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Research Project: Ecologically-Sound Pest, Water and Soil Management Practices for Northern Great Plains Cropping Systems

Location: Agricultural Systems Research

2023 Annual Report

Objective 1: Develop and provide guidance for the use of sustainable crop production strategies for irrigated crop production systems. Subobjective 1.1. Develop diverse sprinkler irrigated cropping systems that include annual legume crops to improve farm economic and environmental sustainability by enhancing system productivity and input use efficiency. Subobjective 1.2. Evaluate the effect of tillage practices on sprinkler irrigated cropping system productivity; input use efficiency; and soil, air, and water quality. Objective 2: Develop no-till sustainable crop production strategies for long-term dryland production systems with diverse crop rotations that include cereals, pulse crops, oilseeds and other bioenergy crops. Subobjective 2.1. Develop no-till diversified dryland crop rotations that include cereal, pulse and oilseed crops, and that increase crop water use efficiency, N-use efficiency, and soil quality while maintaining yield and quality of the individual crops. Subobjective 2.2. Determine the sequence of cereal, pulse, and oilseed crops in no-till dryland rotations that optimizes yield, crop water use efficiency, and N-use efficiency. Subobjective 2.3. Develop dryland crop rotations that reduce periods of fallow in annually cropped systems and increase crop water use efficiency, N-use efficiency, and soil quality.

Agriculture is facing major challenges in providing food, fiber, and fuel to a growing population with limited land and water resources. With rising incomes, longer life spans, changes in dietary preferences, and demands for improved nutrition, pressures are mounting for producers to improve production efficiencies and ecosystem services. In the northern Great Plains, traditional dryland cropping systems that include conventional tillage with crop-fallow are uneconomical and unsustainable. Also, with the availability of unallocated irrigation water in the Missouri and Yellowstone rivers, areas under irrigated cropping systems are poised to increase in the MonDak region (eastern MT, western ND), resulting in new markets and potential for increased crop diversity. To address these critical issues, best practices for conservation tillage and diversified dryland and irrigated cropping systems must be developed. Our proposed research addresses these needs by utilizing cropping system trials to develop scientifically-sound, diversified dryland and irrigated cropping strategies that: (1) improve management of water, soil, and nutrients, through increased efficiency, (2) diversify crop rotations to include cereals, pulse, oilseed, forage, and bioethanol crops, and (3) increase net farm productivity. Successful completion of this project will provide stakeholders and customers with tools to reduce labor, water, input, and energy requirements while increasing crop yield and quality and improving soil and environmental quality. These tools will be transferred to stakeholders through research paper publications, field tours, focus group meetings, agricultural fairs, bulletins, websites, and other outreach activities.

