gci Chen

Nitrogen and harvest management of Conservation Reserve Program (CRP) grassland for sustainable biomass feedstock production

The Biomass Regional Feedstock Partnership has identified grasslands planted under the Conservation Reserve Program (CRP) as a potential source for herbaceous bioenergy feedstock. The goal of this project is to assess the yield potential of CRP grasslands across diverse regions. Consistent with that goal, the objective of this project was to establish yield potential and quality parameters for several different CRP grasslands, representative of different growing environments. Standard field scale agricultural practices were used as management guidelines at each location. The test locations were identified and established based on known regions containing concentrated tracts of CRP grassland and represented variable climatic parameters and production histories. Biomass production potential for CRP land dominated by either warm‐ or cool‐season grass mixtures in each location was evaluated over the course of three growing seasons (2008, 2009, and 2010). Specifically, a mixture of warm‐season perennial grasses was evaluated in North Dakota, Kansas, and Oklahoma, while a cool‐season mixture was evaluated in Montana, Georgia, and Missouri. Maximum biomass yields for the three warm‐season CRP sites ranged from 4.0 to 7.2 Mg ha−1 and for the three cool‐season CRP sites 3.4–6.0 Mg ha−1. Our results demonstrate that CRP grassland has potential as a bioenergy feedstock resource if the appropriate management practices are followed.

Yield response of pea, lentil and chickpea to phosphorus addition in a clay loam soil of central Montana

Production of pea, lentil and chickpea, as a forage and food source, has increasingly become a popular agricultural practice in the northern Great Plains. While many local soils are rich in phosphorus (P), it has been commonly believed that P-fertilization still has potential to promote production. A two-year (2003–2004) field study was conducted to fine-tune P fertilization strategies in a clay loam soil (14 mg Olsen-P kg−1, sodium bicarbonate extractable soil P) of central Montana. Treatments included three varieties for each of the three crop species (pea: Majorest, Mozart and Delta; lentil: Vantage, Richlea and Brewer; and chickpea: Yuma, Myles and Chico), a control (0 P) and three P rates (7.3, 14.7 and 22.0 kg P ha−1) in triple super-phosphate (TSP), arranged in a randomized complete block design with four replicates. Responses of grain and forage yield to P addition varied depending on crop species and varieties within each species. Grain yields correlated quadratically to the rate of P applied for Majoret, Mozart and Brewer. Forage yield of Majoret, Mozart, Vantage and Richlea was significantly increased with P addition. P-addition enhanced vegetative growth as evidenced by the increased shoot-grain ratio. Chickpea varieties did not respond to P fertilization. The best yielding variety in this soil was Mozart, Vantage and Myles from each species, respectively. To facilitate decision making for producers, the relationship between the increased yield and the rate of P application was quantified. Averaged over two years, by growing Majoret, Mozart, Vantage and Richlea for forage at low rate of P application (7.3 kg P ha−1), income was about 1.8–2.3 times of the cost of P fertilizer applied.

Biomass production of herbaceous energy crops in the United States: field trial results and yield potential maps from the multiyear regional feedstock partnership

Current knowledge of yield potential and best agronomic management practices for perennial bioenergy grasses is primarily derived from small‐scale and short‐term studies, yet these studies inform policy at the national scale. In an effort to learn more about how bioenergy grasses perform across multiple locations and years, the U.S. Department of Energy (US DOE)/Sun Grant Initiative Regional Feedstock Partnership was initiated in 2008. The objectives of the Feedstock Partnership were to (1) provide a wide range of information for feedstock selection (species choice) and management practice options for a variety of regions and (2) develop national maps of potential feedstock yield for each of the herbaceous species evaluated. The Feedstock Partnership expands our previous understanding of the bioenergy potential of switchgrass, Miscanthus, sorghum, energycane, and prairie mixtures on Conservation Reserve Program land by conducting long‐term, replicated trials of each species at diverse environments in the U.S. Trials were initiated between 2008 and 2010 and completed between 2012 and 2015 depending on species. Field‐scale plots were utilized for switchgrass and Conservation Reserve Program trials to use traditional agricultural machinery. This is important as we know that the smaller scale studies often overestimated yield potential of some of these species. Insufficient vegetative propagules of energycane and Miscanthus prohibited farm‐scale trials of these species. The Feedstock Partnership studies also confirmed that environmental differences across years and across sites had a large impact on biomass production. Nitrogen application had variable effects across feedstocks, but some nitrogen fertilizer generally had a positive effect. National yield potential maps were developed using PRISM‐ELM for each species in the Feedstock Partnership. This manuscript, with the accompanying supplemental data, will be useful in making decisions about feedstock selection as well as agronomic practices across a wide region of the country.

