US Crop Production Research Articles

Key role of planted and harvested area fluctuations in US crop production shocks

Key role of planted and harvested area fluctuations in US crop production shocks

Landscape complexity and US crop production.

Agricultural expansion and intensification have simplified Earth's landscapes, thereby adversely affecting the biodiversity and ecosystem services that support agricultural production. Field-scale research suggests that increased landcover complexity can improve crop productivity, but less is known about how complexity and crop productivity interact at broader landscape scales. This study evaluates the relationship between landscape complexity and crop yields for counties in the conterminous United States from 2008 to 2018. Our results suggest that the number and quantity of landcover categories on a landscape has a stronger influence on yields than how these landcover categories are arranged on the landscape. Specifically, increased landcover diversity is associated with yield increases for corn and wheat of more than 10%-an effect strength similar to the impact of seasonal precipitation and soil suitability. Notably, landscape configurations that are both moderately complex and also highly diverse are associated with yield increases of more than 20% for corn and wheat. Our findings suggest that increasing the complexity of landcover may provide a way to improve crop productivity in the United States without further extensification or intensification of agriculture.

Mechanism of Resistance to S-metolachlor in Palmer amaranth.

Herbicides are major tools for effective weed management. The evolution of resistance to herbicides in weedy species, especially contributed by non-target-site-based resistance (NTSR) is a worrisome issue in crop production globally. Glyphosate-resistant Palmer amaranth (Amaranthus palmeri) is one of the extremely difficult weeds in southern US crop production. In this study, we present the level and molecular basis of resistance to the chloroacetamide herbicide, S-metolachlor, in six field-evolved A. palmeri populations that had survivors at the recommended field-dose (1.1 kg ai ha−1). These samples were collected in 2014 and 2015. The level of resistance was determined in dose-response assays. The effective dose for 50% control (ED50) of the susceptible population was 27 g ai ha−1, whereas the ED50 of the resistant populations ranged from 88 to 785 g ai ha−1. Therefore, A. palmeri resistance to S-metolachlor evolved in Arkansas as early as 2014. Metabolic-inhibitor and molecular assays indicated NTSR in these populations, mainly driven by GSTs. To understand the mechanism of resistance, selected candidate genes were analyzed in leaves and roots of survivors (with 1 × S-metolachlor). Expression analysis of the candidate genes showed that the primary site of S-metolachlor detoxification in A. palmeri is in the roots. Two GST genes, ApGSTU19 and ApGSTF8 were constitutively highly expressed in roots of all plants across all resistant populations tested. The expression of both GSTs increased further in survivors after treatment with S-metolachlor. The induction level of ApGSTF2 and ApGSTF2like by S-metolachlor differed among resistant populations. Overall, higher expression of ApGSTU19, ApGSTF8, ApGSTF2, and ApGSTF2like, which would lead to higher GST activity in roots, was strongly associated with the resistant phenotype. Phylogenetic relationship and analysis of substrate binding site of candidate genes suggested functional similarities with known metolachlor-detoxifying GSTs, effecting metabolic resistance to S-metolachlor in A. palmeri. Resistance is achieved by elevated baseline expression of these genes and further induction by S-metolachlor in resistant plants.

Irrigation efficiency and water withdrawal in US agriculture

Abstract To meet future food demand and sustainability requirements of society, the agriculture sector faces challenges in both the institutional dimension and the technological dimension. One of the main concerns regarding the current agricultural production pattern is the tremendous amount of water it requires to maintain and boost output. With a changing climate and increasing demand from civil uses, promoting both water allocation efficiency and water application efficiency becomes the focus of policy design. The unintended consequences of water policies, however, have led to extensive debates. This study addresses the key question of whether irrigation efficiency improvement leads to reduced per-area water use. The study assembles a national county-level panel data set on water withdrawal, irrigation technology, and farm operation and demographics. The empirical results show that a higher irrigation efficiency is associated with a lower per-area water application in US crop production. Two alternative efficiency measures are proposed. Depending on how the efficiency is measured, a one standard-deviation efficiency improvement (6–30%) in irrigation can reduce 6–11% of water withdrawal in US crop production. The water saving is about 0.06–0.12 mm/day given a county average irrigation water use of 1.07 mm/day.

Interspecific and intraspecific transference of metabolism-based mesotrione resistance in dioecious weedy Amaranthus.

