Effect of Soil Sampling Density and Landscape Features on Soil Test Phosphorus

Organic and/or inorganic fertilizers are used to promote crop growth yet the rate of fertilizer application is often based on the nitrogen needs of the crop and not the phosphorus needs, especially when utilizing animal manures with low N-to-P ratios as compared to plant N:P uptake. Because of this, soil phosphorus levels in many areas of the world are in excess of crop needs. Excessive levels of phosphorus in water bodies such as streams and lakes can result in a condition known as eutrophication. With eutrophication, nutrients promote algal growth which in turn decreases dissolved oxygen levels in receiving water bodies. The issue of excessive nutrient inputs to waterbodies is of particular importance to Kentucky due to its large agricultural base and the Commonwealth’s link to hypoxia in the Gulf of Mexico. Nutrient management is one way to minimize the impacts of phosphorus on waterways; however, the success of nutrient management is dependent in part on soil sampling strategies. This study examined the effect of soil sampling density (15 × 15 m, 15 × 30 m, and 15 × 60 m) on Soil Test Phosphorus (STP) in three subplots. Results indicated that mean STP values for the subplots did not change with sampling densities; however, maximum STP levels displayed large variations. Depending on the sampling density used and the method of data aggregation (mean vs. maximum), recommended nutrient application rates varied from phosphorus-based to nitrogen-based. Also of importance was the recognition that maximum STP values were driven by a shallow limestone rock layer, which was not visible at the time of sampling. This limestone rock layer, and hence these highest STP values, were immediately upgradient of a sinkhole from which collected soil samples also exhibited higher STP values. When developing nutrient management plans, particularly in karst landscapes where the potential for groundwater contamination and hence surface water contamination is higher, additional consideration should be given to the influence of geologic materials on soil nutrient levels and greater sampling densities around preferential flow paths

Building WF16: construction of a PPNA pisé structure in Southern Jordan

The Pre-Pottery Neolithic A (PPNA) period in Southwest Asia is essential for our understanding of the transition to sedentary, agricultural communities. Developments in architecture are key to understanding this transition, but many aspects of PPNA architecture remain elusive, such as construction techniques, the selection of building materials, and the functional use of space. The primary aim of the research described within this contribution was to build a PPNA-like structure in order to answer questions about PPNA architecture in general, while specifically addressing issues raised by the excavation of structures at the site of WF16, Southern Jordan. The second aim was to display a ‘PPNA’ building to visitors in Wadi Faynan to enhance their understanding of the period. The experimental construction based on one of the WF16 structures showed that 1) required materials can be acquired locally; 2) a construction technique using mud layers as described in this paper was likely used; 3) flat, or very slightly dome-shaped, roofs are functional and can also be used as a solid working platform; 4) the WF16 small semi-subterranean buildings appear inappropriate for housing a nuclear family unit

Creating a National Coalition to Address Tractor Overturn Fatalities.

Tractor overturns continue to be the leading cause of death on U.S. farms. While rollover protective structures (ROPS) are effective in preventing these fatalities, they are underutilized due to a number of barriers. Past programs in the U.S. and abroad have targeted this area of agricultural safety; however, a national program is not yet in place for U.S. farmers. This study seeks to build a national partnership to address tractor overturn fatalities by increasing the number of tractors with ROPS. A diverse, multisector steering committee has been organized and is working together using Whole System in a Room methods. This method brings together partners from nine stakeholder groups to identify and commit to a collaborative solution to the issue

Retrofitting Tractors with Rollover Protective Structures: Perspective of Equipment Dealers

This study was one of a cluster of studies that originated via requests for proposals from the NIOSH National Agricultural Tractor Safety Initiative. The present study design consisted of several steps: (1) formation of an advisory group, (2) development and testing of a standard paper self-responding survey instrument, (3) sample selection of farm equipment dealers, (4) administration of the survey, (5) assessment and analysis of the survey, and (6) in-person response panel of dealers (n = 80) to review results of the questionnaire for further definition and sharpening of the recommendations from the survey. A key finding is that most dealers do not currently sell or install ROPS retrofit kits. Barriers cited by dealers included (1) actual or perceived lack of farmer demand, (2) injury liability, (3) expensive freight for ordering ROPS, (4) lack of dealer awareness of the magnitude of deaths from tractor overturns and the high life-protective factor of ROPS, and (5) difficulty and incursion of non-recoverable expenses in locating and obtaining specific ROPS. Despite not currently selling or installing ROPS, dealers responded favorably about their future potential role in ROPS promotion and sales. Dealers were willing to further promote, sell, and install ROPS if there was demand from farmers. Recommendations include establishing a ROPS “clearing house” that dealers could contact to facilitate locating and obtaining ROPS orders from customers. Additional recommendations include education and social marketing targeting farm machinery dealers as well farmers, manufacturers, and policy makers

