RESEARCH AGENDA FOR THE DEPARTMENT OF SOIL AND GEOLOGICAL SCIENCES
Research areas under DSGS:
In its most common use, the term land refers to the part of the earth’s surface that is not covered by water. FAO (1995) gives land a broader definition which takes into account not only the physical entity, but also the associated physio-biotic and socio-economic as well.
Soil is one of the land resources which, by its importance, has shaped the livelihood and success of many ancient and current communities (Holmes and Hearn, 1942). It is therefore important to map the spatial distribution of the qualities of the soil resource in order to make informed decision about types of land uses we want to allocate and the types of management we will need to implement in specific pieces of land in order to optimize the selected land use types.
The first documentation of spatial soil information in Tanzania was done by Milne in 1936 (Milne, 1936). From that time, several exercises have been done to map the soils of Tanzania. A few exercises have attempted to cover the whole country, but so far, with a coarse scale of over 1:1,000,000; which cannot help farmers and other land users make informed decision at farm scale. Finer scales mapping have been done on request or responding to research question, but they are at varying scales and covering different area which lack continuity. Another feature of these mapping exercises is use of conventional methods which lack flexibility and transferability. The finer scale soil maps are generally owned by different researchers and clients, thus not readily available for public use.
Soil mapping provides basis for land evaluation and crop suitability analyses. It helps to avoid blanket recommendations of soil management such as fertilizer application, irrigation application and crop varieties/types selection.
Currently, researches on soil mapping are leaning towards methods which increase precisions and reliability of the mapped soil properties. The current methods also are geared towards reducing soil survey costs by including modelling and predictive methods.
Research sub themes:
Microorganisms play a major role in agricultural productivity of soils. Their positive exploitation could range from enhanced soil fertility through their role in nutrient recycling due to organic matter degradation to provision of plant protection via production of various biologicals and or/ physical pest control. Use of a wide assortment of plant growth promoting microorganisms such as those involved in nitrogen fixation, phosphate solubilization and nutrient scavenging is another area where the microorganisms do contribute directly to enhancement of soil fertility and land productivity.
Pollution control and ensuring general environmental safety is an important undertaking which has been mentioned in different national documents including the Environmental Management Act 2004 and the National Environmental Policy (NEP) of 1997. The pollution control and general environmental safety can be achieved through the use of microorganisms ranging from those involved in general biodegradation of sewage regimes to those involved in complex tasks such as plastic degrading microorganisms and those involved in bioremediation of heavy metal and/or persistent organic pollutants (POPs)-contaminated soils and water systems. As a nation, we need to improve the contribution of microbiological aspects of soils to overall soil health, increased land productivity and general environmental safety. We also need to explore various beneficial soil microorganisms that enhance soil fertility and thus increase sustainable agricultural productivity of the soils
Research sub themes
Development and testing of microorganisms to be used as tools for environmental cleaning of plastics
Soils occur with a lot of minerals and elements/metals; some could be beneficial or toxic to plants and the environment depending on their concentrations. In soils, metals above the background level can be toxic to plants and may decrease microbial biomass by killing or disabling soil organisms. Some metals, such as cadmium (Cd), lead (Pb), Cr, Ni, mercury (Hg), thallium (Tl), uranium (U), thorium (Th), and arsenic (As), are carcinogenic and highly toxic.
These metals are often considered as contaminants and are nonessential to most living organisms and thus, when occur in soils at high concentrations, could be of concern to agricultural produce and food chains. Source of high concentrations could be due to weathering of parent rocks and contaminations associated with human activities such mining and improper applications of fertilizers or pesticides. Hence, identification and quantification of minerals and metals in soils are essential for proper utilization of these resources and protection of the environment.
Tanzanian agriculture and food systems have the potential not only to meet the local food demand but also produce a surplus for export. Achieving the above requires addressing critical limiting production factors specifically soil and water. Need for improving soil and water management have been stipulated in ASDP II and the National Five Year Development Plan 2015/16 – 2020/21. Soil and water are inefficiently managed resulting in an inefficient utilization of the two natural production resources. The situation is worsened by the changing climate resulting in declining productivity due to reduced soil moisture. This necessitates development of innovative agronomical practices for conserving available soil moisture. The soil and water conservation research should aim at mainstreaming appropriate soil and water management technologies into farming systems which will result into their sustainable use and meeting the needs of current and future generations.
Despite the fact that most farming in Tanzania is undertaken by poorly resourced and poorly educated small holder farmers, most of it is undertaken in old nutrient depleted landscapes. This results to poor crop productivity, since plants performances largely rely on soil fertility and its management. Therefore, there is a need to revise strategies for improving fertility status of these landscapes. Tanzania is now striving to improve crop productivity so as to make the nation food self-sufficient. In its current move for industrialization as described in the Second National Five years Development plan 2016/17 – 2020/21, the country also wants to promote productivity, such that the industries get sufficient agricultural based raw materials within the country.