Location: Agricultural Systems Research2013 Annual Report
1a. Objectives (from AD-416):
1. Develop strategies for irrigated production systems using increased crop diversity, reduced tillage, and emerging technologies to improve agricultural chemical, water and nutrient use efficiencies. 2. Develop biological based disease control strategies for NGP production systems. 3. Develop dryland production strategies with increased crop diversity and advanced technologies to improve agricultural chemical, water, and nutrient use efficiencies to increase competitiveness and enhance natural resource quality.
1b. Approach (from AD-416):
This project involves eight scientists (8 SYs) and many collaborators that represent a broad range of disciplines focused on the long-term, 10- to 12-year goal of developing sustainable strategies for both irrigated and dryland crop production systems for the MonDak region of eastern Montana and western North Dakota. The ASRU is organized to address basic and applied research issues using an interdisciplinary team approach where multiple hypotheses are tested in four large “Unit Projects.” The “Unit Project” objectives are designed to encompass cropping system development, concurrent development and application of “metrics” or indicators of system performance, and the assessment process by which systems are evaluated and judged. There is considerable overlap, but responsibilities can be generally divided into two broad, overlapping categories with four scientists (Allen, Evans, Lartey and Stevens) primarily examining the systems aspects, and four scientists (Caesar-TonThat, Jabro, Lenssen and Sainju) focusing their research on developing and evaluating various metrics of cropping system performance. These Unit projects focus on biologically diverse cropping systems. Biological control research (Obj. 2) of two plant diseases spans both dryland (Obj. 3) and irrigated (Obj. 1) systems. Three of the Unit projects (one irrigated and two dryland) are currently underway and one new irrigated project will be initiated in 2009. Each Unit project will be replaced by a new Unit project as they are completed.
3. Progress Report:
Irrigated Systems: Efforts continued on two long-term cropping systems studies: 1) Sampling and data collection were completed for the third year of a 6-year study comparing a two-year sugarbeet/malt barley rotation to three-year rotations that include legume and/or bioenergy crops; 2) After establishing rotations in FY2012, the first year of data collection was completed in FY2013 for a new 8-year cropping systems study evaluating cropping system diversity and tillage practices on crop yield, weed and disease incidence, and soil quality. The third and final year of data collection was completed for a field study to evaluate how the lateral distance between banded fertilizer and crop row affects early growth and final yield of sugarbeet. Manuscripts were submitted for publication regarding effects of repeated freeze thaw cycles on soil compaction and evaluation of spatial and temporal variability of soils across sugarbeet rows and inter-rows in tillage systems. Sixteen state of the art soil water lysimeters were designed, constructed and placed below the rootzone of corn and soybean irrigated cropping systems under no-till and conventional tillage practices. We continued modeling both dryland and irrigated sites using RZWQM2 model as part of a collaboration with ARS in Ft. Collins, CO. Dryland Systems: All necessary planting, soil sampling, fertilizer application, and harvest activities were completed in a timely manner. Final soil sampling was completed at the conclusion of a long-term (2004-2012) dryland cropping study with varying levels of cropping intensity, tillage, and management. Crop sequences were established and initial soil samples taken including those for soil water and nitrogen in two large and complex dryland long-term (2013-2019 and 2013-2021) unit trials with varying levels of cropping intensity and management. Three plant residue degrading enzyme assays for soil were initiated. Cropping former Conservation Reserve Program (CRP) lands: In a study of croplands converted from CRP, a no-till malt barley-pea rotation with 67 to 134 kg nitrogen/ ha has been shown to reduce soil organic matter, increase soil carbon sequestration, reduce nitrogen losses through soil processes, and decrease global warming potential compared to other annual cropping systems, regardless of irrigation practices, in western North Dakota. Plant disease: The lab developed field trials for control of Cercospora beticola (Cercospora leaf spot) of sugar beet and Peniophora teres (net blotch) of barley with a disease antagonist: Laetisaria arvalis. Due to lack of field space, facilities and personnel, Trichoderma species field trials have been limited to greenhouse studies. We continued to search for other biocontrol agents of diseases, and Peniophora nuda, a novel potential agent was identified. Basic research on P. nuda was conducted in the lab and with collaborators on antagonism and interaction with pathogens as a basis for biocontrol of P. teres and C. beticola. Chitinase-producing bacteria (chitin is a major component of fungi) isolated and identified from pea soil were used to antagonize C. beticola, a major fungal disease of sugar beet.
