Increasing Management Intensity Research Articles

Spatial characteristics of soil enzyme activities and microbial community structure under different land uses in Chongming Island, China: Geostatistical modelling and PCR-RAPD method

Information about soil enzyme activity and soil DNA as indicators of how land use affects soil quality remains unknown for alluvial island. The purpose of this study was to investigate the effects of land use on enzyme activities and soil gene diversity in the Chongming Island, Shanghai, China, with the aim of providing further knowledge about the problems related to soil quality and its evolving spatial characteristic on the Chongming Island. The results indicate that land use causes an important change of organic matter, with either causing a small decrease or an increase in the absolute enzyme activity. With increased management intensity, there is an increase in the number of soils with high organic matter content and a decrease in the soils with low organic matter content. The effect on enzyme activity varies depending on the type of land use or management and the type of enzyme. The orders of the number of gene polymorphic bands under different land uses were as follows: agriculture soil > commercial soil > industrial soil > wetland. The complexities of the behaviors of the soil enzymes indicate that genetic analysis and biomarkers in conjunction with geostatistics method will be a powerful and accurate indicator to evaluate soil quality under land use.

Drying temperature effects on bulk density and carbon density determination in soils of northern New South Wales

There is a widespread and growing need for information relating to soil condition and changes in response to land management pressures. To provide the information needed to quantify land management effects on soil condition, monitoring systems are now being put in place and these programs will generate large numbers of samples. Streamlined procedures for the analysis of large sample numbers are therefore required. Bulk density (BD) is considered to be one of several key indicators for measuring soil physical condition, and is also required to estimate soil carbon density. The standard analytical technique for BD requires drying the soil at 105°C but this procedure creates several logistical and analytical problems. Our initial objective was to derive correction factors between drying temperatures to allow for rapid, low-temperature estimation of BD on large sample numbers. Soil samples were collected from 3 contrasting soil types (basalt, granite, and meta-sediments) in 4 land uses (cultivation, sown pasture, native pasture, woodland) in northern New South Wales to test the effect of soil drying temperature on BD determination. Cores were divided into 4 depths (0–0.05, 0.050–0.10, 0.10–0.20, 0.20–0.30 m), and oven-dried at 40, 70, and 105°C. Drying temperature had no significant effect on BD but the effects of soil type, depth, and land use were significant, varying according to expectations based on previous studies, i.e. higher BD in granite-derived soils and lower in basalt-derived soils, increased BD with depth, and increasing BD with increasing management intensity. These results indicate that lower drying temperatures (40°C) were adequate for the efficient determination of BD especially where analysis of other soil properties from the same sample is required. However, before this approach is applied more widely, further calibration of BD and drying temperature should be undertaken across a wider range of soils, especially on clay-rich soils.

A multi-scale assessment of hurricane impacts on agricultural landscapes based on land use and topographic features