Progress Report
Sub-objective 1.1. The 8-year Nesson Valley North Dakota irrigated cropping systems study was completed in FY 2021. The study was designed to evaluate the effect of cropping system diversity and tillage on crop yield and quality and the three aspects of soil health (biological, chemical, and physical). Three crop rotations were evaluated: (1) sugarbeet-barley, (2) corn-soybean and (3) sugarbeet-corn-soybean-barley. Each rotation was managed: (1) without any tillage (no-till), and (2) with conventional tillage for all crop phases. Crop and soil sample collection was completed as scheduled and data quantifying rotation and tillage effects on crop quality, biomass and yield components are being summarized. Results show a benefit to rotation diversity for soybean, sugarbeet, and corn while barley performed better in a 2-year rotation with sugarbeet than in a 4-year rotation following soybean. The impact of treatments on soil biological communities are being determined based on phospholipid-fatty acid and total carbon assays. Greenhouse gas sample collection to quantify carbon dioxide, nitrous oxide, and methane emissions data was collected for four years. Water movement through the soil profile along with nitrate leaching data was collected for 7 years and data analysis and summarization to determine crop water productivity and nitrogen-use efficiency is underway. A secondary objective of the study at Nesson Valley to quantify the effects of rotation and tillage on Rhizoctonia root and crown rot in sugarbeet was terminated following the 2019 growing season. Sub-objective 1.2. In FY 2023, we will complete the final year of the 6-year Sidney, Montana tillage study where irrigated sugarbeet was grown with conventional tillage or with various modifications of strip tillage and no tillage. The only sugarbeet processing facility in the area closed permanently in March 2023 so corn replaced sugar beet for the final year of the study. Results from the EARC study continue to show that strip-tillage sugarbeet yield compares well to conventional practices, though yield of sugarbeet grown without preplant tillage (no-till) lags somewhat compared to the other two tillage systems . It is notable that in 2021 when we were unable to apply irrigation water from July to September because of an inoperable irrigation system, sugarbeet yield under no-till was the highest of all tillage treatments suggesting greater water-use efficiency with that system. The fifth year of physical soil quality measurements , including soil penetration resistance, moisture content, and bulk density, was completed and the final year’s data are currently being collected. Soil microbial community structure based on phospholipid-fatty acid determinations and total carbon analyses to quantify soil organic matter dynamics are in progress. Soil samples were collected from both sites at planting and following harvest according to the established protocols. Greenhouse gas sampling at EARC to quantify carbon dioxide, nitrous oxide, and methane emissions were terminated after collecting three years of data. Secondary objectives of the EARC study are to (1) evaluate wheat planted in 12-inch rows instead of the more conventional 7.5-inch rows (in final year) and (2) identify the most effective irrigation management practice for dry peas which are a typically grown as a dryland crop (completed). Results show that wheat in 12-inch rows yields up to 10% less than in the conventional 7.5-inch rows. Peas yield 20 to 50% more when irrigated through the early pod-fill growth stage than when no irrigation water is applied in a semi-arid climate with an average of 14 inches of annual precipitation. The final year of the 8-year Nesson Valley irrigated cropping systems study was completed in FY 2021. Yield data from the Nesson Valley study consistently show that sugarbeet and corn yielded about 10% less with no tillage than with full tillage while barley and soybean yields are impacted less by tillage. Sub-objective 2.1. An 8-year dryland cropping systems study near Sidney, Montana, was conducted to compare no-till dryland cropping systems consisting of various cereal grains, pulses and oil seeds with varying levels of diversity (i.e., continuous cropping, 2- and 4-year rotations). Though it was planned to terminate the study in the fall of 2021, poor growing conditions in the final year of the study prompted scientists to extend the study through the fall of 2022. Plant and soil samples to quantify agronomic productivity as well as soil physical, chemical, and biological health parameters were collected according to protocols. Measurements of greenhouse gas emissions measured in an adjacent subordinate study at the same site showed that crop rotation did not significantly affect emissions of carbon dioxide, nitrous oxide or methane gases. Results show that diversified small grain no-till cropping systems that include pea and cool-season oilseeds improve overall system performance compared to continuous no-till small grain monocropping. Canola and camelina were more prone to crop failure than pea, spring wheat, winter wheat, and barley during drought conditions. Weed control was poor in continuous winter wheat and in camelina (Russian thistle, kochia, green foxtail) because (1) warm-season downy brome emerged after the herbicide application window had ended (winter wheat) and (2) there is a lack of compatible herbicides labeled for camelina, which is a relatively new industrial-grade oilseed crop. Researchers also reported only limited effects of cropping system diversity on soil aggregate stability, bulk density, hydraulic conductivity, water retention and soil organic carbon concentration. Adding canola and camelina oilseed crops into small grain rotations has no negative effects but also did not improve these soil properties. Development of measurable positive effects on soil physical properties may require more time in the semi-arid northern Great Plains (NGP) due in part to limited and highly variable annual precipitation and crop residue yields. Sub-objective 2.2. Pulse and cool-season oilseed crops are commonly included in diversified rotations in the NGP but periods of limited rainfall that are common in the NGP impact rotational crops differently. A large 6-year dryland cropping systems study at the Froid dryland research farm was extended to the eighth and final year of data collection. This study was designed to compare various cropping sequences in cropping systems of durum, dry pea, and oil seed crops. Severe hail during the 2018 growing season and severe drought in 2017, 2019 and 2020 caused four consecutive years of crop failure, drastically limiting soil and plant sample collection. Weather conditions in 2022 were wetter than average resulting in better growing conditions than in previous years, though oilseed establishment was still less than ideal. The study was planted and maintained throughout the 2022 growing season. Evaluations of agronomic performance, crop water use efficiency and nitrogen-use efficiency data are in process. From 2013 to 2022, ARS researchers in Sidney, Montana, evaluated durum wheat rotations that included three cool-season oilseed crops (camelina, canola, safflower) and a pulse crop (pea). Oilseeds were particularly prone to crop failure during drought conditions, compared to durum and pea. Contributing factors to low oilseed yield included soil crusting that limited seedling emergence, small seed size with limited reserves for initial growth, and poor seed set from heat-induced flower abortion during reproductive stages of growth. Durum and pea were much less prone to crop failure in times of drought than camelina, canola, and safflower. Research from subordinate studies at the same location showed that diversified cropping systems improve overall grain yield productivity in semi-arid cropping systems compared to the traditional practice of wheat-summer fallow.

