Journal of
Soil Science and Environmental Management

  • Abbreviation: J. Soil Sci. Environ. Manage.
  • Language: English
  • ISSN: 2141-2391
  • DOI: 10.5897/JSSEM
  • Start Year: 2010
  • Published Articles: 287

Full Length Research Paper

Improving the productivity of lowland soils for rice cultivation in Ghana: The role of the ‘Sawah’ system

  Buri M. M., Issaka R. N., Wakatsuki T. and Kawano N.
  1CSIR – Soil Research Institute, Academy Post Office, Kwadaso – Kumasi, Ghana.  2Faculty of Agriculture, Kinki University, Nara – Japan.  3Japan International Research Centre for Agricultural Sciences, Tsukuba, Ibaraki, Japan. 
Email: [email protected]

  •  Accepted: 09 August 2011
  •  Published: 31 March 2012

Abstract

 

Lowlands constitute one of the largest and appropriate environments suitable for rice cultivation in 
Ghana. However, environmental degradation and declining soil productivity, leading to low crop yields 
are major concerns. Some reasons leading to such concerns may be traced to lack of proper 
management of our soil resources and possible unsuitable crop production systems and practices. 
Effective nutrient and water management in addition to suitable land preparation options are key 
factors for the effective and sustainable utilization of these inland valley ecosystems. Proper and 
meaningful management strategies therefore need to be developed in a way as to enable and 
encourage farmers to accept and easily adopt them. Designing and implementation of comprehensive 
and integrated soil management programs that will not only improve and maintain soil fertility but also 
make maximum use of available water are necessary. While research has shown that these 
environments vary considerably in soil type, water holding capacity and nutrient retention, it has been 
further observed that soils of most valleys are dominant in low activity clay minerals which have low 
nutrient and water holding capacities. Adoption of the “Sawah” system will enhance and sustain 
production. The "Sawah" system is characterized by nutrient replenishing mechanisms with intrinsic 
resistance to erosion (better water control and nutrient management). Rice responds better to fertilizer 
(mineral and organic) under the "Sawah" system than the traditional system of rice production in 
Ghana. Rice cultivation under the “Sawah” system in inland valleys in Ghana has lead to significant 
improvement in soil and water management. There has been a gradual and significant increase in rice 
grain yield in the order: farmers practice < only bunded < bunded and puddled < bunded, puddle and 
leveled (“sawah”), across locations and varieties. An integration of available farm manures with mineral 
fertilizer resulted in significant increases in paddy grain yield across locations, thus reducing the over 
reliance of famers on mineral fertilizers to improve soil fertility. From a significant initial increase (from 
less than 1.0 t ha
-1
 to over 4.5 t ha
-1
), mean paddy grain yield under the “Sawah” system consistently 
and continuously increased annually and currently stands at over 6.0 t ha
-1
 among farmer groups. Mean 
net income generated per hector under the “sawah” system also ranged from US $1,500 to US $2,800 
over the same period among farmer-groups. There was also a gradual build up of total carbon and 
exchangeable bases (K, Ca, Mg) leading to improved nutrient levels, even though there was a net loss 
of both total Nitrogen and available Phosphorus over the same period. Ghana (possibly West Africa) 
has the potential to increase local rice production by over 300% when the “Sawah” system is adopted. 
 
Key words: Lowlands, improvement, rice yields, "sawah" system, soil productivity.