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A strategic plan for future USDA- Agricultural Research Service erosion research and model development
No full textSoil erosion is a natural process, and the erosion potential of a site is the result of complex interactions among soil, vegetation, topographic position, land use and management, and climate. Soil erosion occurs when aeolian and hydrologic processes exceed a soil’s inherent resistance to these forces. Soil erosion was recognized as a significant problem at both local and national scales in the United States in the 1920s; by 1935 soil erosion was considered a national disaster, covering over one-half of the country (Sampson and Weyl 1918; Weaver 1935), and is still a concern with 21% of the western United States degraded and vulnerable to accelerated soil erosion (Herrick et al. 2010; Weltz et al. 2014a; Duniway et al. 2019). In 1995, it was estimated that 4 × 109 t (4.4 × 109 tn) of soil was lost from US cropland (Pimentel et al. 1995). The most vulnerable areas for soil movement and thus erosion occur where annual precipitation is 100 to 400 mm y–1 (4 to 16 in yr–1), which limits soil moisture available to sustain plant growth. Anthropogenic-driven dust emissions have dramatically increased across the globe (Webb and Pierre 2018) and in the United States (Neff et al. 2008) over last several decades. On-site and off-site costs associated with wind erosion exceeds US44 billion y–1, or about US40 ac–1) of cropland and pasture (Pimentel et al. 1995), and US132.8 billion or 1% of the US gross domestic product. Erosion increases production costs by ~25% each year
Managing crop nutrients to achieve water quality goals
Get PDFLandscapes and watersheds are inherently leaky and some nutrient loss can be expected with productive agricultural systems. Minimizing these losses, without undermining system sustainability is challenging and should involve an open and constructive discussion among all stakeholders as to what nutrient loss is desired, achievable, and how differences between these two endpoints can be reconciled. This is complicated by short- and long-term variations in weather/climate are a major factor influencing nutrient loss from agricultural lands. Nitrogen (N) loss tends to be spatially extensive, with management of the rate and timing of application, along with cropping systems as being important determining factors. Phosphorus (P) loss, on the other hand tends to be a function of critical sources areas, where coincident source (e.g., soil P and rate, timing, method and type of P applied) and transport factors (e.g., runoff and erosion) define losses. Despite this, legacy N and P from prior land management can mask the benefits of current and future conservation practices (CPs) to reduce losses from agricultural systems. Here, the appropriate use of calibrated and validated nonpoint source watershed models to estimate relative contributions of nutrient sources and outcomes of CP implementation can inform future strategies. However, they must be used in conjunction with and cannot replace water quality monitoring programs. Great strides have been made in nutrient use efficiency via nutrient management, crop selection, and CP adoption, which have reduced the risk of nutrient loss to surface and ground waters. Even so, additional research is needed on the areas of nutrient management on drained lands, fluvial legacies, and socio-economic factors influencing the success of conservation strategies
Soil phosphorus testing on alkaline calcareous soils
Get PDFSoil phosphorus testing made great strides with multiple chemical tests proposed and implemented that have been used for fertilizer management programs for crop production during the previous century. In the latter part of the previous century, the environmental impact of excess nonpoint phosphorus loading from the landscape (e.g. agricultural lands) to waterbodies became an issue of increased concern and soil phosphorus testing came to the forefront of management and monitoring. This article will provide a general overview of the usage of phosphorus testing for agronomic purposes in the United States
Commercial sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2017.
Get PDFRhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 26 commercial cultivars were screened by growing them in a sugar beet field infested with BNYVV in Kimberly, ID during the 2017 growing season in a randomized complete block design with 6 replications. At harvest on 2-3 October 2017, roots were dug and evaluated for symptoms of rhizomania and also placed in an indoor commercial sugar beet storage building. After 147 days in storage, samples were evaluated for surface rot, weight loss, and sucrose loss. Surface root rot ranged from 10 to 85%, weight loss ranged from 14 to 28%, sucrose losses ranged from 25 to 87%, and estimated recoverable sucrose ranged from 596 to 9,111 lb/A. Given these response ranges, selecting cultivars for rhizomania resistance and combining this resistance with storability will lead to considerable economic benefit for the sugar beet industry
Beet curly top resistance in USDA-ARS Ft. Collins germplasm, 2018
Get PDFCurly top caused by Beet curly top virus (BCTV) is a widespread disease problem vectored by the beet leafhopper in semiarid sugar beet production areas. Host resistance is the primary defense against this problem, but resistance in commercial cultivars is only low to intermediate. In order to identify novel sources of curly top resistance, 30 sugar beet lines produced by the USDA-ARS Ft. Collins sugar beet program were screened in a disease nursery in 2018. The lines were arranged in a randomized complete block design with six replications. A curly top epiphytotic was created by releasing six viruliferous beet leafhoppers per plant at the four- to six-leaf growth stage on 25 June. Foliar symptoms were evaluated on 10 July using a scale of 0-9 (0 = healthy and 9 = dead) in a continuous manner. Curly top symptom development was uniform and no other disease problems were evident in the plot area. The disease pressure in the test was moderately severe with good symptom development in the susceptible checks. Based on the visual rating, entry 26 performed the same as the resistant checks. This germplasm line will be reevaluated for potential release to the general public so it can be utilized to improve BCTV resistance in commercial sugar beet cultivars
Survey of selected antibiotic resistance genes in agricultural and non-agricultural soils in south-central Idaho