Increases in ROPS Pricing from 2006-2012 and the Impact on ROPS Demand

In 2006, a social marketing campaign was developed to increase the installation of rollover protective structures (ROPS) on unprotected New York tractors. Using data gathered from the program\u27s hotline, the impact of price increases on farmers\u27 interest in ROPS is examined. Pricing data were obtained for all rigid ROPS kits commercially available in the U.S. since 2006. These data were stratified into two groups of ROPS suppliers: (1) tractor manufacturers that sell ROPS for their own tractors, referred to in this study as original equipment manufacturers (OEMs), and (2) aftermarket (AM) ROPS suppliers. The trend in price increases was contrasted with the change in the consumer price index (CPI), the probability of retrofitting within quintiles of cost was estimated, and the increase in ROPS prices over time was plotted The average price increase for a ROPS kit (excluding shipping and installation) over the six years of the study was 23.3% for OEM versus 60.5% for AM (p \u3c 0.0001). Out-of-pocket expenses held steady for OEM versus a six-year increase of $203 for AM (p = 0.098). The probability of a farmer retrofitting dropped monotonically from 66.9% in the lowest ROPS cost quintile to 23% in the highest. If these trends continue, the proportion of inquiries resulting in a ROPS retrofit will fall below 20% by 2020 for AM ROPS. Based on other trends identified in the literature, it is reasonable to assume that decreases in ROPS installation are likely to affect the tractor owners who are most likely to need these safety devices

The white collar complex is essential for sexual reproduction but dispensable for conidiation and invasive growth in Fusarium verticillioides

Fvwc1 and Fvwc2, orthologues of the wc-1 and wc-2 genes encoding for proteins of the white collar complex (WCC) in Neurospora crassa were cloned from Fusarium verticillioides and lack-of-function wc mutants were obtained by targeted gene disruption. Photo-conidiation was found to be absent in F. verticillioides, on the contrary, the wild type strain produced less conidia under continuous illumination than in the dark. Inactivation of any of the wc genes led to total female sterility, without affecting male fertility or asexual conidiation. No loss in colonization capability/invasive growth of the wc mutants was observed, when assessed on tomato fruits. Both Fvwc1 and Fvwc2 showed constitutive expression in the wild type cultures incubated in the dark and exposure to light caused only negligible increases in their transcription. Both Fvwc1 and Fvwc2 were down-regulated in a ΔFvmat1-2-1 gene disruption mutant, lacking a functional mating type (mat1-2-1) gene, suggesting that the MAT1-2-1 product has a positive regulatory effect on the white collar genes

Light regulation of metabolic pathways in fungi

Light represents a major carrier of information in nature. The molecular machineries translating its electromagnetic energy (photons) into the chemical language of cells transmit vital signals for adjustment of virtually every living organism to its habitat. Fungi react to illumination in various ways, and we found that they initiate considerable adaptations in their metabolic pathways upon growth in light or after perception of a light pulse. Alterations in response to light have predominantly been observed in carotenoid metabolism, polysaccharide and carbohydrate metabolism, fatty acid metabolism, nucleotide and nucleoside metabolism, and in regulation of production of secondary metabolites. Transcription of genes is initiated within minutes, abundance and activity of metabolic enzymes are adjusted, and subsequently, levels of metabolites are altered to cope with the harmful effects of light or to prepare for reproduction, which is dependent on light in many cases. This review aims to give an overview on metabolic pathways impacted by light and to illustrate the physiological significance of light for fungi. We provide a basis for assessment whether a given metabolic pathway might be subject to regulation by light and how these properties can be exploited for improvement of biotechnological processes

ChLae1 and ChVel1 Regulate T-toxin Production, Virulence, Oxidative Stress Response, and Development of the Maize Pathogen Cochliobolus heterostrophus

LaeA and VeA coordinate secondary metabolism and differentiation in response to light signals in Aspergillus spp. Their orthologs, ChLae1 and ChVel1, were identified in the maize pathogen Cochliobolus heterostrophus, known to produce a wealth of secondary metabolites, including the host selective toxin, T-toxin. Produced by race T, T-toxin promotes high virulence to maize carrying Texas male sterile cytoplasm (T-cms). T-toxin production is significantly increased in the dark in wild type (WT), whereas Chvel1 and Chlae1 mutant toxin levels are much reduced in the dark compared to WT. Correspondingly, expression of T-toxin biosynthetic genes (Tox1) is up-regulated in the dark in WT, while dark-induced expression is much reduced/minimal in Chvel1 and Chlae1 mutants. Toxin production and Tox1 gene expression are increased in ChVEL1 overexpression (OE) strains grown in the dark and in ChLAE1 strains grown in either light or dark, compared to WT. These observations establish ChLae1 and ChVel1 as the first factors known to regulate host selective toxin production. Virulence of Chlae1 and Chvel1 mutants and OE strains is altered on both T-cms and normal cytoplasm maize, indicating that both T-toxin mediated super virulence and basic pathogenic ability are affected. Deletion of ChLAE1 or ChVEL1 reduces tolerance to H2O2. Expression of CAT3, one of the three catalase genes, is reduced in the Chvel1 mutant. Chlae1 and Chvel1 mutants also show decreased aerial hyphal growth, increased asexual sporulation and female sterility. ChLAE1 OE strains are female sterile, while ChVEL1 OE strains are more fertile than WT. ChLae1 and ChVel1 repress expression of 1,8-dihydroxynaphthalene (DHN) melanin biosynthesis genes, and, accordingly, melanization is enhanced in Chlae1 and Chvel1 mutants, and reduced in OE strains. Thus, ChLae1 and ChVel1 positively regulate T-toxin biosynthesis, pathogenicity and super virulence, oxidative stress responses, sexual development, and aerial hyphal growth, and negatively control melanin biosynthesis and asexual differentiation