,Biochars are charcoals used as soil amendments, and they have many beneficial effects on soil health. However, one negative effect is biochars often reduce concentrations of soil nitrogen that are available to plants. This is believed to be due to the high carbon and low nitrogen contents of biochars, which deprive soil microbes of nitrogen as they decompose the biochar, and cause microbes to tie up nitrogen from soil. We tested whether we could predict biochar impacts on soil nitrogen from the quantities of carbon and nitrogen in biochar that can be consumed soil microbes. Because biochars are mostly composed of carbon in molecules that can not be consumed by microbes, the microbially-available portion is generally small. We measured the microbially-available carbon and nitrogen in ten biochars, and measured how they impacted nitrogen concentrations in two soils from Oregon.,This dataset includes characteristics of ten biochars and two soils, and measurements from two incubation experiments. In the first experiment we incubated 13C-labeled biochars with two soil for 101 days, and measured production of biochar- and soil-respired CO2 and soil dissolved inorganic nitrogen. In the second experiment we expanded to study ten biochar types, including seven biochars that were not isotopically-labeled. We measured how much dissolved inorganic nitrogen was produced by amended soils over 28 days.,Surprisingly, we found all ten biochars increased rather than decreased soil nitrogen concentrations one month after application. We also found that biochars produced at high temperatures, which were more difficult for soil microbes to consume than low-temperature biochars, stimulated more soil decomposition and released more soil nitrogen. It appeared that microbes increased soil decomposition in response to additions of biochar, and this then increased plant-available nitrogen at least temporarily. These unexpected results show that biochar can sometimes have beneficial impacts on soil nitrogen, and that biochar impacts cannot be readily predicted from the qualities of the biochars themselves. These results are relevant to biochar users, and to biochar producers interested in how to make biochars more beneficial for plant growth. These results indicate that biochar users cannot predict nitrogen impacts, and should therefore monitor soil nitrogen concentrations to ensure levels are sufficient for plant growth.,,

,This dataset includes soil health, crop biomass, and crop yield data for a 13-year corn stover harvest trial in central Iowa.,Following the release in 2005 of the Billion Ton Study assessment of biofuel sources, several soil health assessments associated with harvesting corn stover were initiated across ARS locations to help provide industry guidelines for sustainable stover harvest. This dataset is from a trial conducted by the National Laboratory for Agriculture and Environment from 2007-2021 at the Iowa State University Ag Engineering and Agronomy farm. Management factors evaluated in the trial included the following.,The dataset includes: 1) Crop biomass and yields for all crop phases in every year. 2) Soil organic carbon, total carbon, total nitrogen, and pH to 120 cm depth in 2012, 2016, and 2017. Soil cores from 2005 (pre-study) were also sampled to 90 cm depth. 3) Soil chemistry sampled to 15 cm depth every 1-2 years from 2007 to 2017. 4) Soil strength and compaction was assessed to 60 cm depth in April 2021.,These data have been presented in several manuscripts, including Phillips et al. (in review), O'Brien et al. (2020), and Obrycki et al. (2018).,

,This dataset includes soil wet aggregate stability measurements from the Upper Mississippi River Basin LTAR site in Ames, Iowa. Samples were collected in 2021 from this long-term tillage and cover crop trial in a corn-based agroecosystem.,We measured wet aggregate stability using digital photography to quantify disintegration (slaking) of submerged aggregates over time, similar to the technique described by Fajardo et al. (2016) and Rieke et al. (2021). However, we adapted the technique to larger sample numbers by using a multi-well tray to submerge 20-36 aggregates simultaneously. We used this approach to measure slaking index of 160 soil samples (2120 aggregates).,This dataset includes slaking index calculated for each aggregates, and also summarized by samples. There were usually 10-12 aggregates measured per sample.,We focused primarily on methodological issues, assessing the statistical power of slaking index, needed replication, sensitivity to cultural practices, and sensitivity to sample collection date. We found that small numbers of highly unstable aggregates lead to skewed distributions for slaking index. We concluded at least 20 aggregates per sample were preferred to provide confidence in measurement precision. However, the experiment had high statistical power with only 10-12 replicates per sample. Slaking index was not sensitive to the initial size of dry aggregates (3 to 10 mm diameter); therefore, pre-sieving soils was not necessary. The field trial showed greater aggregate stability under no-till than chisel plow practice, and changing stability over a growing season. These results will be useful to researchers and agricultural practitioners who want a simple, fast, low-cost method for measuring wet aggregate stability on many samples.,

