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Haying bermudagrass [Cynodon dactylon (L.) Pers.] to maximize recovery of P applied in broiler litter may adversely affect forage quality. This 3-yr study (2005–2007) determined harvest management effects on dry matter (DM) yield, P removal, and forage nutritive value in ‘Tifton 44’ bermudagrass at Noxapater and South Farm, MS. Fertilization annually comprised 8.96 Mg ha⁻¹ broiler litter (as-is basis) that provided 243 and 122 kg ha⁻¹ of N and P, respectively, supplemented with 67–110 kg ha⁻¹ N (as ammonium nitrate). After an initial harvest in May, forage was harvested at 28-, 35-, and 49-d intervals and at 3- and 9-cm residual cutting heights. Seasonal trends in P removal closely followed those observed for DM yield and short stubble increased yields of DM and P by approximately 31%. Prolonged regrowth and 3-cm stubble height resulted in the greatest yields of DM and P. Annual P removal at Noxapater did not differ between 35- and 49-d harvest intervals (21.3 vs. 23.0 kg ha⁻¹); whereas it was greatest (P < 0.05) at South Farm for 49-d intervals (23.9 vs. 25.8 kg ha⁻¹). Prolonged regrowth resulted in crude protein (CP) and in vitro true DM digestibility (IVTDMD) below 95 and 610 g kg⁻¹, respectively, suggesting less forage could be consumed by ruminant livestock. In 2007, CP and IVTDMD levels were greatest for 9-cm stubble. Tifton 44 bermudagrass receiving litter should be harvested every 35 d and at 3-cm stubble height to provide the best compromise between DM yield, nutrient removal, and forage nutritive value.

Broiler (Gallus gallus domesticus) litter may have long-lasting plant growth benefits after application is terminated. This study determined residual effects of pelletized litter applied to cotton (Gossypium hirsutum L.) on yield and nutrient utilization of soybean [Glycine max (L.) Merr.]. Treatments were replicated three times. Treatments included pelletized broiler litter subsurface banded to cotton at the rate of 6.7 Mg ha–¹, urea-ammonium nitrate (UAN solution) injected at the rate of 134 kg N ha–¹ and unfertilized control in three previous years (2008–2010). Soybean planted in 2011, 2012, and 2013, and provided no additional litter or fertilizer. Soybean height was determined at 28, 42, 56, 71, 86, 102, and 115 d after planting. Total aboveground biomass, leaf area index (LAI) and plant nutrient concentrations were determined at growth stage R5. Soybean yield and plant nutrient concentrations were greater in pelletized litter than fertilizer N treatments. Soybean plants in plots received pelletized litter were significantly (P < 0.05) taller and had greater leaf area than the fertilizer N and control plots. Total aboveground biomass at R5 did not differ between pelletized litter and fertilizer N treatments; however grain yield was greatest for residual litter treatment. In 2011, soybean grain yield and grain N, P, and K uptake were significantly greater in plots received pelletized litter, as compared with fertilizer N and control plots. Residual effects of pelletized broiler litter in cotton increased soybean production for 1 yr and influenced soil fertility for several years beyond the year of application.

Using poultry litter responsibly in cool-season/bermudagrass [Cynodon dactylon (L.) Pers.] production systems may require supplemental N fertilization. This study determined if productivity in binary mixtures of tall fescue [Schedonorus arundinaceus (Schreb.) Dumort] and bermudagrass could be improved through applying litter and fertilizer N to coincide with seasonal growth activities. The effects of N timing on dry matter (DM) yield, forage N and P contents, and fescue percent stand were investigated in binary mixtures that comprised two tall fescue cultivars, Flecha MaxQ (summer-dormant) and Jesup MaxQ (summer-active) drill-seeded in 2007 into swards of Russell and Tifton 44 bermudagrass. Three seasonal N treatments were each comprised of 8.6 Mg litter ha–¹ (as-is moisture basis) split into two applications per season with additional 168 kg N ha–¹ split into three applications. Based on two spring harvests (April and May), forage DM yield was greater (P < 0.01) for October/January treatment that applied N before April than January/March treatment that applied N in January–July (7.0 vs. 3.0 Mg ha–¹, 2 yr averages). Tall fescue stand count in May was greatest in October/January treatment and was greater in Jesup–Tifton 44 than Flecha–Tifton 44 in 2010 (79 vs. 59%). Based on five annual harvests, October/January treatment had the greatest cumulative N uptake of 189 and 182 kg ha–¹ in 2009 and 2010, respectively, and uptake was generally least in Flecha–bermudagrass associations. Results suggest N application timing to favor tall fescue increased the utilization of applied N and P.

