Integrating farmer knowledge,precision agriculture tools,and crop simulation modelling to evaluate management options for poor-performing patches in cropping fields

Cropping fields often have poor-performing patches. In an attempt to increase production on poor patches, farmers may apply additional fertiliser or ameliorants without economic or scientific justification. Improved understanding of the extent and causes of poor performance, management options, potential crop yield and economic benefits can give farmers the tools to consider management change. This paper presents an approach to integrating farmer knowledge, precision agriculture tools and crop simulation modelling to evaluate management options for poor-performing patches.We surveyed nine cropping fields in Western Australia and showed that (1) farmers have good understanding of the spatial extent and rank performance of poor-performing areas, when compared to NDVI or yield maps, (2) there is a wide range of physical and chemical soil constraints to crop yield in such patches, some of which can be ameliorated to raise yield potential, and others where crop inputs such as fertiliser can be better matched to low yield potential.Management options for poor-performing patches were evaluated through simulation analysis by removal of constraints to rooting to varying extents, and hence plant available water capacity. These examples show that if the constraint is mis-diagnosed then the potential benefits from amelioration can be overstated. In many cases constraints, often associated with physical limitations such as shallow available rooting depth or light-texture cannot be ameliorated or are uneconomic to ameliorate. In such cases the best intervention may be to lower crop inputs to better match the water-limited yield potential of such poor-performing areas.This research integrated farmer knowledge and spatial data to define yield zones in which targeted soil sampling and crop simulation were then used to determine yield potential and particular constraints to that potential. The economic costs and benefits of differential zone management were examined under a range of husbandry scenarios and, importantly, the sensitivity of economic gain to mis-diagnosis or errors in defining the zones was tested. This approach provided farmers with a robust and credible method for making decisions about spatial management of their fields.     

Sheep genetic diversity in Bhutan using microsatellite markers

Genotype data from eight microsatellite markers were used to assess genetic diversity and relationships among five indigenous Bhutanese sheep populations, Sakten, Jakar, Sarpang, Sipsu and Tsirang. Estimates of mean observed and expected heterozygosities, mean number of alleles per locus/population were obtained. The highest observed heterozygosities were found in Jakar (0.657) and Sakten (0.647), while the lowest one was found in Tsirang (0.539). Genetic distances, pairwise proportion of different alleles, UPGMA tree, and principal component analysis indicate close relationship among Tsirang, Sipsu and Sarpang populations, while Jakar and Sakten populations are located in one cluster. These two clusters are separated geographically, and show distinct phenotypic as well as molecular characters. We therefore recommend that the Bhutanese native sheep populations be classified into at least two distinct breeds, Jakar‐Sakten sheep and Sipsu sheep. Since Jakar and Sakten sheep have different morphological phenotypes, further analyses will be required to understand the genetic differences between these two sheep populations.     

Managing Amazonian palms for community use: A case of aguaje palm (Mauritia flexuosa) in Peru

Amazonian palms are prime candidates for sustainable management of non-timber forest products and yet useful species are often harvested destructively. This paper examines a promising management initiative for one of the most useful Amazonian palms – Mauritia flexuosa – in a rural community of northeastern Peru. Based on data from household surveys (n = 57), filmed in-depth interviews, focus groups and participant observation, we identify the factors that influence: (1) the adoption of a locally developed climbing device for wild-harvesting of aguaje palm fruit; (2) the continued practice by some households of palm felling for harvesting fruit; and, (3) investment by households in planting and cultivation of aguaje palm. Our findings identify key conditions for palm management and point to the particular importance of the adoption of palm-climbing devices, not only for reducing wild palm felling but also for stimulating broader community-level conservation as well as efforts to cultivate the palm.     

Chlorpyrifos Toxicosis in Two Cats

Organophosphate compounds are widely employed for control of external parasites in cats and for control of insects in homes and yards. Chlorpyrifos is a long-acting organophosphate (OP) available for use as a systemically and topically acting parasiticide and insecticide in cattle. Its use on cats is not recommended, and no previous clinical cases of toxicosis have been described. Two cases of chronic chlorpyrifos toxicosis in cats are presented and pathophysiology as well as treatment are discussed. The cats had been showing signs of chronic organophosphate toxicosis before diazepam administration. Signs of acute organophosphate toxicosis were precipitated after diazepam was given. Treatment with pralidoxime chloride (2-PAM) and atropine was attempted. Response to treatment was dramatic and complete recovery was achieved with six injections of pralidoxime and atropine administration.     

Global survey of serological evidence of caprine arthritis-encephalitis virus infection

Using caprine arthritis-encephalitis virus antigen in the agar gel immunodiffusion test, 3729 serum samples from goats in over 112 locations around the world were tested for precipitating antibodies. Over 90 per cent of the 1265 positive samples came from Canada, France, Norway, Switzerland and the USA, all of which had 65 per cent reactors or greater. Fiji, Great Britain, Kenya, Mexico, New Zealand and Peru had fewer than 10 per cent positive samples; the majority of these could be traced to importations of goats from countries where there was a high occurrence of precipitating antibody. Somalia, Sudan and South Africa had no reactors among 306 samples. No reactors were found among 1116 samples from domestic and indigenous goats which were known to have had no contact with imported goats from countries which had a high occurrence.