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391.
392.
Samuel A. Hart 《Water, air, and soil pollution》1975,4(2):189-190
The pound of beef in the supermarket meat counter is the result of 25 lbs of manure being left in the field and feedlot. Similar patterns of tremendous quantities of field and processing plant wastes per unit of consumable food exist for all other agricultural commodities. The waste management principles for agricultural wastes are the same as for any other of society's unwanteds, but the fortuitous (not-by-design) ability to dispose of or utilize many agricultural wastes back to the land is explored. The limitations, in economics, technology, and assimilative capacity are considered. 相似文献
393.
Journal of Plant Diseases and Protection - In a survey of Botrytis populations in Northern Germany in 2012-2014, an average of 67.7% and 73.8% of isolates from strawberry and raspberry fields... 相似文献
394.
395.
B.W. Sullivan T.E. Kolb S.C. Hart J.P. Kaye S. Dore M. Montes-Helu 《Forest Ecology and Management》2008,255(12):4047-4055
Forest soils are important components of the global carbon cycle because they both store and release carbon. Carbon dioxide is released from soil to the atmosphere as a result of plant root and microbial respiration. Additionally, soils in dry forests are often sinks of methane from the atmosphere. Both carbon dioxide and methane are greenhouse gases whose increasing concentration in the atmosphere contributes to climate warming. Thinning treatments are being implemented in ponderosa pine forests across the southwestern United States to restore historic forest structure and reduce the risk of severe wildfire. This study addresses how thinning alters fluxes of carbon dioxide and methane in ponderosa pine forest soils within one year of management and examines mechanisms of change. Carbon dioxide and methane fluxes, soil temperature, soil water content, forest floor mass, root mass, understory plant biomass, and soil microbial biomass carbon were measured before and after the implementation of a thinning and in an unthinned forest. Carbon dioxide efflux from soil decreased as a result of thinning in two of three summer months. Average summer carbon dioxide efflux declined by an average of 34 mg C m−2 hr−1 in the first year after thinning. Methane oxidation did not change in response to thinning. Thinning had no significant short-term effect on total forest floor mass, total root biomass, or microbial biomass carbon in the mineral soil. Understory plant biomass increased after thinning. Thinning increased carbon available for decomposition by killing tree roots, but our results suggest that thinning reduced carbon dioxide emissions from the soil because the reduction in belowground autotrophic respiration was larger than the stimulation of heterotrophic respiration. Methane oxidation was probably not affected by thinning because thinning did not alter the forest floor mass enough to affect methane diffusion from the atmosphere into the soil. 相似文献
396.
Levy-Booth DJ Campbell RG Gulden RH Hart MM Powell JR Klironomos JN Pauls KP Swanton CJ Trevors JT Dunfield KE 《Journal of agricultural and food chemistry》2008,56(15):6339-6347
Glyphosate-tolerant, Roundup Ready (RR) soybeans account for about 57% of all genetically modified (GM) crops grown worldwide. The entry of recombinant DNA into soil from GM crops has been identified as an environmental concern due to the possibility of their horizontal transfer to soil microorganisms. RR soybeans contain recombinant gene sequences that can be differentiated from wild-type plant and microbial genes in soil by using a sequence-specific molecular beacon and real-time polymerase chain reaction (PCR). A molecular beacon-based real-time PCR system to quantify a wild-type soybean lectin ( le1) gene was designed to compare amounts of endogenous soybean genes to recombinant DNA in soil. Microcosm studies were carried out to develop methodologies for the detection of recombinant DNA from RR soybeans in soil. RR soybean leaf litterbags were imbedded in the soil under controlled environmental conditions (60% water holding capacity, 10/15 degrees C, and 8/16 h day/night) for 30 days. The soybean biomass decomposition was described using a single-phase exponential equation, and the DNA concentration in planta and in soil was quantified using real-time PCR using sequence-specific molecular beacons for the recombinant cp4 epsps and endogenous soybean lectin ( le1) genes. The biomass of RR soybean leaves was 8.6% less than nontransgenic (NT) soybean leaves after 30 days. The pooled half-disappearance time for cp4 epsps and le1 in RR and of le1 in NT soybean leaves was 1.4 days. All genes from leaves were detected in soil after 30 days. This study provides a methodology for monitoring the entry of RR and NT soybean DNA into soil from decomposing plant residues. 相似文献
397.
