The Original USDA-ARS Experimental Watersheds in Texas and Ohio: Contributions from the Past and Visions for the Future

The USDA Soil Conservation Service (USDA‐SCS) realized the importance of understanding hydrologic processes on agricultural fields and watersheds in the mid‐1930s. Based on this realization, the research program of the Hydrologic Division of SCS established three experimental watersheds across the U.S. to analyze the impact of landuse practices on soil erosion, flood events, water resources, and the agricultural economy. Two of the original watersheds remain in operation today within the USDA Agricultural Research Service (USDA‐ARS): the Blacklands Experimental Watershed (now the Grassland, Soil and Water Research Laboratory) near Riesel, Texas, and the North Appalachian Experimental Watershed near Coshocton, Ohio. These original watersheds were designed for collection of hydrologic data on small watersheds and evaluation of hydrologic and soil loss response as influenced by various agricultural land management practices. A major contribution of these experimental watersheds is the quantification of soil loss reduction under conservation management, which has led to a drastic reduction in soil loss from cultivated agriculture in the 20th century. Riesel watershed studies produced the scientific basis for several watershed models that are now used worldwide to manage water quality and also facilitated fundamental analysis of the agronomic and environmental effects of tillage, fertilizer, and pesticide alternatives. Coshocton watershed studies led to the development of no‐till and pasture management practices to control runoff, erosion, and chemical loss and were instrumental in understanding water quality and hydrologic effects of soil macropores and mining and reclamation activities. The long‐term hydrologic records at each site have also improved understanding and management of water resources in their respective geographic regions. Because of their historical and future value, the USDA‐ARS has a unique responsibility to maintain these long‐term experimental watersheds, which are vital for addressing emerging research needs to meet future water availability, environmental quality, and food and fiber demands

Soil erosion assessment—Mind the gap

Accurate assessment of erosion rates remains an elusive problem because soil loss is strongly nonunique with respect to the main drivers. In addressing the mechanistic causes of erosion responses, we discriminate between macroscale effects of external factors—long studied and referred to as “geomorphic external variability”, and microscale effects, introduced as “geomorphic internal variability.” The latter source of erosion variations represents the knowledge gap, an overlooked but vital element of geomorphic response, significantly impacting the low predictability skill of deterministic models at field‐catchment scales. This is corroborated with experiments using a comprehensive physical model that dynamically updates the soil mass and particle composition. As complete knowledge of microscale conditions for arbitrary location and time is infeasible, we propose that new predictive frameworks of soil erosion should embed stochastic components in deterministic assessments of external and internal types of geomorphic variability.Key PointsSoil loss response to runoff is strongly controlled by “geomorphic internal variability”: microscale factors intrinsic to geomorphic systemPredictive skill of deterministic soil loss models at event scale is likely to remain poorErosion estimates must communicate uncertainty due to geomorphic external and internal types of variabilityPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/136017/1/grl55374-sup-0001-Supplementary.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/136017/2/grl55374.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/136017/3/grl55374_am.pd

Preliminary evaluation of VTA effectiveness to protect runoff water quality on small pork production facilities in Texas

Federal law requires all animal feeding operations to manage manures and wastewater by-products in a manner that is protective of waters of the U.S. As a result, the Texas State Soil and Water Conservation Board (TSSWCB) encourages animal feeding operations to voluntarily participate in the agency’s Water Quality Management Plan Program. Historically, limited participation of the pork industry has occurred largely due to logistical and operational issues on smaller operations. Smaller pork facilities generally operate on smaller tracts of land that do not support traditional animal waste management systems such as waste storage ponds, treatment lagoons, and significant expanses of land application acreage. This project was initiated by the U.S. Department of Agriculture–Agricultural Research Service and Texas Water Resources Institute, with funding from the TSSWCB, to evaluate an alternative wastewater treatment system that includes (1) manure scraping and offsite hauling and (2) a vegetated treatment area (VTA) to treat runoff and wash water prior to leaving the VTA. It is anticipated that this evaluation will provide the scientific basis for considering this system for inclusion as an approved practice in the WQMP Program

