Nutrient Management Behavior on Wisconsin Dairy Farms

Nutrient management plans for livestock operations should account for rates and timing of manure application to cropland, as well as how manure is integrated with other nutrient sources. Little is known, however, about actual nutrient management behavior of farmers, and what changes may be needed for farmers to adhere to nutrient management regulations. Detailed records were kept on fertilizer, manure, and legume N and Papplications on 33 representativeWisconsin dairy farms during the period October 2003 through September 2004. Average available N applications ranged from 118 to 200 kg ha of which 40% was derived from fertilizer, 30% from manure and 30% from previous legume. On a regional basis, the following percentages of corn (Zea mays L.) area fell within available N application categories of 0, 1 to 80, 81 to 160, 161 to 240 and.240 kg ha, respectively: in the Northeast (NE) region, ,1, 26, 33, 21, and 19% of the total corn area surveyed (504 ha); in the South–Central (SC) region, ,1, 39, 41, 14, and 5% of the corn area (576 ha); and in the Southwest (SW) region, 0, 31, 45, 14, and 10% of the corn area (180 ha). Average available P applications ranged from 16 to 18 kg ha, of which 65% came from manure and 35% from fertilizer. On a regional basis, the following percentages of surveyed cropland area fell within available P application categories of 0, 1 to 24, 25 to 48, 49 to 72 and .72 kg ha, respectively: in the NE region, 30, 50, 15, 4, and 1% of the cropland area (1340 ha); in the SC region, 23, 54, 17, 5, and 1% of the cropland area (1168 ha); and in the SW region, 41, 48, 8, 1, and 2% of the cropland area (542 ha). Of the total cropland area (ha) across all regions that received manure during winter, 7 to 25% were within regulated surface water buffer zones. In the NE, SC, and SW regions, 100, 83, and 63% of winter-spread cropland area received available P application rates ,24 kg ha, the 1-yr crop P replacement ceiling set by State regulations. Regional differences in nutrient management behavior due to topography, soils and other factors should be used to better target efforts aimed at improving fertilizer-manure-legumemanagement on Wisconsin dairy farms. APPROXIMATELY two-thirds of Wisconsin’s dairy farms are self-sufficient in grain and forage production and have more than adequate cropland area to spread manure according to newly introduced P-based nutrient management standards (Powell et al., 2002; Saam et al., 2005; DATCP, 2006). Many dairy farmers, however, use only a portion of their total cropland area for manure spreading. On average, 23, 30, and 44% of the total cropland area receives manure annually in the NE, SC and SW regions, respectively (Saam et al., 2005). Differences in manure spreading on Wisconsin dairy farms have been linked to many factors: including the amount of manure actually collected (Powell et al., 2005), the presence ofmanure storage, labor availability andmachinery capacity for manure spreading, variations in the number of days manure can be spread given regional differences in weather and soil conditions, and distances between where manure is produced and fields where manure can be applied (Nowak et al., 1997). Manure spreading is also related to land ownership; as the percentage owned cropland operated by a farmer increases, so does percentage of operated cropland that receives manure (Saam et al., 2005). Livestock operations are currently required to have nutrient management plans to qualify for most federal and state cost-sharing programs aimed at water quality improvements. Nutrient management plans need to account for all nutrient applications to cropland, including fertilizer, manure, previous legume crops grown in rotation with cereals, and other organic amendments. Whereas various tools are available to estimate dairy manure production (e.g., Nennich et al., 2005) and collection (Powell et al., 2005), little information is available on when, where and how much manure is actually applied to cropland; how farmers blend nutrients from various sources; and how well prevailing farmer nutrient management behavior conforms to nutrient management standards. The “On-Farmers’ Ground” (OFG) study was established in 2002 with 54 representative Wisconsin dairy farms to evaluate possible impacts of farm size, operational features, climate, and soils on overall nutrient use (NPM, 2006). The first analysis of the OFG study examined manure collection (Powell et al., 2005). The second analysis validated feed and manure data, and concluded that data collected by farmers and the research team provided accurate information on a whole-farm basis (Powell et al., 2006). The objective of the present analysis was to evaluate nutrient management behavior on a field-by-field basis by determining when, where and how much manure was land applied; how much N and P was applied to cropland as fertilizer and legumeN credits; and evaluate if manure-spreading practices conformed to Wisconsin 590 Nutrient Management Standards (DATCP, 2006). An additional objective was to evaluate possible relationships between farmer nutrient management behavior and operational characteristics of farms, such as farm size, livestock density, manure collection, J.M. Powell, USDA-ARS, Dairy Forage Research Center, 1925 Linden Dr. West, Madison, WI 53706; D.B. Jackson-Smith, Dep. of Sociology, Social Work and Anthropology, Utah State Univ., 216 H Old Main Bldg., Logan, UT 84322; D.F. McCrory, Dep. of Soil Science, Univ. of Wisconsin, 1525 Observatory Dr., Madison, WI 53706 (now in residing in Staffordshire, England); H. Saam, Dep. of Soil Science, Univ. of Wisconsin, 1525 Observatory Dr., Madison, WI 53706 (now with Food Alliance, Portland, OR); and M. Mariola, Rural Sociology Program, Ohio State Univ., 2120 Fyffe Rd., Columbus, OH 43210. Received 14 Apr. 2006. *Corresponding author ([email protected]). Published in Agron. J. 99:211–219 (2007). Integrated Agricultural Systems doi:10.2134/agronj2006.0116 a American Society of Agronomy 677 S. Segoe Rd., Madison, WI 53711 USA Abbreviations: CAFOs: concentrated animal feeding operations; DM, dry matter; NE, Northeast region of Wisconsin; OFG, “On-Farmers’ Ground” study; OM, organic matter; SC, South-Central region of Wisconsin; SWQMA, surface water quality management areas; SW, Southwest region of Wisconsin. R e p ro d u c e d fr o m A g ro n o m y J o u rn a l. P u b lis h e d b y A m e ri c a n S o c ie ty o f A g ro n o m y . A ll c o p y ri g h ts re s e rv e d .