Forage sorghum is an alternative source for biofuel feedstock production and may also provide forage for livestock operations. Introducing biofuel feedstock as a dual-use forage to livestock operations has the potential to increase the adoption of biofuel feedstock production. However, additional technical agronomic information focusing on tillage, row arrangement, and harvest date for forage sorghum planted into pasturelands intended for dual use is needed. Three tillage treatments, disking and rototilling (RT), chisel plow (CP), and no tillage (NT), and two row arrangement treatments, single-row planting with 76.2 cm rows and twin rows of 17.8 cm on 76.2 cm centers, were tested for effects on forage sorghum yield in a 3-cut system. This study tested two sites in Booneville, AR, from 2010 to 2012. Several interactions with year were detected, likely due to large precipitation differences within and among years. The year greatly affected the yield, with greater (p < 0.05) yields in year 1 compared to years 2 and 3 in both locations. No till resulted in lower yields in some years and harvest dates, though no clear trend was detected among tillage treatments over years. Twin rows generally did not improve yield, except for the third harvest date at one location. No strong trends for tillage or row arrangement effects were observed in this study. Inconsistencies may have resulted from the strong influence of year or interactions of multiple factors, which may challenge producers interested in utilizing forage sorghum for biofuels and livestock feed.

Grazing cover crops (CC) could provide an economic incentive to increase adoption rates in the southeastern United States. However, understanding grazing effects on soil properties is lacking for most soils of the region. Effects of grazing or rolling a cereal rye (Secale cereale L.) CC prior to no-till planting cotton (Gossypium hirsutum L.) were determined in 2009 after 4 yr on Cecil soil, in the Southern Piedmont near Watkinsville, GA. The four catchments had a previous long history of no-till cropping with CC. Wet spring conditions in 2009 resulted in visible surface roughness from cattle hooves. Average soil penetration resistance (PR) for the 0- to 30-cm profile was 14% greater following rye CC grazing than rolling (1.95 vs. 1.53 MPa) and was still apparent the following February (1.86 vs. 1.58 MPa) after cotton harvest. Increases in PR at 2.5- to 7.5- and 7.5- to 15-cm soil depths were observed following CC grazing but not rolling. Depth to 2 MPa resistance, considered sufficient to impede root growth, was similar for CC grazing and rolling treatments in March prior to grazing but decreased in the grazed treatment to 10.7 cm in May and 15.6 cm in February. Seasonal runoff data for 2006-2009 indicated no differences between grazed and rolled CC management. We concluded that grazing CC for short periods under wet conditions presents a risk of short-term negative effects even for Southern Piedmont soils where a long history of conservation tillage and CC has improved soil quality.

Winter annual cover crop use is limited in conservation management systems in the United States. Grazing cover crops could encourage cover crop adoption if returns offset establishment costs without reducing crop yields. A 4‐yr field experiment was conducted near Watkinsville, GA, in which a rye ( Secale cereale L.) cover crop was grazed by cattle or roller‐crimped before planting cotton ( Gossypium hirsutum L.). Cattle consumed about 2.4 Mg ha −1 of forage annually but amounts were variable due to weather conditions. Rye residue remaining at cotton planting averaged 6.7 Mg ha −1 for non‐grazed compared with 1.7 Mg ha −1 for grazed treatments. Cotton yields tended to be better in the non‐grazed treatment but were significantly different only in 2009 when yields were reduced in the grazed treatment due to soil compaction. Four‐year average lint yield was 120 kg ha −1 greater for the non‐grazed treatment. Cotton fiber quality parameters were generally better in the non‐grazed treatment but not enough to change crop price. Differences between grazed and non‐grazed returns ranged from $–26 to $355 and averaged $81 ha −1 when based on market year prices. The difference in average return increased to $110 ha −1 when based on 2012 market year prices. Although negative effects of soil compaction were observed the final year, returns from grazing have the potential to offset establishment costs of a rye cover crop and increase profits for cotton producers in the Southern Piedmont of the United States.