Agricultural systems are increasingly vulnerable to the effects of extreme climate events. Yet strategies to reduce risk and vulnerability have not been greatly explored. Here, we examine the vulnerability of coffee agroforestry systems varying in management intensity (e.g. land use) and topographic features to disturbance related to Hurricane Stan in Chiapas, Mexico—a hurricane categorized by heavy rains and mild winds. An approximately 50 km 2 area was chosen within a coffee-growing region where data were collected on a variety of topographic and landscape features (aspect, slope, elevation, distance to river) and vegetation characteristics (canopy cover, vegetation structure, tree density) as predictive factors of vegetation, economic, and landslide damage at three distinct spatial scales. At the plot level, we collected vegetation data later compiled into a vegetation complexity index. At the farm level, we collected data to understand the effect of the hurricane on economic damage and farm area affected by landslides. We also recorded number and volume of roadside landslides as a measure of post-hurricane disturbance. We then conducted a geo-spatial analysis to determine which factors contribute most to landslide occurrence at landscape scales. We found no effect of coffee management on vegetation damage or on economic losses at the plot or farm scale. At the farm scale, increasing management intensity (i.e. reduction in vegetation complexity) correlated with increased proportion of farm area affected by landslides ( P = 0.014). Additionally, reduction in vegetation complexity was correlated with increased number ( P = 0.0224) and volume ( P = 0.062) of roadside landslides at the landscape level. Topographic and landscape features, such as distance to river ( P = 0.004) and wind exposure/aspect ( P = 0.044) strongly influenced landslide frequency at the landscape scale. Forest proximity and proportion of forest cover did not significantly influence the frequency or extent of landslide damage. We created hazard maps using the vegetation complexity index, distance to river, and wind exposure as the heaviest weighted factors to assess areas of the terrain with the greatest vulnerability. These maps present a practical result of this study, and offer a template in which land management policy can develop to lower regional vulnerability to landslide risk. These results show that farmers may be able to reduce vulnerability to extreme storm events by carefully managing their farms. Although farmers may not be able to control negative topographic features of their farms, increasing vegetation complexity within farms may be an efficient strategy to reduce some susceptibility to hurricane disturbance.

Der Einfluss Der Düngung und Nutzung Auf Die Entwicklung Der Kräuter in Grünlandbeständen

(Influence of fertilisation and grassland management on the development of herbs on permanent grassland.) — This investigation was carried out (HBLFA Raumberg-Gumpenstein) with differently kind of fertilisation and cutting regimes on permanent meadows. This paper focuses on influence of grassland management on plant composition with special regard to herbs. Extensive management leads to an increase in herbs. The main reason is an open sward, leading to many gaps. Fodder quality is medium in these species-poor stands. Intensive management practices leads to an increases in the proportion of grasses and several herbs which are adapted to increased management intensity. Fodder quality increases, except of a high degree of coverage by Poa trivialis . Highest plant species richness is related to moderately management practice. Species richness will decreases both extensive and intensive management in a long-term.

Assemblages of wood-inhabiting fungi related to silvicultural management intensity in beech forests in southern Germany

Current silvicultural treatments in beech forests are aimed at achieving thick logs without discoloured hardwood. Therefore intensive thinning is applied already in younger stands with the objective of large-sized trunks at an age of 100 years. However, this approach bears the risk that dead wood structures and broken trees are completely removed from the forest. The impact of three different silvicultural management intensity levels on wood-inhabiting fungi over decades was investigated in a large beech forest (>10,000 ha) in southern Germany in 69 sampling plots: A Intensive Thinning and Logging with high-value trees, B Conservation-Oriented Logging with integration of special structures such as dead wood and broken trees and C Strict Forest Reserves with no logging for 30 years. The analysis of community showed marked differences in the fungus species composition of the three treatments, independent of stand age. The relative frequencies of species between treatments were statistically different. Indicator species for naturalness were more abundant at sites with low silvicultural management intensity. Fomes fomentarius, the most common fungus in virgin forests and strict forest reserves, is almost missing in forests with high-management intensity. The species richness seemed to be lower where intensive thinning was applied (P = 0.051). Species characteristic for coarse woody debris were associated to low management intensity, whereas species with a significant preference for stumps became more frequent with increasing management intensity. A total amount of dead wood higher than 60 m3/ha was found to enable significantly higher numbers of species indicators of naturalness (P = 0.013). In conclusion, when applying intensive silvicultural treatment, the role of dead wood needs to be actively considered in order to maintain the natural biocoenosis of beech forests.

