Location: Columbia Plateau Conservation Research Center
2022 Annual Report
Objectives
Objective 1: Quantify impact of intercropped legume cover crops with winter wheat to increase soil carbon and reduce herbicide and synthetic nitrogen (N) fertilizer inputs.
Sub-objective 1.A: Identify the best performing legume cover crops for intercropping with winter wheat that reduces herbicide and synthetic N while improving precipitation use efficiency in intermediate rainfall zones.
Subobjective 1.B: Examine whether legume cover crop intercropped with winter wheat can increase soil organic carbon (SOC), reduce herbicide and synthetic N fertilizer inputs, and reduce CO2 and CH4 emissions.
Objective 2: Measure deep root-zone water dynamics in dryland cropping systems to optimize water storage with tillage, crop residue, cover crop, and weed management.
Objective 3: Examine the use of biostimulants and biochar (such as thermal carbonized manure) as amendments in dryland wheat production systems in order to improve soil and plant health, profitability, and resilience to extreme weather and climate change.
Sub-objective 3.A: Establish whether the addition of biostimulants to soils can enhance plant growth and soil properties to reduce drought stress under semi-arid dryland wheat production conditions.
Sub-objective 3.B: Determine whether the addition of thermal carbonized manure to soils can increase soil pH in the N fertilizer application zone and enhance plant nutrient uptake under semiarid dryland wheat production systems.
Approach
1.A. Establish intercropped wheat with 4-legumes. Determine grain yields and wheat, legume, and weed biomasses. Apply herbicides while control subplots are covered to count weeds per species. Collect soil samples at the start of the experiment and after the 4th growing season. Determine total, organic and inorganic C, and N; and extractable P, NO3-N, and NH4-N. Collect soil samples for in-season N fertilization and determine dissolved and labile C and N at the time of N fertilization and at harvest. Monitor soil temperature and water. Collect CO2, N2O, and CH4 samples for two years. Perform life cycle analysis (LCA) from greenhouse gas (GHG) emissions from (1) diesel combustion at each stage of crop production, delivery of seed, fertilizers, pesticides, and (2) direct field emission of GHG.
1.B. Measurements are made in 1) wheat-fallow under reduced tillage, 2) no-till annual winter wheat, and 3) no-till wheat–wheat–sorghum/sudangrass. Half of the plots are planted and managed using herbicide. The other plots are intercropped with a legume. Monitor solar radiation with Albedometers. Collect soil samples and determine total and labile C and N as in 1.A. Soil temperature, water and GHG will be monitored, and the LCA will be performed as in 1.A.
2. Install soil water sensors below tillage depth in controlled experiments on post-harvest weed control, alternative crops, cover crops, and in farmer’s fields of selected management practices. Install sensors in 5-cm boreholes to monitor the root zone and below the root zone to detect upward and downward water movement. A minimum of 24 profiles under commercial farm practices in different locations are monitored for the soil and yield response to precipitation events, weed growth, and cropping patterns. Soil water storage, water extraction by the crop, and yield are principal measurements. The data is posted online in real-time.
3.A. Plots of no-till continuous wheat-wheat with 3-N fertilizer rates (0, 50, 100 kg N/ha) will be used. Apply biostimulants to 4 subplots within the N main plots at a rate of 3.7 L/ha at the 4th leaf growth stage. Grain, biomass yields, and harvest index are determined. Shoots and roots are sampled at V6 & maturity and stored (- 80°C) until analyzed. The samples are extracted and analyzed for up to 18 endogenous plant hormones, 8-carbohydrate and 11 phenol monomers. Carbohydrate monomers are hydrolyzed by H2SO4, separated by anion chromatography, and detected by pulsed amperometry. Phenol monomers are extracted by CuO oxidation and NaOH hydrolysis and detected by GC. Amino acid monomers are extracted, separated by anion chromatography and detected by pulsed amperometry.
3.B. Poultry litter will be pyrolyzed and compared with conifer wood and wheat straw biochars and replicated plots will be treated with each of the 3 biochars and incorporated by rotary tillage. Soil cores will be collected before and after application of the biochar. Total soil N, S, and C, extractable NO3 and NH4, micro- and macronutrients, soil pH, and EC are determined. Winter wheat will be seeded by hand for 3 yrs. Micro- and macronutrients in the wheat grain and straw will be determined at harvest.