The effectiveness of fall- or winter-applied poultry litter, relative to spring-applied litter, as row crop fertilizer in the southern and southeastern United States has not been well researched. A 3-yr field study was conducted in northern Mississippi to determine the effectiveness of litter as corn (Zea mays L.) fertilizer and quantify loss of its potency when applied in the fall. The grain yield and biomass of corn that received fall-applied poultry litter (9 or 18 Mg ha–¹) or 202 kg ha–¹ NH₄NO₃–N was compared against that of corn that received the same fertilization treatments applied in the spring including an unfertilized control. Corn fertilized with 18 Mg ha–¹ litter applied in the spring produced 24% less grain yield in the first year but up to 21% more grain yield in the last 2 yr than corn fertilized with spring-applied NH₄NO₃. Unlike the common assumption that 50 to 65% of the total litter N is available in the same year of application, we estimated only 31% of the total N from 18 Mg ha–¹ spring-applied litter was available to corn in the first year. Applying 18 Mg ha–¹ litter in the fall, relative to spring, reduced grain yield by 12.8% and biomass by 15.0% when averaged across the 3 yr. These results show that applying poultry litter in the fall in regions with warm fall and winter months similar to that of northern Mississippi reduces its value as a fertilizer and could potentially increase environmental risk.

Soil sampling guidelines do not exist for fields fertilized with solid manures applied in bands. The objective of this work was to describe the distribution of mineral nutrients and total C and propose a method of taking soil samples that represent the fertility level of a field following manure application in narrow bands below the soil surface. Systematic soil core samples were taken from no-till cotton (L.) plots fertilized with poultry litter in subsurface bands spaced ≈1 m apart and analyzed for total C, total N, and extractable P, K, Mg, Cu, Mn, Fe, and Zn. The results showed that total C and most of the mineral nutrients were not evenly or randomly distributed in the space between and across the bands because of the manure placement in narrow bands, nutrient movement away from the band, and plant uptake. Concentrations of P, K, Mg, Zn, Cu, and B in the soil samples taken over the band were elevated by up to 50 fold compared to the positions away from the band. This distribution shows that taking random soil samples from fields fertilized with manures in bands is not appropriate and that some systematic sampling schemes must be used to more accurately represent the soil nutrient status. We describe a new sampling method that takes into account the band width and the spacing between consecutive bands. The method is based on a proportional mixing of soil cores taken at predetermined distances from the manure band including one core directly over the band.

Published in Agron. J. 104:43–48 (2012) Posted online 10 Nov 2011 doi:10.2134/agronj2011.0093 Copyright © 2012 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. P litter is generated in large quantities in the southeastern United States and has long been recognized as a desirable organic fertilizer since it improves soil fertility by adding essential plant nutrients and organic matter and improves water and nutrient retention (Vest et al., 1994; Moore et al., 1995). Recently, as agricultural input costs for row crops have reduced growers’ profi ts, interest in using poultry litter as an important alternative source of nutrients for crop production has increased. No-till crop production has become the most common form of conservation tillage for corn and its acreage has increased in the United States, with about 408,000 hectares of no-till corn in the southeastern United States in 2004 (CTIC, 2007). Adoption of no-till system and use of poultry litter as alternatives to conventional tillage and inorganic fertilizers may help corn producers to economically boost corn grain yield. However, manure application to no-till, may reduce its eff ectiveness as a nutrient source because of potential N loss via runoff (Westerman et al., 1983; Edwards and Daniel, 1993; Shreve et al., 1995) and ammonia volatilization (Nathan and Malzer, 1994). Volatilization loss of NH3 from surface-applied broiler litter has been reported to exceed 24% with the greatest loss occurring in the fi rst week of application (Sharpe et al., 2004). Th e lack of litter incorporation in no-till cotton (Gossypium hirsutum L.) fi eld leads to a reduction of lint yield by 8% compared to litter incorporation practices (Tewolde et al., 2008). Application of poultry litter under no-till soil management concentrates P at the soil surface that can later dissolve in runoff water (Kleinman and Sharpley, 2003). Th us, the surface broadcast of poultry litter greatly increases nutrient losses from fi elds receiving poultry litter (Pote et al., 2003; Zhao et al., 2001) and appears to be an ineffi cient way of delivering manure nutrients. Use of alternative management practices to eliminate or minimize litter exposure to the air, rain, and runoff should be agronomically and environmentally benefi cial. Several researchers have reported benefi cial eff ects of subsurface banding of broiler litter for crop production, but these studies were mainly focused on perennial forages (Pote et al., 2003, 2009; Sistani et al., 2009, Warren et al., 2008; Watts et al., 2011). For example, subsurface banding of broiler litter into perennial grassland substantially reduce total P and NO3–N concentrations in runoff compared to the traditional surface-broadcast practice (Sistani et al., 2009). Subsurface banding of poultry litter reduced concentrations of inorganic N by 91%, total N by 90%, dissolved reactive P by 86%, and total P by 86% in runoff water compared with surface broadcasted of poultry litter (Watts et al., 2011). Likewise, in a humid climatic condition, placing poultry litter into 8-cmdeep soil-aeration cuts in perennial grasslands reduced nutrient concentrations in runoff by 74 to 90% compared with surface broadcasted poultry litter (Pote et al. (2003) and 2009). Th e eff ect of subsurface banding of broiler litter has also been evaluated for cotton under conventional tillage system. In a conventional tillage system with cotton, preor postplanting of broiler ABSTRACT