Research has suggested that biochar soil amendments have the ability to improve soil water retention, but results have not been consistent or predictable across soil types. The objective of this project was to evaluate the potential for biochar soil amendments to mitigate agricultural drought by characterizing their impacts on soil hydraulics and plant growth across a range of agricultural soil conditions. This data set contains soil moisture retention curves and unsaturated hydraulic conductivities for four Oregon agricultural soils amended with biochar. Gasified biochars made from wheat straw (AgEnergy, Spokane, WA) and conifer wood (BioLogical, Philomath, OR) were tilled into soils at experimental stations in Madras (loam), Pendleton (silt loam), Aurora (sandy loam), and Klamath Falls (loamy sand). The biochars were incorporated by tillage in the fall to a depth of 12 cm at rates equating to 0, 9, 18, and 36 Mg/ha, with three replicate plots per treatment. Soil cores were collected the following spring and used to construct moisture retention curves using a combination of pressure plates, a WP4 water potentiameter instrument, and a HYPROP instrument.

Research has suggested that biochar soil amendments have the ability to improve soil water retention, but results have not been consistent or predictable across soil types. The objective of this project was to evaluate the potential for biochar soil amendments to mitigate agricultural drought by characterizing their impacts on soil hydraulics and plant growth across a range of agricultural soil conditions. This data set contains soil moisture retention curves and unsaturated hydraulic conductivities for four Oregon agricultural soils amended with biochar. Gasified biochars made from wheat straw (AgEnergy, Spokane, WA) and conifer wood (BioLogical, Philomath, OR) were tilled into soils at experimental stations in Madras (loam), Pendleton (silt loam), Aurora (sandy loam), and Klamath Falls (loamy sand). The biochars were incorporated by tillage in the fall to a depth of 12 cm at rates equating to 0, 9, 18, and 36 Mg/ha, with three replicate plots per treatment. Soil cores were collected the following spring and used to construct moisture retention curves using a combination of pressure plates, a WP4 water potentiameter instrument, and a HYPROP instrument.

Research has suggested that biochar soil amendments have the ability to improve soil water retention, but results have not been consistent or predictable across soil types. The objective of this project was to evaluate the potential for biochar soil amendments to mitigate agricultural drought by characterizing their impacts on soil hydraulics and plant growth across a range of agricultural soil conditions. This data set contains soil moisture retention curves and unsaturated hydraulic conductivities for four Oregon agricultural soils amended with biochar. Gasified biochars made from wheat straw (AgEnergy, Spokane, WA) and conifer wood (BioLogical, Philomath, OR) were tilled into soils at experimental stations in Madras (loam), Pendleton (silt loam), Aurora (sandy loam), and Klamath Falls (loamy sand). The biochars were incorporated by tillage in the fall to a depth of 12 cm at rates equating to 0, 9, 18, and 36 Mg/ha, with three replicate plots per treatment. Soil cores were collected the following spring and used to construct moisture retention curves using a combination of pressure plates, a WP4 water potentiameter instrument, and a HYPROP instrument.

,Bioenergy Cropping Systems Study for Resilient Economic Agricultural Practices in Mandan, North Dakota,Rigorous economic analyses are crucial for the successful launch of lignocellulosic bioenergy facilities in 2014 and beyond. Our objectives are to (1) introduce readers to a query tool developed to use data downloaded from the Agricultural Research Service (ARS) REAPnet for constructing enterprise budgets and (2) demonstrate the use of the query tool with REAPnet data from two field research sites (Ames, IA, and Mandan, ND) for evaluating short-term economic performance of various biofuel feedstock production strategies. Our results for both sites showed that short-term (<3 years) impacts on grain profitability were lower at lower average annual crop residue removal rates. However, it will be important to monitor longer term changes to see if grain profitability declines over time and if biomass harvest degrades soil resources. Analyses for Iowa showed short-term breakeven field-edge biomass prices of $26–$42 Mg−1 among the most efficient strategies, while results for North Dakota showed breakeven prices of $54–$73 Mg−1. We suggest that development of the data query tool is important because it helps illustrate several different soil and crop management strategies that could be used to provide sustainable feedstock supplies.,,