Pollen-mediated gene flow (PMGF) might play an important role in dispersing herbicide resistance alleles in dioecious weedy Amaranthus species. Field experiments in a concentric donor-receptor design were conducted to quantify two sets of PMGF studies, an interspecific (Amaranthus tuberculatus×Amaranthus palmeri) and an intraspecific (A. tuberculatus×A. tuberculatus). In both studies, PMGF was evaluated using a resistant A. tuberculatus phenotype with enhanced mesotrione detoxification via P450 enzymes as a source of resistance alleles. For interspecific hybridization, more than 104000 putative hybrid seedlings were screened with three markers, one phenotypic and two molecular. The two molecular markers used, including 2-bp polymorphisms in the internal transcribed spacer region, distinguished A. palmeri, A. tuberculatus and their hybrids. Results showed that 0.1% hybridization between A. tuberculatus×A. palmeri occurred under field research conditions. For intraspecific hybridization, 22582 seedlings were screened to assess the frequency of gene flow. The frequency of gene flow (FGF ) varied with distance, direction and year of the study. The farthest distance for 90% reduction of FGF was at 69m in 2015 however, after averaging across directions it was 13.1 and 26.1m in 2014 and 2015, respectively. This study highlights the transfer of metabolism-based mesotrione resistance from A. tuberculatus to A. palmeri under field research conditions. The results presented here might aid in the rapid detection of A. palmeri among other Amaranthus species and show that PMFG could be expediting the increase of herbicide resistance in A. palmeri and A. tuberculatus across US crop production areas.

Detection of glyphosate residues in companion animal feeds

The widespread adoption of genetically modified, glyphosate-tolerant corn and soybean varieties in US crop production has led to a dramatic increase in glyphosate usage. Though present at or below regulatory limits currently set for human foodstuffs, the concentration of glyphosate in companion animal feed is currently unknown. In the present study, 18 commercial companion animal feeds from eight manufacturers were analyzed for glyphosate residues using ELISA. Every product contained detectable glyphosate residues in the range of 7.83 × 101–2.14 × 103 μg kg−1 dry weight, with the average and medians being 3.57 × 102 and 1.98 × 102 μg kg−1 respectively. Three products were tested for within-bag variation and six were tested for lot to lot variation. Little within-bag variation was found, but the concentration of glyphosate varied by lot in half of the products tested. Glyphosate concentration was significantly correlated with crude fiber content, but not crude fat or crude protein. Average daily intakes by animals consuming feeds containing the median glyphosate concentration are estimated to result in exposures that are 0.68–2.5% of the Allowable Daily Intake (ADI) for humans in the US and EU, which are 1750 and 500 μg kg−1 respectively. Consumption of the most contaminated feed, however, would result in exposure to 7.3% and 25% of the above ADIs, though the relevance of such an exposure to companion animals is currently unknown.Companion animal feeds contained 7.83 × 101–2.14 × 103 μg kg−1 glyphosate which is likely to result in pet exposure that is 4–12 times higher than that of humans on a per Kg basis.

Examining crop price effects on production decision and resource allocation: an ex-ante approach

ABSTRACTThis article examines the output price effects on the US crop production, employing an ex-ante approach to the differential systems of input demand and output supply. The estimation results of the differential input demand show that the expansion of crop production leads to an increase in acreage (i.e. extensive margin) and a proportional rise in input usage improving yield per acre (i.e. intensive margin). The substitutable relationship between fertilizer and land supports that crop producers have an option to choose either intensive or extensive margin in response to changes in their relative prices. In addition, the estimation results of the differential output supply highlight that the composition of crop supply can be altered by changes in ex-ante crop prices. The estimation results suggest that crop producers substitute corn supply for the supply of cotton, wheat and soybeans or vice versa. Based on the estimated elasticities, the decompositions of profit-maximizing input demand are conducted, which reveals that a change in ex-ante crop prices is associated closely with resource reallocation.

Unique challenges and opportunities for northeastern US crop production in a changing climate

Climate change may both exacerbate the vulnerabilities and open up new opportunities for farming in the Northeastern USA. Among the opportunities are double-cropping and new crop options that may come with warmer temperatures and a longer frost-free period. However, prolonged periods of spring rains in recent years have delayed planting and offset the potentially beneficial longer frost-free period. Water management will be a serious challenge for Northeast farmers in the future, with projections for increased frequency of heavy rainfall events, as well as projections for more frequent summer water deficits than this historically humid region has experienced in the past. Adaptations to increase resilience to such changes include expanded irrigation capacity, modernized water monitoring and irrigation scheduling, farm drainage systems that collect excess rain into ponds for use as a water source during dry periods, and improved soil water holding capacity and drainage. Among the greatest vulnerabilities over the next several decades for the economically important perennial fruit crop industry of the region is an extended period of spring frost risk associated with warmer winter and early spring temperatures. Improved real-time frost warning systems, careful site selection for new plantings, and use of misting, wind machine, or other frost protection measures will be important adaptation strategies. Increased weed and pest pressure associated with longer growing seasons and warmer winters is another increasingly important challenge. Pro-active development of non-chemical control strategies, improved regional monitoring, and rapid-response plans for targeted control of invasive weeds and pests will be necessary.

