Location: Agricultural Systems Research2009 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
Two,large irrigation Unit studies comparing the effects of tillage system, high-efficiency irrigation practices and cropping sequence on agronomic and environmental parameters are being conducted. A new irrigated cropping system was initiated in FY2009 comparing 3-year rotations of sugarbeet, barley, corn and edible soybean. Work progressed toward determining best management practices for N fertilization for strip till sugarbeets to evaluate the effects of this tillage system on N availability and uptake. Studies evaluating late-season N fertigation and polymer-coated slow-release urea showed that sugarbeet root yield on sandy soils could be improved without sacrificing sucrose concentration or extractability. Dryland cropping systems research made progress in many areas including starting the second stage of one of two large, multi-site, multidisciplinary studies investigating interactive effects of tillage, diversification, and cultural management practices on crop yield, competitiveness with weeds, water use, nitrogen cycling and N use to improve our understanding of agronomic and environmental sustainability. Data were gathered from five different crop rotation studies. Emphasis is on replacing summer fallow with cool-season crucifers, and tillage, cultural management, and rotation influences on spring wheat, durum, pea, canola, flax, corn, and forage barley. A dryland study on efficacy of L. arvalis as an alternate treatment to synthetic fungicide seed treatment of barley was positive for the second year. Field research with alternative crops and methods to improve their establishment and yield was continued. Two new biomass production studies were started to assess the suitability of various crops to our region for both feed and fuel. Crop growth and yield were measured to compare relative performance and agronomic characteristics of various oil seeds in a dryland environment. Dryland systems studies activities include spring soil sampling, installing access tubes to monitor soil water, measuring soil water content during the growing season, and harvest activities. The effects of soil and crop management practices [tillage, cropping sequence, nitrogen (N) fertilization and cultural practices] were evaluated for soil carbon (C ) and N sequestration and fractions, C and N contents of soil surface residue, GHG emissions, and crop grain and biomass yields in both dryland and irrigated cropping systems. The proportion of specialized bacteria species and fungi associated with soil aggregation, their community structure and enzymatic activity was assessed for cropping systems under different tillage practices and in rotational cropping systems in dryland and irrigated lands. PCR primers and a serum containing antibodies against P. teres cell wall have been generated, and an ELISA assay is being tested for specificity. Plant, weather and management data from both irrigated and dry cropping systems were compiled for RZWQ2 model evaluation. Field and lab data from many irrigated and dryland experiments continue to be analyzed and prepared for publication in peer-reviewed scientific journals and presentation to customers.
1. Improved management practices increase soil nitrogen cycling and reduce nitrogen losses. No-tilled annual cropping systems can increase soil N storage and reduce N fertilization rates and N losses compared with conventional-tilled crop-fallow systems under dryland cropping systems in the Northern Great Plains. Conventional tillage and with crop-fallow practices have reduced soil N storage and increased the need of N fertilization to sustain dryland soil productivity and crop yields in the last 30-50 years in the region. ARS scientists in eastern Montana evaluated the effects of 21 years of tillage and cropping sequence on N cycling in dryland cropping systems. They found that conservation tillage with annual cropping systems increased crop N uptake, soil and residue N storage and N mineralization, and reduced N losses compared with the conventional tillage in a crop-fallow system. N loss through leaching, volatilization, or denitrification was shown to increase with increasing tillage frequency or greater with crop-fallow than with annual cropping. N losses ranged from 9 kg N ha-1 yr-1 in no-tilled annual cropping to as much as 46 kg N ha-1 yr-1 in the conventional-tilled crop-fallow.
2. Strip tillage of sugarbeet reduces both energy use and N fertilizer without decreasing yields. Reduced energy usage is a major economic benefit of reduced tillage systems, which has the advantage of reducing machinery passes (time and equipment maintenance savings. Strip tillage significantly reduced energy (fuel), equipment time, and maintenance requirements as well as provided increased soil water retention efficiencies from winter precipitation and improved soil erosion management for wind compared to conventional methods. It was estimated that switching from chisel plow to strip till would result in an annual on-farm savings of about $50/ha. Whereas switching from moldboard plow to strip till on the same field would annual save about $80/ha. Five years of research has also shown that sugarbeets grown with strip tillage produce similar yields to those grown under conventional practices. In addition, N availability and uptake tend to be somewhat lower with strip tillage than with conventional practices, but sugarbeet yield can be maintained with the same N application rate as is used for conventional tillage systems as long as proper placement and application timing practices are followed.
3. Improved nitrogen fertilizer management for furrow-irrigated sugarbeet. A savings of about $55 per ha can be realized through precision N fertilizer placement-- assuming a nitrogen cost of $1.10 per kg. These techniques can reduce the amount of nitrogen fertilizer required by about 50 kg per ha compared to other common placement methods under furrow irrigation. Evaluations of the impact of various N fertilizer management practices have shown that precision placement of preplant N applications near the crop row (8 cm) using liquid point-injection equipment was superior to banded applications farther from the crop row or broadcast applications. This work also demonstrated that while current sugarbeet varieties respond similarly to nitrogen fertilization, some produced more sucrose per kg of above-ground biomass than did others, especially at lower-than-optimum nitrogen rates. Under deficit nitrogen conditions, varieties that produce higher amounts of sugar by limiting top growth are more profitable than varieties that favor above ground biomass production. Rising N costs may cause growers to reduce the amount of fertilizer applied to minimize purchased input costs.
