Analysis of Differences in Productivity,Profitability and Soil Fertility Between Organic and Conventional Cropping Systems in the Tropics and Sub-tropics

Organic farming aims to stimulate soil fertility by avoiding the use of synthetic fertiliser inputs, relying instead on locally available natural resources. It is regarded by many as a sustainable alternative to conventional fanning because it ensures higher biodiversity, restricts environmental pollution, prevents land degradation and is easy to apply for smallholder and subsistence farmers. Although widely practiced and studied in temperate regions, little is known about the potential overall benefits of organic farming in the tropics and subtropics. This paper addresses this gap by undertaking an analysis of the differences between organic and conventional agriculture in the tropics and sub-tropics based on an extensive literature review including 88 papers with 458 data pairs. The comparison is based on three main indicators： yield, gross margin and soil organic carbon （SOC）. The differences between the organic and conventional systems for each of these main indicators is represented by the ratio of the value of the indicator in the organic system divided by the corresponding value in the conventional system. This was initially calculated for each data pair individually, and grouped by a variety of explanatory factors, such as precipitation, human development level, soil texture, crop type, organic input type, time after conversion and certification. The results demonstrate that under organic management, yields were on average 26% higher, gross margins 51% higher and soil organic carbon 53% higher than under conventional management. The highest yield increases in organic cropping systems were achieved in the least developed countries, in arid regions and on coarse soils. For gross margins, certification was the main reason for differences between organic and conventional systems. Certified farmers, mostly located in developed countries, receive significantly higher prices. Furthermore, organic farming in the driest regions results in higher profits than in other regions. Even though soil organic carbon     

Investigation of the porcine PA28 activator γ-subunit (PSME3) gene: isolation, polymorphism and its chromosomal localization

The PA28 activator γ‐subunit encoded by the PSME3 gene is the third component of the PA28 activator complex, which is the 11S regulator of the 20S proteasome. The open reading frame (ORF) sequence of the porcine PSME3 gene encoding the proteasome activator γ‐subunits (or proteasome activator subunit 3) was determined. The deduced amino acid sequence shows 100% identity with the corresponding human and murine sequence. Two single nucleotide substitutions, one located in intron 5 (I5), the other one in exon 8 (E8), were detected using polymerase chain reaction–restriction fragment‐length polymorphism (PCR–RFLP). Analysis on allele frequencies of the two polymorphic sites determined in different pig breeds (Duroc, Tibet, Qingping, Meishan, Erhualian and Mingzhu) showed large differences between Duroc and Chinese indigenous pig breeds investigated. The PSME3 gene was physically assigned to SSC12p11 – (2/3) p13 in the vicinity of the GH gene. This result provides an additional type I marker to the GH linkage group on SSC12.     

Rate of transformation of atrazine and bentazone in water-saturated sandy subsoils

When pesticides leach through the soil to the upper groundwater zone, it is important to know whether further transformation occurs before the pumping wells for drinking water are reached. Atrazine and bentazone were incubated (at 10°C) in five water-saturated sandy subsoils (collected at depths between 1·5 and 3·5 m), simulating the conditions in the field. In three subsoils with comparatively low pH and intermediate to high redox potential, atrazine was transformed gradually, to leave 1·9%, 6·2% and 17·5% of the dose after about five years. In one of these subsoils, hydroxy-atrazine was detected; the amount corresponded to half of the dose of atrazine. In one anaerobic subsoil with high pH, the transformation of atrazine was comparatively fast (half-life about 0·15 year). Another anaerobic subsoil, with similar pH and a somewhat higher redox potential, however, showed hardly any transformation. Sterilization of the first anaerobic subsoil had no effect on the rate of transformation. In the course of about five years, bentazone in the first three subsoils was transformed gradually to leave <0·25%, 11% and 25% of the dose. Bentazone transformation in the two subsoils with high pH and low redox potential was very slow, but the presence of oxygen in one of these subsoils speeded up the transformation. © 1998 SCI     

Toxoplasma gondii infection in Blanford's fox (Vulpes cana)

Fatal toxoplasmosis was diagnosed in a Blanford's fox (Vulpes cana) from the United Arab Emirates. Toxoplasma gondii-like tachyzoites were found associated with necrosis in intestine, spleen, liver, kidneys, lungs, skeletal muscle, brain and heart. Protozoal tachyzoites reacted positively with T. gondii-specific polyclonal antibodies. Antibodies to T. gondii were detected in 10 of 12 V. cana assayed by the latex agglutination or the modified direct agglutination test.     