Herbage and Animal Responses to Management Intensity of Continuously Stocked Bahiagrass Pastures

There are about 1 million ha of bahiagrass (Paspalum notatum Flügge) pasture in Florida. Rapid population growth is reducing grassland area and may force beef cattle (Bos taurus) producers to achieve economic livelihood on less land. One alternative is to increase management intensity of existing pasture. This research evaluated management intensity effects on beef heifer and bahiagrass pasture performance. Management intensities were low (40 kg N ha−1 yr−1, 1.4 animal units [AU, one AU = 500 kg live weight] ha−1 stocking rate [SR]), moderate (120 kg N ha−1 yr−1, 2.8 AU ha−1 SR), and high (360 kg N ha−1 yr−1, 4.2 AU ha−1 SR). Across 4 yr, herbage mass (3.42 vs. 2.95 Mg ha−1) and allowance (4.8 vs. 1.4 kg forage kg−1 animal weight) were greater for low than high intensity. Herbage accumulation (41 vs. 17 kg ha−1 d−1), crude protein (140 vs. 99 g kg−1), and in vitro digestible organic matter (505 vs. 459 g kg−1) were greater for high than low intensity. Heifer average daily gain was greater for low than high intensity (0.34 vs. 0.28 kg), but gain per hectare (GHA) increased from low to high intensity (101 to 252 kg). Nitrogen fertilizer cost per additional kilogram of GHA above low intensity was $.76 for moderate and $2.01 for high intensity. Increasing management intensity increased bahiagrass herbage accumulation and nutritive value, but GHA did not increase sufficiently to compensate for the additional fertilizer cost, especially for high intensity. Therefore, if land limitations for cattle production become acute, use of more management‐responsive species than bahiagrass probably will be required.

Transpiration and Canopy Stomatal Conductance of 5-Year-Old Loblolly Pine in Response to Intensive Management

Abstract The influence of weed control only (W) versus weed control plus irrigation (WI) and weed control plus irrigation and fertigation (WIF) on canopy stomatal conductance (G S) and transpiration expressed on a ground (E) and leaf area (E L) basis was examined over 1 year in 5-year-old loblolly pine (Pinus taeda L.) to determine whether increased leaf area index (L) in response to intensive silviculture resulted in regulation of G S, whole-tree hydraulic conductance per unit sapwood area (G), or the ratio of transpiring leaf area to conducting sapwood area (A L:A S) to minimize the gradient in water potential from soil to leaf (ΔΨ). Values of E were as high as 3.9 mm d−1 and increased from a total of 357 mm in the W treatment to 529 and 565 mm in the WI and WIF treatments, respectively. Values of E L did not vary with treatment and were, on average, 0.8 mm d−1 in summer and 0.4 mm d−1 in winter. Increasing management intensity increased L by as much as 76% and sapwood area up to 68%, but had no influence on ΔΨ G, G S, or leaf specific hydraulic conductance. High L values realized by intensive management resulted in regulation of A L:A S to maintain ΔΨ with increasing canopy development.

Management intensity affects density fractions of soil organic matter from grazed bahiagrass swards

Soil fertility and agricultural systems sustainability depend upon soil organic matter (SOM). The effects of pasture management intensity on SOM are not well understood. The objectives of this study were to determine the effect of management intensity of ‘Pensacola’ bahiagrass ( Paspalum notatum Flügge) pastures on the light density fraction of SOM (LD-SOM), the fraction that responds most readily to changes in pasture management practices. Pastures were grazed from 2001–2004 at four management intensities, defined as the combination of stocking method, N fertilization, and stocking rate (SR). Treatments were continuously stocked (CS) Low (40 kg N ha −1 yr −1 and SR of 1.4 animal units ha −1 (AU=500 kg live weight)); CS Moderate (120 kg N and SR of 2.8 AU); CS High (360 kg N and SR of 4.2 AU); and rotationally stocked with a 7-d grazing period and 21-d resting period (360 kg N and SR of 4.2 AU). Composite soil samples (0–8 cm) from each pasture were collected in 2004. Management intensity did not affect C and N concentration in the bulk soil, but it did impact C and N concentrations of size fractions of LD-SOM. In particles from 250 to 2000 μm, both C and N concentration were greater with increasing management intensity. In particles<53 μm, however, the lowest management intensity presented the greatest soil C and N concentrations. Increasing C and N in slow turn over SOM fractions with increased management intensity may result in greater C sequestration and potential soil fertility, but the increased likelihood of negative environmental impact and the questionable sustainability of high N fertilizer rates must also be considered.

