TILLAGE AND CROPPING SYSTEMS Tillage and Poultry Litter Application Effects on Cotton Growth and Yield

Triticum spp.), corn (Zea mays L.), and soybean [Glycine max (L.) Merr.], which generally have had success Although use of no-tillage in cotton (Gossypium hirsutum L.) pro with no-tillage. Cotton does not produce enough residuction in the southeast USA has dramatically increased recently, dues to supply the C necessary to increase soil organic reports of reduced seedling emergence, poor plant establishment, reduced growth, delayed maturity, and low yields still constrain adopmatter and improve soil tilth in the seed zone (Reeves, tion. The objective of this study was to evaluate the effect of tillage 1997). In addition, cotton residues do not last long after systems on growth and yield of cotton grown in rotation with a winter harvest to protect the soil from erosion and reduce loss rye (Secale cereale L.) cover crop with poultry litter and ammonium of soil moisture from evaporation. Therefore, without nitrate fertilizer application in north Alabama. Results from 1996 to additional residues to supplement cotton residues, soils 2001 are reported in this paper. Treatment factors were three tillage under no-tillage cotton may develop a crust at the sursystems, two cropping systems, two N sources, and four N levels. face and a compacted layer in the top 5 to 10 cm. Winter rye cover cropping increased surface residue cover by up to The inclusion of winter cover crops in no-tillage cot35, 70, and 100% in conventional tillage, mulch tillage, and no-tillage ton production systems can provide crop residues to systems, respectively. Despite initial differences in rate of seedling make conservation tillage cotton production systems emergence, final seedling establishment averaged 10 seedlings m 1 in all treatments. At the rate of 100 kg N ha 1, the effect of poultry litcomply with the standards set by the Natural Resource ter on cotton growth and yield parameters was generally lower or Conservation Service (Bauer and Busscher, 1996; Dansimilar to that of ammonium nitrate at the rate of 100 kg N ha 1. iel et al., 1999). The benefits of additional residues from However, at 200 kg N ha 1, poultry litter improved cotton growth the cover crops include improving soil water retention, and lint yield compared with ammonium nitrate at 100 kg N ha 1 or increasing soil organic matter, and reducing soil erosion poultry litter at 100 kg N ha 1. Cotton lint yields averaged over all (Schertz and Kemper, 1994; Bradley, 1993; Nyakatawa treatments ranged from 1128 to 1405 kg ha 1 over the study period. et al., 2001). Winter cover crops may also reduce nitrate With adequate N fertility from poultry litter, no-tillage and mulchleaching to the groundwater by picking up excess nutritillage systems with winter rye cover cropping are ideal for cotton ents remaining from the summer cotton crop (Brandiproduction in the southeast USA. Dohrn et al., 1997; Logsdon et al., 2002). The attributes that make winter rye a superior cover crop over legumes include vigorous growth, winter hardiness, early spring A of no-tillage cotton production in the growth, herbicide sensitivity, and mulch persistence southern U.S. states has increased from about (Brown et al., 1985). Rye is a better cover crop than 254 000 ha in 1998 to 784 000 ha in 2002 (CTIC, 2002). wheat in the Tennessee Valley due to better allelopathic Conservation tillage cotton acreage nearly tripled in weed control and more growth with a later planting date Alabama and Georgia during this period. A survey by (Reeves, personal communication, 2004). the National Cotton Council of America reported that Crop rotations of different genus or species improve 57% of the total cotton hectarage in the southeast USA soil fertility, reduce erosion, reduce the buildup of pests, was under no-tillage, which resulted in an average savand increase net profits. Corn, which is an important ings of $50.03/ha ($20.13/acre) for fuel and labor comcrop for the southeast USA, can be grown as a summer pared with conventional tillage (Natl. Cotton Counc. of crop in rotation with cotton to break the life cycles of maAm., 2003). jor cotton insect pests and diseases. Corn also supplies adProblems that have been reported with no-tillage cotditional residues to increase soil organic matter in conserton include soil compaction, poor seedling emergence, vation tillage cotton production systems (Reeves, 1997). poor plant establishment, stunted growth, and reduced Cotton, corn, and winter rye, which are dicot, monocot, yields (Reddy et al., 1994; Schertz and Kemper, 1994; and monocot respectively, have root systems that comRaper et al., 2000; Schwab et al., 2002). There are a number of factors that make no-tillage perform differpliment each other in nutrient uptake when grown in ently on cotton compared with other crops such as wheat rotation, thereby making them more efficient in using soil nutrients. This may reduce the buildup of excess nutrients such as P, which is associated with application C.K. Reddy and E.Z. Nyakatawa, Dep. of Plant and Soil Sci., Alabama of poultry litter based on N content. A&M Univ., Normal, AL 35762; and D.W. Reeves, USDA-ARS, J. Application of poultry litter as a source of N and P Phil Campbell Sr. Nat. Resour. Conserv. Cent., Watkinsville, GA 30677. has been shown to increase yields of crops such as corn Received 7 Nov. 2003. *Corresponding author (ermson.nyakatawa@ email.aamu.edu). and pastures (Sims, 1986; Ma et al., 1999). Furthermore, our studies have shown that poultry litter improves soil Published in Agron. J. 96:1641–1650 (2004). chemical properties compared with inorganic sources of © American Society of Agronomy 677 S. Segoe Rd., Madison, WI 53711 USA N such as ammonium nitrate (Nyakatawa et al., 2001).