Farming Soils, Not Fields: A Strategy for Increasing Fertilizer Profitability

Abstract

Farm fields are traditionally fertilized as one homogeneous soil unit. Most fields, however, contain two or more soils with different crop yield potentials. This study was conducted to (i) measure crop yield differences between contrasting soils within fields, and (ii) compare the economics of “farming soils, not fields,” where contrasting soils in a field receive different vs. uniform rates and formulations of fertilizer. Crop yield variability studies were conducted along 1600 ft transects across several soil units in each of four fields during 1987. Grain yield, test weight, and returns over variable costs varied greatly among soil units in each field (P < 0.05). Soil fertility studies also revealed differences in grain yield, test weight, and returns among soil units in five fields during 1987 and 1988. Fertility studies indicated yields were similar for small grains when recommended fertilizer treatments were applied as soil unit treatments rather than as a field treatment. Returns were $2.06 to $5.14 greater per acre for the soil treatment than for the field treatment in three of five fields, but overall, the returns were not significantly different. A recommended fertilizer treatment was not always the optimum treatment, however. In two fields, additional returns of $21.68 to $23.51 /acre resulted when optimum soil treatments were applied rather than the field treatment. The data reveal the importance of appropriate crop yield goals, accurate soil tests, and reliable fertilizer recommendations when developing a strategy for generating greater returns by farming soil, not fields. Given these caveats, our work suggests that farming soils, not fields will increase fertilizer profitability.

Delineation of Management Zones Using Soil Properties and a Multivariate Geostatistical Approach

“…Determination of these sub-field areas is difficult due to the interactions among several biotic, abiotic and climate factors that affect crop yield. Different approaches have been developed for site-specific management zone delineation: topography and soil properties, including soil survey maps (Carr et al, 1991) and soil sampling (Mulla, 1991); landscape factors obtained from digital elevation models (DEM) (McCann et al, 1996;Lark, 1998;Nolan et al, 2000), aerial photographs of bare soil (Fleming et al, 2000), remote sensing images (Bhatti et al, 1991;Moulin et al, 1998), invasive soil sampling (Mulla, 1991) and non-invasive soil sampling using electrical conductivity Delineation of Management Zones Using Soil Properties and a Multivariate Geostatistical Approach (Johnson et al, 2003;Castrignanò et al, 2006). Therefore, combining several types of data (soil, landscape, crop, yield and multiple remote sensing images) is supposed to partly compensate the weakness of the approaches using a single source of information and, above all, to produce more stable management zones.…”

Satellite Technologies to Support the Sustainability of Agricultural Production

“…This approach is called PF or site-specific management (Brisco et al 1998;Carr et al 1991;Palmer 1996).…”

Influence of soil and N fertilizer on performance of barley and spring wheat cultivars

“…Weather, rotation efTects, and other factors, however, complicated the assessment of soil ffpe contribution on crop performance in both ofthese studies. Ciha (1984) (Carr et al 1991) (48'30'N, 109'48'w) during 1987. Average (Henrikson and selmer-olsen 1970), NH,,oActemperature at Havre ranges from -8'c during extractable K (Knudsen et al 1982), and the winter (1 Dec. to 29 Feb.), to 19'C during the NaHCO,-extractable P (Olsen and .=a<> For personal use only. For personal use only.…”