B799: Field Appraisal of Resource Management Systems Farms Crop Yield and Quality Relationships with Soil Erosion

This document presents objectives and preliminary results of the Field Appraisal of Resource Management Systems (FARMS) study. This study assumes that estimates of soil erosion using the Universal Soil Loss Equation (USLE) represent long-term rather than short- term effects. The FARMS study randomly sampled 2400 plots over a three year period, 1980-82, for: crop management, soils, conservation practices and management, crop yields, soil chemistry, and sociological data. This report presents analyses from the 800 plots sampled in 1980. Statistics of rill and sheet soil erosion, as estimated by the Universal Soil Loss Equation (USLE), are presented. Data are presented for each of the factors in the USLE, for potato yields and quality, for yield of other field crops, and for soil nutrient analyses. A significant response of yield to erosion was found when the dataset was limited to the most commonly found soil, Caribou (144 plots). Data analyses including potato yields for all varieties and soils (429 plots) do not show any relation to predicted erosion. Regression analysis predicts that for each ton increase in soil erosion per acre per year up to 12 tons, a decrease of 2.3 hundred- weight of potatoes per acre will occur. The cover and management factor (C) was found to be the most important variable in the USLE in predicting potato yield decreases. With each increase of 0.1 C, the predicted yield decrease amounted to 17 hundredweight gross for potatoes, and 20 hundredweight decrease for US-1 potatoes per acre.https://digitalcommons.library.umaine.edu/aes_bulletin/1113/thumbnail.jp

B811: Field Appraisal of Resource Management Systems Farms Crop Yield and Quality Relationships with Soil Erosion - 1982

This document presents the objectives and third-year results of the Field Appraisal of Resource Management Systems (FARMS) study. The principal objectives of FARMS were to study the relationship of crop yields to predicted soil erosion and to simulate the economics of this relationship. Crop management, soils, conservation practices and management, crop yields, soil chemistry, and sociological data were collected. The data analyzed in preparing this report are from the 800 plots sampled in 1982. This report presents statistics for rill and sheet soil erosion, which is estimated by the Universal Soil Loss Equation (USLE) and assumed to represent a long term rather than short term effect. The report also presents summary statistics for each of the factors in the USLE: for potato yields and quality, for yields of four other field crops, and for soil nutrient analyses.https://digitalcommons.library.umaine.edu/aes_bulletin/1107/thumbnail.jp

B805: Field Appraisal of Resource Management Systems: Crop Yield and Quality Relationships with Soil Erosion—1981

This document presents objectives and results of the Field Appraisal of Resource Management Systems (FARMS) study\u27S second year. The principal objectives of FARMS were to study the relationship of crop yields to soil erosion and to simulate the economic nature of this relationship. Crop management, soils, conservation practices and management, crop yields, soil chemistry, and sociological data were collected from 800 plots in 1981. This report presents statistics for rill and sheet soil erosion, which are estimated by the Universal Soil Loss Equation (USLE) and assumed to represent a long-term rather than short-term effect. The report also presents summary statistics for each of the factors in the USLE: for potato yields and quality, for yields of six other field crops, and for soil nutrient analyses. No general response of potato yield and quality to predicted soil erosion was found. However, individual potato varieties responded differently to predicted soil erosion. Potato yields and specific gravity were found to be significantly related to the Cover and Management factor (C). Potato yield was found to decrease as intensity of potato production increased in the rotation period. Potato yields were significantly reduced when the previous crop was potatoes in comparison to grain or hay.https://digitalcommons.library.umaine.edu/aes_bulletin/1056/thumbnail.jp

A comparison of calcium-activated potassium channel currents in cell- attached and excised patches

Single channel currents from Ca-activated K channels were recorded from cell-attached patches, which were then excised from 1321N1 human astrocytoma cells. Cells were depolarized with K (110 mM) so that the membrane potential was known in both patch configurations, and the Ca ionophore A23187 or ionomycin (20-100 microM) was used to equilibrate intracellular and extracellular [Ca] (0.3 or 1 microM). Measurements of intracellular [Ca] with the fluorescent Ca indicator quin2 verified that [Ca] equilibration apparently occurred in our experiments. Under these conditions, where both membrane potential and intracellular [Ca] were known, we found that the dependence of the channel percent open time on membrane potential and [Ca] was similar in both the cell- attached and excised patch configuration for several minutes after excision. Current-voltage relations were also similar, and autocorrelation functions constructed from the single channel currents revealed no obvious change in channel gating upon patch excision. These findings suggest that the results of studies that use excised membrane patches can be extrapolated to the K-depolarized cell-attached configuration, and that the relation between [Ca] and channel activity can be used to obtain a quantitative measure of [Ca] near the membrane intracellular surface

