Conservation Agriculture and Crop Diversification

Crop Diversification and Conservation Agriculture Effects on Weed Dynamics and Crop Productivity under the prevailing climate change in Tigray Region, Northern Ethiopia

Haftamu Gebretsadik Gebrehiwot

Mekelle University

Department of Dryland Crop and Horticultural Sciences

  1. Lars Olav Brandsæter (Associate Prof., Main Supervisor)

  2. Jan Netland (Dr., Co-Supervisor)1

  3. Jens B Aune (Prof., Co-Supervisor)1

  4. Girmay Tesfay (Dr. , Co-Supervisor)

Norwegian University of Life Sciences, Department of Plant Sciences, Norway
Mekelle University, Department of Natural Resources Economics and Management, Ethiopia


Agriculture in Ethiopia is the corner stone and pillar of its economy and on which most of its population is employed. Out of the total available land area of Ethiopia (i.e. 112.3million hectare), about 16 million hectares are suitable for the production of both annual and perennial crops (Central Statistical Authority (CSA, 2011). Of the potential arable land, more than 11 million hectares are under cultivation mainly using seasonal rainfall (CSA, 2011). The irrigation potential of Ethiopia is not well known and different estimates had been reported. Some of the earliest reports include 1-1.5mil.ha (World Bank, 1973), up to 2.3million ha (Ministry of Agriculture of Ethiopia (MoA, 1986), up to 2.8million ha (International Fund for Agricultural Development (IFAD, 1987), and the highest estimates was given by the Indian engineering firm Water and Power Consulting Services’ (WAPCOS,1995) and estimates to be 3.5 million ha.However, FAO estimates that the irrigation potential can reach at a maximum up to 5.7 million ha though most quoted potential can go down to 2.7million ha (FAO, 2012). Based on the total arable land of Ethiopia which is about 11.8million ha (GTP, 2011), the irrigation potential accounts only for nearly 23% of the total arable land. Therefore, it can be concluded that crop production in Ethiopia is based mainly on seasonal rainfall. Crop production in Ethiopia is mostly mixed with livestock production and both are mutually interlinked for as fur as its agricultural history. The biggest challenge today is to fulfill the food demand of the ever growing human population of the country. There are opportunities and bottlenecks which favor and pull down the pace respectively of crop production in the country. The country is endowed with a wide range of agro-climatic conditions (FAO, 2012) that are favorable for growing many tropical, subtropical and temperate crops. It is thought as center of diversity for many agricultural crops and hosts the largest number of livestock. Despite these opportunities, the majority of its people are resource poor. The major bottlenecks contributing on such shortage of food supply include negative climate changes (such as shortage and unevenly distributed rainfall, recurrent drought and long dry spells), population pressure, weak use and adoption of agricultural technologies and insufficient supply and use of agricultural inputs.

Grain crops are the most important field crops, occupying 86 percent of area planted (CSA, 2012) and are main stay of most Ethiopians. The principal grain crops are teff, wheat, barley, (primarily cool-weather crops) and corn, sorghum, and millet (warm weather grain crops).  Teff is the most preferred crop grown in the cooler highlands, while sorghum is the principal lowland crop because it thrives well in semi-arid environments due to its hardy and drought resistant properties.  Crop production in Ethiopia is complex, involving substantial variation in crops grown across the country’s different agro-ecological zones. Five major grain crops (teff, wheat, maize, sorghum and barley) occupy the largest acreage and food supply in the country accounting for about three-quarters of total cultivated area, 29 percent of agricultural GDP in 2005/06 (14 percent of total GDP) and 64 percent of calories consumed (Alemayoh S. et al., 2010). Generally, cereals (grain crops) are cultivated by about 11.2 million farmers and produce annually about 12 million tons of grains which account about 68% of the total agricultural production of the country (CSA, 2012). Among the five major cereal crops, teff accounts for 28 percent of total cereal area, while maize stands for 27 percent of total annual cereal production (CSA, 2012). To produce such amount of grains in the country, farmers use such agricultural inputs as fertilizers (organic and inorganic), improved seeds and chemicals (mainly herbicides, insecticides, Acaricides and so on). The intensive use of fertilizers especially inorganic ones in Ethiopia has of recent history. However, the introduction and use of improved seeds in the country owns little bit longer history mainly after the beginning of agricultural research in the 1950sE.C.

Most of the small scale farmers are limited users (only 25% of the total Farmers) of agricultural inputs such as inorganic fertilizers (CSA, 2012). Though low input, weed infestation remain the main factor which significantly reduces yield of cereal crops. Most commonly, they invest to their maximum potential for weed control especially when they produce cereals such as teff and maize. This is under conventional production systems. If they are to work with conservation agriculture, they need to have different technologies to combat weeds and have high productivity from season to season. To sustain their production, famers need urgent response from researchers in the way such as delivering them information such as temporal and spatial dynamics of weeds under this prevailing climate change and their methods of control.

There are different approaches, though not proved, to control weeds under the different production systems of our small scale farmers which also help them adapt the climate change:

  • Using cover crops intercropped with cereal crops such as maize
  • Hand weeding
  • Using different implements which may be animal/tractor drawn
  • Intensive and effective land preparation mechanisms such as tillage
  • Finally using herbicides (of course this may not be advisable in the eye of climate change adaptation and environmental protection)
  • In rare cases, the use of biological control (using different insects and pathogens which attack weeds but it is not advisable as it is costly and sometimes dangerous)

For this research, cereal and pulse crops will be considered to develop and prove the approaches of weed control and investigate on the synergetic effects of diversification and intensive production systems of crops on temporal and spatial dynamics of weeds under the prevailing climate change.

Therefore, the objectives of this research will be:

  • To screen effective species of cover crop (s) (legume crop) in suppressing weeds and intercropping with maize
  • To elucidate the temporal and spatial dynamics of weeds under maize/pulse mixed cropping systems
  • To determine the critical period of weed control for teff under the practices of conservation agriculture
  • To develop and evaluate different agronomic practices of teff which effectively control weeds and enhance its productivity under the prevailing climate change
  • To evaluate the effect of different organic and inorganic fertilizer types on weed biomass, incidence and severity in teff production systems
  • To observe the efficacy of different herbicides and select the best which can be used during the production of different cereal crops under conservation agriculture
  • To elaborate the economics of weed control in crop production under the prevailing climate change


This research incorporates six different experiments aiming at finding out the weed and crop production dynamics under the prevailing climate change. These will be conducted in NORHED – CSA project sites around Mekelle, Tigray, Northern Ethiopia. The treatments which are going to be considered in this research include different types of legumes serving as cover crops, cereals i.e. teff and maize, chemicals specifically herbicides and different agronomic practices which have contribution on weed dynamics. Data related to weed spatial and temporal dynamics, agronomy, crop, soil, climate and other related socio economic will be collected from different sites within the project research sites in and around Mekelle. The data collection will be conducted by a trained personals under the close follow-ups by me as a researcher. For socio-economic data, semi-structured questionnaire and focused group discussion whenever necessary will be used. Different data collection sheets will be developed and used during the experiment period. All these collected data will be organized, summarized and analyzed using different appropriate statistical software packages such R, JMP and MSTATC.

Crop Diversification and Conservation Agriculture Effects on Weed Dynamics and Crop Productivity under the prevailing climate change in Tigray Region, Northern Ethiopia

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