Volume 8, Issue 4
October - December 2019
CONTENT
Chair's Foreword
Research into Indigenous Technologies (evaluation of soil and water conservation measures)
Earth Science Events
References and selected reading
Chair's Foreword*
We address indigenous soil and water conservation (SWC) measures and progress so far made in their modern evaluation to put our indigenous technologies on a sound scientific footing. By and large, results so far indicated that stone bunds served to conserve soil and water and increase crop yields. Also, studies evaluating Zai planting pits show almost unequivocally that they are a very effective means of improving soil fertility, conserving soil and water, as well as increasing crop yields. Barriers to establishing the effectiveness of these soil and water conservation measures presented themselves as ranging in form from political reforms and a focus on externally driven projects to misleading mathematical/physical models developed in very different conditions to those they are applied to - as in the case of work undertaken in the highlands of Ethiopia. As a result of model predictions being found at odds with measurements made in the field over a decade, caution was warranted in the application of such models.
Research into Indigenous Technologies (evaluation of soil and water conservation measures)
It remains a challenge for African science institutions, to put African indigenous technologies on a sound scientific footing by evaluation of their effectiveness. This work has already began, as we see from various studies coming out of Ethiopia on the effectiveness of stone bunds as a soil and water conservation (SWC) measure and also effectiveness of Zai planting pits in West Africa in Burkina Faso.
There has been a fair volume of study conducted on soil/stone bunds, which are a long established traditional measure to reduce runoff erosive energy and water and soil losses. A study by Adimassu, Mekonnen, Yirga and Kessler [1] in 2014 compared the performance of three distinct treatments:
a) (sb): Barley cultivated land with graded soil bunds;
b) (F): Fallow land and
c) (Bc): Barley cultivated land without soil bunds protection.
Results showed that treatment Sb brought about significant reduction in runoff and soil losses. Plots with Sb reduced the annual runoff by about 28% and the average annual soil loss by about 47%. Consequently Sb also reduced the loss of soil nutrients and organic carbon. Because the absolute losses were still high, there was a need to supplement Sb with land management measures to further control erosion and improve soil fertility. It was noted that despite positive impacts on soil quality Sb did not increase crop yield. In fact, Sb decreased yield. But this was explained exactly by the amount of land lost to soil bunding as opposed to being used to grow crops.
A study conducted by Hengsdijk et al [2] in which a suite of physical models have been applied to the Ethiopian highlands suggest ineffectiveness of SWC measures. But the study results were at odds with field measurements made by researchers from various international institutions over ten years in the Tigray region of Ethiopia [3]. This led the authors to conclude, in their response to the paper by Hengsdijk et al, that there was a need to proceed with caution in applying physical models in cases where the conditions are quite different from those in which the model is developed.
Other studies suggest that traditional soil and water conservation measures like stone bunds can increase crop yield as well as conserve soil and water. The 2007 study by Nyssen, et al [4], supports the effectiveness of stone bunds in increasing crop yields by 53%. It was also indicated that stone bunds were made more productive by the planting of trees.
A very helpful review of the science behind the effectiveness of the Zai planting pit system is provided by Danjuma et al (2015)[5].
We learn that Zai (ancestral planting pits) provides an effective way of improving the management of degraded land and reducing soil erosion, vegetation loss and biodiversity, as well as improving grain yield.
Zai is a term used by Burkina Faso farmers to refer to small planting pits of 20-30 cm diameter and 10-20 cm depth and spaced 60-80 cm apart. It is a traditional land rehabilitation technology promoted by farmers in Burkina Faso to rehabilitate degraded drylands, and restore soil fertility. This technology is mainly applied in semi-arid areas, on slopes less than 5%. According to World Bank, Zai can increase production by 500% if well executed. Manure is added to each planting pit. The organic matter attracts termites that are especially important in improving soil structure. This increased the water holding capacity of the soil 500%,
It is highly notable that in the recent history of the development of land rehabilitation in Africa there has rightly been a light shone on some exceptional individual innovators in soil and water conservation and land rehabilitation from a degraded state. In 1984 a farmer named Yacouba Sawadogo began organising semi-annual market days to promote the use of Zai planting pits. By the year 2000, Yacouba's market days involved farmers from more than 100 villages in Burkina Faso. This was complimented by establishment of Zai schools and training run by other farmers from 1992 to 2009.
