Impact of nigerian agricultural policies on crop production and the environment
SummaryNigerian efforts in agricultural development over the past three decades have failed to improve the country's economy. A review of the sector depicts a gloomy picture. Performance is reflected in environmental degradation, mounting food deficits, and decline in both gross domestic product and export earnings, while retail food prices and import bills have been increasing. These effects have further impoverished the smallholder farmers, locking them into a poverty web. The Government must seek to establish agricultural strategies which promote political stability, self reliance, public participation, sustained production and environmental security.
Impacts of Environmental Degradation on Profitability of Cassava Production in Southeast, Nigeria
This paper examines the impacts of soil erosion on profitability of cassava production in Enugu State, Nigeria. The study specifically compared the costs and returns of the farmers operating on eroded and non-eroded farms and explicitly analyzed the factors influencing profitability of cassava farming enterprise using partial budgetary technique and regression analysis. A multistage sampling procedure was used to select 200 cassava farmers for the study. Primary data were collected on respondents’ age, sex, educational background, farm size, as well as on quantities and prices of inputs and outputs using pre-tested questionnaire. Partial budgetary analysis showed that farmers operating on eroded farms recorded lower crop yield resulting in a significant difference (p<0.05) between the average gross margin earned per hectare on non-eroded ( N 185, 553) and eroded ( N 152, 312) farms. Regression model estimates showed that farm size, labor, input-usage and access to extension services positively and significantly influenced profitability of cassava farming enterprise; whereas incidence of soil erosion and large household size have negative effects on  profitability of cassava farming enterprise in the study area. Cassava farmers in the study area could substantially increase their profit if farmers have access to more land, credit to purchase farm inputs and extension services geared towards good agricultural practices and soil conservation methods. It is also pertinent for government to design and implement special schemes to control and mitigate the effect of soil erosion in order to forestall continuous degradation of arable lands. Keywords: Profitability; Budgetary technique; Multiple regression; Soil erosion; Cassava farmers.
Energy skin effect of propellant particles in Electrothermal-Chemical Launcher
A numerical model of the radiation has been employed by a Monte Carlo method and statistical physics to simulate the process of a capillary plasma source for Electrothermal-Chemical (ETC) Launcher. The effect on propellants with different physical parameters is discussed. The plasma-propellant interaction is also discussed when combined with a thermal model. Results show that radiant energy only causes a small field around the plasma injector in the propellant bed. The responses of energy flux and propellant particles on radiation are both in the order of picosecond. The strong instantaneous radiation is responsible for the transmission of energy to the propellant particles leading to ignition. Compared with conventional ignition, the energy absorbed by propellant particles is used to increase quickly the temperature in the surface layer of propellant particles. This energy skin effect in the propellant particle surface appears to be the main cause of plasma ignition.