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41.
E. K. Bünemann P. Marschner R. J. Smernik M. Conyers A. M. McNeill 《Biology and Fertility of Soils》2008,44(5):717-726
Agricultural management can affect soil organic matter chemistry and microbial community structure, but the relationship between
the two is not well understood. We investigated the effect of crop rotation, tillage and stubble management on forms of soil
phosphorus (P) as determined by solution 31P nuclear magnetic resonance spectroscopy and microbial community composition using fatty acid methyl ester analysis in a
long-term field experiment (26 years) on a Chromic Luvisol in New South Wales, Australia. An increase in soil organic carbon,
nitrogen and phosphorus compared to the beginning of the experiment was found in a rotation of wheat and subterranean clover
with direct drill and mulching, while stubble burning in wheat–lupin and wheat–wheat rotations led to soil organic matter
losses. Microbial biomass was highest in the treatment with maximum organic matter contents. The same soil P forms were detected
in all samples, but in different amounts. Changes in organic P occurred mainly in the monoester region, with an increase or
decrease in peaks that were present also in the sample taken before the beginning of the experiment in 1979. The microbial
community composition differed between the five treatments and was affected primarily by crop rotations and to a lesser degree
by tillage. A linkage between soil P forms and signature fatty acids was tentatively established, but needs to be verified
in further studies. 相似文献
42.
Dong-nan CUI Xiong-bing TU Kun HAO Aftab Raza Jun CHEN Mark McNeill Ze-hua ZHANG 《农业科学学报》2019,18(11):2579-2588
Maternal photoperiodic response is a key factor that affects offspring diapause in migratory locust, Locusta migratoria L. (Orthoptera: Acridoidea). Although many aspects of insect diapause have been studied, little is known about the molecular mechanisms of maternal photoperiodic response that influence diapause regulation. To gain insight into the possible mechanisms of maternal photoperiod influence on diapause regulation, proteomics data by label-free quantification analysis were generated from non-diapause and diapause eggs. A total of 175 proteins were differentially expressed between diapause and non-diapause eggs. Among them, 24 proteins were upregulated, and 151 proteins were downregulated. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichments were performed on all differentially expressed proteins (DEPs) and showed that peroxisome, insect hormone biosynthesis, and longevity regulating pathway may be related to diapause of migratory locust. Furthermore, we used qRT-PCR to verify some results of the proteomic analysis. Proteins such as hexamerin-like protein 4, juvenile hormone epoxide hydrolase 1 (JHEH1), cytochrome P450 and heat shock protein (HSP) 20.7 were predicted to be involved in diapause. This study provides an important reference for future research that will explore the mechanisms of diapause induced by maternal effects in migratory locust. 相似文献
43.
Barling KS McNeill JW Thompson JA Paschal JC McCollum FT Craig TM Adams LG 《Journal of the American Veterinary Medical Association》2000,217(9):1356-1360
OBJECTIVE: To determine the seroprevalence for Neospora caninum in a population of beef calves in a feedlot and the association of serologic status with postweaning weight gain and carcass measurements. DESIGN: Longitudinal observational study. ANIMALS: 1,009 weaned beef steers from 92 herds. PROCEDURE: Samples were obtained from all steers at time of arrival at a feedlot. Serologic status for Neospora spp was determined, using an agglutination test. Results of serologic testing were compared with calf growth and carcass data, using multivariate regression with generalized estimating equations. RESULTS: Of 1,009 calves, 131 (12.98%) were seropositive, and 54 of 92 (58.7%) consignments had > or = 1 seropositive calf. Median within-consignment prevalence for consignments in which there was > or = 1 seropositive calf was 20%. Seropositive status was associated with significant reductions in average daily gain, live body weight at slaughter, and hot carcass weight and an increase in ribeye area-to-hot carcass weight ratio. Seropositive status also was associated with significant increases in cost of treatment and significant reductions in income. Sick seropositive calves had the highest cost of treatment. An economic loss of $15.62/calf was projected for seropositive calves. CONCLUSIONS AND CLINICAL RELEVANCE: Significant reductions in postweaning weight gain, carcass weight, and economic return were associated with detection of antibodies to N caninum in beef calves in a feedlot. 相似文献
44.
45.
Nitrogen and sulphur management: challenges for organic sources in temperate agricultural systems 总被引:2,自引:0,他引:2
A.M. McNeill J. Eriksen L. Bergström K.A. Smith H. Marstorp H. Kirchmann I. Nilsson 《Soil Use and Management》2005,21(1):82-93
Abstract. A current global trend towards intensification or specialization of agricultural enterprises has been accompanied by increasing public awareness of associated environmental consequences. Air and water pollution from losses of nutrients, such as nitrogen (N) and sulphur (S), are a major concern. Governments have initiated extensive regulatory frameworks, including various land use policies, in an attempt to control or reduce the losses. This paper presents an overview of critical input and loss processes affecting N and S for temperate climates, and provides some background to the discussion in subsequent papers evaluating specific farming systems. Management effects on potential gaseous and leaching losses, the lack of synchrony between supply of nutrients and plant demand, and options for optimizing the efficiency of N and S use are reviewed. Integration of inorganic and organic fertilizer inputs and the equitable re-distribution of nutrients from manure are discussed. The paper concludes by highlighting a need for innovative research that is also targeted to practical approaches for reducing N and S losses, and improving the overall synchrony between supply and demand. 相似文献
46.
J P Morgan G L Fisher K L McNeill J Oyama 《American journal of veterinary research》1979,40(3):346-350
Chronic centrifugation of 85- to 92-day-old Beagles at 2.0 X g and 2.6 X g for 26 weeks during the time of active skeletal growth caused skeletal abnormalities in the radius and the ulna of ten of 11 dogs. The pattern of change mimicked that found in naturally occurring and experimentally induced premature distal ulnar physeal closure or delayed growth at this physis. Minimal changes in bone density were detected by sensitive photon absorptiometric techniques. Skeletal abnormalities also were found in five of the six cage-control dogs, although the run-control dogs were radiographically normal. 相似文献
47.
48.
Clayton R. Butterly Ann M. McNeill Jeff A. Baldock Petra Marschner 《Biology and Fertility of Soils》2011,47(1):41-50
Drying–rewetting (DRW) cycles are important for soil organic matter turnover; however, few studies have considered the short-term
effects on nutrient availability. The pulses in soil respiration, extractable C, P and N pools were quantified after a single
DRW cycle (ten sampling times over 49 h). Soil was pre-incubated with or without glucose (2.5 g kg−1) for 10 days to induce differences in the size and activity of the microflora and then either subjected to a single DRW cycle
(7-day drying period) or kept constantly moist. A resin extractable P (Presin) method was used and compared to extraction of dissolved organic (DOP) and inorganic P (DIP) with a salt solution. The pulse
in soil respiration, extractable organic C (EOC), Presin, DOP and DIP was immediate and greatest in the first 2 h. The Presin pulse was two to three times that measured by solution extraction (DIP). Also, Presin quantified temporal changes in P not apparent in DIP, indicating the advantage of anion-exchange membranes in quantifying
short-term changes in P availability. The Presin pulse was smaller in the soil incubated with glucose showing that P pulses will be quantitatively smaller in a soil with
an active microbial biomass. In contrast to P, pre-incubation with glucose did not alter EOC concentration or the pulse in
EOC after rewetting. The Presin pulse had disappeared by 49 h after DRW despite continued elevated rates of respiration. The sustained increase in DIP following
DRW may have implications for plant availability or environmental losses. 相似文献
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