1. Tillage has an impact on soil pore size distribution and available water capacity. Increasing periods of drought are limiting the amount of water available for crop production. Soil pore-size distribution is considered one of the most important physical characteristics that affects water movement, aeration, and water storage in the soil and, ultimately, water availability to plants. Soil pores and pore size are affected by soil structure, texture, organic matter content and tillage practices. ARS researchers in Sidney, Montana, conducted a long-term study to evaluate the effect of tillage on pore-size distribution in the top 30 cm of a sandy loam soil. Results showed that intensively tilled soil has a higher amount of large pores and a lower amount of small pores compared to untilled soils, at least in the short-term. The greater number of small pores in untilled soils led to improved available water capacity compared to tilled soils. Moreover, increasing soil organic matter levels were observed in the top soil layer in the no-tillage systems over the 8-year study. Consequently, the long-term impact of converting to no-tillage could eventually improve soil pore size distribution, pore connectivity, plant available water capacity, as well as other physical, chemical and biological properties compared to intensive tillage. This work improves our understanding of how various tillage practices affect water use efficiency, environmental quality, and soil health. Overall, shifting to a conservation tillage system provides better economic and environmental benefits to farmers compared to intensive tillage practices.

2. Soil microbial community structure under perennial bioenergy crops treated with different nitrogen fertilizer. Perennial grasses are potential bioenergy feedstocks that may help improve soil health by sustaining soil biology as a result of their extensive root systems and the continuous ground cover they provide. Realization of these soil health benefits requires multiple years of perennial grass production. ARS scientists in Sidney, Montana, evaluated effects of two perennial grass species grown with varying nitrogen fertilizer rates over 11 years on soil microbial communities compared to annual spring wheat (WH) grown with a typical amount (80 kg N per hectare) of nitrogen fertilizer. Perennial grasses evaluated were intermediate wheatgrass (IWG) and switchgrass (SG). Each species was grown with nitrogen fertilization rates ranging from 0 to 84 kg N per hectare. Research has shown that soils where fungi and certain types of bacteria predominate tend to exhibit enhanced storage of stable organic carbon while soils where other types of bacteria predominate are characterized by more easily-degraded carbon that may lead to carbon loss. A specialized type of fungi called arbuscular mycorrhizal fungi (AMF) forms a symbiotic association with plant roots that enhances the plant’s access to water and nutrients. Using a laboratory procedure that quantifies these microbial groups, we found that adding more nitrogen decreased AMF and increased the proportion of bacteria that is correlated with carbon degradation. Both perennial grass species enhanced AMF and the type of bacteria related to greater carbon storage compared to WH. Switchgrass promoted these beneficial microbial groups more effectively than IWG. Soil microbial communities mediate many essential soil functions and results from this study will help growers select bioenergy perennial grass species and nitrogen fertilizer rates that optimize soil biological health and enhance sustainable production.

3. Legume-nonlegume crop rotations can increase crop yields and economic returns. Producers in dryland cropping systems in the northern Great Plains have been using crop-fallow and continuous monocropping as conventional cropping systems for the last several decades. Both cropping systems can reduce crop yields either by reducing annualized yield and or by increasing weed and pest infestations. The crop-fallow system can also reduce soil health. Information is needed about how legume-nonlegume crop rotation replacing fallow or cereal monocropping can affect soil health, crop yields, and economic returns. ARS researchers in Sidney, Montana, working on the effects of long-term crop rotations on 66 soil properties, crop yields, and economic returns at two dryland farm sites, reported that crop rotation affected variably on soil properties, but increased crop yields compared with continuous monocropping at both sites. Furthermore, crop rotation increased net economic returns compared to continuous monocropping, regardless of study sites. These results suggest that legume-nonlegume crop rotations can sustain crop yields and enhance producers’ farm income compared to continuous monocropping in dryland cropping systems in the northern Great Plains.