Expansion of the MANAGE Database with Forest and Drainage Studies

The “Measured Annual Nutrient loads from AGricultural Environments” (MANAGE) database was published in 2006 to expand an early 1980s compilation of nutrient export (load) data from cultivated and pasture/range land at the field or farm scale. Then in 2008, MANAGE was updated with 15 additional studies, and nitrogen (N) and phosphorus (P) concentrations in runoff were added. Since then, MANAGE has undergone significant expansion adding N and P water quality along with relevant management and site characteristic data from: (1) 30 runoff studies from forested land uses, (2) 91 drainage water quality studies from drained land, and (3) 12 additional runoff studies from cultivated and pasture/range land uses. In this expansion, an application timing category was added to the existing fertilizer data categories (rate, placement, formulation) to facilitate analysis of 4R Nutrient Stewardship, which emphasizes right fertilizer source, rate, time, and place. In addition, crop yield and N and P uptake data were added, although this information was only available for 21 and 7% of studies, respectively. Inclusion of these additional data from cultivated, pasture/range, and forest land uses as well as artificially drained agricultural land should facilitate expanded spatial analyses and improved understanding of regional differences, management practice effectiveness, and impacts of land use conversions and management techniques

Riparian buffer systems for Oklahoma

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311.Biosystems and Agricultural Engineerin

The inositol pyrophosphate metabolism of Dictyostelium discoideum does not regulate inorganic polyphosphate (polyP) synthesis

Initial studies on the inositol phosphates metabolism were enabled by the social amoeba Dictyostelium discoideum. The abundant amount of inositol hexakisphosphate (IP6 also known as Phytic acid) present in the amoeba allowed the discovery of the more polar inositol pyrophosphates, IP7 and IP8, possessing one or two high energy phosphoanhydride bonds, respectively. Considering the contemporary growing interest in inositol pyrophosphates, it is surprising that in recent years D. discoideum, has contributed little to our understanding of their metabolism and function. This work fulfils this lacuna, by analysing the ip6k, ppip5k and ip6k-ppip5K amoeba null strains using PAGE, 13C-NMR and CE-MS analysis. Our study reveals an inositol pyrophosphate metabolism more complex than previously thought. The amoeba Ip6k synthesizes the 4/6-IP7 in contrast to the 5-IP7 isomer synthesized by the mammalian homologue. The amoeba Ppip5k synthesizes the same 1/3-IP7 as the mammalian enzyme. In D. discoideum, the ip6k strain possesses residual amounts of IP7. The residual IP7 is also present in the ip6k-ppip5K strain, while the ppip5k single mutant shows a decrease in both IP7 and IP8 levels. This phenotype is in contrast to the increase in IP7 observable in the yeast vip1Δ strain. The presence of IP8 in ppip5k and the presence of IP7 in ip6k-ppip5K indicate the existence of an additional inositol pyrophosphate synthesizing enzyme. Additionally, we investigated the existence of a metabolic relationship between inositol pyrophosphate synthesis and inorganic polyphosphate (polyP) metabolism as observed in yeast. These studies reveal that contrary to the yeast, Ip6k and Ppip5k do not control polyP cellular level in amoeba