Field test of a mathematical model for non-equilibrium transport of pesticides in soil

A model for the transport of pesticides in non-structured arable soil has been tested under field conditions. Three classes of sorption site are distinguished in the model. Sorption at class 1 sites is assumed to be at equilibrium whereas sorption at class 2 and class 3 sites is calculated using rate equations. Class 2 sites equilibrate on a time scale of days and class 3 sites equilibrate on a time scale of hundreds of days. In the model, the liquid phase is assumed to be homogeneous and completely mobile. The model was validated in two field experiments on a loamy sand soil using the herbicides cyanazine and metribuzin and using bromide ion as a tracer of liquid flow in soil. Ignoring sorption at class 3 sites resulted in large discrepancies between calculated and measured concentration profiles. Calculated concentration profiles were sensitive to the desorption rate constant for class 3 sites.     

Contributions to an animal trait ontology

Improved understanding of the biology of traits of livestock species necessitates the use and combination of information that is stored in a variety of different sources such as databases and literature. The ability to effectively combine information from different sources, however, depends on a high level of standardization within and between various resources, at least with respect to the used terminology. Ontologies represent a set of concepts that facilitate standardization of terminology within specific domains of interest. The biological mechanisms underlying quantitative traits of farm animal species related to reproduction and host pathogen interactions are complex and not well understood. This knowledge could be improved through the availability of domain-specific ontologies that provide enhanced possibilities for data annotation, data retrieval, data integration, data exchange, data analysis, and ontology-based searches. Here we describe a framework for domain-specific ontologies and the development of 2 first-generation ontologies: Reproductive Trait and Phenotype Ontology (REPO) and Host Pathogen Interactions Ontology . In these first-generation ontologies, we focused on "female fertility in cattle" and "interactions between pigs and Salmonella". Through this, we contribute to the global initiative toward the development of an Animal Trait Ontology for livestock species. To demonstrate its usefulness, we show how REPO can be used to select candidate genes for fertility.     

Short-term and long-term PQ, QT and R-R intervals' variability at the resting condition and after exercise testing in healthy Anglo-Arabian horses

The duration of electrocardiographic (ECG) parameters: PQ, QT and R-R intervals change during long-term and short-term observation as the consequence of the fluctuations in autonomic nervous system activity among others dependent on the exercise and resting. There is no data of horse breed influence on these parameters. The aim of the study was to assess the duration and the variability of the PQ, QT and R-R intervals in the resting conditions and after exercise testing in Anglo-Arabian horses. Material and Methods: 27 healthy Anglo-Arabian horses aged 3.4 +/- 1.0 years (15 male, 12 female) had ECG examination in the standing position using Einthoven system of leads. The longest and the shortest PQ, QT and R-R intervals were measured after night rest and after exercise testing and the means were calculated. Conclusions: 1) In Anglo-Arabian horses the difference between the longest and the shortest PQ interval at rest vs. after exercise is 0.06 +/- 0.05 vs. 0.03 +/- 0.02, QT interval is 0.04 +/- 0.03 vs. 0.04 +/- 0.04, R-R interval 0.19 +/- 0.15 vs. 0.08 +/- 0.11. 2) The PQ and R-R intervals reveal high short-term variability either at the resting conditions or after exercise testing. 3) After exercise testing PQ, QT and R-R intervals are shorter than at the resting conditions. The delta PQ and R-R are 2 times smaller in contrast to delta QT which is constant. 4) The PQ and R-R interval variability was greater at the baseline condition than after exercise testing. The QT variability was similar at baseline condition to that after exercise testing.