Bioenergy feedstock production systems face many challenges, among which is the lack of guidelines on sustainable biomass harvest thresholds and tillage cropping systems that maintain soil quality and productivity. We used the ALMANAC crop model to evaluate four biomass removal rates, 0%, 50%, 75% and 100%, and four tillage cropping systems, continuous No Till (NT), and Conventional Till (CT), and periodically plowed or subsoiled NT lands at Shorter, AL, for a Lynchburg loamy sand soil, over 51 yr of actual weather data: 1960–2010. Farmers periodically plow or subsoil NT lands to alleviate problems of drainage, pests, and soil compaction. Given the importance of soil organic carbon (SOC) as a soil quality indicator, we premised sustainability upon the maintenance of SOC at or above the initial SOC levels. As expected, NT had the highest SOC and lowest bulk density (BD) across the four biomass removal rates and gained the highest percent SOC over the 51-yr simulation period. For this study, the 75% biomass removal rate was applied sustainably on NT energy sorghum production systems, giving an annual harvestable biomass yield of 18.0±0.9, residue biomass, 6.2±0.3, and a root biomass of 7.2±0.4Mgha−1. However, the 75% removal rate also significantly increased soil bulk density, a critical indicator of soil compaction, by 30%. Compared to conventional tillage, subsoil tillage maintained SOC and better alleviated soil compaction in NT systems, but at the reduced biomass removal threshold of 50%. Long-term biomass removal resulted in reduced total biomass yields over time due to nutrient depletion as reflected by increased N stress days on subsequent crops. We attributed the N stress to N immobilization by the decomposing residues, reduced mineralization and N losses. Additional inputs will be needed to avoid increased N uptake from the soil which could result in soil mining.

The Southern United States has sufficient rainfall and appropriate climate to supply a significant portion of the energy needs of our nation. However, harvesting large biomass crops can be difficult given the intense rainfall and high winds that can accompany hurricanes and tropical depressions. These weather events can flatten bioenergy crops leaving them difficult to harvest. This study examined the potential of using existing hay equipment to harvest artificially flattened sorghum sudangrass, a potential bioenergy crop. Results showed that rotary-type windrowers were better able to harvest downed bioenergy crops than sickle-type windrowers. Additionally, no significant differences in harvested biomass was found in the direction the windrowers were operated in relation to the downed bioenergy crops, regardless of the harvesting direction. Our major conclusion was that completely flattened biomass resulted in the highest losses with more than 20% of the bioenergy crop remaining in the field after harvest. Even though existing agricultural equipment was capable of harvesting large amounts of bioenergy crops that have been downed, improvements may be necessary to increase their capability for handling this problematic scenario.

First-order soil surveys (scales >1:12,000) are essential for detailed land use assessment. Recently developed technologies depicting landscape variability at high resolution are useful for first-order survey development. Our objective was to compare a first-order soil survey created using conventional techniques versus a multivariate first-order survey developed using terrain attributes calculated from digital elevation models and electrical conductivity (EC) mapping. Two research sites (Macon [9 ha] and Dale [8 ha]) were located in the Coastal Plain physiographic region of Alabama, and first-order soil surveys (scale >1:12,000) were generated using conventional techniques. Soils are largely Aquic, Oxyaquic, and Typic Paleudults at the Macon site and Typic Kandiudults that differ in particle size family at the Dale site. Elevation data were collected using real-time kinematic global positioning system, terrain attributes were calculated, and field-scale EC data were collected. Three principal factors described 81% and 80% of the terrain and EC variability for the Macon and Dale sites, respectively, and fuzzy k-means clustering of principal factor scores was used to create multivariate zones. Random pedon sampling was used to compare techniques, and a rigid similar-dissimilar rule (one-class) was used for accuracy assessment. Probabilities of success (p) for observing the named soil within a map unit for the multivariate zone approach averaged 50% and 76% for the Macon and Dale sites, respectively, which was slightly less than the conventional approach. Estimated errors and confidence interval calculation indicate that for these Alabama Coastal Plain landscapes the overall accuracy of the two approaches was similar.

Renewable energy sources are necessary to reduce the U.S. dependence on foreign oil. Sorghum (Sorghum bicolor L.) may be a reasonable alternative as an energy crop in the southern U.S. because it could easily fit into existing production systems, it is drought resistant, and it has large biomass production potential. An experiment was conducted to evaluate several types of sorghum as bioenergy crops in Alabama: grain sorghum – NK300 (GS), forage sorghum – SS 506 (FS), and photoperiod sensitive forage sorghum – 1990 (PS). These sorghum crops were compared to forage corn (Zea mays L.) – Pioneer 31G65 in 2008 and 2009 with and without irrigation, and under conventional (total disked area, 0.15 m deep) and conservation tillage (in-row subsoiling, 0.30 m deep) in a strip-split-plot design. The parameters evaluated were: plant population (PP), plant height (PH), sorghum/corn aboveground dry matter (ADM), biomass moisture content (ABMC), and biomass quality (holocellulose, lignin, and ash). Sorghum had greater ADM than corn; however, corn had lower ABMC than sorghum. Lodging was observed in PS and FS, probably due to high plant populations (>370,000 plants ha−1). Irrigation affected ADM positively in both years, but conservation systems improved ADM production only in 2009. Holocellulose, lignin, and ash variation differed significantly among crops but were lower than 8.3%, 2.0% and 1.9%, respectively, for both years and considered minor. Under conditions of this study, PS was considered the best variety for ADM production as it yielded 26.0 and 30.1 Mg ha−1 at 18 and 24 weeks after planting (WAP).