PAM: Decision Support for Long-Term Palmer Amaranth (Amaranthus palmeri) Control

Palmer amaranth is the most troublesome weed problem in mid-southern US crop production. Herbicides continue to be the most commonly employed method for managing Palmer amaranth, despite the weed’s widespread resistance to them. Therefore, farmers need research and extension efforts that promote the adoption of integrated weed management (IWM) techniques. Producers, crop consultants, educators, and researchers would be more likely to deploy diversified chemical and nonchemical weed management options if they are more informed about long-term biological and economic implications via user-friendly decision-support software. Described within is a recently developed software that demonstrates the effects of Palmer amaranth management practices on soil seedbank, risk of resistance evolution, and economics over a 10-year planning horizon. Aiding this objective is a point-and-click interface that provides feedback on resistance risk, yield potential, profitability, soil seedbank dynamics, and error checking of management options.

What do farmers' weed control decisions imply about glyphosate resistance? Evidence from surveys of US corn fields.

The first case of glyphosate-resistant weeds in the United States was documented in 1998, 2 years after the commercialization of genetically engineered herbicide-resistant (HR) corn and soybeans. Currently, over 15 glyphosate-resistant weed species affect US crop production areas. These weeds have the potential to reduce yields, increase costs, and lower farm profitability. The objective of our study is to develop a behavioral model of farmers' weed management decisions and use it to analyze weed resistance to glyphosate in US corn farms. On average, we find that weed control increased US corn yields by 3700 kg ha-1 (worth approximately $US 255 ha-1 ) in 2005 and 3500 kg ha-1 (worth approximately $US 575 ha-1 ) in 2010. If glyphosate resistant weeds were absent, glyphosate killed approximately 99% of weeds, on average, when applied at the label rate in HR production systems. Average control was dramatically lower in states where glyphosate resistance was widespread. We find that glyphosate resistance had a significant impact on weed control costs and corn yields of US farmers in 2005 and 2010. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

A Review of Silicon in Soils and Plants and Its Role in US Agriculture

Silicon (Si) is the second most abundant element in the earth’s crust and plays a number of important roles in the mineral nutrition of plants. In the past 20 years, the scientific documentation on the benefits of Si to crops has helped establish Si fertilization as an agronomic practice in many agricultural lands worldwide. However, very little information has been consolidated on the use of Si specifically for US agriculture. Consequently, the objectives of this review are to provide (1) information on the dynamics of Si in soil, use, and sources; (2) a history and up-to-date documentation on Si-related research in many areas of US production agriculture; and (3) perspectives on Si as a plant beneficial nutrient and the potential of Si fertilization as an agronomic practice in US crop production systems. The Si-driven mechanisms enhancing the productivity of a wide array of crops under stressed conditions are discussed in this review. Based on the recent 10-year average production level and published shoot Si content, the principal crops grown in the United States can collectively take up 9.55 million tons of Si annually, whereas the annual Si removal rate for the entire US cropland area is estimated at 21.1 million tons. On the basis of this projected annual Si removal rate, adoption of continuous intensive farming systems in the country, low solubility of soil Si, and complex chemical dynamics of Si in soil, increasing plant-available Si levels through fertilization is therefore foreseen a logical agronomic practice for US agriculture.

Atmospheric inversion of surface carbon flux with consideration of the spatial distribution of US crop production and consumption

Abstract. In order to improve quantification of the spatial distribution of carbon sinks and sources in the conterminous US, we conduct a nested global atmospheric inversion with detailed spatial information on crop production and consumption. County-level cropland net primary productivity, harvested biomass, soil carbon change, and human and livestock consumption data over the conterminous US are used for this purpose. Time-dependent Bayesian synthesis inversions are conducted based on CO2 observations at 210 stations to infer CO2 fluxes globally at monthly time steps with a nested focus on 30 regions in North America. Prior land surface carbon fluxes are first generated using a biospheric model, and the inversions are constrained using prior fluxes with and without adjustments for crop production and consumption over the 2002–2007 period. After these adjustments, the inverted regional carbon sink in the US Midwest increases from 0.25 ± 0.03 to 0.42 ± 0.13 Pg C yr−1, whereas the large sink in the US southeast forest region is weakened from 0.41 ± 0.12 to 0.29 ± 0.12 Pg C yr−1. These adjustments also reduce the inverted sink in the west region from 0.066 ± 0.04 to 0.040 ± 0.02 Pg C yr−1 because of high crop consumption and respiration by humans and livestock. The general pattern of sink increases in crop production areas and sink decreases (or source increases) in crop consumption areas highlights the importance of considering the lateral carbon transfer in crop products in atmospheric inverse modeling, which provides a reliable atmospheric perspective of the overall carbon balance at the continental scale but is unreliable for separating fluxes from different ecosystems.

