likely preserve key freshwater ecosystem services and assist proactive mitigation, especially for semiarid regions vulnerable to changing climate conditions.

Retiring Land to Save Water: Participation in Colorado’s Republican River Conservation Reserve Enhancement Program

Agricultural land retirement is increasingly used to manage water resources. This study uses well-level enrollment data to explore the factors that influence landowner participation in the Colorado Republican River Conservation Reserve Enhancement Program. An empirical model of enrollment is informed by a theoretical model of participation that incorporates aquifer and soil characteristics in addition to financial incentives. Our results reveal that enrollment is predicted to increase by 0.087 percentage points with a $10 increase in the incentives offered. The probability of enrollment is also influenced by the aquifer’s saturated thickness and the soil characteristics that impact land productivity.

Grasslands, wetlands, and agriculture: the fate of land expiring from the Conservation Reserve Program in the Midwestern United States

The Conservation Reserve Program (CRP) is the largest agricultural land-retirement program in the United States, providing many environmental benefits, including wildlife habitat and improved air, water, and soil quality. Since 2007, however, CRP area has declined by over 25% nationally with much of this land returning to agriculture. Despite this trend, it is unclear what types of CRP land are being converted, to what crops, and where. All of these specific factors greatly affect environmental impacts. To answer these questions, we quantified shifts in expiring CRP parcels to five major crop-types (corn, soy, winter and spring wheat, and sorghum) in a 12-state, Midwestern region of the United States using a US Department of Agriculture (USDA), field-level CRP database and USDA’s Cropland Data Layer. For the years 2010 through 2013, we estimate almost 30%, or more than 530 000 ha, of expiring CRP land returned to the production of these five crops in our study area, with soy and corn accounting for the vast majority of these shifts. Grasslands were the largest type of CRP land converted (360 000 ha), followed by specifically designated wildlife habitat (76 000 ha), and wetland areas (53 000 ha). These wetland areas were not just wetlands themselves, but also a mix of land covers enhancing or protecting wetland ecosystem services (e.g., wetland buffers). Areas in the Dakotas, Nebraska, and southern Iowa were hotspots of change, with the highest areas of CRP land moving back to agriculture. By contrast, we estimate only a small amount (∼3%) of the expiring land shifted into similar, non-CRP land-retirement or easement programs. Reconciling needs for food, feed, fuel, and healthy ecosystems is an immense challenge for farmers, conservationists, and state and federal agencies. Reduced enrollment and the turnover of CRP land from conservation to agriculture raises questions about sustaining ecosystem services in this region.

Stream Sediment Sources in Midwest Agricultural Basins with Land Retirement along Channel.

Documenting the effects of agricultural land retirement on stream-sediment sources is critical to identifying management practices that improve water quality and aquatic habitat. Particularly difficult to quantify are the effects from conservation easements that commonly are discontinuous along channelized streams and ditches throughout the agricultural midwestern United States. Our hypotheses were that sediment from cropland, retired land, stream banks, and roads would be discernible using isotopic and elemental concentrations and that source contributions would vary with land retirement distribution along tributaries of West Fork Beaver Creek in Minnesota. Channel-bed and suspended sediment were sampled at nine locations and compared with local source samples by using linear discriminant analysis and a four-source mixing model that evaluated seven tracers: In, P, total C, Be, Tl, Th, and Ti. The proportion of sediment sources differed significantly between suspended and channel-bed sediment. Retired land contributed to channel-bed sediment but was not discernible as a source of suspended sediment, suggesting that retired-land material was not mobilized during high-flow conditions. Stream banks were a large contributor to suspended sediment; however, the percentage of stream-bank sediment in the channel bed was lower in basins with more continuous retired land along the riparian corridor. Cropland sediments had the highest P concentrations; basins with the highest cropland-sediment contributions also had the highest P concentrations. Along stream reaches with retired land, there was a lower proportion of cropland material in suspended sediment relative to sites that had almost no land retirement, indicating less movement of nutrients and sediment from cropland to the channel as a result of land retirement.