Long-term fresh tomato (Solanum lycopersicum L.) production data were used to estimate cultural and environmental impacts on marketable tomato yields in eastern Oklahoma. Quantifying the interactive effects of planting date and growing season duration and the effects of cumulative heat units and heat unit accumulation rate on marketable yields allowed for productivity estimates based on past temperature conditions. Simulated increases in air temperature were predicted to reduce yields and increase the amount of cropland needed to meet local consumption demands. Consequently, local tomato production in Oklahoma may be negatively impacted under elevated temperature conditions projected under global climate change.

The inclusion of cover crops in cropping systems brings both direct and indirect costs and benefits. Farmers will adopt and continue to utilize cover crops in their production systems as long as the perceived benefit of using cover crops (e.g. increased yield, higher profits, and improved soil productivity) is positive. The perceived benefits, while partially based on actual changes, may be influenced by demographic, economic and management factors. The purpose of this paper is to examine the demographic and management factors affecting the perceived benefit, in terms of improved crop yield, of using winter annual cover crops. A tobit model is estimated using survey data of Alabama farmers examining cover crop use and management. The model examines the potential effect of different agronomic, demographic and management factors on the perceived yield gain from using winter cover crops of Alabama row crop producers. Estimation results indicated that growing peanuts, growing soybeans, high debt, high gross farm sales, use of conservation tillage, increased application of N to the cash crop after a legume cover crop, and applying N to the cover crop had a positive and statistically significant impact on farmers’ perceived yield gain from using a cover crop. In contrast, number of years farming, farm size, and high cover crop costs had a negative and statistically significant impact on farmers’ perceived yield gain from using a cover crop. Understanding the perceived benefits of using winter cover crops and the factors that shape these perceptions can provide insight into the decision making process farmers make in deciding to adopt and/or retain the use of cover crops on their farm.

To evaluate row spacing and seeding rate effects on yield and plant stand characteristics of high-biomass sorghum, a photoperiod-sensitive cultivar was sown at three different row spacings (76, 38, and 19cm) and seeding rates (218,000, 306,000, and 393,000seedsha−1 for one site-year and 116,000, 204,000, and 291,000seedsha−1 for three site-years) from 2009 to 2010 in Alabama and Arkansas, USA. Measurements included above-ground dry matter production, plant height, stem density, and stem diameter. Narrower row spacing (i.e. 19cm) produced the highest biomass for all site-years. Increasing seeding rate did not affect yield for three of the site-years, and decreased yield for one. The 19cm row spacing produced the highest stem densities. Plant height increased with increasing seeding rates at one site and decreased with higher seeding rates at another site. At one location, stem diameter declined as seeding rates and stem density increased. It was concluded that narrower row spacing (19cm) provides the maximum yield benefit by significantly increasing stem density, and low seeding rates (116,000seedsha−1) are preferable because higher seeding rates do not positively affect yield and may cause morphological changes (i.e. taller plants with thinner stems) conducive to lodging.

Deep tillage operations required to alleviate soil compaction common in the Southeastern US remain energy intensive and expensive. Equipment performance and in-field efficiency are two variables that can be improved to minimize fuel consumption and ultimately reduce input costs for crop production. The objective of this study was to investigate the effects of transmission gear selection on fuel costs, draft, and other equipment performance variables using two deep tillage implements. Three different transmission gears were selected which represented slow, normal, and fast operating speeds for two typical in-row, integral subsoilers (KMC generation I rip-strip and Bigham Brothers Paratill (TM)). Tractor fuel consumption, slip, axle torque, and engine speed were measured in real-time along with transverse and vertical draft forces. Results indicated a 105% increase in fuel consumption rate, a 28% increase in implement draft, and a 255% increase in power between the slow and fast speed for the Paratill (TM). The KMC showed a 115% increase in fuel consumption rate, a 37% increase in implement draft, and a 283% increase in power between the slow and fast speeds. Good comparisons were found between measured and estimated, using published equations, for fuel consumption (-5.3% to 4.9%) and draft (-3.6% to 17.7%). For the Paratill (TM), the normal speed produced the lowest fuel cost ($ 5.10/ha) but operating at this speed reduced productivity rate from 4.55 ha/h at the fast speed down to 3.23 ha/h. Conversely, the KMC fast speed provided the lowest fuel cost ($ 5.35/ha) and highest productivity rate (4.35 ha/h) for this implement. In general, the Paratill (TM) provided the highest productivity and lowest fuel cost when operated at the typical speeds in the Southeastern US (around the normal to fast) mostly likely due to the lower required draft. In summary, the minimum fuel usage for each implement occurred at a different ground speed however, productivity was maximized at the fast speed with data reported useful to practitioners managing these style tillage implements. Published by Elsevier B.V.

