Nitrogen use efficiency by maize as affected by a mucuna short fallow and P application in the coastal savanna of West Africa

• Published in: Nutrient cycling in agroecosystems Vol. 71; no. 3; pp. 227 - 237
• Main Authors: Fofana, B., Tamélokpo, A., Wopereis, M. C. S., Breman, H., Dzotsi, K., Carsky, R. J.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01-03-2005
• Subjects: Agricultural production; Agronomy; Cereal crops; Coastal zone; Constraining; Corn; Crop residues; Crop yield; Crops; Efficiency; Farmers; Fertilization; Hydroxyapatite; Mineral fertilizers; Nitrogen; Nutrients; Recovery; Residues; Savannahs; Soil conditions; Soil degradation; Soil fertility; Soil investigations; Soil management; Soil nutrients; Soil types; Supplying; Weather; Togo; Benin
• ISSN: 1385-1314; 1573-0867
• DOI: 10.1007/s10705-004-5084-0

Maize is the primary food crop grown by farmers in the coastal savanna region of Togo and Benin on degraded (rhodic ferralsols), low in soil K-supplying capacity, and non-degraded (plinthic acrisols) soils. Agronomic trials were conducted during 1999–2002 in southern Togo on both soil types to investigate the impact of N and P fertilization and the introduction of a mucuna short fallow (MSF) on yield, indigenous N supply of the soil, N recovery fraction and internal efficiency of maize. In all plots, an annual basal dose of 100 kg K ha−1 was applied to the maize crop. Maize and mucuna crop residues were incorporated into the soil during land preparation. Treatment yields were primarily below 80% of CERES-MAIZE simulated weather-defined maize yield potentials, indicating that nutrients were more limiting than weather conditions. On degraded soil (DS), maize yields increased from 0.4 t ha−1 to 2.8 t ha−1 from 1999 to 2001, without N or P application, in the absence of MSF, with annual K application and incorporation of maize crop residues. Application of N and P mineral fertilizer resulted in yield gains of 1–1.5 t ha−1. With MSF, additional yield gains of between 0.5 and 1.0 t ha−1 were obtained at low N application rates. N supply of the soil increased from 10 to 42 kg ha−1 from 1999 to 2001 and to 58 kg N ha−1 with MSF. Application of P resulted in significant improvements in N recovery fraction, and greatest gains were obtained with MSF and P application. MSF did not significantly affect internal N efficiency, which averaged 45 kg grain (kg N uptake)−1. On non-degraded soils (NDS) and without N or P application, in the absence of MSF, maize yields were about 3 t ha−1 from 1999 to 2001, with N supply of the soil ranging from 55 to 110 kg N ha−1. Application of 40 kg P ha−1 alone resulted in significant maize yield gains of between 1.0 (1999) and 1.5 (2001) t ha−1. Inclusion of MSF did not significantly improve maize yields and even reduced N recovery fraction as determined in the third cropping year (2001). Results illustrate the importance of site-specific integrated soil fertility management recommendations for the southern regions of Togo and Benin that consider indigenous soil nutrient-supplying capacity and yield potential. On DS, the main nutrients limiting maize growth were N and probably K. On NDS, nutrients limiting growth were mainly N and P. Even on DS rapid gains in productivity can be obtained, with MSF serving as a means to allow farmers with limited financial means to restore the fertility of such soils. MSF cannot be recommended on relatively fertile NDS.