4. Improving establishment of perennial native grasses and forbs. Perennial grasses and forbs can improve water use efficiency and water quality, prevent soil erosion, and provide wildlife and pollinator habitat. However, establishment success of perennial mixes is often limited in semi-arid environments. From 2017 to 2022, ARS researchers in Sidney, Montana, evaluated four strategies to improve the establishment of perennial mixes of native grasses and forbs. The least successful treatment was the Business as Usual (BAU) approach, which included chemical fallow weed management prior to planting a mix comprised of four grass and three forb species. The most successful alternative treatment included cover crop weed management prior to planting a mix comprised of eight grass and nine forb species. Seeding year (2017 versus 2018) had a major impact on establishment success, underlying the need to better understand environmental conditions during the establishment phase. Competition from weeds limited establishment success at all three Montana research sites. Overall, establishment frequency and survival were dynamic, suggesting that perennial stands need to be monitored for several years to determine establishment success or failure.

5. Switchgrass with recommended nitrogen fertilization rate can reduce carbon footprint. Perennial bioenergy crops produce large biomass and can replace a significant portion of fossil fuels because they produce less greenhouse gas emissions. Perennial bioenergy crops also can reduce greenhouse gas emissions compared to annual crops. ARS researchers at Sidney, Montana, calculated the carbon (C) footprint of perennial bioenergy crops by quantifying the amount of carbon stored in the shoot, root, and soil, and carbon lost through soil respiration. By using this approach, they were able to determine if perennial agroecosystems act as a carbon source or sink. The researchers reported that shoot carbon was greater for switchgrass, but root carbon varied with perennial grass species and nitrogen fertilization rates. Carbon dioxide emissions were greater for smooth bromegrass and switchgrass than intermediate wheatgrass. Carbon balance was greater for switchgrass than other perennial grasses at higher nitrogen fertilization rates. Shoot, root, and soil C as well as C balance were lower, but carbon dioxide emissions were greater for spring wheat than for perennial bioenergy crops. Producers can use switchgrass with recommended nitrogen rates to store more carbon in the plant and soil, resulting in carbon sink.

6. Autoclaved citrate-extractable protein can be an important indicator of soil health. Nitrogen is one of the most important nutrients required for plant growth and is applied in large amounts as fertilizer to many agricultural soils to ensure adequate soil fertility. Nitrogen is present in many different chemical forms in the soil as it cycles between various organic and inorganic forms. Given the essential role of nitrogen in plant growth and crop yield, one or more of these soil nitrogen fractions may have potential value as soil health indicators. Using soil collected from two long-term dryland field studies, ARS researchers in Sidney, Montana, collaborated with the Soil Health Institute to evaluate soil nitrogen fractions for their potential as soil health indicators based on how well they correlated with crop yield and 66 soil properties. They reported that potential nitrogen mineralization and autoclaved citrate-extractable protein were the soil nitrogen fractions most sensitive to management practices and related to most soil properties and long-term crop yields. Other soil nitrogen fractions showing less potential were soil total nitrogen, water-extractable nitrogen, ammonium-nitrogen, and nitrate-nitrogen. Although potential nitrogen mineralization was related to most soil properties and crop yield, it is not an ideal soil health indicator because the laboratory procedure for measuring it is time-consuming. On the other hand, autoclaved citrate-extractable protein may be the most suitable nitrogen-based indicator of soil health because it is easily and rapidly determined and is related to most soil properties and crop yield. One of the greatest challenges of improving soil health is the lack of simple and reliable assays of soil properties that are correlated with a productive soil ecosystem. This research provides evidence that autoclaved citrate-extractable protein may be a valuable indicator of soil health in semiarid dryland cropping systems.

