Local Understandings of Soil Fertility, Rainfall and Conservation Agriculture in Laikipia, Kenya: A Qualitative Analysis.

Conservation Agriculture (CA) is mostly referred to in the literature as having three principles at the core of its identity: minimum soil disturbance, permanent organic soil cover and crop diversity. This farming package has been described as suitable to improve yields and livelihoods of smallholders in semi-arid regions of Kenya, which since the colonial period have been heavily subjected to tillage. Our study is based on a qualitative approach that followed local meanings and understandings of soil fertility, rainfall and CA in Ethi and Umande located in the semi-arid region of Laikipia, Kenya. Farm visits, 53 semistructured interviews, informal talks were carried out from April to June 2015. Ethi and Umande locations were part of a resettlement programme after the independence of Kenya that joined together people coming from different farming contexts. Since the 1970–80s, state and NGOs have been promoting several approaches to control erosion and boost soil fertility. In this context, CA has also been promoted preferentially since 2007. Interviewees were well acquainted with soil erosion and the methods to control it. Today, rainfall amount and distribution are identified as major constraints to crop performance. Soil fertility is understood as being under control since farmers use several methods to boost it (inorganic fertilisers, manure, terraces, agroforestry, vegetation barriers). CA is recognised to deliver better yields but it is not able to perform well under severe drought and does not provide yields as high as ‘promised’ in promotion campaigns. Moreover, CA is mainly understood as “cultivating with chemicals”, “kulima na dawa”, in kiswahili. A dominant view is that CA is about minimum tillage and use of pre-emergence herbicides. It is relevant to reflect about what kind of CA is being promoted and if elements like soil cover and crop rotation are given due attention. CA based on these two ideas, minimum tillage and use of herbicides, is hard to stand as a programme to be promoted and up-scaled. Therefore CA appears not to be recognised as a convincing approach to improve the livelihoods in Laikipia.

Characterization of traditional raw materials used in housing construction in Huambo Region - Angola

The sustainability of buildings associated to the use of raw earth has motivated the studies and the development of techniques and methods in the context of this type of construction. In the region of Huambo, Angola, these construction techniques are widely used, especially for low-income families who represent the majority of the population. Much of the buildings in Huambo province are built with adobe. Due to the climate in this region, subtropical, hot and humid, with altitudes above 1000 meters and extensive river system, these buildings are particularly vulnerable to the action of water and develop, in many situations, early degradation. The Huambo Province is located in central Angola, has 36 km2 area and approximately 2 million inhabitants. This work aims to evaluate, by conducting in-situ tests, physical and mechanical properties of adobe blocks typically used in the construction of those buildings. The methodology is based on field campaigns where in-situ expeditious tests were performed in soils (smell test, color, touch, brightness, sedimentation, ball, hardness, etc.) and tests on adobes blocks made with traditional procedures, particularly in terms of durability and erodibility (erosion test at Geelong method; evaluation test of wet / dry cycle, applying the New Zealand standards 4297: 1998; 4297: 1998 and 4297: 1999). The results will contribute to the characterization of the geomaterials and methods used in construction with earth in Huambo Province, contributing to the improvement of these sustainable solutions, with a strong presence in this region. The results of this study will also contribute to the proposal of constructive solutions with improved performance characteristics, comfort, safety and durability.