Excessive nutrient and sediment losses in runoff from pastures can lead to accelerated eutrophication. Several studies have shown that grazing management practices impact soil physical properties. Many studies have shown that rotational grazing can minimize soil compaction when compared to overgrazing, resulting in increased forage yields and vegetative cover. Improved forage growth reduces rainfall impact, increases infiltration rates, and prevents soil erosion. However, very limited information exists on the effects of grazing management on soil erosion. Likewise, few studies have shown the effects of buffer strips on sediment losses from grazed pastures. The objectives of this study were to evaluate the effects of grazing management practices on: (1) forage growth, (2) soil physical properties, (3) pasture hydrology, and (4) nutrient, metal, and sediment loads in runoff from pastureland receiving broiler litter. Field studies were conducted for seven years on 15 small watersheds (0.14 ha each). The soil series at this site are Enders (clayey, mixed, thermic, Typic Fragiudult) and Leadvale (fine silty, siliceous, thermic Typic Fragiudult), with Enders occurring at the top and Leadvale at the bottom of the slope. The watersheds were hydrologically isolated from each other and surrounded by earthen berms that were constructed with off-site soil. Barbed-wire fences were constructed on top of each of the berms. The base of each watershed narrowed to a point and was equipped with a covered 30.5 cm H-series fiberglass flume equipped with a pressure transducer for measuring runoff volumes. The transducer was connected to a housed automatic water sampler. The watersheds were hayed during year 1 when background data was collected. During years 2-7, five grazing-management strategies (GMS) were evaluated; (1) hayed, (2) overgrazed, (3) rotationally grazed, (4) rotationally grazed with an application buffer, and (5) rotationally grazed with a fenced riparian buffer. There were three replications per treatment in a completely randomized design. Broiler litter was applied during years 2-7 at a rate of 5.6 Mg ha-1. Soil bulk density increased as grazing pressure increased and was lowest under hayed conditions. Runoff volumes were highly correlated to bulk density. Percent cover and forage production were inversely related to stocking density, with hayed watersheds having the highest yields. Average annual sediment losses at the edge of field were 79.4, 70.9, 71.0, 37.1, and 26.5 kg ha-1 for overgrazed, rotationally grazed, rotationally grazed with buffer, rotationally grazed with fenced riparian buffer and hayfields, respectively. These results indicate that pasture management influences a wide range of parameters, including forage yields, hydrology, nutrient runoff, and soil erosion.

The southeastern U.S. has a tremendous potential to grow a biomass crop during winter months when cash crops are not normally produced. These cover crops have proven to be extremely valuable to reduce soil erosion and improve soil quality. However, an opportunity to potentially harvest a portion of the cover crop for bioenergy purposes exists and needs to be considered to maximize the production potential of southeastern soils. An experiment was performed to determine if harvesting these cover crops could adversely affect soil properties or subsequent cash and cover crop yields. The experiment also included the effects of conducting an in-row subsoiling operation at different times of the year Results from cone index measurements indicated that soil strength was significantly increased when the cover crop was harvested and not left on the soil surface to decompose. Not surprisingly, cotton and peanut cash crop yields declined by an average of 9% when the cover crop was harvested. Succeeding cover crop yields were also reduced by 17% due to the harvesting of previous cover crops. Conducting an in-row subsoiling operation in the fall of the year prior to planting the cover crop increased cover crop biomass by more than 18% over spring in-row subsoiling but had little impact on cash crop yields. Recommendations from this study should include a caution to producers who may want to consider their cover crops as a potential bioenergy crop. Reductions in both cash and cover crop production can result if cover crops are harvested instead of left on the surface to enhance soil quality. Additionally, scheduling a necessary in-row subsoiling operation in the fall of the year instead of waiting until the spring will improve cover crop yields.