Published in Agron. J. 103:1704–1711 (2011) Posted online 20 Sept 2011 doi:10.2134/agronj2011.0174 Copyright © 2011 by the American Society of Agronomy, 5585 Guilford Road, Madison, WI 53711. All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. P litter, which is composed of manure and one of several bedding materials, is generated as a byproduct of the chicken (Gallus gallus) or turkey (Meleagris gallopavo) production industry. Poultry litter contains many of the plant nutrients and therefore is land-applied as a fertilizer and as a way of environmentally acceptable waste management. Poultry litter has proven to be an effective fertilizer for agronomic and horticultural crops (Demir et al., 2010; Sistani et al., 2008; Tewolde et al., 2008), forage and pasture crops (McGrath et al., 2010; Sistani et al., 2004), and for forest and other trees (Blazier et al., 2008; Friend et al., 2006). In the southern and southeastern United States, much of the litter generated in the region is applied to forage and pasture fields, but an increasing amount also is applied to row crops, partly because new research in the past 10 yr has shown the benefit of using litter for cotton and other row crop production. In the upland soils of the southern and southeastern United States, research has shown that fertilizing cotton with poultry litter often results in increased lint yield relative to fertilizing with single-nutrient synthetic fertilizers (Endale et al., 2002; Reddy et al., 2007; Tewolde et al., 2008; Tewolde et al., 2009). In an Atwood silt loam soil (fine-silty, mixed, semiactive, thermic Typic Paleudalfs) in northern Mississippi, broiler litter increased cotton lint yield by 10% under conventional till and by 14% under no-till relative to the standard local fertilization with inorganic fertilizers although litter supplied the same amount of plant available N as the standard local fertilization (Tewolde et al., 2008). In the Black Belt Prairie clay soils of Mississippi, fertilizing cotton with high rates of broiler litter increased cotton lint yield by as much as 26% above that of the local recommendation with conventional fertilizers (Tewolde et al., 2009). On a Decatur silt loam soil (fine, kaolinitic, thermic Rhodic Paleudults) in Alabama, Reddy et al. (2007) found a 5-yr average lint yield increase of about 7% if cotton was fertilized with fresh poultry litter relative to that fertilized with urea. In Georgia on a Cecil sandy loam soil (fine, kaolinitic, thermic Typic Kanhapludults), Endale et al. (2002) showed that no-till cotton yield was better when fertilized with poultry litter than with conventional inorganic fertilizers although the differences were not always significant. This superiority of litter to synthetic fertilizers for cotton production may be related to the ability of litter to supply many of the essential metal and other mineral nutrients in addition to the usual N, P, and K. Whether the better yield performance of cotton fertilized with poultry litter in some soils is due to better mineral nutrition is not well investigated. Further, the mineral nutrient profile of cotton fertilized with broiler litter vs. conventional inorganic fertilizer with rates that range between deficient to sufficient to excess is not well documented. Comparisons of litter-fertilized cotton against cotton fertilized with a selected rate of synthetic fertilizers have been reported. But, while such comparisons are useful, a greater understanding of the contribution of litter-derived mineral nutrients to lint yield may be gained when comparing AbStrACt Poultry litter is a superior fertilizer for cotton (Gossypium hirsutum L.) production in some soils, but whether this superiority is related with its ability to supply multiple mineral nutrients has not been well investigated in the field. The objective of this research was to determine if the yield increasing effect of litter relative to inorganic N fertilizers may be related with better mineral nutrition and to compare the nutrient profile of litterand inorganic N-fertilized cotton. Cotton was fertilized with six broiler litter rates ranging from 2.2 to 13.4 Mg ha–1 or six NH4NO3–N rates ranging from 34 to 168 kg ha –1 plus an unfertilized control (UTC) in northern Mississippi in a silt loam upland soil. Fertilizing with litter resulted in greater concentration of extractable soil P, K, Ca, Mg, Cu, Zn, and Na than fertilizing with NH4NO3, but these increases did not always result in greater concentrations of these elements in aboveground plant parts. Only concentrations of K, B, and Na were increased by litter in plant parts. The two fertilizers had the same effect on soil Mn concentration, but NH4NO3, relative to litter, elevated Mn concentration in plant parts by as much as twofold, a result that seemed to be related to soil pH decline. The results suggest that the better yield performance of fertilizing cotton with poultry litter than with NH4NO3–N in this soil may have been due to a more ideal soil pH, favorable tissue Mn concentration, and improved K and B nutrition.