Litter Mass, Deposition Rate, and Chemical Composition in Bahiagrass Pastures Managed at Different Intensities

ABSTRACTPlant litter is an important pathway of nutrient return to the soil in grazed swards, but the effects of pasture management on litter mass and composition are not well understood. This research evaluated the effect of management intensity, defined in terms of N fertilization and stocking rate (SR), on litter mass, deposition rate, and chemical composition in continuously stocked ‘Pensacola’ bahiagrass (Paspalum notatum Flügge) pastures growing on Pomona and Smyrna sands. Treatments were three management intensities: Low (40 kg N ha−1 yr−1 and 1.3 animal units [AU, one AU = 500 kg live weight] ha−1 SR), Moderate (120 kg N ha−1 yr−1 and 2.7 AU ha−1 SR), and High (360 kg N ha−1 yr−1 and 4.0 AU ha−1 SR). Greater management intensity resulted in less litter mass on the pasture early in the growing season and more litter mass later in the season. Rate of litter deposition was generally greatest for High and ranged between 23 and 40 kg organic matter (OM) ha−1 d−1 compared with 13 to 30 kg OM ha−1 d−1 for Low and Moderate management intensities. Increasing management intensity from Low to High resulted in greater litter N (14.1 vs. 22.9 g kg−1) and P (0.8 vs. 1.3 g kg−1) concentrations and lesser C:N (∼40 vs. 22), C:P (649 vs. 433), and lignin:N (5.8 vs. 4.4) ratios. More intensive pasture management was associated with greater litter deposition rate and litter quality than less intensive management, suggesting a larger nutrient contribution from litter in intensively managed swards.

Litter Decomposition and Mineralization in Bahiagrass Pastures Managed at Different Intensities

ABSTRACTPlant litter is an important nutrient pool in grassland ecosystems. Management practices affect litter quality and may affect nutrient dynamics in pastures by altering the rates of nutrient mineralization and immobilization. The effect of management intensity on litter decomposition and nutrient disappearance was evaluated in a litter bag study on continuously stocked ‘Pensacola’ bahiagrass (Paspalum notatum Flügge) pastures growing on Pomona and Smyrna sands. Treatments were three management intensities: Low (40 kg N ha−1yr−1 and 1.3 animal units [AU, one AU = 500 kg live weight] ha−1 stocking rate [SR]), Moderate (120 kg N ha−1 yr−1 and 2.7 AU ha−1 SR), and High (360 kg N ha−1 yr−1 and 4.0 AU ha−1 SR). Litter relative decomposition rate (k) was greater for High (0.0030 g g−1 d−1) than Low (0.0016 g g−1 d−1). Litter N, acid detergent insoluble N (ADIN), and lignin concentrations were greater for High than the other intensities at the end of the 168‐d incubation period because of faster decomposition of soluble compounds. Across management intensities, approximately one‐half of litter N remaining at the end of the incubation period was bound to acid detergent fiber (ADF). Net N mineralization through 128 d of incubation was only 200 to 300 g kg−1 of total N. Increasing management intensity resulted in faster litter turnover and greater nutrient release, but nutrient release from litter was small and significant quantities of nutrients were immobilized even under the most intensive management.

