The largest portion of Alabama's rapidly growing poultry industry is geographically concentrated in the Sand Mountain region of northern Alabama. The result is that large amounts of waste are applied to relatively small areas of agricultural soils. A study was conducted to determine the effects of long‐term broiler waste (litter) application on environmentally related soil conditions in the region. The region has an average annual rainfall of 1325 mm, which is evenly distributed throughout the year, a thermic temperature regime, and soils in the region are of the Ultisol order. In each of four major broiler‐producing counties, three pairs of sites consisting of long‐term (15–28 yr) littered and nonlittered fields on matching soil series and maintained under perennial tall fescue (Festuca arundinacea Schreb.) were sampled. Soil cores were taken to 3 m or lithic contact and depth‐incremented samples (0–15, 15–30, and each subsequent 30‐cm interval) were analyzed for organic C, total N, NO3‐N, pH, electrical conductivity, and acid‐extractable P, K, Ca, Mg, Cu, and Zn. Litter application increased organic C and total N to depths of 15 and 30 cm, respectively, as compared with nonlittered soils, whereas pH was 0.5 units higher to a depth of 60 cm under littered soils. Significant accumulation of NO3‐N was found in littered soils to or near bedrock. Extractable P concentrations in littered soils were more than six times greater than in nonlittered soils to a depth of 60 cm. Elevated levels of extractable K, Ca, and Mg to depths greater than 60 cm also were found as a result of long‐term litter use. Extractable Cu and Zn had accumulated in littered soils to a depth of 45 cm. These findings indicate that long‐term land application of broiler litter, at present rates, has altered soil chemical conditions and has created a potential for adverse environmental impacts in the Sand Mountain region of Alabama.

The tropical legume 'Tropic Sun' sunn hemp (Crotalaria juncea L.) may have potential as an alternative legume cover crop or as forage for cattle in southern temperate regions. This study determined dry-matter production, chemical composition, and N release from sunn hemp residue under conventional and no-tillage systems as might be used in corn (Zea mays L.) production. Sunn hemp was sown in mid-August and mowed in early December on a Norfolk sandy loam (fine-loamy, siliceous, thermic Typic Kandiudult) and a Lucedale fine sandy loam (fine-loamy, siliceous, thermic Rhodic Paleudult) in Alabama (1991 1992). Mesh bags were used to determine residue decomposition and N release. Average dry-matter production was 5.9 Mg ha" 1 9 to 12 wk after planting. At mowing, residue N content averaged 126 kg ha~'. Residue overwintered on the soil surface until early April. During the first 4 wk following mowing, N release from residue was 50%. In April, N remaining in overwintered residue was only 38% of that after mowing in December (45 kg N ha' 1 ). Nitrogen release from residue during the subsequent corn growing season was 13% in no-tillage and 43% in conventional tillage. Sunn hemp produced sufficient dry matter to cover and protect the soil from erosion and provided sufficient N to benefit a succeeding summer crop. In addition, forage quality of leaves was suitable to provide late summer and fall grazing. Sunn hemp has potential to be managed as an alternative to winter legume cover crops in warm temperate regions.

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An experiment was conducted on Norfolk sandy loam soil (Fineloamy, siliceous, thermic Typic Kandiudults) during two years to determine the feasibility of using field chlorophyll measurements for evaluation of corn (Zea mays L.) N status. Nitrogen was applied at rates of 56, 112, 168, 224, 280 and 336 kg ha -1 to establish a range of corn chlorophyll levels, tissue N concentrations, and grain yields. At the V10 and midsilk stages of growth, field chlorophyll measurements were taken with a hand-held chlorophyll meter (SPAD-502 Chlorophyll Meter, Minolta Camera Co., Ltd., Japan) 3 and tissue N was determined. A typical curvilinear grain yield response to N fertilizer was observed both years; maximum agronomic yields were obtained with 227 and 242 kg N ha 1 , respectively, in 1990 and 1991. Tissue N concentrations at V10 and midsiik were a good predictor of grain yield. Field chlorophyll measurements were highly correlated with tissue N concentrations at both growth stages during both years of the study. Field chlorophyll measurements had excellent grain yield prediction capabilities, even at V10, which shows promise for utilization of this tool for in-season N recommendations. However, further calibration of field chlorophyll measurements will be required prior to routine use for corn N recommendation purposes.

kg Ϫ1 (Nicholson et al., 1999), and 743 and 501 mg kg Ϫ1 (Jackson et al., 1999). Arsenic concentration in PL is Trace elements are added to poultry feed for disease prevention variable, for example Sims and Wolf (1994; and refer-and enhanced feed efficiency. High concentrations are found in poultry litter (PL), which raises concerns regarding trace element loading ences therein) reported a range in As concentration of soils. Trace metal cation solubility from PL may be enhanced by from 0 to 77 mg kg Ϫ1 . Other studies have also reported complexation with dissolved organic carbon (DOC). Mineralization As concentrations within this range, for example 30 to of organo-As compounds may result in more toxic species such as 37 mg kg Ϫ1 (van der Watt et al., 1994), 43 mg kg Ϫ1 As(III) and As(V). Speciation of these elements in PL leachates (Moore et al., 1998), and 35 mg kg Ϫ1 (Jackson et al., should assist in predicting their fate in soil. Elemental concentrations 1999). Furthermore, there is evidence that As in PL of 40 PL samples from the southeastern USA were determined. Watermay be readily soluble; 72% of total As was solubilized soluble extractions (WSE) were fractionated into hydrophobic, anfrom PL in a water extraction (Jackson and Miller, ionic, and cationic species with solid-phase extraction columns. Arse-1999). nic speciation of seven As species, including the main As poultry feed Increased concentrations of Cu and Zn in the surface additives, roxarsone (ROX; 3-nitro-4-hydroxyphenylarsonic acid) and p-arsanilic acid (p-ASA; 4-aminophenylarsonic acid), was performed horizons of soil receiving annual applications of PL have by ion chromatography-inductively coupled plasma-mass spectrome-been identified (Kingery et al., 1994). Copper and Zn try (IC-ICP-MS). Total As concentrations in the litter varied from concentrations in the surface of a soil profile that had 1 to 39 mg kg Ϫ1 , averaging 16 mg kg Ϫ1 . Mean total Cu, Ni, and Zn received PL applications over 25 yr were significantly concentrations were 479, 11, and 373 mg kg Ϫ1 , respectively. Copper higher than an unamended soil. Furthermore the results and Ni were relatively soluble (49 and 41% respectively) while only of this study suggest that Zn is fairly mobile in the profile 6% of Zn was soluble. Arsenic was highly soluble with an average (Han et al., 2000). Initial soluble As concentrations of of 71% WSE. Roxarsone was the major As species in 50% of PL Ͼ200 g L Ϫ1 were reported in runoff from a field soil samples. However, the presence of As(V) as the major species in amended with 9 Mg PL ha Ϫ1 and runoff concentrations 50% of the PL samples indicates that mineralization of ROX had 7 d after application were still Ͼ50 g L Ϫ1 (Moore et al.,

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