Georgia growers can benefit from double-cropping grain sorghum following watermelon to maximize land use and add economic value to their operations. However, capitalizing on the economic advantages of harvesting two crops within a single season must account for potential herbicide injury to rotational crops. An integrated weed management strategy that includes a preplant application of fomesafen and terbacil is recommended for weed control in watermelon production systems. However, currently labeled plant-back restrictions for grain sorghum require a minimum of 10 and 24 mo for fomesafen and terbacil, respectively. Therefore this research aimed to determine the tolerance of grain sorghum to fomesafen and terbacil following soil applications applied 90 to 100 d before planting (DBP). Experiments were conducted at the University of Georgia Ponder Research Farm from 2019 to 2023. The experimental design was a randomized complete block with four replicates. Five rates of fomesafen (35, 70, 140, 210, and 280 g ai ha−1), four rates of terbacil (3.5, 7.0, 10.5, and 14.0 g ai ha−1), and a nontreated control were evaluated. In 2019, fomesafen caused significant sorghum leaf necrosis, plant density reductions, height reductions, and yield reductions of at least 16%, especially when applied at rates ≥ 210 g ai ha−1. Terbacil had little to no effect on sorghum injury, density, height, or yield in any year. These results suggest that sorghum has sufficient tolerance to terbacil when applied 90 to 100 DBP. In four of five years, sorghum had an acceptable tolerance to fomesafen when applied 90 to 100 DBP. However, yield losses observed in 2019 suggest that caution should be taken when fomesafen is applied 90 to 100 DBP grain sorghum at ≥ 210 g ai ha−1.

Acetochlor [2-chloro-N-(ethoxymethyl)-N-(2-ethyl-6-methylphenyl)acetamide], alachlor [2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide], and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] were applied in 280 L of water/ha to plots covered with 0 to 6720 kg/ha of wheat (Triticum aestivum L.) straw. At straw levels of 1120 kg/ha or greater, 50% or less of the applied herbicides were received by the soil surface before irrigation. Sprinkle irrigation (1.3 cm) washed 15 to 20% of the originally applied herbicide into the soil regardless of straw level. More metolachlor was retained on the straw than acetochlor or alachlor. Analysis of the wheat straw indicated that little water-extractable herbicide remained for all herbicides. Initial herbicidal activity on grain sorghum [Sorghum bicolor (L.) Moench.] was reduced by the presence of wheat straw at the time of application, with acetochlor being least affected and alachlor most affected. Ten days after treatment, less than 10% of the original alachlor and acetochlor remained in the soil. When planted at this time, grain sorghum response was inversely related to the amount of straw mulch that was originally present. Metolachlor residues in the soil on day 10 were 11 to 26% of that on day 0 and there was comparably less reduction in activity on grain sorghum.

Field experiments to compare the loss of oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide) from straw-mulched and nonmulched soils indicated that oryzalin disappeared more rapidly in soils covered by straw in 1980 and 1981 but not in 1982. It appeared that greater rainfall in 1982 was responsible for this difference. Straw mulch on the soil at the time of application reduced the amount of oryzalin reaching the soil surface after subsequent rains or irrigation. Straw levels of 2250 or 4500 kg/ha, when present at the time of treatment, reduced oryzalin concentration in the soil by approximately 15 or 43%, respectively, following 1.3 cm of water applied by sprinkle irrigation. Increasing the straw levels above 4500 kg/ha did not significantly affect the amount of oryzalin detected in the soil beneath the straw mulch.

Norflurazon [4-chloro-5-(methylamino)-2-(3-(trifluoromethyl)phenyl)-3(2H)-pyridazinone] persistence in five Georgia soils after application to the same plots in 1982 and 1983 was characterized by rapid initial degradation followed by slow loss of the herbicide. The rate of norflurazon loss at each location for each year was not affected by application rate (1.7 or 3.4 kg ai/ha). Relative rates of norflurazon loss were Dothan loamy sand ≥ Greenville sandy clay loam ≥ Rome gravelly clay loam = Appling coarse sanely loam > Bradson clay loam. The rate of dissipation was slower in 1983 than 1982 in the Greenville and Appling soils. Cool and/or dry environmental conditions combined with higher soil organic matter content caused slower herbicide loss. Norflurazon residue 1 yr after treatment in all soils was greater in 1983 than in 1982. Significant injury to grain sorghum [Sorghum bicolor (L.) Moench. ‘BR 64’) was observed in the spring of 1984 at all locations in all plots that were treated with norflurazon for the previous two seasons. The degree of injury corresponded to the concentration of norflurazon detected at that sampling date. Leaching did not appear to be an important method of norflurazon loss.

Weed-control evaluations in ratoon-cropped grain sorghum [Sorghum bicolor (L.) Moench.] indicated that acceptable broadleaf weed control (>80%) in the second crop could be achieved by the use of a contact herbicide plus a residual herbicide applied after first harvest. Annual grasses, especially volunteer grain sorghum, were controlled in the second crop with metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] plus propazine [2-chloro-4,6-bis(isopropylamino)-s-triazine] applied preemergence at planting and followed by metolachlor, cyanazine {2-[[4-chloro-6-(ethylamino)-s-triazin-2-yl] amino]-2-methylpropionitrile}, or pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine] applied after first harvest. Second-crop grain yields were not adversely affected by any treatments, and it appeared that satisfactory weed control in the first crop lessened the need for a residual herbicide in the second crop.

This study investigates reasons for adoption of best management practices (BMP), crawfish farmers' participation in the Environmental Quality Incentives Program (EQIP), and economic impacts of BMP adoption using data from a 2008 survey of crawfish producers. Most-cited reasons for BMP adoption are farmers' perceptions of increases in profit and long-run productivity. Land tenancy, education, double-cropping or crop rotation, and proximity to a stream influence EQIP participation. Perceptions of economic profits depend on the practices used. Participation in EQIP negatively impacts farmers' perceptions of profitability from adopting BMPs. The results underscore the importance of economic incentives in promoting BMP adoption.

The importance of timeliness is investigated in the selection of machinery complements for double-crop wheat and soybean production in the southeastern coastal plain. An intertemporal stochastic simulation model was developed to generate probability distributions that were evaluated with stochastic dominance analysis. This research investigated the importance of intertemporal production linkages and inadequate soil moisture on machinery selection. Failure to include these dimensions can result in erroneous machinery choices.