Partição da biomassa e qualidade da forragem de Bahiagrass: &lt;em&gt;Paspalun notatum&lt;/em&gt; cv. pensacola no centro-norte da Flórida

This experiment evaluated a pensacola Bahiagrass pasture (Paspalum notatum Flüggeé). It was conducted near Gainesville, Florida, USA, to measure the effect of pasture management on biomass allocation (kg ha -1) of herbage, litter, root+rhizome, as well as forage quality. Treatments were three continuously stocked (low, moderate, and high, receiving 40, 120, and 360 kg N fertilizer ha-1 yr-1and with stocking rates of 1.2, 2.4, and 3.6 AU ha-1, respectively) and one rotationally stocked (RS; 7 -d grazing and 21-d rest periods; N rate of 360 kg ha-1 yr-1, 1 AU = 500 kg) pasture. The root+rhizome biomass was 4 to 12 times greater than herbage biomass. There was no effect of treatment on root+rhizome biomass. The root+rhizome biomass decreased during the grazing season. The greater manageme nt intensity imposed on high and RS pastures resulted in greater herbage biomass. The root/herbage ratio decreased with the intensification of management. The litter biomass turned to be greater than herbage biomass in the high and RS treatment, characteri zing the different cycling pattern that goes through the animal excretions. Treatments affected neither herbage NDF nor IVDOM, but increasing management intensity tended to result in high IVDOM.

Site index functions using site descriptors for Pinus patula plantations in South Africa

The quantification of the complex interaction of water and nutrients on forest productivity has long been a challenge to forest scientists worldwide. South Africa is no exception, and an industry that is experiencing increased management intensity, requires reliable decision support systems to remain competitive. Empirical growth models as well as site quality prediction models have played a significant role in forest management to date. However, there is a definite need for models incorporating process-based information to permit better assessment of management options as well as to capture dynamics caused by climate changes. The Mpumalanga escarpment area, one of the major timber growing areas in South Africa, was used as a study area, with data on Pinus patula growth. Two site quality prediction models were developed, using multiple regression techniques. Both models use a range of site factors that express the moisture and nutrient balance of the specific site. These models were found to predict site index values with a high degree of accuracy to be used as management tools. A third model was produced by combining a site quality prediction model with a Chapman–Richards type model in order to provide a site-specific growth curve. The performance of these models was compared with a process-based model called 3-PG, using independent site and growth data from the study area. Although some encouraging results were found with the 3-PG model for the prediction of growth curves, significant deviations existed between observed and predicted values of MAI 20 values. Possible reasons for the difference in accuracy between the models are discussed. Future research is required to enable the proper parameterisation of the 3-PG model for South African conditions. The 3-PG model can potentially contribute substantially to a wide spectrum of applications to, and interpretations of, existing high resolution site classification systems in South Africa, especially in the fields of growth and yield prediction and economic analysis of forest site potential.

Effects of Management Intensity and Season on Arboreal Ant Diversity and Abundance in Coffee Agroecosystems

Agricultural intensification decreases arthropod predator diversity, abundance and population stability, and may affect interactions between top predators and their arthropod prey – ultimately affecting ecosystem services. Coffee management intensification (reduction or removal of shade trees) reduces diversity of arthropod predators (ground-foraging ants). Because ants provide ecosystem services by controlling pests, influences of intensification on arboreal, coffee-foraging ant diversity and abundance are important. We here address how coffee intensification affects: (1) coffee-foraging ant diversity and abundance and (2) seasonal fluctuations in ant abundance. In each of four coffee sites of varying management intensity in Chiapas, Mexico, we sampled vegetation and using two methods, sampled ant diversity and abundance over two years. Sites significantly differed in vegetation and management intensity. Coffee-foraging ant diversity generally decreased with increasing management intensity (16–26% fewer species observed in the most intensively-managed site). Ant abundance was higher in the wet season. Management intensity, however, did not influence ant abundance or seasonal fluctuations in abundance. Our results highlight the importance of diverse agricultural systems in maintaining arthropod predator diversity, and point to one model system in which we may effectively test how diversity per se affects ecosystem services.

