Because large amounts of poultry wastes are often applied to hilly land in the southeastern United States, information is needed on the environmental hazards of this practice. A rainfall simulator was used to study the effect of application of poultry litter (manure plus wood residues) on runoff water quality and soil loss, on moderately sloping (7%) land. Increasing rates of litter were surface-applied on fallow soil and grassland and also incorporated in the fallow soil. Runoff and soil loss were drastically decreased by litter application on fallow soil, and runoff was reduced on the grassed soil. The grassed soil had little soil loss with or without litter application. The coliform bacterial content of runoff water from plots receiving the higher application rates of surface-applied litter was appreciable afterward. Incorporating litter into soil generally reduced coliforms during the later stages of runoff. Moderate applications of poultry manure to sloping land (especially grassland) should not create a major water quality problem, unless excessive rainfall occurs.

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Evaluation of several mulching methods used by different highway departments showed that 2 tons of grain straw per acre provided adequate protection to newly prepared and seeded 2½:1 backslopes when subjected to l‐year frequency storms, 1.3 inches of rain in 30 minutes. However, when subjected to a 10‐year frequency storm, 2.7 inches in 60 minutes, two treatments stood out as superior. These were “whisker dams”, called the Florida method, which permitted 41% runoff and 10 tons per acre soil loss; and surface mulch, called the Cartersville method, which permitted 40% runoff and 11 tons per acre soil loss. In all cases where asphalt spray was a part of the treatment, the effectiveness of mulch was decreased when tested by the 10‐year frequency storm. Runoff and soil loss from mulch and mulch plus asphalt were 1.1. inches and 11 tons per acre and 1.3 inches and 32 tons per acre, respectively. Mulch mixed and mulch mixed plus asphalt were the same‐l.3 inches and 27 tons per acre‐indicating that the asphalt had no beneficial effect. The California method was a checkerboard arrangement of straw pressed into the surface. This treatment was inferior to the “whisker dams” because the staggered arrangement permitted more soil transport by over‐land flow. Runoff and soil loss for these two treatments were 1.2 inches and 44 tons per acre and 1.1 inches and 10 tons per acre, respectively. Bare, unprotected backslopes eroded at the rate of 97 tons per acre and permitted 62% runoff. Six months or more after planting, satisfactory stands had been established with all mulch treatments.

The soil and nutrient losses in runoff for selected cropping systems were studied using artificial rainfall techniques on three soils in Puerto Rico in 1967. This study was undertaken to determine the erosion control effectiveness of and nutrient removal in runoff from selected cropping systems. Soils were Humatas clay, Juncos silty clay, and Pandura sandy loam. Artificial rain was applied at 6.4 cm/hr fox 60 rain (Storm 1), followed 10 min later by 12.7 cm/hr for 60 min (Storm 2). Storms and 2 were combined and designated storm 3, representing less than 2‐ to more than 500‐year frequency storms. Cropping systems tested were fallow, conventional tobacco (Nicotiana sp.), mulch‐tilled tobacco, tobacco in grass strips, pangolagrass (Digitaria decumbens), and pangolagrass with all aboveground parts removed. Slopes ranged from 26 to 46%; plots were 10.7 m long. Test areas had been in grass for several years. Final infiltration rates were 3.7, 0.9, and 6.2 cm/hr for Humatas clay, Juncos silty clay, and Pandura sandy loam, respectively. All soils were highly aggregated and remained so throughout all storms. The low infiltration rates of Juncos silty clay are misleading. Actually, most of the rainfall infiltrated this soil but returned as interflow at the lower end of the plots. All soils were quite resistant to erosion due to their high degree of aggregation and in part to the grass grown in previous years. Tillage increased storage capacity in the soil and reduced runoff. All cropping treatments were effective in reducing erosion when compared with fallow, except on Humatas clay, where the fallow treatment permitted the least erosion. Average erosion on all treatments from Humatas, Juncos, and Pandura soils were: Storm 1 — 0.87, 0.51, and 0.06; storm 2 — 5.12, 1.20, and 6.63; and storm 3 — 6.00, 1.72, and 6.69 MT/ha, respectively. Nitrogen, potassium, calcium, magnesium, sulfur, and chlorine in runoff were measured from conventionally tilled tobacco during storm 1. Treated plots received by broadcasting 1,120 kg/ha (2.27 kg/plot) of 12‐6‐16 (N, P2O5, K2O) fertilizer 1 kr before tests began. Concentrations were high at the initiation of runoff and decreased with time as the volume of runoff increased. The average concentration of N ranged from 0.01 to 2.02 ppm, which is well below accepted public health standards. Potassium ranged from 0.01 to 2.29 ppm. Concentrations were highest fox all nutrients in runoff from the fertilized Juncos silty clay plots, because almost all runoff from this soil was actually interflow—infiltrated water that moved through the tilled zone and along the tilled‐untilled interface and then surfaced at the lower end of the plot. Although measured as runoff, no surface flow occurred except at the lower 0.3 to 0.6 m of the plots.

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