Integrated Organic-Inorganic Fertilizer Management for Rice Production on the Vertisols of the Accra Plains of Ghana

Abstract

Studies were conducted at the Agricultural Research Centre, Kpong, of the University of Ghana, to find solution to the problem of low rice yields on the Vertisols of the Accra Plains. Rice yields from continuously cropped fields have been observed to decline with time, even with the application of recommended levels of inorganic fertilizers. The decline in yield has been attributed to low inherent soil fertility, which is partly the result of low levels of soil organic matter (OM). As part of the study, cow dung (CD) and poultry manure (PM) were separately applied to the soil at 20 t ha -1 solely and also 5, 10 and 15 t ha , on the Vertisols of the Accra Plains. Studies were also conducted on the redox potential of CD, PM and rice straw (RS). The application of 10 t ha -1 CD and urea fertilizer (at 45 kg N ha -1 ) and 10 t ha -1 PM and urea (at 60 kg N ha -1 ) both gave paddy yields of 4.7 t ha -1 , which did not differ significantly from the yield of 5.3 t ha -1 , obtained under the recommended inorganic nitrogen fertilizer application of 90 kg N ha -1 . This indicates a synergistic effect of OM and urea on soil fertility. The redox potential studies showed that RS had greater propensity to bring about reduced soil condition in paddy fields than CD and PM, while PM brought about greater reduction than CD.

The growth response of coffee (Coffea arabica L) plants to organic manure, inorganic fertilizers and integrated soil fertility management under different irrigation water supply levels

“…Using organic manure and integrating it with inorganic fertilizer managed to produce a growth pattern (as measured through leaf and primary development) that is comparable to that of recommended levels of inorganic fertilizers. The competitive performance of integrated fertilizer to inorganic fertilizers was also reported by Nyalemegbe (2009) who concluded that combining poultry manure with inorganic fertilizers resulted in similar yields in rice as those obtained from using inorganic fertilizers alone. In addition, composted humus could add to other sources of organic soil nutrients that could be combined with inorganic fertilizers such as composted coffee pulp, cattle manure, poultry manure, sugarcane filter cake and crop residues (Chemura et al 2010b;Van der Vossen 2005).…”

“…The most common sources of organic manure used in crop production are livestock dung, composted and green crop residues, farmyard matter and organic manure from natural systems and material production systems (Lekasi et al 2001;Mufwanzala and Dikinya 2010;Satyanarayana et al 2002). The need for renewable, locally available and cheaper options for supplying nutrient to crops is increasingly becoming important because of the need for sustainable agriculture (Ahmad et al 2006;Baker et al 2001;Nyalemegbe et al 2009;Zafar et al 2011). With growing demands for sustainably produced agricultural produce for environmental, social and food safety reasons, the use and recycling of organic matter is becoming inevitable, particularly for the export market, which depended on commodities such as coffee.…”

“…Reliance on inorganic fertilizers may not be sustainable in the long term given that soils may lose microorganisms and become acidic, having unstable aggregates leading to erosion and general degradation, and this may explain yield decline with time despite the consistent use of inorganic fertilizers (Nyalemegbe et al 2009). Despite this, access to fertilizers especially by smallholder farmers is affected by many factors, some of which are artificial (Ebong and Ebong 2006).…”

“…Given that the negative nutrient balance from use of organic manures is only apparent in yielding coffee, it may be that organic manures, or at least integrated, are able to provide a positive nutrient balance when the coffee has not reached bearing age. Some studies have shown that integrating organic and inorganic fertilizers is competitive in terms of growth and economic returns for crops (Ahmad et al 2006;Nyalemegbe and Oteng 2009;Reganold et al 2001) and other cultures (Afzal et al 2007). …”

Influence of Rice Straw Compost Combined With Mineral Nitrogen Fertilizer on Egyptian Hybrid Rice 1 Productivity and Some Rice Pests

“…It was pointed out that agriculture without insecticides, as in case of organic farming, has been considered to keep the natural balance, as well as preserve the native diversity Buri et al (2004) in an experiment with poultry manure, cattle manure, and rice husks, applied solely or in combination with mineral fertilizer (using urea or sulphate of ammonia as N source) found that a combination of a half rate of organic fertilizer and a half rate of mineral fertilizer significantly contributed to the growth and yield of rice. Similarly, Nyalemegbe et al (2009) found that combining 10 t ha -1 of cow dung with 45 kg N ha -1 urea, or 10 t ha -1 poultry manure with 60 kg N ha -1 , gave higher yields comparable to those under high levels of nitrogen application (i.e., 90 and 120 kg N ha -1 ) applied solely. Nyalemegbe et al (20090 found that rice straw surpassed poultry manure and cow dung in the Vertisols of the Accra Plains of Ghana.…”