Progress Report
This report documents progress for new project 2074-11120-005-000D, which started in October 2021 and continues work from expired project 2074-11120-004-000D, “Maximizing Long-term Soil Productivity and Dryland Cropping Efficiency for Low Precipitation Environments.”
In support of Sub-objective 1A, background soil samples with depth were collected and analyzed for carbon (C) and nitrogen (N). Weed infestation was evaluated by counting weed species in ½ x 1 m2 frames in each of the intercropped treatments. Weather, soil water and soil temperature data collections will continue until next growing season. This work supports the development of fundamental knowledge of and practices for soil-based management that contribute to greater agricultural productivity, reduced reliance on inputs, resilience to disturbances, and ecosystem services.
In support of Sub-objective 1B, 108 greenhouse gas (carbon dioxide, nitrous oxide, and methane) samples were collected from wheat and wheat-pea intercropped plots and analyzed weekly during the winter wheat growing season (October- July). Monthly collection from August to September will continue, including surface soil temperature and soil moisture measurements. This work contributes to quantifying driving factors in soil carbon cycling, including organic matter dynamics, carbon sequestration, and carbon dioxide, nitrous oxide, and methane emissions.
In support of Objective 2, researchers in Pendleton, Oregon, located two sites where three fields under contrasting management can be reached with underground cables. At one of the sites, we installed two profiles of soil water sensors in each field. Sensors are placed at 30 cm depth increments and the data is being recorded continuously. In addition, we collected standard soil samples from two sets of on-farm plots and two sets of research station plots to compare soil water under different population densities of Russian thistle allowed to grow following wheat harvest. In another set of plots at the research station we measured water use by single plants of Russian thistle, prickly lettuce, kochia, and spring wheat. Repeats of the farm field and plot work are underway this summer. This research contributes to developing cropping systems that enhance agroecosystems and promote resilience to climate change.
Progress was made on projects which contribute to advancing our understanding of innovative, nontraditional soil amendment research, including biostimulants, to develop cropping systems that enhance agroecosystems and promote resilience to climate change. In support of Sub-objective 3A, eighty-four soil samples were collected, and samples were analyzed for nutrients, C and N. Biostimulants plots were established, but no biostimulants were applied because of high winter precipitation. In support of Sub-objective 3B, four replications of biochar plots were established and 24 soil samples were collected at six depth increments for pH, nutrient, C and N analysis.
Accomplishments
1. Synchronizing nitrogen fertilization and planting date improves productivity and profitability. Synchronizing nitrogen (N) fertilization with planting date could enhance water and nutrient use efficiency and profitability of upland rice production. An ARS researcher in Pendleton, Oregon, with researchers at Prince of Songkla University, Hat Yai, Thailand, conducted a study to assess the upland rice responses to four N fertilizer rates and three planting dates during two growing seasons. There was a linear relationship between N rate, grain yield, above-ground biomass, and a significant seasonal effect. Maximum profitability from grain yield was at 80-pound N/acre under all planting times. However, the highest marginal benefit-cost ratio was at 54-pound N/acre under intermediate planting dates during both seasons. The findings show that N fertilization rates of 80-pound/acre and rice planting at the end of September and the start of October would enhance productivity, resource use efficiency and maximize profitability.
2. Predicting soil organic carbon (SOC) dynamics of the integrated crop-livestock system. Land degradation and reduction in productivity have resulted in losses of soil organic carbon (SOC) in agricultural areas in Brazil. An ARS researcher in Pendleton, Oregon, with researchers at Embrapa, Santo Antonio de Goias, Brazil, evaluated the predictive performance of the CQESTR carbon prediction model for a tropical savannah and examined the effect of integrated management systems, including the Integrated Crop-Livestock System (ICLS) scenarios on SOC stocks. Two long-term paddocks were used under similar soils and climate conditions. In Paddock-4 (P4), the rotation was corn and 3.5/4.5 years pasture, while crop rotations in Paddock-5 (P5) included 2.5 years of soybean, dryland rice, and corn followed by 2.5/3.5 years pasture. Measured and CQESTR simulated values were significantly correlated (r = 0.94), indicating that the model captured dynamics of SOC. Predicted SOC increased by 28% and 19% under current management for P4 and P5, respectively, by 2039. ICLS increased SOC compared to grain cropping systems under both no-till and conventional tillage due to high biomass. These results will be of great interest to land managers, other scientists and policy makers striving to adapt agricultural and climate change policies.