Collembola abundances and assemblage structures in conventionally tilled and conservation tillage arable systems

Summary Reduced biodiversity is associated with increased management intensity and reduced environmental heterogeneity but reduced tillage has been shown to lessen the severity of the effects. In this study we compare the effects, on the abundance and assemblage structure of Collembola, of conventional tillage with a form of reduced tillage management called ECOtillage and we examine the responses of the Collembola to straw incorporation into the soil. Conservation tillage (ECOtillage) resulted in elevated abundances of most collembolan species compared with conventional tillage practices but has little effect on species richness. The addition of straw residue did not enhance the diversity of Collembola and reduced overall abundances.

Production, allocation, and stemwood growth efficiency of Pinus taeda L. stands in response to 6 years of intensive management

Loblolly pine ( Pinus taeda L.) is a highly plastic species with respect to growth responses to forest management. Loblolly pine is the most planted species across the southern United States, a region with the most expansive and intensively managed forest plantations in the world. Management intensity, using tools such as site preparation and fertilization, is increasing greatly in scope over time. To better define to the productive potential of loblolly pine under intensive management, the influence of 6 years of management with weed control (W), weed control plus irrigation (WI), weed control plus irrigation and fertigation (irrigation with a fertilizer solution) (WIF), or weed control plus irrigation, fertigation, and pest control (WIFP) since plantation establishment on stand productivity in loblolly pine was examined. The site is located near Bainbridge, GA (30°48′N latitude and 84°39′W longitude) and is of medium quality (site index=18 m, base age 25). Increasing management intensity greatly accelerated stand development and biomass accumulation. At age 6 total production (above plus belowground) was nearly doubled from 50 to 93 Mg ha −1 in WIFP stands compared to W stands, and standing stem biomass increased from 24 Mg ha −1 in W stands to 48 Mg ha −1 in response to WIFP treatment. Stem current annual increment (CAI) peaked at age 5 in the WIF and WIFP stands at 17–18 Mg ha −1 per year at a basal area between 18 and 21 m 2 ha −1. Year to year variation in CAI was better explained by previous-year leaf area index (LAI) than current-year LAI. Maximum stemwood production in loblolly pine was achieved through large increases in LAI and small decreases in allocation to woody roots (tap+coarse roots) versus woody shoots (stem+branches) associated with intensive treatments.

Observational and simulated evidence of ecological shifts within the soil nematode community of agroecosystems under conventional and organic farming

Summary Soil sustainability implies a sufficient diversity and abundance of organisms to perform soil functions and to resist environmental stress. Previous studies have shown the importance of functional biodiversity for soil organisms. Soil samples have been collected within the framework of a long‐term monitoring programme in the Netherlands. Nematological and microbiological techniques were combined to facilitate a more comprehensive understanding of possible below‐ground effects of land management. A possible bias due to stochastic circumstances was investigated. The Mantel test showed that the diversity at species level is largely related to air temperature, but at genus level the effect of temperature disappears. No direct influence of rainfall on the soil biodiversity was found in our model. To extrapolate our data to a national level, habitat–response relationships for soil organisms have been derived. Generalized linear models (GLMs) and Monte Carlo simulation allowed the estimation of the probability of occurrence at a given abundance for 95 nematode genera. Our study describes the influence of abiotic conditions and land use intensity on the composition of nematode communities in grasslands on sand. The results obtained reveal a major influence of pH and livestock density on the diversity of the nematode community at both taxonomic levels as well as at different trophic levels (feeding habits). The presence and abundance of soil nematodes decrease with cattle pressure. Functional diversity decreases with increasing management intensity. It is shown that the Shannon diversities of bacterial feeding nematodes and fungal feeding nematodes are strictly related to cattle pressure, whereas the bacterial biomass occurring under organic farming scores higher than in other farming systems.

