Adaptation Of Farming Practices Research Articles

Relative success of frost-resistant variants of Avena fatua: a field experiment

AbstractWhile climate change mainly applies to global warming and subsequent drought periods, freezing periods also are changing and may trigger genetic adaptation. However, there are few prospective, experimental demonstrations. This paper investigates how effectively genetic frost-resistant variants can respond differently to frost periods, especially in farmers’ fields where various other selection pressures occur. An experiment using Avena fatua variants was set up in the field over 8 years of winter crop rotation. The frequency of each variant identified by their leaf isozymes was estimated every year. Six years were necessary to observe a weak trend towards an increased frequency of the frost-resistant phenotype, while the other variants had apparent erratic behaviour. Selection of the frost-resistant variant was challenged by irregular low temperature selection pressure, differential dormancy, germination and seed production, and possibly herbicide sensitivity that mitigated the expression of the selection response. This experiment shows how plant polymorphism and farmers’ practices that superimpose habitat unpredictability diversify possible responses to selection pressures and delay adaptation. However, if climate change brings both higher mean temperatures and extreme values, changes of apparent plant phenology could happen for weeds species displaying the appropriate genetic variability within the time-frame of farmers’ career, thus necessitating correlative adaptation of farming practices.

English

English

Adaptation of farming practices could buffer effects of climate change on Northern Prairie wetlands

Wetlands of the Prairie Pothole Region of North America are vulnerable to climate change. Adaptation of farming practices to mitigate adverse impacts of climate change on wetland water levels is a potential watershed management option. We chose a modeling approach (WETSIM 3.2) to examine the effects of changes in climate and watershed cover on the water levels of a semi-permanent wetland in eastern South Dakota. Land-use practices simulated were unmanaged grassland, grassland managed with moderately heavy grazing, and cultivated crops. Climate scenarios were developed by adjusting the historical climate in combinations of 2°C and 4°C air temperature and ±10% precipitation. For these climate change scenarios, simulations of land use that produced water levels equal to or greater than unmanaged grassland under historical climate were judged to have mitigative potential against a drier climate. Water levels in wetlands surrounded by managed grasslands were significantly greater than those surrounded by unmanaged grassland. Management reduced both the proportion of years the wetland went dry and the frequency of dry periods, producing the most dynamic vegetation cycle for this modeled wetland. Both cultivated crops and managed grassland achieved water levels that were equal or greater than unmanaged grassland under historical climate for the 2°C rise in air temperature, and the 2°C rise plus 10% increase in precipitation scenarios. Managed grassland also produced water levels that were equal or greater than unmanaged grassland under historical climate for the 4°C rise plus 10% increase in precipitation scenario. Although these modeling results stand as hypotheses, they indicate that amelioration potential exists for a change in climate up to an increase of 2°C or 4°C with a concomitant 10% increase in precipitation. Few empirical data exist to verify the results of such land-use simulations; however, adaptation of farming practices is one possible mitigation avenue available for prairie wetlands.

Tree planting, local knowledge and species preference in the South Tongu District of Ghana: Some perspectives

This paper explores the link between local knowledge and tree specie preference in the South Tongu District of Ghana. It is based on a field study that observed, inter alia, that even though Neem is not commonly promoted in Ghanaian afforestation programmes, it is highly popular in the area. Local farmers' preferences for tree species are governed by several factors –; suitability to local climate, availability and access to markets, perceived economic value and availability of wood fuel dependent enterprises. The survey further demonstrates that local knowledge is incorporated into decision-making regarding adaptation of farming practices to changing rainfall patterns; and also plays a role in influencing specie preference. Some likely implications, which these may have on conservation policy and planning in the study area, are also explained.