The authors admit that the main constraint of the Zai technique is the labour involved in constructing the system. Studies cited between 300 and 450 hours of labour per hectare needed to dig holes for pits and 250 labour hours per hectare to add manure.
However, the socio-economic benefits from Zai pits are transformational for both community and environment if well executed. These benefits are numerous and include
- working well in compliment with other techniques such as stone contour bunding to restore degraded soil
- serving to collect and concentrate water at the plant as needed
- being an innovation that addresses the effects of land degradation, soil erosion and soil moisture stress
- being a good means of restoring soil health
- improving poor grain yields and quality of the product.
 |
| Stone and Soil Bunds serve to reduce runoff erositivity, soil material and water losses |
a) (sb): Barley cultivated land with graded soil bunds;
b) (F): Fallow land and
c) (Bc): Barley cultivated land without soil bunds protection.
Results showed that treatment Sb brought about significant reduction in runoff and soil losses. Plots with Sb reduced the annual runoff by about 28% and the average annual soil loss by about 47%. Consequently Sb also reduced the loss of soil nutrients and organic carbon. Because the absolute losses were still high, there was a need to supplement Sb with land management measures to further control erosion and improve soil fertility. It was noted that despite positive impacts on soil quality Sb did not increase crop yield. In fact, Sb decreased yield. But this was explained exactly by the amount of land lost to soil bunding as opposed to being used to grow crops.
A study conducted by Hengsdijk et al [2] in which a suite of physical models have been applied to the Ethiopian highlands suggest ineffectiveness of SWC measures. But the study results were at odds with field measurements made by researchers from various international institutions over ten years in the Tigray region of Ethiopia [3]. This led the authors to conclude, in their response to the paper by Hengsdijk et al, that there was a need to proceed with caution in applying physical models in cases where the conditions are quite different from those in which the model is developed.
Other studies suggest that traditional soil and water conservation measures like stone bunds can increase crop yield as well as conserve soil and water. The 2007 study by Nyssen, et al [4], supports the effectiveness of stone bunds in increasing crop yields by 53%. It was also indicated that stone bunds were made more productive by the planting of trees.
 |
| Zai planting pits with manure placed to improve soil fertility and moisture retention |
A very helpful review of the science behind the effectiveness of the Zai planting pit system is provided by Danjuma et al (2015)[5].
We learn that Zai (ancestral planting pits) provides an effective way of improving the management of degraded land and reducing soil erosion, vegetation loss and biodiversity, as well as improving grain yield.
Zai is a term used by Burkina Faso farmers to refer to small planting pits of 20-30 cm diameter and 10-20 cm depth and spaced 60-80 cm apart. It is a traditional land rehabilitation technology promoted by farmers in Burkina Faso to rehabilitate degraded drylands, and restore soil fertility. This technology is mainly applied in semi-arid areas, on slopes less than 5%. According to World Bank, Zai can increase production by 500% if well executed. Manure is added to each planting pit. The organic matter attracts termites that are especially important in improving soil structure. This increased the water holding capacity of the soil 500%,
It is highly notable that in the recent history of the development of land rehabilitation in Africa there has rightly been a light shone on some exceptional individual innovators in soil and water conservation and land rehabilitation from a degraded state. In 1984 a farmer named Yacouba Sawadogo began organising semi-annual market days to promote the use of Zai planting pits. By the year 2000, Yacouba's market days involved farmers from more than 100 villages in Burkina Faso. This was complimented by establishment of Zai schools and training run by other farmers from 1992 to 2009.
The authors admit that the main constraint of the Zai technique is the labour involved in constructing the system. Studies cited between 300 and 450 hours of labour per hectare needed to dig holes for pits and 250 labour hours per hectare to add manure.
However, the socio-economic benefits from Zai pits are transformational for both community and environment if well executed. These benefits are numerous and include
- working well in compliment with other techniques such as stone contour bunding to restore degraded soil
- serving to collect and concentrate water at the plant as needed
- being an innovation that addresses the effects of land degradation, soil erosion and soil moisture stress
- being a good means of restoring soil health
- improving poor grain yields and quality of the product.
