OBJECTIVE 1. Develop and evaluate management strategies for sustainable use of agricultural production, including integrated crop - livestock systems. • Sub-objective 1.1 Sustainably intensify dryland agricultural production systems by including cover crops. • Sub-objective 1.2 Sustainably intensify dryland agricultural systems by integrating crops and livestock. • Sub-objective 1.3 Sustainably intensify dryland agricultural systems by including biofuel-focused cropping systems. OBJECTIVE 2. Determine economic, environmental and production tradeoffs of improved soil management practices in the northern Great Plains. • Sub-objective 2.1 Quantify ecosystem services within dryland agricultural production systems. • Sub-objective 2.2 Determine tradeoffs between production, economic, and ecosystem service outcomes to sustainably intensify dryland agricultural production systems.
An expanding human population, increasing worldwide demand for meat and continued biofuel demand will require intensified agricultural production to meet food and fuel needs. The concept of sustainable intensification or increasing food production on the same area while minimizing environmental impacts and increasing the flow of ecosystem services has been advocated as a means to address this challenge. This project will fill significant information gaps related to management alternatives needed to sustainably intensify agricultural production systems on the northern Great Plains. We will: 1) evaluate three different methods to intensify current cropping systems common in the northern Great Plains including (i) inclusion of cover crops; (ii) integration of crop-livestock systems; and (iii) biofuel focused cropping systems; and 2) quantify ecosystem services of dryland agriculture production systems and potential tradeoffs among production, economic and environmental outcomes associated with these production systems. Successful conclusion of this project will provide producers, policy makers and government agencies with potential methods to sustainably intensify dryland agricultural production systems in the northern Great Plains and an evaluation of the impacts of these methods. These results will be communicated to stakeholders through peer-reviewed papers, on-farm research, decision tool development and other outreach activities.
Subobjective 1.1 – Fifteen mixtures of four cover crops (forage radish, red clover, triticale, and proso millet) were planted in spring 2014, autumn 2014, and spring 2015. Preliminary yield data from spring and autumn of 2014 indicated that mixtures of cover crops were as productive as monocultures. Late summer planting of cover crops was marginally successful. There were no differences among cover crop mixtures or monocultures in the amount of weed biomass from invasive species. The second year of the experiment will be completed in 2015. In the rainout shelter study, root barriers and soil moisture and temperature sensors were installed in the rainout shelter in summer 2014. A winter wheat crop was seeded in Fall 2014 to detect any major soil differences caused by the installation of the root barriers and sensors. The winter wheat was terminated in Spring 2015 and the cover crop mixtures and spring wheat check were seeded. All plots are under a simulated drought this growing season (75% of normal growing season precipitation). The location’s soil microbiologist changed jobs last year but the hyphal in growth core sampling was retained in case other collaborators may be interested. A preliminary investigation was conducted to evaluate effects of three phenolic compounds on nutrient retention in soil. Samples of surface soil were treated with water (control) or solutions of increasingly complex compounds; benzoic acid (BA), gallic acid (GA), or ß-1,2,3,4,6-penta-O-galloyl-D-glucose (PGG) at four concentrations. Each compound reduced the amount of nitrogen (N) extracted with water, with greatest response to BA. However, PGG, a tannin, reduced the solubility of N only with hot water, suggesting its effects are mostly on organic forms of N. Unlike N, solutions of GA and PGG increased extraction of phosphorus (P). Extraction of potassium (K), calcium (Ca) and magnesium (Mg) were strongly increased by BA and GA but comparatively unaffected by PGG. Extraction of manganese (Mn) was increased mainly by GA. These preliminary findings suggest some plant secondary compounds affect nutrient retention in soil, and thus may be part of future management strategies to improve nutrient-use efficiency. Subobjective 1.2 – Alternative methods for establishing cover crops during corn and spring wheat growing seasons were tested again in 2014, after modifying treatments to reduce weed pressures. These adjustments were based on experience from 2013. Preliminary results from 2014 showed that interseeding soybean