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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Soil, Water & Air Resources Research » Research » Research Project #434863

Research Project: Soil Health: Biotic Fertilizers Facilitate the Soil Biological Processes to Enhance Agricultural Efficiency

Location: Soil, Water & Air Resources Research

Project Number: 5030-11610-005-75-T
Project Type: Trust Fund Cooperative Agreement

Start Date: Jul 1, 2018
End Date: Jun 30, 2020

Objective:
1) Evaluate the role of biotic soil amendments on soil biological activity and nutrient cycling under laboratory conditions; 2) Evaluate the role of biotic soil amendments on soil health and soil functions and crop productivity under field environments.

Approach:
The initial studies under this agreement focus on the evaluation of the impact of biotic soil amendments on soil health parameters under laboratory conditions using intact soil cores. An assessment will be made of the effect of biotic soil amendments on soil biological activity using respiration and carbon dioxide evolution from the soil as the primary variable along with changes in the soil aggregate stability. A series of laboratory incubation studies in combination with mixtures of plant species for different soils will be conducted for different soil moisture and temperature regimes. The soils used in these analyses will represent a range of soils typical of agricultural production systems in Iowa and Washington. The first incubation will be conducted on soil with no plants and the second with a small grain, and a third treatment with a small grain, a legume, and a brassica species to evaluate the added effect of root material on the soil biological system. The response of the biotic fertilizer will be compared to no addition of nutrients and to an incorporated urea fertilizer to determine the effect of on the mineralization of nitrogen within the soil column. All sensors are recorded every minute and summarized into 10 minute averages. Periodic samples are collected of the surface soil to evaluate the changes in the microbial biomass in the soil and changes in the soil aggregate stability. Mineralization of nitrogen studies will be conducted after addition of the biotic fertilizer and the urea source. Each of these treatments will be replicated six times to allow the entire experiment to be conducted in one growth chamber. Field studies will be conducted to evaluate the changes in soil properties after application of biological fertilizers in a corn-soybean rotation. These studies will apply biotic fertilizer at a rate of 168 kg/ha compared to urea at the same rate under a no-till system. Measurements will be made of the changes in the soil surface properties, e.g., wet aggregate stability and microbial biomass, and the corn response to fertilizer sources through evaluation of leaf chlorophyll content of the canopy throughout the growing season and yield components. These experiments are conducted on a Canisteo soil and replicated three times.