This research evaluated differences in yields and associated downside risk from using no‐till and tillage practices. Yields from 442 paired tillage experiments across the United States were evaluated with respect to six crops and environmental factors including geographic location, annual precipitation, soil texture, and time since conversion from tillage to no‐till. Results indicated that mean yields for sorghum [Sorghum bicolor (L.) Moench] and wheat (Triticum aestivum L.) with no‐till were greater than with tillage. In addition, no‐till tended to produce similar or greater mean yields than tillage for crops grown on loamy soils in the Southern Seaboard and Mississippi Portal regions. A warmer and more humid climate and warmer soils in these regions relative to the Heartland, Basin and Range, and Fruitful Rim regions appear to favor no‐till on loamy soils. With the exception of corn (Zea mays L.) and cotton (Gossypium hirsutum L.) in the Southern Seaboard region, no‐till performed poorly on sandy soils. Crops grown in the Southern Seaboard were less likely to have lower no‐till yields than tillage yields on loamy soils and thus had lower downside yield risk than other farm resource regions. Consistent with mean yield results, soybean [Glycine max (L.) Merr.] and wheat grown on sandy soils in the Southern Seaboard region using no‐till had larger downside yield risks than when produced with no‐till on loamy soils. The key findings of this study support the hypothesis that soil and climate factors impact no‐till yields relative to tillage yields and may be an important factor influencing risk and expected return and the adoption of the practice by farmers.

No abstract

Research on how land suitability affects yields and breakeven prices for switchgrass (Panicum virgatum L.) grown as a bioenergy crop is lacking for the U.S. Southeast. Data from a 3‐yr multilocation experiment at Milan, TN, were analyzed to determine the influence of soil drainage and landscape position on switchgrass yield and farm‐gate breakeven price. Plots were seeded in 2004 with ‘Alamo’ at 2.8, 5.6, 8.4, 11.2, and 14.0 kg ha−1 pure live seed (PLS). Plots were split in 2005 and N was applied at 0, 67, 134, and 201 kg N ha−1. Farm‐gate breakeven prices for 5‐ and 10‐yr production contracts were determined by calculating unit production costs from enterprise budgets that varied by input level and yield. Maximum yields occurred at 67 kg N ha−1 on well‐drained soils and at higher N levels on less‐well‐drained soils. Yield response to seeding rate (SR) was insignificant or small relative to other factors. Averaged across treatments, the well‐drained upland location suitable for row crops had the largest yield (17.7 Mg ha−1) and lowest breakeven price ($46 Mg−1) for a 10‐yr period. In contrast, the poorly drained flood plain location considered marginal yielded lowest (8.5 Mg ha−1) and had the highest breakeven price ($69 Mg−1). Breakeven prices were sensitive to yield, N price, and fuel price. Results suggest a lower breakeven price for switchgrass in the U.S. Southeast as compared with other U.S. regions, mainly due to high yields for the Alamo variety.

Prepartum intramammary antibiotic infusion of heifer mammary glands at 7 or 14 d before expected parturition is an effective procedure for eliminating many infections in heifers during late gestation and for reducing the prevalence of mastitis in heifers during early lactation and throughout lactation. Mastitis pathogens were isolated from 76% of samples obtained from untreated control quarters 7 d before expected calving, from 47% of samples obtained 3 d after calving, and from 29% of samples obtained 10 d postpartum. Mastitis pathogens were isolated from about 30% of control quarters through 240 d of lactation. A similar percentage of samples (70%) was positive for mastitis pathogens at C-7 before antibiotic treatment. However, only 8% of samples obtained at 3 d after calving and 4% of samples obtained at 10 d postpartum from quarters of antibiotic-treated heifers contained mastitis pathogens. Throughout the remainder of lactation, mastitis pathogens were isolated from an average of about 11% of quarters. The percentage of samples with mastitis pathogens was higher in untreated controls than in antibiotic-treated quarters at all sampling intervals during lactation. A similar response was observed in heifers that were treated with antibiotics at 14 d before expected parturition. Prepartum antibiotic-treated heifers produced significantly more milk than control heifers and had significantly lower somatic cell count scores than untreated control heifers. These observations are likely associated with or due to the lower prevalence of mastitis pathogen isolation in prepartum antibiotic-treated heifers throughout lactation. Prepartum antibiotic-treated heifers produced 531 kg more milk than heifers in the untreated control group. Multiplying this increase by a milk price of 0.407 dollars/kg yielded a 216.24 dollars per-heifer increase in gross revenue. The cost of treatment, including the cost of testing for antibiotic residues, was estimated at 15.60 dollars for a net revenue of 200.64 dollars per heifer. Prepartum antibiotic treatment to reduce the rate of mastitis in heifers during lactation was highly effective and economically beneficial.

Probit analysis identified factors that influence the adoption of precision farming technologies by Southeastern cotton farmers. Younger, more educated farmers who operated larger farms and were optimistic about the future of precision farming were most likely to adopt site-specific information technology. The probability of adopting variable-rate input application technology was higher for younger farmers who operated larger farms, owned more of the land they farmed, were more informed about the costs and benefits of precision farming, and were optimistic about the future of precision farming. Computer use was not important, possibly because custom hiring shifts the burden of computer use to agribusiness firms.

This research evaluated the factors that influenced cotton (Gossypium hirsutum L.) producers to adopt remote sensing for variable-rate application of inputs. A logit model estimated with data from a 2005 mail survey of cotton producers in 11 southern USA states was used to evaluate the adoption of remote sensing. The most frequently made management decisions using remote sensing were the application of plant growth regulators, the identification of drainage problems and the management of harvest aids. A producer who was younger, more highly educated and had a larger farm with irrigated cotton was more likely to adopt remote sensing. In addition, farmers who used portable computers in fields and produced their own map-based prescriptions had a greater probability of using remote sensing. The results suggest that value-added map-making services from imagery providers greatly increased the likelihood of a farmer being a user of remote sensing.

No abstract

Soybean [Glycine max (L.) Merr.] production in the upper midsouthern United States is primarily nonirrigated. Reliance on rainfall to coincide with the soybean reproductive stages oft en results in low seed yields due to drought. Maturity Group (MG) III soybean cultivars have been introduced to this region to utilize early-season rains and avoid late-season drought. Th e objective of this research was to identify the relationship between seeding rate and fi nal population on narrow (38 cm) and wide (76 cm) rows in nonirrigated MG III soybean grown in the upper midsouthern United States. Field experiments conducted during 2006 and 2007, using MG III cultivars 'Asgrow 3906' and 'Pioneer 93M90', were planted in mid-May in narrow and wide rows to determine seeding rates and fi nal plant populations that optimize yield. Rainfall in 2006 necessitated seeding rates of 358,400 to 378,600 seed ha −1 and fi nal plant populations of 288,900 to 326,500 plants ha −1 for optimum yield. Drought in 2007 resulted in soybean planted on 38-and 76-cm row spacing producing optimum yields from 192,800 and 92,100 plants ha −1 , respectively. Narrow rows generally produced yields greater than or equal to those obtained from wide rows. Th ese data suggest that MG III cultivars should be planted on narrow row spacing to a fi nal population of 300,000 plants ha −1 to provide optimum yields when planted on nonirrigated sites in the upper midsouthern United States.