Changes in climate are already expected to have serious negative impacts on food production in some parts of the globe, especially in sub-Saharan Africa. In the Offin river basin in Ghana, crop farming is mainly rain fed and a piece of land is farmed regularly over a long period, thus the land looses its fertility. Moreover, soil organic matter is very critical in maintaining soil quality, i.e., soil stability and supply of nutrients. Any form of loss in soil organic matter (SOM) is strongly linked with a decrease in aggregate stability (Haynes,1997; Dominy and Haynes, 2002; Graham et al., 2002) and eventually breakdown of soil structure (Cook et al., 1992).

Existing land use and management strategies as well as agricultural practices in the Offin River basin have the tendency to negatively affect food production. Burning as a land preparation measure and continuous cropping without any form of manuring has the tendency of degrading the soil within a few years. It was realized during the study that,
land preparation for crop farming involves total clearing of vegetation on the land, burning and dressing of the land to make it bare for planting season. This situation enhances rain runoff and rapid erosion since there are no cover crops to protect the soil from rain and wind. In particular, it is the top few centimeters of soil that are often of critical importance for the supply of nutrients, maintenance of an open pore structure for infiltration of water and thus plant productivity (Murphy et al., 1998) and so even slight erosion significantly affects nutrient availability.

The soil is a major sink for carbon and is actually the largest carbon sink over which we
have control (Carbon Coalition, 2008). Land use practices affect the ability of the soil to
retain carbon from getting released into the atmosphere. Nearly 90% of soil organic carbon (SOC) in surface soils are said to be located within soil aggregates (Jastrow et al., 1996). These so-called soil aggregates are ‘clumps’ of soil particles that are held together by moist clay, organic matter, organic compounds and by fungal hyphae. The soil macro-aggregates (>250 µm) often contain more organic matter than microaggregates (<250 µm), because the macro-aggregates include microaggregates plus organic matter serving as an intra-macroaggregate binding agent. The carbon lost from cultivated fields is largely that fraction which is easily mineralized or decomposed and this happens to be the macroaggregates. Soil microaggregates are particularly crucial to long-term sequestration because they protect carbon (C) against decomposition, resulting in much longer residence times for C.

From the study conducted on small traditionally managed farms in the Offin river basin in the Ashanti region of Ghana, soil samples showed that large macro-aggregates of organic carbon across landuse systems had more aggregates by proportion of the total soil mass. This suggests that organic carbon (OC) in the soil is relatively less decomposed and there is going to be more decomposition of the C into micro-aggregates. This has serious implications for effective carbon sequestration and climate change because where the soil has more macro-aggregates than micro-aggregates, as occurs in the study area, there is definitely going to be more decomposition of the macro-aggregates till it reaches the stable micro-aggregates and in the process more carbon will be released into the atmosphere.

This article presents some observations and findings of a study on agricultural land use systems in the River Offin basin in Ghana. The Offin River basin is located in mid-Ghana within the moist semi-deciduous forest zone. The major occupation of the people living in the basin is crop farming; mainly cocoa as a cash crop and food crops. The study sought to establish the impact of different agricultural land use systems in the basin on soil carbon dynamics and how it affects carbon sequestration/management in the basin. The final part also explores how these land use practices can be modified to suit the grand objective of climate change mitigation.

In the Offin river basin, like all other farming communities in Ghana, the “slash and burn” practice of land preparation for the planting season is the most widely practiced. By this practice, large tracts of vegetation are completely cleared, debris or biomass burnt and land made bare (without any vegetation) before planting. This has serious implications for the environment as it contributes to release of carbon into the atmosphere and destroys entire ecosystems. Due to the usual focus on the CO2 released by big industries, the world gradually looses sight of the volumes of CO2 being released through “slash and burn” practices all over the world. For instance, few people realize that Indonesia is the third largest emitter of greenhouse gases on the planet, after the United States and China; and 85% of Indonesia’s emissions are related to land use: the clearing of land for agriculture and infrastructure, and the burning of forests and peatlands (PEACE, 2007). Carbon dioxide (77%), nitrous oxide (8%), and methane (14%) are the three main greenhouse gases that trap infrared radiation and contribute to climate change (Scherr and Sthapit, 2009) and all these gases can be released through improper land management and agricultural practices.

There are also a number of interventions that can be introduced to yield the same results of sustainable land management and increased food production but with very little negative effects on the climate. Some of such preferable interventions which can be introduced in the study area include composting with plant waste, planting of nitrogen fixing cover crops which will also serve to prevent erosion and green manuring i.e. crops grown during fallows to be plowed into the soil to add nutrients and organic matter). Intercropping is already being practiced in the study area and the farmers should be helped by researchers to plant the right crops in their intercropping in order to achieve the desired results.

There should be conscious efforts at encouraging organic farming in the Offin basin because of the immense benefits to be derived and its suitability for the communities. There is enough material available for organic farming, and coupled with the farmers’ inability to purchase inorganic fertilizers, organic farming becomes a better option.

Enter the new world of climate control. Geoengineering, or bio-engineering, is simply the application of engineering principles to living biological systems in an effort to improve them. But the world does not function as it does in a controlled lab, and these attempts have resulted in some spectacular failures in the
past. When Australia wanted to control their native Cane Beetle population, they introduced a couple hundred Cane toads from Hawaii and watched the toad population explode to over 200 million and wreak havoc on their ecosystems. In order to combat erosion in the United States, Kudzu, a Japanese vine, was introduced that, as the Americans discovered, found near-perfect growing conditions there and exploded over approximately 25 000 square kilometers. Attempts to control this vine, coupled with cropland damage, cost an astounding $500 million per year. The vine expands at a rate of 150 000 acres per year. Examples such as these caution us to be wary. But in a rapidly warming world, do we have a choice?

Underground heating pipelines can be traced from a high ground during first snowfalls; until even brand new “elite” buildings use windows for Regulating temperature in the rooms; until municipalities hold to a dreadful practice of
massively burning the fuels remaining at the end of the heating season, it will be impossible to predict how much heat Russia actually needs. Thus, in terms of energy saving, more efficient and rational use of energy in all the sectors of the economy would bring much better results than uncertain climate change consequences. With respect to agricultural productivity, it would be best to start thinking of improving the irrigation infrastructure in the drought-threatened regions rather than dream about growing tropical fruits in the country’s north. In other words, climate change will not make Russia a green and easy world as most of the people assume. Only dispelling this rosy myth will motivate Russian people to make a strong bottom-up push that the country’s policy-makers so badly need.