with corn provided additional cover with no reduction in corn yield. Other methods establishing cover crops in corn were not successful or resulted in corn crop failure. Methods for establishing cover crops in spring wheat generally resulted in poor wheat yields, due either to weed pressure or to sprouting grain in wheat that had been swathed to allow for cover crop planting. Results were used in guiding treatments that were implemented in the integrated crop livestock treatments in spring 2015. Subobjective 1.3 - The second rotation cycle was completed in the Bioenergy Cropping Systems Study. Soil samples were collected to a depth of 120 cm from all plots during the reporting period (Sub-objective 1.3). Samples were dried and processed for soil carbon analysis. Due to limitations the current cover crop mix imposes on herbicide options available during in dry pea growing season, the cover crop mix used in the pea/cover crop treatment will be changed to forage soybean, spring triticale, vine pea, lentil, red clover, and purple top turnip beginning autumn 2015. Subobjective 2.1 - Soil samples were collected to a 30 cm depth from four paired experimental treatments (‘business as usual’ vs. conservation agriculture) within established long-term studies at NGPRL. Samples were processed and analyzed, and first year results were presented at the ASA-CSSA-SSSA annual meeting. Six on-farm sites associated with the study were established in Emmons County, North Dakota. Soil ecosystem services and crop yield assessments will be made on these sites. The Long-Term Agroecosystem Research (LTAR) network developed standard methods for wind erosion research and model development. In support of this effort, field measurements of wind sediment transport rates will be assessed at the NGPRL and best management practices can be identified and tested. Site selection has been completed for the wind erosion tower and all materials and instrumentation needed for site implementation have been purchased or constructed. In July 2015, collaborators from the USDA-ARS Jornada Experimental Range (wind erosion network lead) traveled to the NGPRL to install instrumentation and connect to the wind erosion network. Subobjective 2.2 – Production and management data from the long-term studies at NGPRL have been consolidated into a standard database to use for tradeoff analysis, and initial enterprise budgets were constructed. These enterprise budgets will be used to calculate economic returns for each management system in quantifying tradeoffs among economic returns and ecosystem services.
1. Updated tool for cover crop selection. Producers are interested in growing cover crops for the multiple benefits they may provide. However, there are many cover crop choices, many of which are unfamiliar to producers. ARS researchers in Mandan, North Dakota developed an updated Cover Crop Chart (CCC) as a user-friendly tool to determining the suitability of cover crops for addressing different production and natural resource goals. The chart categorizes 57 cover crops based on the plant type and general growth characteristics, and provides basic descriptive information. The CCC is available via the internet and is being used by producers and conservation agencies to increase cover crop use.
2. Rapeseed to jet fuel life-cycle assessment. Rapeseed is a candidate crop for producing renewable jet fuel, improving soils and reducing greenhouse gas emissions. Scientists at Michigan Technological University, in collaboration with ARS researchers at Mandan, North Dakota, estimated that growing rapeseed in place of fallow in rotation with wheat in 10 Western U.S. states could have positive or negative effects on soil organic carbon depending on production practices and location. Using the best production practices of no-tillage and high residue retention, renewable jet fuel from rapeseed could result in greenhouse gas reductions of 65-96% compared with petroleum jet fuel.
Pothula, A.K., Igathinathane, C., Shen, J., Nichols, K., Archer, D.W. 2015. Milled industrial beet color kinetics and total soluble solid contents by image analysis. Industrial Crops and Products. 65:159-169.
Halvorson, J.J., Belesky, D.P., Godwin, H.W. 2015. Seedling performance associated with live or herbicide treated tall fescue. International Journal of Agronomy. DOI:10.1155/2015/841213.
Wang, G., Nyren, P., Xue, Q., Aberle, E., Eriksmoen, E., Bradbury, G., Liebig, M.A., Nichols, K.A., Nyren, A. 2014. Establishment and yield of perennial grass monocultures and binary mixtures for bioenergy in North Dakota. Agronomy Journal. 106:1605-1613.
Ukaew, S., Beck, E., Archer, D.W., Shonnard, D.R. 2015. Estimation of soil carbon change from rotation cropping of rapeseed with wheat in the hydrotreated renewable jet life cycle. International Journal of Life Cycle Assessment. 20:608-622.