Crop rotations in the United States increasingly involve few crops dominated by corn frequently combined with soybeans. We assess factors tied to corn acreage intensification over the past two decades. Using state-level data of 11 U.S. Corn Belt states from 2000 to 2021, we applied a panel fixed effects instrumental variable modeling approach to investigate these linkages. Findings suggest Conservation Reserve Program acreage releases, crop prices, ethanol demand, farm size, productivity, and genetically modified varieties positively impact corn acreage intensity. These results imply crop planting decisions are complex and are not uniquely attributed to biofuel considerations.

Rush skeletonweed is an aggressive perennial weed that establishes itself on land in the Conservation Reserve Program (CRP), and persists during cropping following contract expiration. It depletes critical soil moisture required for yield potential of winter wheat. In a winter wheat/fallow cropping system, weed control is maintained with glyphosate and tillage during conventional fallow, and with herbicides only in no-till fallow. Research was conducted for control of rush skeletonweed at two sites in eastern Washington, Lacrosse and Hay, to compare the effectiveness of a weed-sensing sprayer and broadcast applications of four herbicides (aminopyralid, chlorsulfuron + metsulfuron, clopyralid, and glyphosate). Experimental design was a split-plot with herbicide and application type as main and subplot factors, respectively. Herbicides were applied in the fall at either broadcast or spot-spraying rates depending on sprayer type. Rush skeletonweed density in May was reduced with use of aminopyralid (1.1 plants m−2), glyphosate (1.4 plants m−2), clopyralid (1.7 plants m−2), and chlorsulfuron + metsulfuron (1.8 plants m−2) compared with the nontreated check (2.6 plants m−2). No treatment differences were observed after May 2019. There was no interaction between herbicide and application system. Area covered using the weed-sensing sprayer was, on average, 52% (P < 0.001) less than the broadcast application at the Lacrosse location but only 20% (P = 0.01) at the Hay location. Spray reduction is dependent on foliar cover in relation to weed density and size. At Lacrosse, the weed-sensing sprayer reduced costs for all herbicide treatments except aminopyralid, with savings up to US$6.80 per hectare. At Hay, the weed-sensing sprayer resulted in economic loss for all products because of higher rush skeletonweed density. The weed-sensing sprayer is a viable fallow weed control tool when weed densities are low or patchy.

I directly estimate the acre-for-acre impact of crop insurance participation on Conservation Reserve Program (CRP) enrollment at the county level. The government may be sponsoring competing interests if subsidized insurance expands production at the expense of CRP. I employ an instrumental variables technique to correct for endogeneity in insurance decisions. Results suggest that an additional 1,000 acres insured reduces CRP enrollment by about three acres, though effect sizes vary by region. Local policy initiatives such as conservation compliance incentives could help offset local environmental consequences of converting land from CRP to insured production.

A field study was established in southern Iowa in 1994 to study seasonal and long-term weed population dynamics on land being brought back into production after 8 yr as part of the conservation reserve program (CRP). The study was a split-plot design with four replications; two tillage regimes, two crop rotations, and three herbicide application methods were used. Even though the tillage regime did not influence individual weed population density throughout the study, the no-till (NT) regime had more weeds compared to conventional tillage (CT). However, when weeds were grouped into categories, tillage influenced broadleaf weeds in 1994 and 1996 and total weeds in 1995. Plots under the NT regime had an average of 46 broadleaf weeds m−2 compared to 27 in CT in 1994, with Amaranthus rudis Sauer (common waterhemp) being the most prevalent. NT had a total of 186 weeds m−2 compared to 125 m−2 weeds in CT in 1995; however, in 1996, CT plots had 184 weeds m−2 compared to 121 m−2 in the NT regime. Except for broadleaf weeds in 1994, crop rotation did not influence the number of weeds, and herbicide application methods had the greatest effect on weed populations. Overall, weed populations were greater in 1997, 1996, and 1995 than in 1994 for all herbicide application methods. The no-herbicide treatment had the highest number of weeds throughout the study. The total number of weeds in band and broadcast treatments averaged 41 and 26 m−2 in 1994; 96 and 24 m−2 in 1995; 96 and 12 m−2 in 1996; and 109 and 95 m−2 in 1997. The use of broadcast herbicides in NT should be recommended for land coming out of CRP. Regardless of the herbicide application method or crop rotation, CT plots had better yields for both Zea mays L. (corn) and Glycine max L. (soybean). Glycine max had a better stand compared to Z. mays in the first year, indicating that a rotation starting with G. max might be preferred in the land coming out of CRP.

