|Myers, David - UNIV OF MO|
Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 30, 2005
Publication Date: November 1, 2005
Repository URL: http://www.ars.usda.gov/sp2UserFiles/Place/36221500/cswq-0187-179145.pdf
Citation: Lerch, R.N., Kitchen, N.R., Kremer, R.J., Donald, W.W., Alberts, E.E., Sadler, E.J., Sudduth, K.A., Myers, D.B., Ghidey, F. 2005. Development of a conservation-oriented precision agriculture system: Water and soil quality assessment. Journal of Soil and Water Conservation. 60(6):411-421. Interpretive Summary: Precision farming has been called farming of the future because it uses innovative sensors and computers for gathering information about differences in soils and crops within fields, so that fields can be managed to account for those differences. For over a decade, ARS researchers intensively monitored soil and water quality on a conventionally managed field within the claypan soil region of Missouri. This report was the first of two, and it concerns the soil and water quality associated with this conventionally managed field. The second paper reports the use of precision agriculture technologies to map spatial variation in grain yield, soil fertility, and profitability. These two assessments were then combined to develop a precision agriculture system (PAS) that addressed both production and conservation goals. Generally, leaching of fertilizers and herbicides to ground water was minimal, but the conventional management system reduced the quality of surface runoff. Preliminary spatial assessments and mapping showed that the northern half of the field was the main source of herbicides, nutrients, and sediment transported in surface runoff from this field. Over the last 150-200 years, the patterns of soil erosion controlled the variation in soil quality, water quality, and crop productivity currently observed in this field. Therefore, variability in soil erosion across the field was useful for developing the PAS. The developed PAS plan calls for dividing the field into three management zones, each with its own crop rotation and suite of site-specific management practices designed to enhance farmer profitability yet prevent degradation of soil and water resources. This research benefits farmers by using precision agriculture technologies because they improve efficiency, and thus increase their profits. The general public benefits because practices and chemical inputs are targeted to sub-field areas where they will be utilized most efficiently, decreasing over-application and reducing the potential for pesticide, nutrient, and sediment contamination of lakes and streams.
Technical Abstract: A comprehensive approach to achieving sustained crop productivity and profitability requires implementation of conservation systems that simultaneously consider soil and water quality. The objectives of this study were to: 1) assess long-term surface and ground water quality in a conventionally managed field; 2) compare long-term changes in soil quality under conventional management; and 3) use this assessment to support development of the precision agriculture system (PAS) presented in the companion paper. The study site was a 36-ha field in the Central Claypan Area of northeastern Missouri. The field was managed in a corn-soybean rotation using mulch tillage and soil incorporated fertilizer and pre-emergence herbicide inputs for 13 years (1991-2003). In general, agrichemical leaching to ground water was minimal, but the existing management system negatively impacted the quality of surface runoff in five of the nine years reported. Preliminary spatial assessment indicated that the northern half of the field has been the main source of herbicides, nutrients, and sediment transported in surface runoff from this field. Topsoil loss and, therefore, decreased depth to the claypan from historic erosion of the field was a key soil quality indicator related to limitations in crop productivity. Spatial variability in soil loss over the last 150-200 years controls the soil quality, water quality, and crop productivity patterns currently observed within this field. Therefore, spatial variability in soil erosion, or a surrogate measure such as depth to claypan, serves as a useful basis for the development of a comprehensive PAS.