Increasing interest of using broiler litter in the fall for row crops has implications for leaching losses of nutrients, particularly N. Any cultural practice that prevents nutrient losses could be agronomically beneficial and improve soil fertility. A field study was conducted in 2007 and 2008 on Leeper silty clay loam (fine, smectitic, nonacid, thermic Vertic Epiaquepts) soil to evaluate the impacts of a winter rye (Secale cereal L.) cover crop and broiler litter timing on cotton (Gossypium hirsutum L.) yield, yield components and leaching loss of NO 3 -N. Broiler litter was applied to the soil at the rates of 0, 4.5, 9, and 13.4 Mg ha -1 in the fall and spring for both cover and no cover crop and incorporated immediately. Winter rye cover crop was planted following broiler litter application in the fall. Averaged across cropping system and broiler litter timing, cotton lint yield and yield components increased with increasing broiler litter application. Application of broiler litter at a rate >9 Mg ha -1 was not advantageous and exceeded N need for optimum lint yield as evidenced by increasing postharvest NO 3 -N in the soil profile. In the absence of cover crop and averaged across litter rates, spring-applied broiler litter had the best agronomic response and increased lint yield by 19 and 18% compared with fall-applied litter in 2007 and 2008, respectively. Seeding a winter rye cover crop to fall-applied broiler litter did not benefit cotton lint yield and yield components but substantially reduced leaching loss of NO 3 -N.

Understanding the eff ects of management practices on soil properties is necessary because soil properties are directly related to the capacity of soil to function. Soil physical, chemical and biological properties were determined aft er 3 yr in three cropping sequences [continuous cotton (Gossypium hirsutum L.) (CCC), cotton-corn (Zea mays L.)-cotton (CMC), and corncotton-cotton (MCC) each at four broiler litter fertilization rates (0, 4.5, 9, and 13.4 Mg ha –1 ) to a soil depth of 15 cm on a Catalpa silty clay loam soil in Verona, MS. Inorganic N fertilizer was applied at the rate of 123 kg ha –1 yr –1 to cotton and 180 kg ha –1 yr –1 to corn. Averaged across crop sequences, broiler litter application signifi cantly increased soil nutrient concentrations, microbial biomass C (MBC), total porosity, and aggregate stability (AS). Th e inclusion of corn into rotation with cotton increased soil MBC, AS, and reduced bulk density (D b ). Application of broiler litter at rate greater than 9 Mg ha –1 to CCC resulted in increasing NO 3 –N concentration at the lower 30-cm depth and P accumulation by fourfold at the 0- to 5-cm depth. Rotating cotton with corn in this study improved soil quality parameters and decreased NO 3 –N and P accumulation at the soil surface by approximately 24 and 20%, respectively. Hence, corn is sown in rotation with cotton in Mississippi, the Mississippian cotton industry could potentially improve soil organic carbon, nutrient cycling, and soil quality if broiler litter is used as the nutrient source.

Poultry litter may benefit continuous cotton (Gossypium hirsutum L.) production in the heavier Midsouth soils in the same way as crop rotation. The objective of this research was to determine the effectiveness of poultry litter in maintaining yield of continuous cotton compared with cotton-corn (Zea mays L.) rotation in the Black Belt Prairie clay soils of Mississippi. The research was conducted in a Catalpa silty clay loam soil in northern Mississippi. Three main plots with the sequence cotton-cotton-cotton, cotton-corn-cotton, and corn-cotton-cotton in 2003―2004―2005 were split into five subplots each ofwhich received 0, 4.5, 9.0, 13.5 Mg litter ha ―1 yr ―1 , or 123 kg N ha ―1 yr ―1 as urea-ammonium nitrate solution (32% N; UAN) (conventional inorganic fertilization, CIF). The CIF received 180 kg ha ―1 UAN-N when planted with corn. The results showed 3-yr continuous cotton produced about the same lint yield as cotton that followed corn or 1 yr cotton. Unlike soils in other locations where ≤9.0 Mg ha ―1 litter was adequate to produce yield equal to standard inorganic fertilization, cotton in this soil responded to litter up to 13.5 Mg ha ―1 , which suggests lint yield in this clayey soil may be optimized with greater litter fertilization rate than in lighter soils. Cotton fertilized with 13.5 Mg ha ―1 litter, regardless of the rotation, outyielded the CIF by up to 26%. Overall, the results show adequate fertilization with poultry litter may be more important to improving and maintaining lint yield in this soil than the perceived benefit of a short-term rotation with corn.