Earth Science Events
April 16-17, 2020
Earth and Space Science and Engineering
VISION:
VENUE: Cape Town, South Africa
June 29, 2020
International Conference on Oceanography and Earth Sciences
VISION: Aims to bring together leading academic scientists, professors, students and research scholars to exchange experiences and share research results about all aspects of oceanography and earth sciences,
VENUE: Marrakesh, Morocco.
November 5-6, 2020
International Conference on Earth Sciences and Climate Change
VISION: Various aspects of earth sciences and climate change including, biodiversity, bio-degradation, conservation, deforestation, impact on human health health among many other issues.
VENUE: Marrakesh, Morocco.
References and selected reading
1] Adimassu, Z., Mekonnen, K., Yirga, C., and A. Kessler, Effect of soil bunds on runoff, soil and nutrient losses and crop yield in the central highlands of Ethiopia, Land Degrad. Develop. 25: 554-564 (2014).
2] Hengsdijk, H., Maijerink, G., Mosugu, M., 2005. Modelling the effect of three soil and water conservation practices in Tigray.[ Agric. Ecosys. Environ. 105 (2005), 29-40.
3] Nyssen, J., Nigussie Haregeweyn, Desheemaeker, K., Desta Gebremichael, Vancampenhout, K., Poesen, J., Mitiku Haile, Buytaert, W., Naudts, J., Deckers, J., Govers, G., Comment on "Modelling the effect of soil and water conservation practices in Tigray Ethiopia" , Agric. Ecosys. Environ. 114 (2006), 407-411.
4] Nyssen, J., Poesen, J., Desta Gebremichael, Vancampenhout, K., D'aes, M., Gebremedhin Yihdego, Govers, G., Leirs, H., Moeyersons, J., Naudts, J., Nigussie Haregeweyn, Mitiku Haile, Deckers, J., Interdisciplinary onsite evaluationof stone bunds to control soil erosion on cropland in Northern Ethiopia, Soil and Tillage Res. 94 (2007), 151-163.
5] Danjuma, M.N., and Mohammed, S., Zai Pits: A Catalyst for Restoration in the Drylands, IOSR Journal of Agric. & Vet. Sci. (IOSR), Volume 8, Issue 2 Ver.1 (Feb 2015)pp. 01-04.
*Board of the Society of African Earth Scientists: Dr Enas Ahmed (Egypt), Osmin Callis (Secretary - Guyana/Nigeria), Mathada Humphrey (South Africa), Ndivhuwo Cecilia Mukosi (South Africa), Damola Nadi (Nigeria), Dr Chukwunyere Kamalu (Chair - Nigeria).
2] Hengsdijk, H., Maijerink, G., Mosugu, M., 2005. Modelling the effect of three soil and water conservation practices in Tigray.[ Agric. Ecosys. Environ. 105 (2005), 29-40.
3] Nyssen, J., Nigussie Haregeweyn, Desheemaeker, K., Desta Gebremichael, Vancampenhout, K., Poesen, J., Mitiku Haile, Buytaert, W., Naudts, J., Deckers, J., Govers, G., Comment on "Modelling the effect of soil and water conservation practices in Tigray Ethiopia" , Agric. Ecosys. Environ. 114 (2006), 407-411.
4] Nyssen, J., Poesen, J., Desta Gebremichael, Vancampenhout, K., D'aes, M., Gebremedhin Yihdego, Govers, G., Leirs, H., Moeyersons, J., Naudts, J., Nigussie Haregeweyn, Mitiku Haile, Deckers, J., Interdisciplinary onsite evaluationof stone bunds to control soil erosion on cropland in Northern Ethiopia, Soil and Tillage Res. 94 (2007), 151-163.
5] Danjuma, M.N., and Mohammed, S., Zai Pits: A Catalyst for Restoration in the Drylands, IOSR Journal of Agric. & Vet. Sci. (IOSR), Volume 8, Issue 2 Ver.1 (Feb 2015)pp. 01-04.
*Board of the Society of African Earth Scientists: Dr Enas Ahmed (Egypt), Osmin Callis (Secretary - Guyana/Nigeria), Mathada Humphrey (South Africa), Ndivhuwo Cecilia Mukosi (South Africa), Damola Nadi (Nigeria), Dr Chukwunyere Kamalu (Chair - Nigeria).
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