ARS | Publication request: WITHIN FIELD VARIATIONS IN YIELDS AND SOILS: IMPLICATIONS FOR IMPROVED MANAGEMENT

Submitted to: Annual Missouri Water Quality Conference
Publication Type: Proceedings
Publication Acceptance Date: September 15, 1995
Publication Date: N/A

Technical Abstract: Recent advances in technology and improvements in data management have made it possible to implement site specific crop management (SSCM), which aims to improve production efficiency by adjusting the application of chemicals to local conditions in the field. An important part of site specific crop management is to identify the range and magnitude of variability present, and then develop management strategies to account for field heterogeneity. Measurements have shown that significant variability exits within fields for such parameters as soil moisture, water holding capacity, soil nutrients, soil pH, claypan characteristics, crop growth, and crop yields. Intensive sampling has shown that most soil nutrients and pH exhibit strong spatial trends coupled with large differences in nutrient status across a field. The nutrient and pH test levels ranged from very low to very high levels within fields. Yield monitors have been used to map crop yields and dwithout exception there was at least a 2:1 difference in yield within each field. Soil moisture status was the dominant yield determining factor and tended to mask any soil nutrient effects, although soil nutrient status affected crop yield in certain areas of fields. The use of soil nutrient maps to determine fertilizer recommendations can potentially have an economic and environmental benefit. However, realization of the full benefits of site specific crop management requires that the critical factors which cause variations in yield can be related to measured crop growth parameters. The use of soil and yield maps to determine the "cause and effect" relationship between the soil nutrient levels and crop yield is extremely challenging.