The effectiveness of poultry litter as cotton (Gossypium hirsutum L.) fertilizer is not well documented for upland soils in the southern and southeastern United States. The objective of this research was to measure cotton yield response to broiler litter fertilization in contrast to inorganic N fertilization and to quantify yield reduction due to lack of incorporation under no-till and conventional-till systems in an upland soil. Six treatments were tested in two unreplicated adjacent fields, one under no-till (NT) and the other under conventional-till (CT) management, from 2003 to 2006 near Pontotoc, MS. The treatments consisted of an unfertilized control (UTC), a standard fertilization (STD) with urea-ammonium nitrate solution (UAN), fertilization with ∼5.2 Mg ha -1 incorporated or unincorporated broiler litter to supply 67% of the N need plus 34 kg ha -1 UAN-N to supply 33% of the N need, and fertilization with ∼7.8 Mg ha -1 incorporated or unincorporated broiler litter. Lint yield results showed broiler litter was a more effective cotton fertilizer than inorganic fertilizers under both NT and CT systems. The UTC produced an average across years of 870 kg ha -1 lint under NT and 1105 kg ha -1 under CT. The STD treatment increased yield over the UTC by only 121 kg ha -1 (14%) under the NT and did not affect yield under the CT. Fertilization with litter-only when incorporated, relative to the UTC, increased lint yield by 260 kg ha -1 (30%) under NT and by 137 kg ha -1 (12%) under CT. The yield of this incorporated litter-only treatment exceeded the yield of the STD treatment by 139 kg ha -1 (14%) under NT and by 115 kg ha -1 (10%) under CT. Fertilization with litter also resulted in greater leaf area index but less chlorophyll index than the STD treatment. Lack of litter incorporation reduced yield by up to 84 kg ha -1 under NT but did not affect yield under CT. Overall, broiler litter appears to be a more effective cotton fertilizer than conventional inorganic N fertilizers for this upland soil, but the inherent inability to incorporate under no-till may reduce this benefit.

Applying broiler litter to the soil surface of a no-till field of cotton (Gossypium hirsutum L.) increases the potential loss of its nutrients via runoffand volatilization. An experiment was conducted over 3 yr on an upland Atwood silt loam soil (fine-silty, mixed, semiactive, thermic Typic Paleudalfs) near Pontotoc, MS, to determine the effect of broiler litter incorporation into the surface soil of no-till cotton on nutrient availability, movement, and accumulation. The experimental design was a randomized complete block with six treatments replicated four times. Treatments were an unfertilized control, inorganic N-P-K fertilizer at the recommended rate, broiler litter at the rate of 5.2 Mg ha -1 plus 34 kg ha -1 supplemental N, and broiler litter at 7.8 Mg ha -1 without supplemental N. A surface incorporated treatment was also included for each litter rate to test for the effects of incorporation. Broiler litter significantly increased soil nutrient concentrations compared to the control. Incorporating litter into the surface soil retained more nutrients in the soil and enhanced C sequestration over nonincorporation, indicating losses of nutrients without incorporation. Application of litter at the higher rate exceeded cotton nutrient utilization as evidenced by increasing soil NO 3 -N and accumulation of P, K, Cu, and Zn in the top 5 cm of the soil. Incorporating litter increased soil nutrient content higher than nonincorporation. Incorporation of litter into the surface soil of a no-till cotton significantly reduces nutrient losses from the field.