3. Improving soil carbon estimates in the DAYCENT model improved soil carbon prediction under future climate change scenarios. Soil carbon models help us understand climate change but a major challenge in these models is accurately representing soil processes that affect soil organic carbon (SOC) storage. ARS researchers in Pendleton, Oregon; Beltsville, Maryland; Lincoln, Nebraska; along with researchers at the Woodwell Climate Research Center and Rodale Institute, Falmouth, Massachusetts, updated the DAYCENT model with measured SOC data obtained from long-term ARS research locations, then compared the modified model (DCmod) with the default model (DCdef) to evaluate how SOC responded to current and future scenarios of climate change in the U.S. Great Plains region. The DCmod improved predictions of current SOC compared to DCdef and suggested that soils in managed grasslands and croplands today have lost 4% and 40%, respectively, of the original SOC in native Great Plains soils. Losses of SOC were predicted under all future modeling scenarios. These results will be of great interest to other scientists and to policy makers striving to adapt agricultural and climate change policies in a rapidly changing world.
4. Wheat stubble management to maximize water for the next crop. With changes in equipment, dryland farmers need an updated evaluation of how the height of wheat stubble left after harvest affects overwinter precipitation capture and water retention in the soil during the dry summer months. ARS researchers in Pendleton, Oregon, along with collaborators at Washington State University, created stubble-height treatments of short (8 cm), medium (25 cm), and tall (75 cm), plus tall stubble mowed short in mid-June. On average, tall-and medium-height stubble captured more overwinter precipitation than short stubble, but tall stubble lost more water during summer. Mowing tall stubble in June did not improve water retention. Soil temperatures were progressively warmer in short, mowed, medium, and tall stubble with significant differences of over 1 degree C among treatments. At the end of fallow, medium stubble had the most soil water. Medium-height winter wheat stubble is the best option for soil water retention in Pacific Northwest drylands.
Review Publications
Oliveira, J.M., Gollany, H.T., Polumsky, R.W., Madari, B.E., Leite, L.F., Machado, P.L., Carvalho, M.T. 2022. Predicting soil organic carbon dynamics of integrated crop-livestock system in Brazil using the CQESTR model. Frontiers in Environmental Science. 10. Article 826786. https://doi.org/10.3389/fenvs.2022.826786.
Dangal, S.R., Schwalm, C., Cavigelli, M.A., Gollany, H.T., Jin, V.L., Sanderman, J. 2022. Improving soil carbon estimates by linking conceptual pools against measurable carbon fractions in the DAYCENT Model Version 4.5. Journal of Advances in Modeling Earth Systems. https://doi.org/10.1029/2021MS002622.
Hussain, T., Gollany, H.T., Hussain, N., Ahmed, M., Tahir, M., Duangpan, S. 2022. Synchronizing nitrogen fertilization and planting date to improve resource use efficiency, productivity, and profitability of upland rice. Frontiers in Plant Science. 13. Article 895811. https://doi.org/10.3389/fpls.2022.895811.
Schillinger, W.F., Wuest, S.B. 2021. Wheat stubble height effects on soil water capture and retention during long fallow. Agricultural Water Management. 256. Article 107117. https://doi.org/10.1016/j.agwat.2021.107117.
Sanderman, J., Savage, K., Dangal, S.R., Duran, G., Rivard, C., Cavigelli, M.A., Gollany, H.T., Jin, V.L., Liebig, M.A., Omondi, E.C., Rui, Y., Stewart, C. 2021. Can agricultural management induced changes in soil organic carbon be detected using mid-infrared spectroscopy? Remote Sensing. 13(12). Article 2265. https://doi.org/10.3390/rs13122265.
Gollany, H.T., Del Grosso, S.J., Dell, C.J., Adler, P.R., Polumsky, R.W. 2021. Assessing the effectiveness of agricultural conservation practices in maintaining soil organic carbon under contrasting agroecosystems and a changing climate. Soil Science Society of America Journal. 85(5):1362-1379. https://doi.org/10.1002/saj2.20232.
Wuest, S.B., Reardon, C.L. 2021. Electrostatic method to remove particulate organic matter from soil. The Journal of Visualized Experiments (JoVE). 168. Article e61915. https://doi.org/10.3791/61915.