Get PDFAgroecosystems are regions of intense agriculture production, which could be a potential hotspot for antibiotic resistance. In this study, agricultural soils (cropland, inactive cropland, pastureland, rangeland) and non-agricultural soils (recreational, residential, industrial, natural) were collected in south-central Idaho, then analyzed using quantitative real-time PCR (qPCR) to determine the occurrence and abundance of a class 1 integron-integrase gene (intI1) and six antibiotic resistance genes (ARGs): blaCTX-M-1, erm(B), sul1, tet(B), tet(M), and tet(X). All of the ARGs (except blaCTX-M-1) and intI1 were detected in some of the soils (15 to 60 detections out of 98 samples), with sul1 and intI1 being detected the most frequently. Except for a few instances, erm(B), tet(B), and tet(X) were primarily detected in the cropland soils. In addition, intI1, sul1, and tet(M) were detected more frequently in the cropland soils and in greater relative abundances on average than in all other soils. The results from this study provide evidence that intensively managed cropland soils have a resistome that is greatly altered from that of other agricultural and native soils
Beet curly top resistance in USDA-ARS Plant Introduction Lines, 2018
Get PDFCurly top caused by Beet curly top virus (BCTV) is a widespread disease problem vectored by the beet leafhopper in semiarid sugar beet production areas. Host resistance is the primary defense against this problem, but resistance in commercial cultivars is only low to intermediate. In order to identify novel sources of curly top resistance, 30 sugar beet USDA-ARS Plant Introduction (PI) lines were screened in a disease nursery in 2018. The lines were arranged in a randomized complete block design with six replications. A curly top epiphytotic was created by releasing six viruliferous beet leafhoppers per plant at the four- to six-leaf growth stage on 25 June. Foliar symptoms were evaluated on 10 July using a scale of 0-9 (0 = healthy and 9 = dead) in a continuous manner. Curly top symptom development was uniform and no other disease problems were evident in the plot area. The disease pressure in the test was severe with good symptom development in the susceptible checks. Based on the visual rating, five entries (18, 22, 26, 27, and 29) performed the same as the resistant check. These germplasm lines will be investigated further for incorporation into germplasm lines so they can be utilized to improve BCTV resistance in commercial sugar beet cultivars
Catalog of Penicillium spp. causing blue mold of bulbs, roots, and tubers
Get PDFAccuracy of assignment of specific epithets to Penicillium isolates documented as agents of blue mold of edible and ornamental bulb, root and tuber crops is highly variable. Methods have ranged from appropriate (recent morpho-cultural criteria, metabolite production, and/or DNA sequences), to plausible (morpho-cultural criteria in older monographs), to suspect (no method specified, or identification via inappropriate literature). A catalogue of names appropriately to plausibly assigned is presented, with authors and places of publication, indications on host range, and methods used for identification. Names are tabulated by category: segregates of P. corymbiferum, i.e., names in subgenus Penicillium, series Corymbifera associated with Liliaceae, sensu lato; names in subgenus Penicillium, not in series Corymbifera but associated with Liliaceae; names not in subgenus Penicillium but associated with Liliaceae; names associated with Beta vulgaris (beets and sugar beets), and names associated with mostly tropical or subtropical roots and tubers. Ambiguities or deficiencies in assignment of certain specific epithets are noted
Ft. Collins sugar beet germplasm evaluated for rhizomania and storage rot resistance in Idaho, 2018
Get PDFRhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet germplasm lines with resistance to BNYVV and storage rots, 30 lines from the USDA-ARS Ft. Collins sugar beet program and four check cultivars were screened. The lines were grown in a sugar beet field infested with BNYVV during the 2018 growing season in a randomized complete block design with 6 replications. At harvest on 15 October 2018, roots were dug and evaluated for rhizomania symptoms and also placed in an indoor commercial sugar beet storage building. After 119 days in storage, samples were evaluated for the percentage of root surface area covered by fungal growth or rot. Rhizomania symptom development in the field was uniform and other disease problems were not evident in the plot area. The BNYVV susceptible check plots had 97% foliar symptoms and high root disease severity ratings. The three resistant checks had 0 to 6% foliar symptoms and low root ratings. Based on root ratings, three entries (4, 13, and 14) had resistance similar to the resistant checks. However, entry 13 (20121018HO-119) was the only entry that performed well for all variables. Entry 13 may serve as a starting point for identifying additional sources of resistance to BNYVV and storage rots
Greenhouse gas emissions from an irrigated crop rotation utilizing dairy manure
Get PDFInformation on greenhouse gas (GHG) emissions from manure application in cropping systems of the irrigated mountain west region is needed. The effects of manure application rate and timing on GHG emissions from a four-year commercial rotation under sprinkler irrigation was investigated. Treatments included dry manure rates of 52 or 18 Mg/ha applied annually or 36 Mg/ha applied biennially as well as fertilizer and control treatments. Cumulative losses of N2O-N over the rotation ranged from 1.4 to 8.4 kg/ha with the 52 Mg/ha manure application losing the greatest amount of N2O-N. Calculated emission factors indicated that 0.13 to 0.24% of total N applied was lost as N2O-N, much less than the emission factor of 1% used by the IPCC. Cumulative CO2-C losses were greater in the manure treatments compared to the fertilizer and controls, with approximately 7% of carbon added lost as CO2-C. These soils acted as a sink for CH4-C with average fluxes ranging from -0.1 to -0.3 kg/ha. Maximum N2O-N flux levels occurred at soil moisture contents ranging from 0.3 to 0.4 m3/m3 and temperature near 25 °C, while CO2-C emissions occurred over broader soil moisture and temperature conditions. The overall global warming potential (GWP) associated with manure application indicated that the manure treatments had a net negative GWP while fertilizer treatment was near neutral. A better understanding of regional soil and climatic conditions that affect GHG emissions will enable the development of emission factors more appropriate for use in GHG inventory efforts