Review Publications
Sainju, U.M., Liptzin, D., Jabro, J.D. 2022. Relating soil physical properties to other soil properties and crop yields. Scientific Reports. 12. Article 22025.
Zhang, N., Sainju, U.M., Zhao, F., Ghimire, R., Ren, C., Laiang, Y., Yang, C., Wang, J. 2023. Mulching decreased the abundance of microbial functional genes in phosphorus cycling under maize. Applied Soil Ecology. 187. Article 104833.
Sainju, U.M., Liptzin, D. 2022. Relating soil chemical properties to other soil properties and dryland crop production. Frontiers in Environmental Science. 10. Article 1005114.
Jabro, J.D., Stevens, W.B. 2022. Pore size distribution derived from soil-water retention characteristic curve as affected by tillage intensity. Water. Special Issue 14(21). Article 3517.
Sainju, U.M., Allen, B.L. 2022. Carbon footprint of perennial bioenergy crop production receiving various nitrogen fertilization rates. Science of the Total Environment. 861. Article 16063.
Sainju, U.M. 2022. The impact of no-till crop rotation on dryland soil properties and crop yields. Agronomy Journal. 114(5):2796-2810.
Sainju, U.M., Liptzin, D., Stevens, W.B. 2022. Autoclaved citrate-extractable protein as a soil health indicator relates to soil properties and crop production. Nutrient Cycling in Agroecosystems. 124:315-333.
Yang, C., Sainju, U.M., Li, C., Fu, X., Zhao, F., Wang, J. 2023. Long-term chemical and organic fertilization differently affect soil aggregates and associated carbon and nitrogen in the Loess Plateau of China. 13(6). Article 1466.
Liang, Y., Yang, C., Sainju, U.M., Zhang, N., Zhao, F., Wang, J. 2023. Differential responses of soil microbial N-cycling functional genes to 35-yr applications of chemical fertilizer and organic manure in wheat field soil on loess plateau.. Science of the Total Environment. 13(6). Article 1516.
Sainju, U.M., Liptzin, D., Rana Dangi, S. 2022. Enzyme activities as soil health indicators in relation to soil characteristics and crop production. Agrosystems, Geosciences & Environment. 5(3). Article e20297.
Klopp, H.W., Jabro, J.D., Allen, B.L., Sainju, U.M., Stevens, W.B., Rana Dangi, S. 2023. Does increasing diversity of small grain cropping systems improve aggregate stability and soil hydraulic properties? Agronomy. 13. Article 1567.
Liptzin, D., Norris, C.E., Cappellazzi, S.B., Bean, G.M., Cope, M., Greub, K.L., Rieke, E.L., Tracy, P.W., Aberle, E., Ashworth, A.J., Baumhardt, R.L., Dell, C.J., Derner, J.D., Ducey, T.F., Novak, J.M., Dungan, R.S., Fortuna, A., Kautz, M.A., Kitchen, N.R., Leytem, A.B., Liebig, M.A., Moore Jr., P.A., Osborne, S.L., Owens, P.R., Sainju, U.M., Sherrod, L.A., Watts, D.B. 2022. An evaluation of carbon indicators of soil health in long-term agricultural experiments. Soil Biology and Biochemistry. 172. Article 108708.
Liptzin, D., Rieke, E.L., Cappellazzi, S.B., Mac Bean, G., Cope, M., Greub, K.H., Norris, C.E., Tracy, P.W., Aberle, P.W., Ashworth, A.J., Baumhardt, R.L., Dell, C.J., Derner, J.D., Ducey, T.F., Dungan, R.S., Fortuna, A., Franzluebbers, A.J., Kautz, M.A., Kitchen, N.R., Leytem, A.B., Liebig, M.A., Moore Jr, P.A., Osborne, S.L., Owens, P.R., Sainju, U.M., Sherrod, L.A., Watts, D.B. 2023. An evaluation of nitrogen indicators for soil health in long-term agricultural experiments. Soil Science Society of America Journal. 87(4):868-884.
Rieke, E.L., Bagnall, D.K., Morgan, C., Greub, K., Bean, G.M., Cappellazzi, S.B., Cope, M., Liptzin, D., Norris, C.E., Tracy, P.W., Ashworth, A.J., Baumhardt, R.L., Dell, C.J., Derner, J.D., Ducey, T.F., Fortuna, A., Kautz, M.A., Kitchen, N.R., Leytem, A.B., Liebig, M.A., Moore Jr., P.A., Osborne, S.L., Owens, P.R., Sainju, U.M., Sherrod, L.A., Watts, D.B., et al. 2022. Evaluation of aggregate stability methods for soil health. Geoderma. 428. Article 116156.
Johnsrude, L.M., Scheffel, A.J., Allen, B.L., Wettstein, S.G. 2023. Composition analysis of canola and intermediate wheatgrass biomass and the effects of extraction. BioResources. 18(1):1653-1663.