Grazing Intensity and the Diversity of Grasshoppers, Butterflies, and Trap‐Nesting Bees and Wasps

Abstract: The maintenance of grasslands as distinct habitats depends on regular management, usually through grazing or mowing, but their species diversity is known to decline with increasing management intensity. The reduction of management intensity can be a useful tool for the long‐term conservation of the biological diversity of grasslands. We analyzed floral and faunal diversity on intensively and extensively (unintensively) grazed pastures and on 5‐ to 10‐year‐old ungrazed grasslands in northern Germany. Each of the three grassland habitats differing in grazing intensity was replicated six times. We related diverse taxa such as grasshoppers, butterfly adults and lepidopteran larvae, and trap‐nesting solitary bees and wasps to vegetation structure. There was an increase of species richness and abundance from pastures to ungrazed grasslands. The percentage of parasitism of the most abundant trap‐nesting species, the digger‐wasp ( Trypoxylon figulus), was also higher on ungrazed grasslands. Decreased grazing on pastures enhanced species richness for adult butterflies only, whereas the abundance of adult butterflies, solitary bees and wasps, and their natural enemies increased. Although the differences in insect diversity between pastures and ungrazed grassland could be attributed to a greater vegetation height and heterogeneity ( bottom‐up effects) on ungrazed areas, the differences between intensively and extensively grazed pastures could not be explained by changes in vegetation characteristics. Hence, intensive grazing appeared to affect the insect communities through the disruption of plant‐insect interactions. A mosaic of extensively grazed grassland and grassland left ungrazed for a few years may be a good means by which to maintain biodiversity and the strength of trophic interactions.

Influence of velvetleaf (Abutilon theophrasti) and common sunflower (Helianthus annuus) density variation on weed management outcomes

Interactions between initial weed seedling density and postemergence herbicide and mechanical weed control were studied in two field experiments conducted between 1994 and 1996. Increasing seedbank densities of velvetleaf (0 to 500 seed m–2) in soybean or common sunflower (250 to 2,500 seed 1.3 m–2) in corn or soybean were established at Lincoln and Mead, NE, respectively. Emerged seedlings were treated with increasing intensities of weed control from none to bentazon alone or with interrow cultivation. A positive linear relationship between initial seedling density and density of surviving seedlings was consistently observed. As initial seedling density increased, more survivors were present after treatment. As intensity of weed control increased, the number of seedling survivors decreased. Resulting reproductive fitness decreased with increasing management intensity but remained positive when regressed against surviving seedling densities. Weed management outcomes were dependent on initial seedling density, such that the absolute number of survivors increased, while proportion of survivors appeared constant within the density ranges studied. These research findings emphasize the need to account for weed infestation level when assessing efficacy of weed management systems and provide evidence that patchy weed distributions may persist in part because of the need for considerably higher management intensities in high density patch centers.

Sustainable agriculture in the Corn Belt: Production-side progress and demand-side constraints

AbstractThis paper explores the constraints to sustainable agriculture in the Com Belt stemming from the trend toward increased farm size and the continued dependence of the region on undifferentiated farm commodities produced for regional, national, and international markets. It is based on a three-county comparison of 14 full-time farmers who have embraced sustainable principles and practices, and a randomly sampled group of 25 farmers. An encouraging finding was the substantial progress made towards lower-input production of com and soybeans by the nine farmers who had adopted the ridge tillage system, which uses elevated seedbeds, banded herbicides, and post-plant nitrogen application to reduce both soil erosion and synthetic chemical inputs while maintaining yields. However, operators of large farms that depend on hired labor and highly dispersed field sites regarded these practices as too risky at their scale of production despite their short-term economic and long-term environmental benefits. The region's commercial farmers appear split between family farmers who wish to avoid the headaches of scale expansion and hired labor, and therefore, embrace more efficient low-input systems such as ridge tillage versus those who reject the increased management intensity and risks of lower-input systems in favor of scale expansion via more chemical-intensive no-till systems. Although ridge tillage represents movement toward low-input cash grain production, low-input production systems alone are not sufficient to improve the underlying social welfare of rural areas. Arresting the trend towards fewer and larger farms will also require development of more specialized or more localized markets for sustainably produced commodities.