Knowledge of the magnitude of P extracted and removed by harvested crop is an important component of effectively managing poultry litter to minimize or prevent the buildup of P in soil. This knowledge does not exist or is not well documented in cotton fertilized with litter as the primary fertilizer. The objective of this research was to quantify the magnitude of P extracted by cotton when fertilized with broiler litter and to determine whether supplementing litter with inorganic N improves P extraction. The research was conducted from 2002 to 2004 on two commercial farms representing a conventional-till at Cruger and a no-till at Coffeeville, MS, USA. At each location, the treatments consisted of an unfertilized control; a farm standard (STD) fertilized with inorganic fertilizers; and broiler litter of 2.2, 4.5, and 6.7 Mg ha -1 in an incomplete factorial combination with 0, 34, or 67 kg ha -1 N as urea ammonium nitrate (UAN) solution. The unfertilized control extracted an average across years of 27.7 kg P ha -1 at Cruger and 26.0 kg P ha -1 1 at Coffeeville. Application of both litter and UAN-N decreased tissue P concentration but increased extracted amount of P because of increases in dry weight. The largest end-of-season P extraction in this research, which included 53.9 kg P ha -1 in 2004 at Cruger and 49.3 kg P ha -1 in 2002 at Coffeeville, was recorded for the treatment that received the largest litter rate of 6.7 Mg ha -1 supplemented with 34 or 67 kg ha -1 UAN-N. Applied P always exceeded extracted P in all 3 yr at both locations when the litter rate was 4.5 or 6.7 Mg ha -1 . Extracted P equaled or exceeded applied P when 2.2 Mg ha -1 lifter was applied. Increasing litter rate decreased phosphorus extraction efficiency (PEE) while supplemental UAN-N increased PEE. An average of 53% of the total P extracted was partitioned to seed with an additional 2.4% partitioned to lint for a total of 55% that would be removed with harvested crop. Nitrogen fertilization appeared to shift P partitioning from vegetative to reproductive parts. Supplementing litter with inorganic N may be an effective strategy not only in extracting additional P from soils but also in increasing the fraction partitioned to seed so that more P is removed from the field.

Poultry litter is generated in large quantities in the same south-eastern U.S. states where cotton (Gossypium hirsutum L.) is a dominant field crop, but is rarely used as a primary cotton fertilizer partly because of lack of adequate management recommendations. This research was conducted to determine adequate rates of broiler litter and whether supplementation with inorganic N would be necessary for optimum cotton lint yield and fiber quality. The research was conducted from 2002 to 2004 on two commercial farms representing conventional-till (CT) and no-till (NT) systems. The treatments consisted of an unfertilized control, a farm standard (STD) fertilized with inorganic fertilizers, and broiler litter of 2.2, 4.5, and 6.7 M g ha -1 in an incomplete factorial combination with 0, 34, or 67 kg ha -1 N as urea-ammonium nitrate solution (UAN). Litter without supplemental UAN-N increased yield by 23 to 110 kg lint ha -1 for every 1.0 Mg ha -1 litter under both CT and NT. The often-recommended litter rate of 4.5 Mg ha -1 was not adequate to increase yield to be equivalent to that of the STD that received 101 to 135 kg ha -1 as UAN. It was necessary to supplement this or the other litter rates with 34 or 67 kg ha -1 UAN-N to support yield equal to or greater than the yield of the STD. The most consistently well-performing treatment under both tillage systems in all years was the 4.5 Mg ha -1 litter supplemented with 67 kg ha -1 UAN-N. Lint yield was highly correlated (r 2 = 0.83-0.97) with applied total plant-available N (N TPA ) under both systems. Fiber quality, fiber length and micronaire in particular, also responded to N TPA , but the responses were smaller than lint yield. Litter when adequately supplemented with UAN-N did not adversely affect fiber quality. These results show broiler litter as much as 4.5 Mg ha -1 should be supplemented with inorganic N fertilizers when used as a primary cotton fertilizer and when the expected yield is ≈1700 kg ha -1 under CT and ≈1500 kg ha -1 under NT.

A greenhouse study was conducted to determine the effects of soil type on the response of 'Russell' bermudagrass [Cynodon dactylon (L.) Pers.] to broiler litter applications. Soils included Leeper day loam (fine, smectitic, nonacid, thermic Vertic Epiaquept), Marietta silt loam (fine-silty, mixed, active, thermic Oxyaquic Fraglossudalf), and Ruston sandy loam (fine-loamy, siliceous, semiactive, thermic Typic Paleudult). The experimental design was a randomized complete block with a split plot arrangement of treatments replicated three times. Soil was used as main plot factor and broiler litter rates of 0, 4.6, 9.2, and 13.8 Mg ha -1 equivalent to approximately 0, 175, 350, and 525 kg total N ha -1 yr -1 were considered as subplot. The changes in dry matter yield (DMY) decreased in the order of Ruston > Leeper > Marietta. Regardless of soil type, broiler litter rates > 350 kg total N ha -1 did not increase DMY yield and nutrient uptake. Bermudagrass N concentration increased as broiler litter rate increased and the greatest value was recorded for Marietta soil, 24.2 g kg -1 . The large DMY observed in Ruston soil diluted plant N concentration to about 23.7 g kg -1 despite high percentage N recovery. Bermudagrass P concentration was not affected by either broiler litter rate or soil type. Bermudagrass K concentration increased as broiler litter rate increased and was greatest on Ruston soil (23.5 g kg -1 ). Recovery efficiency for N and K was approximately 60% greater in Ruston than in Marietta and Leeper soils and was reflected in residual soil NO 3 -N and P concentrations that decreased in the order of Marietta > Leeper > Ruston. Application of broiler litter to bermudagrass grown on the Ruston soil appears to be more sustainable.

