ABSTRACT
Cotton is an important crop in the USA with many opportunities for farmers to use precision agriculture (PA) methods profitably. The area farmed, crop value, cost of production and cost of fertilizer all lead one to expect that PA can be used effectively. In 2007 cotton producers, located primarily in the south and western USA (Figure CS4.1) (NASS, 2009), farmed 3.4% of the 129 million ha planted in principal crops. This made cotton the fifth largest crop by land area, following maize (27.6%), soya beans (24.7%), hay (18.7%) and wheat (17.0%) (NASS, 2011). Some counties in Texas had more than 50% of their cropland in cotton, while Alabama, Arkansas, Arizona, Georgia, Louisiana, North Carolina, Texas and Tennessee had counties with between 25% and 50% of their cropland in cotton (Figure CS4.2) (NASS, 2009). The average value of cotton production was US$1779 ha−1, higher than for maize (US$1576 ha−1), soya beans (US$1110 ha−1) and wheat (US$531 ha−1) (ERS, 2010, 2011). Higher value comes at greater cost; the average variable cost of producing cotton was US$1143 ha−1, compared with US$638 ha−1 for maize, US$265 ha−1 for wheat and US$327 ha−1 for soya beans. Of these crops, cotton had the second largest average fertilizer cost of US$182 ha−1, following maize (US$248 ha−1), but greater than for soya beans (US$44 ha−1) and wheat (US$102 ha−1) (ERS, 2011). The high value and cost of cotton production, especially fertilizer cost, provide ample incentive for cotton farmers to adopt PA for fertility management (Larson et al., 2005). Hectares of cotton harvested by county in 2007. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203128329/a011d8fc-9f32-4393-94eb-d61d75d70272/content/figcs4_1_B.jpg" xmlns:xlink="https://www.w3.org/1999/xlink"/> Ratio of land in cotton to all cropland by county in 2007. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203128329/a011d8fc-9f32-4393-94eb-d61d75d70272/content/figcs4_2_B.jpg" xmlns:xlink="https://www.w3.org/1999/xlink"/>