The influence of tillage, crop rotation, and weed management regimes on the weed seedbank in land previously under the conservation reserve program (CRP) for 8 yr was determined from 1994 through 1997. The study was a split-plot design with four replications, two tillage systems, two crop rotations, and three weed management treatments. Eleven weed species were recorded in 1994 and 1995, and 13 in 1996 and 1997. The weed seedbank was dominated by broadleaf species. In 1994, the first year after CRP, the seed population density in the top 15 cm of the soil profile was 51,480 seeds m−2, of which 60 and 20% were pigweed and common lambsquarters. The population density of pigweed seeds in the seedbank increased over time and reached 51,670 seeds m−2 in 1996. In contrast, the seed population density for foxtail species was only 417 seeds m−2 in 1994, but it increased to 7,820 seeds m−2 in 1997. The large increase in foxtail species seed population density in the 4-yr period was mainly in the no-herbicide weed management treatment. The weed seedbank was reduced similarly by band and broadcast herbicide treatments. Tillage and crop rotation did not influence the weed seedbank or Shannon's diversity index, nor did they interact with the weed management treatments in any of the years. The weed seedbank population density varied with the years and time of soil sampling. Weed seed population densities tended to be greater in the fall but declined significantly by time of the spring sampling. The no-herbicide treatment had a more diverse weed seedbank compared with band and broadcast herbicide weed management treatments. An average of one grass and three broadleaf weed species were identified in the three weed management treatments. Band and broadcast herbicide treatments reduced the weed seedbank population density but did not affect the number of broadleaf weed species observed.

In Alaska Conservation Reserve Program (CRP) lands, succession of fields planted with grass and clover to shrubs and small trees is resulting in program compliance problems related to ease of reconversion to crop lands. Standard practice for slowing this succession is mowing every 2 to 3 yr, which does not kill the woody vegetation. A field study was conducted at three sites over 2 yr to determine if 2,4-D (2.2 kg ae ha−1 2-ethylhexyl ester) or triclopyr (2.2 kg ae ha−1 butoxyethyl ester) applied broadcast or 2,4-D (2.2 kg ae ha−1 2,4-D dimethylamine salt) or triclopyr (1.7 kg ae ha−1 triclopyr triethylamine salt) applied with a Diamond Wet Blade™ mower (DWB) would result in longer shrub control compared to mowing. Mowing was conducted at both 15 and 45 cm above ground level and herbicides were applied with the DWB at three rates. Measurements 2 yr after treatment (YAT) confirmed that both herbicides reduced shrub cover about 50% compared to controls. Reduced rates of the herbicides applied with the DWB did not result in decreased shrub control. Grass cover was negatively correlated with shrub cover. Typically, mower height did not alter treatment effects. Treatments had little impact on forb cover and composition 2 YAT, with the exception of fireweed, which was generally reduced where herbicides were applied. Application of 2,4-D and triclopyr does not decrease the frequency of shrub control in CRP lands in Alaska. Use of 2,4-D and triclopyr with or without mowing resulted in no widespread improvement over the current practice of mowing to 15 cm every 2 to 3 yr.