AccuPAR, which is a relatively new instrument for estimating leaf area index (LAI) by measuring light interception, has wide distribution but only limited independent evaluation of its accuracy. The objective of this study was to evaluate the accuracy of AccuPAR for estimating LAI of cotton (Gossypium hirsutum L.) planted on different row spacings. Cotton LAI was measured nondestructively with AccuPAR and destructively by taking plant samples three to four times during each growing season in 2002 and 2003 on research conducted at three locations in Mississippi, USA. The results suggested that meter accuracy was affected by differences between row spacing and the length of the light-sensing segment of the meter. Supplemental tests showed that meter accuracy improved with meter placement, which eliminated length differences and with near solar noon measurements, which minimized row-to-row shading overlap. We conclude that the meter can more accurately estimate row crop LAI when the under-canopy placement of the meter and the time of measurement are selected so that the light-sensing segment of the meter captures shading of an entire row cross-section and that row-to-row shading overlap is eliminated or minimized.

Two field experiments were conducted to evaluate the effects of comparable rates of swine lagoon effluent and commercial fertilizer at different harvest dates on dry matter yield and nutritive value of bermudagrass (Cynodon dactylon L.) grown on an add Vaiden silty clay (very fine, montmorillonitic, thermic, Vertic Hapludalf) and johnsongrass (Sorghum halepense L.) grown on an alkaline Okolona silty clay (fine, montmorillonitic, therimic, Typic Chromudert). At each site, a randomized complete block design with a factorial arrangement of treatments replicated four times was used. Treatments were multiple effluent irrigations resulting in four N rates from 0 to 665 kg N ha - 1 yr - 1 . In each block, commercial fertilizer (N, P, and K) treatments were applied to additional plots at rates equivalent to swine effluent rates. Total dry matter yield and crude protein (CP) for bermudagrass and johnsongrass reached a plateau with application of approximately 450 kg N ha - 1 from either swine effluent or commercial fertilizer. Neutral detergent fiber (NDF) and add detergent fiber (ADF) peaked at the low fertilization rate and then declined with increasing effluent and commercial fertilizer rates. An inverse relationship was obtained for in vitro true digestibility (IVTD) in response to fertilization rate for both grasses. Forage dry matter, CP, NDF, and ADF levels peaked in the July harvest and then declined, but forage IVTD level declined in July harvest. Only in July 1996, forage NO 3 -N concentration was lower for swine effluent than commercial fertilizer. Swine effluent and commercial fertilizer had similar effects on forage dry matter yield and nutritive value.

Although most of the N required by soybean [Glycine max (L.) Merr.] is provided through the process of symbiotic N 2 fixation, supplemental N using broiler litter may boost soybean grain yields. The effects of broiler litter and commercial fertilizer applications on soybean yield, N and P uptake, and residual soil N and P were evaluated on a Leeper silty clay loam (fine, smectitic, nonacid, thermic Vertic Epiaquepts) at the Mississippi Agriculture and Forestry Experiment Station in Starkville, MS. Treatments were broiler litter application at the rates of 0, 40, 80, 160 kg plant available N (PAN) ha -1 and commercial fertilizer at equivalent to broiler litter PAN and P rates. Soybean grain yield and N and P uptake were quadratically increased with increasing broiler litter and commercial fertilizer application rates. Soybean grain yield and N uptake from broiler litter applications were significantly greater than those from commercial fertilizer. Soybean grain yield was not correlated to soybean P uptake but linearly increased with increasing N uptake. Application of broiler litter at rates > 80 kg PAN ha -1 were not effectively used by soybean as evidenced by declining apparent recovery values, increasing residual soil NO 3 -N concentrations, and increasing P accumulation at the top 15 cm of the soil profile. For every unit of N uptake, broiler litter treatment produced 3.4% more grain yield than commercial fertilizer. The results of this study indicate that application of broiler litter to soybean may be beneficial.