Relations between Retired Agricultural Land, Water Quality, and Aquatic‐Community Health, Minnesota River Basin

The relative importance of agricultural land retirement on water quality and aquatic-community health was investigated in the Minnesota River Basin. Eighty-two sites, with drainage areas ranging from 4.3 to 2200 km, were examined for nutrient concentrations, measures of aquatic-community health (e.g., fish index of biotic integrity [IBI] scores), and environmental factors (e.g., drainage area and amount of agricultural land retirement). The relation of proximity of agricultural land retirement to the stream was determined by calculating the land retirement percent in various riparian zones. Spearman's rho results indicated that IBI score was not correlated to the percentage of agricultural land retirement at the basin scale ( = 0.070); however, IBI score was correlated to retired land percentage in the 50- to 400-m riparian zones surrounding the streams ( < 0.05), indicating that riparian agricultural land retirement may have more influence on aquatic-community health than does agricultural land retirement in upland areas. Multivariate analysis of covariance and analysis of covariance models indicated that other environmental factors (such as drainage area and lacustrine and palustrine features) commonly were correlated to aquatic-community health measures, as were in-stream factors (standard deviation of water depth and substrate type). These results indicate that although agricultural land retirement is significantly related to fish communities as measured by the IBI scores, a combination of basin, riparian, and in-stream factors act together to influence IBI scores.

Nitrogen deposition and loss of biological diversity: Agricultural land retirement as a policy response

Current levels of nitrogen deposition, especially ammonia, seriously impact upon ecosystems biological diversity. However, land use policy maintaining and enhancing key ecosystems in the UK in most cases does not explicitly take account of this pollution in terms of onsite management prescriptions. In this paper the economic potential of agricultural land retirement to reduce localised nitrogen deposition is examined. Employing a case study that combines nitrogen deposition modelling and agricultural land use change, reductions in nitrogen deposition necessary to reverse the loss of floral diversity are examined. The results indicate that agricultural land retirement is in principle a potentially useful policy instrument for dealing with nitrogen deposition from extensive livestock production.

A Water Transfer and Agricultural Land Retirement in a Drainage Problem Area

The increasing scarcity of water in California and the rising cost of compliance with environmental regulations are motivating some farmers in the San Joaquin Valley to sell their land and water, and discontinue production of irrigated crops. In the summer of 2004, all landowners in the 3,700-ha Broadview Water District decided to sell their land to Westlands Water District. The land sales have been completed and Westlands has acquired Broadview's water supply contract. Farmland in Broadview will no longer be irrigated. We describe what motivated the purchase and sale of land and water in Broadview and discuss the potential gains to participants. We describe also the potential public benefits that include an increase in economic activity and environmental enhancement in the San Joaquin Valley. Farm workers displaced by land retirement in Broadview will find employment in the Westlands Water District. Tenant farmers in Broadview will need to find other land on which to continue farming after the land sales are completed. The challenge they face is caused partly by a regional trend toward greater production of perennial crops that is leaving less land available for annual leases.

Agricultural Land Retirement and Slippage: Lessons from an Australian Case Study

This paper uses a Computable General Equilibrium (CGE) model to examine the economic implications of agricultural land retirement from wool production for conservation in Australia. Employing an innovative specific-factors characterization of production to generate short-run and long-run results, we show that the potential welfare gains from land retirement can be significant. However, in several scenarios examined we find that slippage in agricultural production is significant, resulting in reduced welfare. Our slippage results provide insights into the relationship between the potential causes of slippage and describe how a land retirement policy can be designed to minimize this effect. (JEL C68, Q24)

Agricultural land retirement: lessons from an Australian case study

In this paper, we analyse the case for agricultural land retirement in Australia. For the case study considered, using defined criteria, we demonstrate that land retirement is an effective policy option. This finding depends crucially on the magnitude and sign of the price effect resulting from a fall in wool production because of agricultural land retirement. Uniquely in the literature, we argue that the price effect will positively contribute to a benefit–cost analysis of agricultural land retirement. We detail the necessary conditions that need to prevail for this to occur. We also explain why the expected benefits of land-use change are fewer than might be expected in the case study.