Bede?S.?MickanEmail author Lynette?K.?Abbott Jingwei?Fan Miranda?M.?Hart Kadambot?H.?M.?Siddique Zakaria?M.?Solaiman Sasha?N.?Jenkins 《Biology and Fertility of Soils》2018,54(1):55-70
Applications of compost and clay to ameliorate soil constraints such as water stress are potential management strategies for sandy agricultural soils. Water repellent sandy soils in rain-fed agricultural systems limit production and have negative environmental effects associated with leaching and soil erosion. The aim was to determine whether compost and clay amendments in a sandy agricultural soil influenced the rhizosphere microbiome of Trifolium subterraneum under differing water regimes. Soil was amended with compost (2% w/w), clay (5% w/w) and a combination of both, in a glasshouse experiment with well-watered and water-stressed (70 and 35% field capacity) treatments. Ion Torrent 16S rRNA sequencing and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) analysis of functional gene prediction were used to characterise the rhizosphere bacterial community and its functional component involved in nitrogen (N) cycling and soil carbon (C) degradation. Compost soil treatments increased the relative abundance of copiotrophic bacteria, decreased labile C and increased the abundance of recalcitrant C degrading genes. Predicted N cycling genes increased with the addition of clay (N2 fixation, nitrification, denitrification) and compost + clay (N2 fixation, denitrification) and decreased with compost (for denitrification) amendment. Water stress did not alter the relative abundance of phylum level taxa in the presence of compost, although copiotrophic Actinobacteria increased in relative abundance with addition of clay and with compost + clay. A significant role of compost and clay under water stress in influencing the composition of rhizosphere bacteria and their implications for N cycling and C degradation was demonstrated. 相似文献
398.
Effects of supplemental dietary vitamin C on quality of semen from Nile tilapia (Oreochromis niloticus) breeders 下载免费PDF全文
NLAF Sarmento EFF Martins DC Costa WS Silva CC Mattioli MR Luz RK Luz 《Reproduction in domestic animals》2017,52(1):144-152
The objective of this study was to evaluate the effects of vitamin C on growth and quality of semen from Oreochromis niloticus breeders. One hundred and sixty males were fed with different levels of vitamin C (0, 261, 599 and 942 mg/kg diet). The higher weight values were recorded for 599 (166 g) and 942 (175 g) mg of vitamin C/kg diet. Sperm motility, vigour and concentration were higher with 599 and 942 mg of vitamin C/kg diet. The semen volume, gonadosomatic index and plasma protein data from the last week showed a direct relationship with increasing levels of vitamin C. No changes were observed in the hepatosomatic index and blood glucose. The haematocrit and erythrocyte showed higher values estimated by equations derived at 850 and 638 mg vitamin C/kg diet, respectively. The leucocytes were inversely proportional to the increasing levels of vitamin C. After 100 days of feeding, animals fed the diet containing 942 mg vitamin C/kg diet had higher sperm motility, linearity, curvilinear velocity, straight line velocity and average path velocity (p < .05). Higher values of beat cross‐frequency were observed in broodfish fed diets containing 942 and 599 mg vitamin C/kg. The different vitamin C levels did not cause differences in straightness, lateral head displacement and sperm morphology. For Nile tilapia males on intensive rearing and handling conditions, vitamin C levels between 599 and 942 mg/kg may be used for a better performance and quality of semen. 相似文献
399.
K.E. Schober T.M. Hart J.A. Stern X. Li V.F. Samii L.J. Zekas B.A. Scansen J.D. Bonagura 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2010,24(6):1358-1368
Background: Echocardiographic prediction of congestive heart failure (CHF) in dogs has not been prospectively evaluated. Hypothesis: CHF can be predicted by Doppler echocardiographic (DE) variables of left ventricular (LV) filling in dogs with degenerative mitral valve disease (MVD) and dilated cardiomyopathy (DCM). Animals: Sixty‐three client‐owned dogs. Methods: Prospective clinical cohort study. Physical examination, thoracic radiography, analysis of natriuretic peptides, and transthoracic echocardiography were performed. Diagnosis of CHF was based upon clinical and radiographic findings. Presence or absence of CHF was predicted using receiver‐operating characteristic (ROC) curve, multivariate logistic and stepwise regression, and best subsets analyses. Results: Presence of CHF secondary to MVD or DCM could best be predicted by E : isovolumic relaxation time (IVRT) (area under the ROC curve [AUC]=0.97, P < .001), respiration rate (AUC=0.94, P < .001), Diastolic Functional Class (AUC=0.93, P < .001), and a combination of Diastolic Functional Class, IVRT, and respiration rate (R2=0.80, P < .001) or Diastolic Functional Class (AUC=1.00, P < .001), respiration rate (AUC=1.00, P < .001), and E : IVRT (AUC=0.99, P < .001), and a combination of Diastolic Functional Class and E : IVRT (R2=0.94, P < .001), respectively, whereas other variables including N‐terminal pro‐brain natriuretic peptide, E : Ea, and E : Vp were less useful. Conclusion and Clinical Importance: Various DE variables can be used to predict CHF in dogs with MVD and DCM. Determination of the clinical benefit of such variables in initiating, modulating, and assessing success of treatments for CHF needs further study. 相似文献
400.
Jann HW Hart JC Moorman VJ Strauss PM Fackelman GE 《The Canadian veterinary journal. La revue veterinaire canadienne》2010,51(8):881-884
A 2-year-old alpaca was presented for acute onset right forelimb lameness. Clinical findings included bilateral carpal valgus (more severe in the affected forelimb) and medial instability of the right radio-carpal joint. Surgical treatment consisted of radio-carpal joint arthrodesis, which is presented as a therapeutic option for severe carpal instability secondary to injury to the supporting ligamentous structures of the carpus. 相似文献