Improving the productivity of lowland soils for rice cultivation in Ghana: The role of the Sawah system
Year: 2012
Type: article
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.
DOI: 10.5897/jssem11.070
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W2149192055