Upland vegetated buffers are widely regarded as being necessary to protect wetlands, streams, and other aquatic resources. Buffer size requirements, however, have typically been established by political acceptability, not scientific merit. This often leads to insufficiently buffered aquatic resources. In order to assist public agencies in formulating appropriate buffer standards, we conducted a literature search of the scientific functions of buffers. The literature search reconfirmed the need for buffers and emplmsized the importance of considering specific buffer functions. A range of buffer widths from 3 m to 200 m was found to be effective, depending on site-specific conditions; a buffer of at least 15 m was found to be necessary to protect wetlands and streams under most conditions. Abbreviations: VFSs, vegetated filter strips; HSI, habitat suitability index; DHD, direct human disturbance.

Radical changes in crop production have occurred in the southeastern USA in recent years. Peanut (Arachis hypogaea L.) and cotton (Gossypium hirsutum L.) are now planted in direct rotation, and conservation tillage is commonly used for both crops. Comprehensive data is lacking on crop and pest management recommendations in those systems, so a long‐term study was conducted in Tifton, GA on the effects of tillage systems on crop and pest management in a peanut–cotton rotation. Systems evaluated were conventional, reduced, and minimum tillage. Plots in conventional tillage systems were harrowed, deep‐turned, and planted each year. In reduced tillage systems, plots were harrowed in the fall and planted to rye (Secale cereale L.), and crops were planted into killed rye. In minimum tillage systems, plots were neither tilled nor planted to rye and remained nontilled during the winter, and crops were planted directly into the previous crop stubble. Weed control was based on species present and tillage system. Peanut was either treated with flutolanil [3′‐isopropoxy‐2‐(trifluoromethyl) benzanilide] for soil‐borne disease control or not treated (control). Yields were sustained for 5 yr with no difference in peanut or cotton yields among tillage systems. Flutolanil controlled soil‐borne diseases and increased peanut yields, working equally well in all three tillage systems. Weed densities and species composition changed, causing more intensive and costly weed control in reduced and minimum tillage systems than in conventional tillage systems. Spotted wilt (tomato spotted wilt tospovirus) incidence was 42% lower in reduced and minimum tillage systems than in conventional tillage systems and is now part of the recommended strategy to manage the disease.

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Runoff from crop land can enhance eutrophication of fresh water and hypoxia in sea water. We simulated rain at 25 mm hr‐1 for 2 hr, 8 d prior and 1, 14, 29, 49 and 108 d after fertilization and planting of corn (Zea mays L.). Experimental sites received 50 kg N, 45 kg P, and 125 kg K ha‐1 as granulated fertilizer broadcast and incorporated to a depth of 150 mm. An additional 118 kg N ha‐1 was surface‐banded as solution fertilizer at Day 28, which was 1 d prior to the Day 29 rain. The study was conducted for 2 yr on a Tifton loamy sand (fine‐loamy, siliceous, thermic Plinthic Kandiudults) with a slope of 4.5%, on micro‐ (5.57 m2) and meso‐scale (622 m2) plots. Runoff was equal for the two scales of plots. There were greater runoff losses of soluble‐P from meso‐ (1.4 kg ha‐1) than from micro‐plots (1.0 kg ha‐1). Nitrate‐N losses averaged 2.7 kg ha‐1 and bioavailable‐P losses were 2.3 kg ha‐1. Greatest NO3‐N and soluble‐P losses occurred the day after application of the soild fertilizer, whereas bioavailable‐P loss was greatest at Day 14 and 29. No increase in NO3‐N losses was found 1 d after the application of urea ammonium nitrate solution, possibly indicating that liquid fertilizers are not as susceptible to runoff losses as solid fertilizers. Results of this study should encourage the use of small plots, thereby saving research time and expense and provide data useful for estimating losses at similar sites.

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