Project description

Fertilizer is traditionally applied at uniform rates across fields because of time and cost considerations. However, because of the spatial variability of most landscapes, not all areas in the fields require the same levels of fertilizer and over-application of nitrogen (N) on corn has resulted in elevated levels of N in ground and surface waters. Our overall goal is to increase the efficiency of site-specific management of primary plant nutrients and other soil properties and thereby increase the profitability of farming and decrease negative environmental impact. This project consists of two strategies: (a) improved acquisition and usage of thematic soil maps and (b) in-season nitrogen management of corn based on crop sensing. Soil-based approaches will focus on developing on-the-go sensors and advanced geostatistical techniques for soil mapping at high spatial resolution. Crop-based N management will focus on developing canopy reflectance thresholds for triggering in-season N applications and field testing of sensor/applicator systems in combination with imagery from satellites and aircraft.

Objectives

(1) develop technology for improved mapping of physical and chemical soil properties and to quantify the costs and errors associated with different strategies, (2) develop objective procedures for defining finite management elements (zones), (3) develop algorithms for triggering N applications based on in-season canopy reflectance data, (4) demonstrate the ability of high-clearance applicator systems to reduce total N applications, (5) assess the performance of site-specific management strategies, and (6) disseminate the developed tools and educate public and private sector professionals and producers in the science and engineering of site-specific nutrient management. Interdisciplinary on-farm research will be conducted at several sites in Nebraska in close collaboration with producers, crop consultants, and data providing or engineering companies to ensure practicality of the developed tools and methods. The project will document acceptance of the technology, impacts on farm practice, and improvements in fertilizer use efficiency.

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