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Feyereisen G.W.,U.S. Department of Agriculture | Francesconi W.,International Center for Tropical Agriculture | Smith D.R.,U.S. Department of Agriculture | Papiernik S.K.,U.S. Department of Agriculture | And 2 more authors.
Journal of Environmental Quality | Year: 2015

Open surface inlets that connect to subsurface tile drainage systems provide a direct pathway for movement of sediment, nutrients, and agrochemicals to surface waters. This study was conducted to determine the reduction in drainage effluent total suspended sediment (TSS) and phosphorus (P) concentrations and loads when open surface inlets were replaced with blind (in gravel capped with 30 cm of soil) or gravel (in very coarse sand/fine gravel) inlets. In Indiana, a pair of closed depressions in adjacent fields was fitted with open inlet tile risers and blind inlets in 2005 and monitored for flow and water chemistry. Paired comparisons on a storm event basis during the growing season for years 2006 to 2013 showed that TSS loads were 40.4 and 14.4 kg ha-1 event-1 for tile risers and blind inlets, respectively. Total P (TP) and soluble reactive P (SRP) loads were 66 and 50% less for the blind inlets, respectively. In Minnesota, TSS and SRP concentrations were monitored for 3 yr before and after modification of 24 open inlets to gravel inlets in an unreplicated large-field on-farm study. Median TSS concentrations were 97 and 8.3 mg L-1 and median SRP concentrations were 0.099 and 0.064 mg L-1 for the open inlet and gravel inlet periods, respectively. Median TSS and SRP concentrations were elevated for snowmelt vs. non-snowmelt seasons for open and gravel inlets. Both replacement designs reduced suspended sediment and P concentrations and loads. The Indiana study suggests blind inlets will be effective beyond a 10-yr service life. © American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. Source


Derpsch R.,International Consultant in Conservation Agriculture No till | Franzluebbers A.J.,U.S. Department of Agriculture | Duiker S.W.,Pennsylvania State University | Reicosky D.C.,North Central Soil Conservation Research Laboratory | And 5 more authors.
Soil and Tillage Research | Year: 2014

No-tillage/conservation agriculture systems research has now been performed for more than half a century in many countries around the world, primarily for economic reasons, but also to reduce labour and energy consumption and improve environmental outcomes. However, an integrated approach to understanding this system requires standardized research methodology based on site-specific conditions. We contend that broad understanding is lacking of what conservation agriculture systems research means. This has led to a situation of conflicting research results because different technologies, methodologies, and definitions of conservation agriculture systems have been applied. The term no-tillage has been used despite considerable soil movement in the previous crop, to inject fertilizer or to establish the current crop. Similarly, the term no-tillage has been used for systems with very little or no crop mulch cover, extended fallow periods, alternating tillage and no-tillage, or crops grown in monoculture. By not performing no-tillage research in a systems approach, many problems can be encountered such as reduced yields, high erosion, low infiltration, elevated fertilizer and high pesticide use. Materials and methods in an experiment are often not descriptive enough to unveil peculiarities. By analysing the function of components of conservation agriculture systems in monofactorial experiments, synergetic interactions among components can be overlooked. In this editorial, we discuss the need to thoroughly describe materials and methods to avoid confusing interpretations of results. We contend that standardization of research methodologies in no-tillage/conservation agriculture systems is needed based on a thorough description of the whole system so that results from different researchers and regions of the world can be logically compared. © 2013. Source


Forcella F.,North Central Soil Conservation Research Laboratory | Papiernik S.K.,North Central Soil Conservation Research Laboratory | Papiernik S.K.,North Central Agricultural Research Laboratory | Gesch R.W.,North Central Soil Conservation Research Laboratory
Weed Technology | Year: 2011

Cuphea is a new crop of temperate regions that produces seed oil that can substitute for imported coconut and palm kernel oils. Only four herbicides are known to be tolerated by cuphea to date. More herbicides, especially POST products, are needed for continued commercialization. In Minnesota and North Dakota, where cuphea currently is grown, greater control of Canada thistle and biennial wormwood is needed in cuphea. Because clopyralid is effective on both of these species, it was tested at rates ranging from about 25 to 850 g ae ha -1 in greenhouse and field trials. Visual assessment of injury, height, growth, and seed yield of cuphea were not reduced significantly in field-grown plants when clopyralid was applied at rates up to 400 g ae ha -1. Thus, at the rate commonly used in other crops, 200 g ae ha -1, clopyralid can be applied safely to cuphea. © Weed Science Society of America. Source


Eberle C.A.,North Central Soil Conservation Research Laboratory | Forcella F.,North Central Soil Conservation Research Laboratory | Gesch R.,North Central Soil Conservation Research Laboratory | Weyers S.,North Central Soil Conservation Research Laboratory | And 2 more authors.
PLoS ONE | Year: 2014

Echium (Echium plantagineum L.) is an alternative oilseed crop in summer-wet temperate regions that provides floral resources to pollinators. Its seed oil is rich in omega-3 fatty acids, such as stearidonic acid, which is desired highly by the cosmetic industry. Seeds were sown in field plots over three years in western Minnesota in spring (early-sown) or early summer (late-sown), and flower abundance, pollinator visitation, and seed yields were studied. Initial flowering commenced 41 to 55 d after sowing, and anthesis duration (first flowering to harvest) was 34 to 70 d. Late sowing dates delayed anthesis, but increased the intensity of visitation by pollinators. Cumulative flower densities ranged from 1 to 4.5 billion ha21. Flowers attracted numerous honey bees (Apis mellifera L.), as many as 35 per minute of observation, which represented about 50% of all insect visitors. Early-sown echium produced seed yields up to 750 kg ha21, which were 2-29 times higher than those of late-sown echium. Early sowing of echium in Minnesota provides abundant floral resources for pollinators for up to two months and simultaneously produces seed yields whose profits rival those of corn (Zea mays L.). Source

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