Project Number: 6206-12000-003-00
Project Type: Appropriated

Start Date: Mar 11, 2012
End Date: Oct 31, 2015

Objective:
Our goal in performing these research objectives is to develop a knowledge base and complementary technology to assist farmers and ranchers implement profitable, sustainable, environmentally friendly production systems. Achievement of the following research objectives during the next 2 years (24 months) will contribute to informed management of agricultural production systems based on ecosystem services, including C sequestration, increased fertilizer use efficiency, and improved water quality. Objective 1: Develop new strategies to improve crop fertilizer use efficiency for agronomic, economic and environmental benefits. Subobjective 1A: Make final determinations of runoff water quality impacts of fertilizer recommendations based on enhanced soil testing methods. Subobjective 1B: Conduct final evaluations of liquid fertilizer injection guided by GPS auto-steer technology in terms of yield and economics. Objective 2: Develop strategies to assess and manage the consequences for soil productivity, including carbon, of changing crop production strategies. Subobjective 2A: Conduct evaluations of short-term carbon mineralization and water extractable organic C and N as a predictor of potential nitrogen mineralization in soil under conventional (inorganic) and organic fertilization.

Approach:
To determine runoff water quality impacts of fertilizer recommendations based on enhanced soil testing methods, water quality samples from 6 field-scale cultivated watersheds at the Riesel Watersheds will be collected and analyzed. To evaluate the impacts of liquid fertilizer injection guided by GPS auto-steer technology on crop yield and economics, four replicated treatments (0, 20, 30, and 40 gal rates of 24-8-0 liquid fertilizer) will be implemented on two 25-ac fields, and crop yield, cost, and revenue data will be collected and analyzed. To evaluate short-term carbon mineralization and water extractable organic C and N as a predictor of potential nitrogen mineralization, soil samples will be collected from across the country and include samples from the NAPT soil database. Each sample will be analyzed using the ARS-developed Solvita respiration method and other currently used mineralization tests.