Protein Kinase C Phosphorylates RGS2 and Modulates Its Capacity for Negative Regulation of Gα 11 Signaling

RGS proteins (regulators of G protein signaling) attenuate heterotrimeric G protein signaling by functioning as both GTPase-activating proteins (GAPs) and inhibitors of G protein/effector interaction. RGS2 has been shown to regulate Galpha(q)-mediated inositol lipid signaling. Although purified RGS2 blocks PLC-beta activation by the nonhydrolyzable GTP analog guanosine 5'-O-thiophosphate (GTPgammaS), its capacity to regulate inositol lipid signaling under conditions where GTPase-promoted hydrolysis of GTP is operative has not been fully explored. Utilizing the turkey erythrocyte membrane model of inositol lipid signaling, we investigated regulation by RGS2 of both GTP and GTPgammaS-stimulated Galpha(11) signaling. Different inhibitory potencies of RGS2 were observed under conditions assessing its activity as a GAP versus as an effector antagonist; i.e. RGS2 was a 10-20-fold more potent inhibitor of aluminum fluoride and GTP-stimulated PLC-betat activity than of GTPgammaS-promoted PLC-betat activity. We also examined whether RGS2 was regulated by downstream components of the inositol lipid signaling pathway. RGS2 was phosphorylated by PKC in vitro to a stoichiometry of approximately unity by both a mixture of PKC isozymes and individual calcium and phospholipid-dependent PKC isoforms. Moreover, RGS2 was phosphorylated in intact COS7 cells in response to PKC activation by 4beta-phorbol 12beta-myristate 13alpha-acetate and, to a lesser extent, by the P2Y(2) receptor agonist UTP. In vitro phosphorylation of RGS2 by PKC decreased its capacity to attenuate both GTP and GTPgammaS-stimulated PLC-betat activation, with the extent of attenuation correlating with the level of RGS2 phosphorylation. A phosphorylation-dependent inhibition of RGS2 GAP activity was also observed in proteoliposomes reconstituted with purified P2Y(1) receptor and Galpha(q)betagamma. These results identify for the first time a phosphorylation-induced change in the activity of an RGS protein and suggest a mechanism for potentiation of inositol lipid signaling by PKC

Blueberry Research Progress Report

The 1976 edition of the Blueberry Research Progress Report was prepared for the Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Effect of Plant-Water Stress on Lowbush Blueberry Growth, Yield and Quality 2. Insects Affecting the Blueberry 3. The Development of Blueberry Varieties Adapted to Maine 4. Weed Control in Blueberry Fields 5. Pruning of Blueberries 6. Integrated Management of Blueberry Fields 7. The Physiology and Biochemistry of the Development of the Lowbush Blueberry Fruit 8. Survey of Red Leaf Disease of Blueberries 9. Blossom Blight of Blueberries 10. Blueberry Marketing and Cost Analysis of Producing Blueberries 11. Factors Regulating Rhizome Initiation and Development in the Lowbush Blueberry 12. New Food Products and Servic

Blueberry Research Progress Report

The 1975 edition of the Blueberry Research Progress Report was prepared for the Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Insects Affecting the Blueberry 2. Weed Control in Blueberry Fields 3. Pruning of Blueberries 4. Integrated Management of Blueberry Fields 5. Selective Thinning of Black Barrenberries in Lowbush Blueberry Fields with Ethrel 6. The Physiology and Biochemistry of the Development of the Lowbush Blueberry Fruit 7. The Development of Blueberry Varieties Adapted to Maine 8. Factors Regulating Rhizome Initiation and Development in the Lowbush Blueberry 9. Mechanical Blueberry Harvesting 10. Blueberry Marketing and Cost Analysis of Producing Blueberries 11. New Food Products and Servic

Purification from Sf9 cells and characterization of recombinant Gq alpha and G11 alpha. Activation of purified phospholipase C isozymes by G alpha subunits