Spatiotemporal patterns of cropland area and net primary production in the central United States estimated from USDA agricultural information

The central United States, which is dominated by agriculture, has been selected as the first North American Carbon Program intensive campaign. Data sets that describe spatiotemporal variability in carbon fluxes are needed to support this campaign. Here we report the behavior of county cropland net primary production (NPP) in the first intensive region derived using USDA information together with crop‐specific parameters that convert agronomic data into carbon fluxes. Total cropland area in the eight‐state region was ∼550,000 km2 (40% of total area), with some interannual variability but no temporal trend from 1972 to 2001. Regional production (P) was 0.3 Pg C yr−1 in the late 1990s, roughly 64% of the total US crop production. P was highest in the central counties (>1.2 Tg C yr−1). In contrast to area, both NPP (flux per unit area) and P (spatially aggregated flux) increased during the study period (46 and 51%, respectively). Corn was the dominant crop type grown in the region, contributing 58% of the total production, with soybeans second most productive but substantially less (20%) despite similar harvested area. Maximum year‐to‐year variability in P was high, generally greater than 30% for most counties, though exceeding 80% for some counties.

Effects of climate change on US crop production: simulation results using two different GCM scenarios. Part I: Wheat, potato, maize, and citrus

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 20:259-270 (2002) - doi:10.3354/cr020259 Effects of climate change on US crop production: simulation results using two different GCM scenarios. Part I: Wheat, potato, maize, and citrus F. N. Tubiello1,*, C. Rosenzweig1, R. A. Goldberg1, S. Jagtap2, J. W. Jones2 1Columbia University and NASA-Goddard Institute Space Studies, Armstrong Hall, 2880 Broadway, New York, New York 10025, USA 2College of Agricultural and Life Sciences, University of Florida, PO Box 110270, Gainesville, Florida 32611, USA *E-mail: franci@giss.nasa.gov ABSTRACT: We projected US agricultural production in 2030 and 2090 at 45 representative sites, using 2 scenarios of climate change, developed with the Hadley Centre Model and the Canadian Centre Climate Model, and the DSSAT (Decision Support Systems for Agro-technology Transfer) dynamic crop-growth models. These simulation results have previously been aggregated nationally with the aid of economic models to show an increase in overall US agricultural output under climate change. In this work, we analyzed the regional distribution of the simulated yields, showing that positive results largely depend on the precipitation increases projected by the climate scenarios. In contrast, in some important rainfed production areas where precipitation was projected to decrease, such as the Kansas and Oklahoma Bread Basket regions under the Canadian Centre Climate Model scenario, climate change resulted in significant reductions of grain yield (-30 to -40%), accompanied by increased year-to-year variability. We also discussed the response to additional factors affecting the simulated US crop production under climate change, such as higher temperature and elevated CO2. KEY WORDS: Climate change · Agriculture · Elevated CO2 · US National Assessment · Adaptation Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 20, No. 3. Online publication date: April 26, 2002 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2002 Inter-Research.

Assessing the role of US agriculture in reducing greenhouse gas emissions and generating additional environmental benefits

This study measures the changes in Greenhouse Gas (GHG) emissions from US crop production under a scenario where farmers face higher energy prices with the implementation of the Kyoto Protocol. The focus is on predicting the impact on direct and indirect energy, resource use, and measuring the changes in specific GHGs. The study also assesses the potential for additional environmental benefits from the changes in agricultural resource use. The analyses rely on the results from a calibrated mathematical programming model of regional US crop production. The model accounts for input substitution when farmers are faced with external shocks. The results suggest that when energy prices increase, there is a relatively small decrease in total harvested acreage, but a more significant drop in the use of energy-intensive resources. Overall, GHG emissions from US crop production decrease by 20%, suggesting agriculture is more effective in abating GHG emissions than the other sectors of US economy. There is also a good potential for additional positive environmental externalities from the decreases in resources used in crop production.