Understanding manure nutrient dynamics in soil with any crop is an important management practice for farmers and producers to document accountability and to use manure resources optimally. A field experiment was conducted to quantify input, output, and the year-round major plant nutrient dynamics in a fine sandy loam soil supplied with 15.75 Mg ha -1 yr -1 broiler litter. Soil samples were collected from pre-established plots of common bermudagrass [Cynodon dactylon (L.) Pers.] and hybrid bermudagrass Cultivars Coastal and Tifton 85 for nutrient analysis. Coastal and Tifton 85 produced significantly greater annual dry matter yield (16 948 and 18 772 kg ha -1 ) than common bermudagrass (11 238 kg ha -1 ). Tifton 85 was most efficient and removed 344, 58, and 472 kg ha -1 N, P, and K, respectively. The removal efficiency of these nutrients for Tifton 85 was 73, 18, and 114%, respectively. Soil pH varied from 6.0 to 6.6 until it decreased unexpectedly to 5.6 by the end of 2001. Total soil C increased from 11.4 g kg -1 to 17.9 g kg -1 by the end of the second year. At all sampling dates, the NO 3 -N concentration was greater than NH 4 -N while total N decreased during the maximum uptake in late spring and summer. Both total P and Mehlich-3 extractable P concentrations increased mainly in the 5- to 10-cm depth, indicating slight leaching of P. Results indicated that top yield from hybrid bermudagrass cultivars is possible with broiler litter as a sole fertilizer source. However, considerable nutrient imbalances in soil may occur in the long term if improper litter rates are used.

Bermudagrass [Cynodon dactylon (L.) Pers.] has great potential to recover nutrients due to its pronounced yield response to N. Our objective was to determine differences in forage dry matter (DM) yield, nutrient concentration, and nutrient uptake among diverse bermudagrass cultivars fertilized with swine effluent. 'Alicia', 'Brazos', 'Coastal', 'Russell', 'Tifton 44', and 'Tifton 85' hybrid bermudagrass and common bermudagrass were grown on a Brooksville silty clay loam (fine, smectitic, thermic Aquic Hapludert) and fertilized with effluent to provide 370 and 61 kg ha -1 yr -1 N and P, respectively (mean of 3 yr), and on an Atwood silt loam (fine-silty, mixed, thermic Typic Paleudalf) and fertilized to provide 200 and 38 kg ha -1 yr -1 N and P, respectively. Annual DM yields of Brazos, Coastal, Russell, and Tifton 85 were similar on Brooksville (23.3-24.2 Mg ha -1 ) and Atwood (12.3-14.1 Mg ha -1 ) soils. Annual N and P uptake ranged from 422 to 467 kg N ha -1 and 50 to 58 kg P ha -1 on the Brooksville soil and from 181 to 230 kg N ha -1 and 32 to 40 kg P ha -1 on the Atwood soil. Common bermudagrass uptake of N and P was similar to or greater than all hybrids except Russell on Atwood soil due to greater herbage N and P concentration. Hybrids generally recovered more K, Cu, and Zn than common bermudagrass. Relatively small differences in nutrient uptake among the bermudagrass cultivars suggest that forage quality, winter hardiness, and establishment cost be given equal consideration when choosing a cultivar.

Efficient crop utilization of N and P derived from anaerobic swine (Sus scrofa domesticus) lagoon effluent is critical to minimizing offsite nutrient movement. The objective of this study was to determine the effects of variable rates of swine lagoon effluent and fertilizer N and P on yield and nutrient utilization of forage grasses on an acid Vaiden silty clay (very fine, montmorillonitic, thermic, Vertic Hapludalf) and an alkaline Okolona silty clay (fine, montmorillonitic, thermic, Typic Chromudert). Treatments were multiple effluent irrigations resulting in four N and P rates from 0 to 665 and 0 to 94 kg ha -1 yr -1 N and P, respectively. Fertilizer treatments were also established at equivalent N and P rates. Similar growth responses were obtained for bermudagrass [Cynodon dactylon (L.) Pers.] or johnsongrass [Sorghum halepense (L.) Pers.] regardless of nutrient source. Application of either effluent or fertilizer at rates >448 kg N ha -1 did not effectively increase dry matter yield. Total N accumulation reflected both increasing dry matter yield and tissue N concentration while P accumulation depended primarily on increasing yield. Forage grass accumulation of N and P was similar between sources, but recovery efficiency for both elements declined with increasing rates. Similarity in N and P availability of effluent to fertilizer simplifies nutrient management although potential N loss by NH 3 volatilization is likely greater for effluent while fertilizer may result in greater end-of-season soil NO - 3 -N levels at equivalent rates of applied N.