Home About us Contact
|
Home About us Contact | ||
|
|
||
Modern Agriculture (modern + agriculture)
Selected AbstractsChanges of traditional agrarian landscapes and their conservation implications: a case study of butterflies in RomaniaDIVERSITY AND DISTRIBUTIONS, Issue 6 2007Thomas Schmitt ABSTRACT Global biodiversity is decreasing as a result of human activities. In many parts of the world, this decrease is due to the destruction of natural habitats. The European perspective is different. Here, traditional agricultural landscapes developed into species-rich habitats. However, the European biodiversity heritage is strongly endangered. One of the countries where this biodiversity is best preserved is Romania. We analyse the possible changes in Romania's land-use patterns and their possible benefits and hazards with respect to biodiversity. As model group, we used butterflies, whose habitat requirements are well understood. We determined the ecological importance of different land-use types for the conservation of butterflies, underlining the special importance of Romania's semi-natural grasslands for nature conservation. We found that increasing modern agriculture and abandonment of less productive sites both affect biodiversity negatively , the former immediately and the latter after a lag phase of several years. These perspectives are discussed in the light of the integration of Romania into the European Union. [source] DOMESTICATION OF MAIZE, SORGHUM, AND SUGARCANE DID NOT DRIVE THE DIVERGENCE OF THEIR SMUT PATHOGENSEVOLUTION, Issue 2 2007Andrew B. Munkacsi We investigated two alternative hypotheses for the origin of crop pathogen species: that human-mediated agricultural practices drove the divergence of many crop plant pathogen species or that coevolutionary processes in natural populations of the crops' ancestors drove divergence of pathogen species. We distinguished between these two hypotheses by constructing a robust multigene phylogeny and estimating the dates of divergence among four, monophyletic species of smut fungi (Ustilago maydis, U. scitaminea, Sporisorium reilianum, S. sorghi) known to specifically infect maize, sorghum, sugarcane, and their wild ancestors. Without a fossil record for smut fungi, we calibrated the pathogen species' divergence times to their plant host divergence times. Specifically, a calibration date of 10,000 years was employed to test the hypothesis that the fungal species originated at the time of domestication of their current hosts and a calibration date of 50 million years was employed to test the hypothesis that the fungal species originated on wild ancestors of their domesticated hosts. Substitution rates at five protein coding genes were calculated and rates obtained for the 10,000 year calibration date were orders of magnitude faster than those commonly reported for eukaryotes, thus rejecting the hypothesis that these smut pathogen species diverged at the time of domestication. In contrast, substitution rates obtained for the 50 million year calibration were comparable to eukaryotic substitution rates. We used the 50 million year calibration to estimate divergence times of taxa in two datasets, one comprised solely the focal species and one comprised the focal species and additional related taxa. Both datasets indicate that all taxa diverged millions of years ago, strongly supporting the hypothesis that smut species diverged before the time of domestication and modern agriculture. Thus, smut species diverged in the ecological context of natural host plant and fungal populations. [source] When Land Was Cheap, and Labor Dear: James Madison's ,Address to the Albemarle Agricultural Society' and the Problem of Southern Agricultural ReformHISTORY COMPASS (ELECTRONIC), Issue 3 2008Lynn A. Nelson James Madison's 1818 Address to the Albemarle Agricultural Society offers new insight into the diverse historiography of agricultural reform in the American South. Madison described a planet with limited resources, accused Virginia farmers of wasting what little they had, and offered suggestions for ways to intensify cultivation. Many scholars have analyzed the southern agricultural reform crusade, but differ widely on whether it was successful, and the reasons why. Madison tried to balance high farming with southern independence. Southern farming could not imitate modern agriculture from England and the Northeastern states because of the region's ecological distinctiveness. Madison was reluctant to risk tested adaptations by importing to crops, animals, and fertilizers. Southern farmers reflected his ecological conservatism, and the movement for reform stalled. [source] Deployment of diversity for enhanced crop functionANNALS OF APPLIED BIOLOGY, Issue 3 2009A.C. Newton Abstract Mixtures of genotypes are the norm in natural and seminatural ecosystems and subsistence agriculture but have been replaced by pure genotypes in modern agriculture to maximise profitability in high-input systems. However, crop function with respect to the stability of yield and quality in particular tends to be lost in this process. Diversity can be reintroduced into cropping systems as a trait not only to confer stability but also to exploit synergies between component genotypes, compensating for potential performance losses against the best performing genotype in any given season or location. Quality need not be compromised, and research has demonstrated practical development and deployment approaches, which challenge the assumed benefits of current approaches to agronomy and achieve enhanced crop function. [source] | ||||||||||