1. Perennial grass biomass is influenced more by grass species than by nitrogen fertilization. Perennial grasses grown in dryland (non-irrigated) systems can potentially be used for cellulosic ethanol production or as feed for livestock. ARS researchers at Sidney, MT investigated the response of nitrogen fertilization on three grass species targeted for biomass production. Results suggested that in wetter than normal years intermediate wheatgrass yields are about 25 to 50% greater than those for smooth brome and switchgrass, but that in average rainfall years biomass yield is similar. The response of the grass species to the four nitrogen fertilizer rates was similar, and only during a wet year was a 20% increase in biomass observed at the greatest nitrogen rate (75 kg/ha) compared to the control (0 kg/ha). Perennial grass biomass production in the Northern Great Plains is possible, but inconsistent response to nitrogen fertilizer and inconsistent yields associated with dryland climate could limit its use as a feedstock.
2. Improved management technique can sustain malt yield and quality and increase soil organic matter. Traditional farming systems, such as conventional tillage with malt barley-fallow, have reduced annualized malt barley yield and soil organic matter. Improved management practices are needed to sustain malt barley production. Scientists at ARS, Sidney, MT evaluated the effects of tillage, cropping sequence, and nitrogen fertilization on malt barley yield and quality and soil carbon and nitrogen levels from 2006 to 2011. Their study revealed that no-till malt barley-pea rotation with 40 kg nitrogen/ha can sustain malt barley yield and quality, reduce nitrogen fertilization rate, increase carbon sequestration, and decrease nitrogen loss compared to the traditional systems.
3. Fungi that degrade dead plant material increase under no-till management of dryland barley in the Northern Great Plains. Literature on the long-term effects of improved management practices for dryland barley cropping system on soil microbial community and activity is sparse. ARS researchers in Sidney, MT investigated the long-term effects of barley cropping practices and rotation sequence on microbial communities and their enzymes that degrade dead plant material. Treatments were no-till continuous malt barley, no-till malt barley-pea, and conventional-till malt barley-fallow. The amount of fungi and plant degrading enzyme activity significantly increased under no-till treatments compared to conventional tillage, suggesting cost savings and healthier soil for barley producers in the Northern Great Plains.
4. Natural shrink-swell cycles reduce soil compaction from agricultural practices. In recent years, intensive farming and heavier machinery have led to increased soil compaction prompting greater local and global concerns regarding reductions in crop production and soil quality in mechanized modern agricultural systems. That concern has led to increased use of deep tillage and other soil management techniques by producers, which involve considerable expenditures of time, money and fuel. ARS scientists in Sidney, MT have found that frequent shrink-swell cycles in clayey soils caused by periodic drying-wetting processes help alleviate soil compaction at the 0 to 12 inch depth, which encompasses the underground root zones of many crops. These results demonstrate how natural shrink-swell resulting can reduce the need to employ additional costly measures to achieve the same agricultural productivity in clayey soils compacted by heavy machinery.
5. Sheep grazing can be used to sustain crop yields and increase soil carbon and nitrogen storage. Sheep grazing is a cost-effective method of controlling weeds compared to herbicide application or tillage, but little is known about its effect on soil carbon and nitrogen levels in the Northern Great Plains. In collaboration with Montana State University, scientists at ARS, Sidney, MT examined the effects of sheep grazing compared to herbicide application and tillage on soil carbon and nitrogen and crop yields under dryland annual and perennial cropping systems from 2009 to 2011 in western Montana. Results showed that sheep grazing for weed control increased soil carbon and nitrogen storage without affecting crop yields, especially in annual cropping systems, compared to herbicide application.
6. A healthier soil environment under strip tillage for sugarbeet. Strip tillage (which disturbs only the portion of the soil that is to contain the seed row) can save producers up to $100/acre due to reduction in input costs (fuel, energy, time and labor), but it is unclear if it leaves the soils too compacted for efficient sugarbeet production. ARS scientists at Sidney, MT conducted a 2-yr study on clay loam soil to evaluate soil compaction in sugarbeet fields under conventional and strip tillage practices. Results showed that soil penetration resistance was considerably greater under conventional tillage (230 psi) than under strip tillage (165 psi) when averaged across all positions in sugarbeet rows and inter-rows (2 ft long) and all depths (between 0 to 30 inches). This demonstrates that strip tillage can help farmers maintain better soil health and quality through improved soil water retention, soil infiltration, increased organic matter content, and reduced erosion, therefore contributing to more sustainable or even increased crop yields with lowered input costs.
Sainju, U.M., Lenssen, A.W., Caesar, T., Jabro, J.D., Lartey, R.T., Evans, R.G., Allen, B.L. 2012. Tillage, crop rotation, and cultural practice effects on dryland soil carbon fractions. Open Journal of Soil Science. 2(3):242-255.