In 1998, 1,260 soil samples were collected from 63 of 99 Iowa counties to characterize the weed seedbanks in fields under the conservation reserve program (CRP) and adjacent fields under continuous cultivation. Five annual grass and 13 broadleaf weed species were identified in both the CRP and adjacent cultivated fields. Seedbank differences between CRP and adjacent cultivated fields were evident only for foxtails, common lambsquarters, pigweeds, and sweetclover, with the average of 3,288, 10,681, 38, and 1,709 seeds/m2, respectively; the corresponding seed population in adjacent CRP fields was 59, 57, 1,924, and 74%, respectively. However, weed species diversity was not significantly different between fields in CRP and continuous cultivation. Only CRP fields in the northwest Iowa crop-reporting district had a higher foxtail species seed population (4,915 seeds/m2) than the adjacent cultivated fields (1,782 seeds/m2). Land under CRP in northern (N), eastern, and southern (S) districts had 58% (4,158 seeds/m2), 6% (312 seeds/m2), and 18% (594 seeds/m2) of the continuously cultivated foxtail species seedbank. Common lambsquarters seed populations were 4,128 and 3,801 seeds/m2 in the cultivated fields of the N and central (C) districts, compared with 772 and 252 seeds/m2 in adjacent CRP fields, respectively. Pigweed species seeds were more numerous in the cultivated fields than in adjacent CRP fields in the northeast, C, and S Iowa districts. Sweetclover seed population was consistently higher in CRP land because it was included as part of the CRP covers seeding. Overall, broadleaf weed seeds comprised 90% of the seedbanks in both CRP and adjacent cultivated land. A competitive cover crop canopy in CRP probably reduced weed seedbanks by suppression of weeds and seed production. Also, annual seed production, differences in weed biology, and differential herbicide performance in cultivated fields may have contributed to higher seed populations.

Conservation programs faced with limited budgets often use a competitive enrollment mechanism. Goals of enrollment might include minimizing program expenditures, encouraging broad participation, and inducing adoption of enhanced environmental practices. We use experimental methods to evaluate an auction mechanism that incorporates bid maximums and quality adjustments. We examine this mechanism's performance characteristics when opportunity costs are heterogeneous across potential participants, and when costs are only approximately known by the purchaser. We find that overly stringent maximums can increase overall expenditures, and that when quality of offers is important, substantial increases in offer maximums can yield a better quality-adjusted result.

Data on owner and land characteristics are used to analyze factors affecting participation decisions in Delaware's agricultural lands preservation program, federal commodity programs, and federal conservation programs. A trivariate probit model estimates a set of random utility models of participation. Participation decisions at the state and federal levels are found to be driven by many of the same observed factors, but uncorrelated in unobserved characteristics. The important exceptions are that owners of small parcels under development pressure and with parcels of relatively low environmental quality tend to enroll in commodity programs rather than preservation. In part, the complex policy environment may therefore limit the effectiveness of programs seeking to preserve parcels with the highest environmental quality or facing the greatest development pressure.

This paper presents the methodology, assumptions, and data used to generate regional and national environmental benefit estimates of the USDA's Conservation Reserve Program (CRP). It's assumed that, without the program, production and conservation practices on CRP lands would be the same as those used on surrounding lands. When range and forest lands are (are not) included as land-use options, 54 (71) percent of the CRP land would be in crop production—which is consistent with past analyses. Soil erosion would be 222 to 248 million tons per year—about 11 percent—higher than the current level. Benefits are estimated by applying environmental benefit models, estimated in previous analyses, to the CRP's estimated effect on erosion and wildlife habitat. Nationally, the CRP is estimated to provide $1.3 billion in annual benefits, which represents 75 to 80 percent of the program's cost. In seven of the 10 USDA Farm Production Regions, the CRP's environmental benefits exceed costs. Thus, reallocating acreage to these regions could increase net program benefits. However, because many benefits could not be estimated, one cannot conclude that regional and national benefits do not exceed costs.

Conservation initiatives in the 1985 Farm Bill affected farmers' decisions regarding soil conservation. A farmer survey was conducted and a multi-period mixed-integer programming model was developed to determine an optimal farm plan with choices of crop-tillage combinations and land retirement Results indicate that farmers' incentives to reduce soil loss in the Sand Mountain region in Alabama are not substantially affected by provisions of the 1985 Farm Bill. The bid price for the Conservation Reserve Program will have to be considerably higher than 1988 levels to provide an incentive to remove land from production.

The Conservation Reserve Program (CRP) takes cropland out of production for 10 years, reducing grain supplies available to elevators. Results suggest that the program has negatively impacted elevator merchandising margins, but that elevators adjusted rather quickly to CRP changes, making most of the adjustment within 1 year. The reduction in margins reflects an element of pressure on agribusinesses that has not been measured in previous studies.