Impacts of management practices on bioenergy feedstock yield and economic feasibility on Conservation Reserve Program grasslands

Perennial grass mixtures planted on Conservation Reserve Program (CRP) land are a potential source of dedicated bioenergy feedstock. Long‐term nitrogen (N) and harvest management are critical factors for maximizing biomass yield while maintaining the longevity of grass stands. A six‐year farm‐scale study was conducted to understand the impact of weather variability on biomass yield, determine optimal N fertilization and harvest timing management practices for sustainable biomass production, and estimate economic viability at six CRP sites in the United States. Precipitation during the growing season was a critical factor for annual biomass production across all regions, and annual biomass production was severely reduced when growing season precipitation was below 50% of average. The N rate of 112 kg ha−1 produced the highest biomass yield at each location. Harvest timing resulting in the highest biomass yield was site‐specific and was a factor of predominant grass type, seasonal precipitation, and the number of harvests taken per year. The use of N fertilizer for yield enhancement unambiguously increased the cost of biomass regardless of the harvest timing for all six sites. The breakeven price of biomass at the farmgate ranged from

Lentil Response to Nitrogen Application and Rhizobia Inoculation

37 to

Efficacy of starter N fertilizer and rhizobia inoculant in dry pea (Pisum sativum Linn.) production in a semi-arid temperate environment

311 Mg−1 depending on the rate of N application, timing of harvesting, and location when foregone opportunity costs were not considered. Breakeven prices ranged from

Evaluation of Dry Peas (Pisum sativum L.) Varieties for Seedling Vigor Indices in Eastern Montana

69 to

ROW CONFIGURATION AND NITROGEN APPLICATION FOR BARLEY-PEA INTERCROPPING IN MONTANA

526 Mg−1 when the loss of CRP land rental payments was included as an opportunity cost. Annual cost of the CRP to the federal government could be reduced by over 8% in the states included in this study; however, this would require the biomass price to be much higher than in the case where the landowner receives the CRP land rent. This field research demonstrated the importance of long‐term, farm‐scale research for accurate estimation of biomass feedstock production and economic viability from perennial grasslands.

Determining the feasibility of early seeding canola in the northern great plains

ABSTRACT Lentils (Lens culinaris L.) are an important component of the dryland farming systems in the western USA. Optimum nitrogen (N) management can enhance yield and quality of lentils. We conducted a field (at two locations, one with previous history of lentil and the other one without lentil history) and a greenhouse study to evaluate response of lentil to the application of rhizobium inoculant and starter N (control, 22 kg N ha−1 in the form of urea [U], 22 kg N ha−1 in the form of slow-release or environmentally safe nitrogen [ESN], and 22 kg N ha−1 U + 22 kg N ha−1 ESN). In both, the field and the laboratory studies, lentil yield did not respond positively to the experimental treatments. Lentil average yield was 1216 and 1420 kg ha−1 at the field condition. In this rain-fed system, lentil yield was mainly limited by moisture availability, and the application of an external N did not contribute to the yield enhancement. Both of these treatments, however, increased protein content. Compared to the control, the application of rhizobium plus U and ESN enhanced protein content by about 34% (from 23.1 to 30.9%). The application of U+ESN also considerably increased postharvest residual nitrate (NO3)-N in the soil, which can be easily leached and creates environmental pollution. Briefly, the application of U+ESN increases lentil protein content, but more efforts are needed to optimize N management in lentils in order to reduce the environmental concerns in the shallow soil.

Hard Red Spring Wheat Response to Row Spacing, Seeding Rate, and Nitrogen

ABSTRACT Uncertainties exist about the importance of rhizobia inoculant and starter nitrogen (N) application in dry pea (Pisum sativum L.) production. Three field experiments were conducted to evaluate how rhizobia inoculant and starter N fertilizer affect pea seed yield and protein concentration in a semi-arid environment in central Montana. Commercial rhizobia inoculant was mixed with seed prior to planting at the manufacturer’s recommended rate. Starter N fertilizers were applied into the same furrow as seed at 0, 22, 44 and 88 kg ha−1 as urea, slow-release polymer-coated N fertilizer (ESN), and a combination of both. The application of rhizobia inoculant had no or a very small beneficial effect on pea yield in lands with a previous history of peas. In a land without pea history, application of rhizobia increased pea seed yield by 16%. The positive effect of starter N was only pronounced when initial soil N was low (≤ 10 kg ha−1 nitrate-nitrogen), which increased net return by up to US