Agricultural production responds to social, political, economic, environmental, and technological drivers that influence producers' decisions and shape the individual systems through modification of management practices, crop and livestock mix, and marketing strategy. We use an interview and discussion approach with producer panels to examine production systems in the eastern United States and explore key drivers impacting their unique characteristics and development. The internal social driver that values the farming lifestyle is a principle factor that leads people to choose farming. Irrespective of location, farming is first and foremost a lifestyle choice. The choice of type of production system is partly a lifestyle preference and partly influenced by other external factors, including economic and environmental elements. A second principle driver is economic, arising from a need to make a living, and tempers the internal social driver. Economic return is partially a function of the marketability of products. Marketing channels are dependent on social drivers, including education of producers and consumers, community support and community values. Farmers in the Northeast are able to take a more active role in determining contract terms than those in the Southeast, and are also more aggressive in developing new markets. Development of local markets and community support strengthens the link between farmers and consumers, and reinforces the economic sustainability of Northeastern production systems. With decreased reliance on external risk reduction approaches, Northeastern producers bear greater risk, but also have greater flexibility in altering the crop and livestock mix and are better able to respond to consumer demand.

Cotton ( Gossypium hirsutum L.) producers are faced with numerous production choices including cotton varieties, herbicide technology, tillage systems, and row spacing. A study was conducted to compare cotton production across conventional, glyphosate-tolerant, and glufosinate-tolerant varieties in both conventional and conservation tillage systems for standard row (102 cm) and narrow row (38 cm) cotton planting patterns. The experiment was conducted during the 2004–2006 growing seasons at the Field Crops Unit, E.V. Smith Research Center, near Shorter, AL in long-term tillage plots. Data collection included plant populations within row spacings, plant biomass and height at 1st square, mid-bloom, and lint yields. Plant biomass measured at 1st square and mid-bloom was affected by growing season with 38 cm cotton plant biomass averaging 34% greater in 2004 and 2005, however, the effect of tillage system was contradictory within the growing season. Mid-bloom plant biomass also varied across growing seasons with 21% more plant biomass recorded in 38 cm rows averaged across all three growing seasons. Plant heights were shorter for 38 cm cotton compared to 102 cm cotton, regardless of growth stage or tillage system. No differences in cotton development were observed across varieties. Cotton planted in 38 cm rows yielded equivalent to 102 cm cotton during two of the three experimental years and was superior to 102 cm cotton the remaining year, which corresponded to the best growing season observed during the experimental period. These results indicate that 38 cm cotton production can produce yields that are at least equivalent to standard 102 cm cotton, despite differences in plant development. The productivity of a narrow row cotton production system may be attractive to some growers, but economic evaluations are required to determine if the system is profitable on a large scale based on equivalent or marginal lint yield increases.

Winter annual grazing combined with vegetable production can potentially improve the sustainability of farming operations, particularly in the Southeast. However, winter grazing creates excessive soil compaction, which can adversely affect yields of subsequent summer crops. We initiated a study to determine the optimal tillage system following winter grazing for production of sweet corn (Zea mays, L.), Southern field pea (Vigna unguiculata L.), and watermelon (Citrullus lanatus L.) on a Wynnville fine sandy loam, in north-central Alabama of the southeastern U.S. from 2001 to 2003. Each fall, all plots were planted to ryegrass (Lolium multiflorum L.) and stocked with 6.7 cattle ha−1. In the spring, three surface tillage treatments (chisel/disk/level, disk/level, no surface tillage) and three deep tillage treatments (no deep tillage, in-row subsoiling, paratill) were arranged in a factorial randomized complete block design with four replications. Sweet corn ear weights responded to a combination of surface and deep tillage in 2002 and 2003. In 2001, the average response to surface tillage was 105% greater than no-surface tillage, compared with only a 14% increase with deep tillage over no-deep tillage in 2001. Southern field pea grown after winter annual grazing yielded 22% greater 2 of 3 years following surface tillage with disking; inclusion of chisel plowing with the disking showed no benefit. Watermelon yields following winter annual grazing were 39% and 58% greater in 2001 and 2002 with deep tillage alone, specifically in-row subsoiling, without any surface tillage. The tillage system for vegetable growers who choose to complement their operations with winter-annual grazing varies with the vegetable grown. In general, sweet corn responded best to a combination of surface and deep tillage, Southern field pea required only disking, and watermelon responded to in-row deep tillage with no additional surface tillage.