The study examines Louisiana small farmers' reasons for not participating in the Conservation Reserve Program (CRP), their awareness of the program, and their willingness to participate in the program. The results suggest that: farmers do not participate in the CRP if revenues from cropland are an important source of income, or if they are tenants; awareness is significantly related to education, income, race, and average return per acre; willingness is positively influenced by payment per acre, age, and farm status. Participation depends on whether payments per acre are comparable to the opportunity costs of removing cropland from production.

Among Conservation Reserve Program (CRP) participants, there is a distinction between farm households using the program to ease out of farming and those using the program to augment production receipts. We find evidence that factors other than crop or livestock revenue and environmental factors are associated with program participation and acreage enrollment among farmers who continue agricultural production. Program payments and farm size are positively associated with the amount of land enrolled in the CRP, and characteristics of participants in land retirement and working-lands CRP components are similar.

Four policy alternatives for CRP lands upon expiration of the current contracts in Hale County, Texas are evaluated using chance-constrained programming. It was found that if CRP contracts are extended at the current average rental rate, 40 percent of the current enrollment would be expected to return to crop production, while 66 percent would return to crop production if the program were eliminated. The results also indicate that the marginal value of CRP payments to producers is lower than the marginal value of deficiency payments.

The future use of Conservation Reserve Program (CRP) lands is an important agricultural policy issue. To examine the effects of factors that influence landowners' post-contract use of CRP lands, a survey of Texas High Plains CRP contract holders was conducted in 1992. This study analyzes the results of the survey using a qualitative choice model. It was found that the presence of a livestock enterprise in the current contract holder's operation increases the probability of these acres remaining in the established cover. Contract holders who value the commodity base have an increased probability of returning their acres to crop production.

Over $1.7 billion has been spent on the Conservation Reserve Program (CRP) since 1985. The purpose of this study is to show that these expenditures have aided the environment. Rather than quantify changes in environmental variables, a spatial econometric model is used to test if CRP enrollments are greater in counties with poorer environmental quality. In seven of nine regions, CRP enrollments are higher in counties with an environmental concern. This positive finding justifies past expenditures by the CRP and supports continued funding as an environmental program. The CRP is targeting current environmental concerns that will lead to future improvement.

Perennial wheat offers a new solution to the long-standing problems of soil erosion and degradation associated with conventional annual small-grain cropping systems in the Pacific Northwest region. Using classical breeding methods, new types of wheat have been developed that maintain the key characteristics of annual wheat, but continue to grow after harvest. Following dormancy in the winter, growth is initiated from the roots or crowns in the spring, allowing a crop to be harvested every fall. By retaining constant soil cover over multiple years, wind and water erosion would be dramatically reduced. In addition, the costs associated with annual seeding and tillage would be minimized, and unlike many reduced tillage systems, it is expected that standard seeding equipment would be suitable for stand establishment. Other potential benefits of perennial wheat include improved wildlife habitat, more efficient use of available water, provision of a potent carbon sink, and the possibility of integrating straw retrieval into a small grains cropping system. Past attempts in the first half of the last century failed to develop perennial wheat as a viable crop, primarily because of low yields, and the research was ultimately abandoned. Perennial wheat production may now be viewed as acceptable for highly erodible land or for obtaining carbon sequestration credits. This paper presents an overview of solutions to the obstacles encountered by previous researchers, introduces some of the newly developed perennial wheat lines, and discusses considerations for management practices.

The sustainability of farming systems must be assessed by their potential environmental, economic, and social performance. We present a case study to illustrate an assessment of relative sustainability that uses all three performance criteria.

We developed two scenarios for farmland currently enrolled in the Conservation Reserve Program (CRP) in Putnam County, Missouri: a conventional scenario reflecting farming practices typical of northern Missouri, and an alternative that we hypothesize to be more environmentally sound. We used selected economic and social indicators to assess whether the latter would be at least as economically viable and socially responsible as the conventional system.

Estimated direct farm income was $3.4 million for the alternative and $2.4 million for the conventional scenario. The alternative system applies more labor and management to a given land resource and may support more farming families. Estimated total community economic impacts were 25% greater for the alternative than the conventional farming scenario. CRP land, therefore, could be returned to production in a way that could significantly enhance local economic and social benefits while retaining many of the CRP's environmental benefits.