Environmental Management of Grazing Lands

Bacteria levels are the number one cause of water quality impairment in Texas. Several recent Total Maximum Daily Loads (TMDLs) in Texas, such as those implemented in the Peach Creek and Leon River watersheds, have identified grazing cattle as a contributor to bacterial water quality impairments in those watersheds through both direct deposition and runoff of their fecal matter to streams. To address this issue, the Texas State Soil and Water Conservation Board (TSSWCB) and the Natural Resources Conservation Service (NRCS) funded this project to assist with development and delivery of technical information and support to ranchers on protection and enhancement of the functions and values of grasslands. A number of best management practices (BMPs) have been identified to reduce bacteria runoff from grazing lands and direct deposition into streams. The primary focus of these BMPs is to maintain adequate ground cover and minimize concentrated livestock areas, especially on sensitive areas such as riparian areas. Maintaining adequate ground cover and plant density improves the filtering capacity of the vegetation and enhances water infiltration into the soil. Minimizing concentrated livestock areas, trailing, and trampling reduces soil compaction, reduces excess runoff and subsequent soil erosion, and enhances fecal matter distribution and ground cover. Specific BMPs identified include grazing management, fencing, alternate water sources, hardened watering points, controlled access, supplemental feed placement, and shade or cover manipulation (NRCS 2007). This project accomplished several objectives, including: 1) compiling existing information on environmental management of grazing lands, 2) evaluating and demonstrating the effectiveness of proper grazing management in reducing bacterial runoff from grazing lands, 3) initiating evaluation of the effect of complementary practices (i.e. alternative water supplies and shade) on cattle behavior and stream water quality, and 4) promoting adoption of appropriate grazing land management practices. Evaluation and demonstration of the effect of grazing management on bacteria runoff at the USDA-ARS Riesel Watersheds has produced some interesting results. The site mean concentration of E. coli (i.e. flow weighted concentration) at the ungrazed native prairie site was surprisingly high (1.0E+04 cfu/100 ml), greatly exceeding the Texas Surface Water Quality Standards single sample standard for E. coli (394 cfu/100 ml) as well as the geometric mean (126 cfu/100 ml). It is important to note that these standards apply to waterbodies, such as streams and reservoirs, but not to edge-of-field runoff as described here. Also, the E. coli concentration seen in the runoff from the moderately grazed bermudagrass site (2.3E+04 cfu/100 ml) was significantly higher (more than double) than that observed at the native prairie site. These levels, however, are consistent with the findings of other researchers. The pre-BMP implementation evaluation of the effectiveness of alternative water supplies and shade on cattle behavior and stream water quality (E. coli) has been completed at the 2S Ranch, near Lockhart. This evaluation showed that when alternative water was not available, E. coli levels increased as the stream flowed through the ranch. Quarterly evaluation of cattle behavior using GPS collars indicated cattle spent only 4.5% of the time within 35 feet of the stream when alternative water was not available. When alternative water was provided, however, this percent time that cattle spent within 35 feet of the stream was reduced to 1.1%, a 75% reduction. This reduction is consistent with the findings of other researchers. Post-BMP evaluation has been initiated and will continue for another year now that alternative water and shade has been provided. Much was done through this project to increase awareness of the bacteria issue and BMPs to address them. AgriLife Extension and TWRI developed fact sheets, provided posters and presentations, conducted site tours, and developed a Web site to help disseminate information. These outreach activities reached local, state, and national audiences. The Web site alone has reached 539 unique visitors during the project. Much is left to do, however. Evaluation of grazing management, alternative water supplies, and shade will continue. Data on other practices (i.e. using rip-rap to reduce access to riparian areas, providing controlled access points, etc.) and groups of practices is still needed to provide cattlemen with a “toolbox” for addressing the bacteria issue. Modification of water quality standards may also be appropriate to address the high levels of E. coli found in runoff from ungrazed sites. Education programs need to be conducted state- and nation-wide to assist cattlemen in addressing bacteria issues

ITPK1 is an InsP6/ADP phosphotransferase that controls phosphate signaling in Arabidopsis

In plants, phosphate (Pi) homeostasis is regulated by the interaction of PHR transcription factors with stand-alone SPX proteins, which act as sensors for inositol pyrophosphates. Here, we combined different methods to obtain a comprehensive picture of how inositol (pyro)phosphate metabolism is regulated by Pi and dependent on the inositol phosphate kinase ITPK1. We found that inositol pyrophosphates are more responsive to Pi than lower inositol phosphates, a response conserved across kingdoms. With CE-ESI-MS we could separate different InsP7 isomers in Arabidopsis and rice, and identify 4/6-InsP7 and a PP-InsP4 isomer hitherto not reported in plants. We found that the inositol pyrophosphates 1/3-InsP7, 5-InsP7 and InsP8 increase severalfold in shoots after Pi resupply and that tissue-specific accumulation of inositol pyrophosphates relies on ITPK1 activities and MRP5-dependent InsP6 compartmentalization. Notably, ITPK1 is critical for Pi-dependent 5-InsP7 and InsP8 synthesis in planta and its activity regulates Pi starvation responses in a PHR-dependent manner. Furthermore, we demonstrate that ITPK1-mediated conversion of InsP6 to 5-InsP7 requires high ATP concentrations and that Arabidopsis ITPK1 has an ADP phosphotransferase activity to dephosphorylate specifically 5-InsP7 under low ATP. Collectively, our study provides deeper insights into Pi-dependent changes in nutritional and energetic states with the synthesis of regulatory inositol pyrophosphates