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ARS Home » Midwest Area » Morris, Minnesota » Soil Management Research » Research » Research Project #431884

Research Project: Stewardship of Upper Midwest Soil and Air Resources through Regionally Adapted Management Practices

Location: Soil Management Research

Project Number: 5060-11610-003-00-D
Project Type: In-House Appropriated

Start Date: Nov 3, 2016
End Date: Nov 2, 2021

Objective:
Objective 1: Evaluate conservation practices adapted for use in short-growing seasons to enhance soil quality, improve nutrient use efficiency and sustain agronomic productivity. Objective 2: Integrate soil and crop management practices that enable sustainable, climate-resilient agriculture for the Upper Midwest.

Approach:
Two objectives are being addressed using a temporally-stratified and multi-faceted approach to select, evaluate and initiate integrated conservation practices for regional suitability. Data from seven long-term studies are providing the foundation for evaluating individual and integrated practices using statistical modeling and management assessment indices. These studies were designed with several types of conservation practices including tillage, conversion of perennials, including perennial in extended rotations, addition of cover crops and impacts of variable stover harvest rates. Each experiment study was set out as a randomized complete block or as a split plot – with randomized complete block within the spilt. All have four replications of each treatment. These long-term studies have SOC and corn grain yield data in common; so those variables will be used if conversion to 1) conservation tillage; 2) perennial grasses; or 3) including a winter rye cover crop increase SOC and if returning all crop biomass increases SOC compared harvesting stover. Soil quality assessment indices approach: Assessment one tests the hypothesis that soil quality assessment scores will be greater (indicting improved soil quality) following multiple years of deploying a conservation practice compared to business as usual. Assessment scores at two (or more) time points from existing datasets from the long term studies will be used to determine if soil quality appears to be aggrading, degrading or remaining the same over time. A second assessment will be made using data collected form a common future data set from studies that will have been in place at least 10 years compare treatments lacking conservation to treatments with one or more conservation practices deployed. Comparisons of management strategies will be made using a mixed model ANOVA procedure to assess soil scores among treatments. The ability of annual rye grass or forage radish to improve nutrient use efficiency in corn is being addressed. The null-hypotheses for this experiment are that yield, and N use of corn grown following cover crops (annual rye grass or forage radish) will not differ from corn grown without a preceding cover crop, and that the nitrogen fertilizer requirements will be similar for corn following wheat with or without a cover crop. Treatments were arranged in a replicated, randomized complete block design, which was blocked by field location and replicated four times. Cover crop shoot and root biomass, crop yield and N uptake, and soil N levels will be measured. Statistical analyses will analyze linear and quadratic effects of N treatments. Using a mixed-model ANOVA, cover crop will be treated as a fixed effect, N-rates as a continuous variable, and replication (within a site year) and site-year as random effects.