4. Integrated Dryland Production Systems Enhance Long-term Production. Inclusion of annual cool-season forages in diversified cropping systems decreases pesticide use and increases productivity of pea and spring wheat. Diversified, intensified cropping systems are replacing wheat-summer fallow systems in the Northern Great Plains. Spring wheat grown every third or fourth year in diversified cropping systems has been shown to have higher yields and quality and fewer weeds and weed seed production compared to spring wheat grown continuously or planted every other year. Field pea grown every third or fourth year in diversified systems has higher yields and fewer weeds compared to pea grown every other year. Field pea produced in alternate year rotations has improved yield compared to field pea following broadleaf crops in stacked rotations.
5. Roots reduce nitrogen leaching loss and maintain soil organic matter. Little is known about root distribution of crops grown under dryland cropping systems and its effect on water and nutrient uptake and soil organic matter. In dryland cropping systems, root growth depends on limited soil water availability and may influence soil C and N sequestration. Root biomass and C and N contents to a depth of 120 cm were determined in 4-year-old dryland alfalfa and durum-annual forage sequences and related them with soil water and C and N contents in eastern Montana. Root biomass and C and N contents were greater but soil water and nitrate-N contents were lower in alfalfa than in durum-forage sequences. In contrast, soil N content was greater in durum-pea/barley mixture hay than in durum-foxtail millet hay. Alfalfa may reduce N leaching and maintain higher soil C and N storage compared with durum-annual forage sequences due to its greater root biomass and C and N inputs. Because of greater N input, durum-pea/forage barley mixture may increase soil N levels more than alfalfa alone.
6. Automated water sampler developed for estimating drainage below the soil surface. Various water samplers are widely used to monitor and measure drainage water and chemical leaching under saturated and unsaturated soil conditions below the root zone, but few work well. The performance and accuracy of an automated, low cost sampler for estimating drainage water below the rootzone of a sugarbeet-potato-barley rotation under two irrigation frequencies was evaluated. Statistical analyses indicated an excellent agreement between the manually extracted and logged drainage water volumes. Three years of results have confirmed that automated samplers are accurate, effective and provided convenient means for estimating water drainage below the soil surface zone without the need for costly and manually time-consuming electronic and other supportive systems. The direct impact of this research that NRCS, farmers and others can economically more accurately determine the amount of fertilizer and irrigation to use on their crops to maintain yields yet avoid groundwater contamination.
7. Dryland Corn Seeding Rate and Row Configurations Impact Yield And Water Productivity. Altering management practices in dryland corn production increased yield potential, improves water productivity, and reduces input costs in a semi-arid environment. In regions that receive on average as little as 13-15 inches annual precipitation, limited crop-available water in the soil during critical growth stages typically limits yield more than other growth factors. When planting rates exceeded 15,000 seeds per acre in these areas of low annual rainfall, corn utilized the limited available soil moisture early in the growing season to produce vegetative growth at the expense of grain fill. Conversely, when corn was planted at rates as low as 10,000 seeds per acre, there was greater soil water during the reproductive stages resulting in both greater corn grain yield and a greater proportion of total biomass as grain. Planting corn in a skip-row configuration (plant 2 rows skip 1 row) had little impact on grain yield, though biomass yield was often greater than when corn is planted in every row.
8. Methods developed for quick detection of Pyrenophora teres. These new protocols enable rapid confirmation of observed symptoms in addition to determining lesion area in drawing conclusion on disease severity of Pyrenophora teres, a major disease causing organism in barley. Application of these protocol to detect the organism in soils and in plant tissues will enable determination of efficacy of applied biological agents in managing Net blotch on barley. Antibodies for detection of P. teres by ELISA was developed and is undergoing various tests. Preliminary results have shown positive results on infected leaves. Primers were developed for rapid PCR detection protocol. Several tests showed the primers lacked adequate specificity for the protocol so project personnel determined additional DNA sequences to improve the protocol. In the process, they have so far determined 924 base pairs, and are continuing to determine additional sequences in case the present sequence proves to be inadequate. The entire sequence will eventually be submitted to GenBank for universal accession. Based on an earlier technique, a PCR protocol was developed for rapid detection of P. teres without the need to isolate, sub-culture and purify the DNA from infected plant tissues.
Kaiser, D.E., Mallarino, A.P., Haq, M.U., Allen, B.L. 2009. Runoff Phosphorus Loss Immediately after Poultry Manure Application as Influenced by the Application Rate and Tillage. Journal of Environmental Quality. 38: 299-308.