Members of the Gq alpha subfamily of heterotrimeric guanine nucleotide-binding proteins (G proteins) activate phospholipase C (PLC). The complementary DNAs (cDNAs) for the G protein alpha subunits Gq alpha and G11 alpha were expressed in insect (Sf9) cells using recombinant baculovirus. Active, nonaggregated, and membrane-associated protein was generated only when the alpha subunit cDNA was expressed together with cDNAs encoding G protein beta and gamma subunits. Recombinant alpha subunits (rGq alpha and rG11 alpha) were purified by three-step procedures, as was a PLC-activating alpha subunit(s) endogenous to Sf9 cells. Guanosine 5'-3-(thio)triphosphate (GTP gamma S) activated rGq alpha and rG11 alpha with an apparent K0.5 of 30 microM; similarly high concentrations of the nucleotide were required to observe [35S]GTP gamma S binding to rGq alpha. Activated rGq alpha and rG11 alpha each stimulated all three isoforms of purified PLC-beta with the rank order of potency PLC-beta 1 = PLC-beta 3 > or = PLC-beta 2; both alpha subunits also stimulated PLC-beta 1 and PLC-beta 3 to a much greater extent (10-fold) than they did PLC-beta 2. In contrast, activated rGq alpha and rG11 alpha failed to stimulate either PLC-delta 1 or PLC- gamma 1. Recombinant Gi alpha 1, Gi alpha 2, Gi alpha 3, Go alpha (A), Gs alpha, and Gz alpha all failed to stimulate any of the isoforms of PLC. The apparent affinities of rGq alpha and rG11 alpha for PLC-beta 1 and their capacities to activate the enzyme were similar to values observed for purified brain Gq alpha/11 alpha. Purified brain beta gamma subunits also stimulated the three isoforms of PLC-beta. The capacities of rGq alpha and rG11 alpha to activate PLC-beta 1 and PLC- beta 3 greatly exceeded those of beta gamma, whereas Gq alpha, G11 alpha and beta gamma were roughly equiefficacious with PLC-beta 2; the alpha subunits were more potent than beta gamma in all cases. The effects of alpha and beta gamma together were nonadditive for both PLC- beta 1 and PLC-beta 2. These results demonstrate that Gq alpha and G11 alpha specifically and selectively stimulate beta isoforms of PLC and confirm the idea that these members of the Gq alpha subfamily of G proteins are physiological regulators of this signaling pathway

Blueberry Advisory Committee Research Report

The 1988 edition of the Blueberry Advisory Committee Research Reports was prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers with the Maine Agricultural Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include: 1. Monitoring methods, economic injury levels, and action thresholds for blueberry spanworm larvae in vegetative year fields. 2. Control of secondary blueberry pests 3. Control of blueberry maggot 4. Effect of pruning practices on blueberry insect abundance 5. Survey of Fungi Contaminating Lowbush Blueberries 6. Nutrition Survey 1988 7. Phosphorus Dose/Response Curve 8. Effect of Several Mulches on Frost Heaving, Soil Moisture, Soil Temperature and Rhizome Development 9. Influence of Mulch Sources on Clonal Spread-SCS Study, Deblois 10. Effect of Surface Mulches on Stabilizing Lowbush Blueberry Soil in Barren Areas 11. Nitrogen-Phosphorus Study 12. Changes in Sugar and Organic Acids of Blueberries During Development, Preprocess Lag Time and Storage 13. Characterization of Pectin in Blueberries 14. Effect of Hexazinone (VELPAR) on Species Distribution in Lowbush Blueberry Fields 15. Evaluation of Setyhoxydim (POAST) for Bunchgrass Control 16. Evaluation and modification of commercial wipers 17. Evaluation of Five Preemergence Herbicides for Control of Oatgrass and Bunchgrass 18. Effect of rate and formulation of hexazinone (VELPAR) on bunchberry 19. Bracken fern control alternatives 20. Hexazinone (VELPAR) and terbacil (SINBAR) combinations for weed control 21. Evaluation of hexazinone (VELPAR) with spot treatments of glyphosate (ROUNDUP) or sethoxydin (POAST) for bunchgrass control 22. Directed sprays of glyphosate (ROUNDUP) for bunchberry control. 23. Evaluation of Postemergence Applications of Chlorimuron for Bunchberry Control 24. Seedling Pruning Study 25. Blueberry Harvester Trials 26. Blueberry Extension Progra

Blueberry Progress Reports

The 1978 edition of the Blueberry Progress Reports was prepared for the Maine Blueberry Commission and the University of Maine Blueberry Advisory Committee by researchers with the Maine Life Sciences and Agriculture Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include: 1. Weed Control in Blueberry Fields 2. Pruning of Blueberries 3. Integrated Management of Blueberry Fields 4. Factors Regulating Rhizome Initiation and Development in the Lowbush Blueberry 5. Effect of Plant-Water Stress on Lowbush Blueberry Growth Yield and Quality 6. Blossom Blight of Blueberries 7. Botrytis Blossom Blight of Lowbush Blueberries 8. Insects Affecting the Blueberry 9. Treatment of Blueberries with Potassium Sorbate to Reduce Spoilage During Temporary Storage 10. Cooperative Extension Activitie