University of Gothenburg, School of Business, Economics and Law, Working Papers in Economics, No. 406, November Kassie, Menale, Precious Zikhali, John Pender and Gunnar Kohlin (2009)

An analysis of plot-level data from Ethiopia reveals that agro-ecological conditions play a crucial role in determining which cultivation technology is most appropriate for adoption be farmers.

A central issue of agrarian development in different countries and regions has been the choice of farming technology. Intensive cultivation, comprising of the use of high-yielding seeds and chemical inputs, have been widely adopted across the world and has borne fruit in terms of raising crop productivity including that of food-grains. In particular, the success of the Green Revolution in Asia has encouraged policymakers in different countries to pursue policies that recommend the adoption of chemically intensive cultivation practices. Many African countries, including Ethiopia, have undertaken comprehensive measures to technologically upgrade the sphere of agriculture in a bid to raise farm output and productivity.
           
While chemical input based intensive cultivation has been fairly successful in many regions in the past, it has been increasingly recognized that different agro-ecological conditions demand the use of varying technologies. In particular, arid and semi-arid conditions, which are prevalent in many parts of Africa, are less conducive to water-intensive cultivation technologies like the Green revolution and alternative sustainable agricultural practices are found to be more productive. Conservation agriculture involving zero- or reduced tillage is one such cultivation method among others. From the perspective of climate change and emerging resource constraints (particularly for water) in several nations of Africa, including Ethiopia, the conservation of soil and water using reduced tillage cultivation may be more suitable and sustainable.
           
An important issue that needs to be probed regarding conservation agriculture is the crop yields that are generated though such practice and its economic feasibility. Kassie et.al examines the economic sustainability of reduced tillage cultivation under varying agro-ecological conditions and contrasts this cultivation method with the usually prevalent intensive cultivation practices. The study is based on plot-level data from two regions of Ethiopia, Amhara and Tigray, with distinct agro-ecological characteristics. While Amhara is a high-rainfall area (1981 mm per annum), Tigray is a region with scanty rainfall (648 mm per annum) and has a soil with very low water retention capacity. The dataset used for the study consists of 935 farm household, 435 in Amhara and 500 in Tigray.
           
The authors have conducted a semi-parametric analysis on the dataset using the Propensity Score Matching (PSM) technique to make the selection of observable farms relevant to the issue of technology choice. Since farms may not adopt a technology due to reasons which are not directly related with their production conditions, capacities and outcomes, a simple comparison between adopters and non-adopters may end up in a comparison of non-comparables. For example, the lack of any agency-led programme on conservation agriculture and the lack of awareness may also lead to farmers not practicing reduced tillage but this has nothing to do with the appropriate of the technology given their conditions of production.

Effectively, the study identifies four sets of farm households for comparison. These are i) chemical fertilizer and regular tillage versus no fertilizer and regular tillage, ii) reduced tillage and no fertilizer versus regular tillage and no fertilizer, iii) reduced tillage and fertilizer versus reduced tillage and iv) reduced tillage and fertilizer versus regular tillage and fertilizer. These four sets of comparison can successfully identify the differential effects of reduced tillage under different fertilizer regimes and the same for fertilizer-use under varying tillage regimes. A parametric analysis using a switching regression framework is carried out to isolate the effects of reduced tillage and fertilizer-intensive cultivation on productivity.

The analysis results indicate that the use of chemical fertilizers enhanced crop productivity in both regions but significantly only in the high-rainfall region. In Tigray under semi-arid conditions, the effect of chemical fertilizers on yields is not significant under both regular tillage and reduced tillage. In contrast, reduced tillage has a significant impact on productivities and revenues in Tigray, with or without fertilizers. In Amhara, however, reduced tillage leads to quite low yields and it is not economically sustainable to adopt the technology given the soil and water conditions in the region.

The authors point towards to importance of agro-ecological conditions in the determination of suitable farming technologies. Presently, the focused policy of the Ethiopian government to promote chemical input based intensive cultivation among farmers does not take this into account. The study shows that the adoption of intensive agriculture is more suitable only in high rainfall areas with high water-retention capacity and reduced tillage does not work very well in such areas.

However, in the case of dryland agriculture dependent on sparse and inconsistent rainfall, conservation agriculture techniques like reduced tillage can profoundly help farmers to increase yields and incomes. While use of more chemical inputs is counter-productive in such areas, reduced tillage cultivation effectively helps the farmer to reduce production costs and risks of buying fertilizers on credit, diminishes the chances of crop-failure due to moisture stress and increases the overall environmental benefits to the farming society. The authors conclude that an integrated promotion of reduced tillage among farmers in semi-arid Ethiopia can make agriculture sustainable in both economic and environmental terms.