Simulating response of maize to previous velvet bean (Mucuna pruriens) crop and nitrogen fertiliser in Malawi uri icon

abstract

  • A velvet bean (Mucuno pruriens L.) module for the agricultural production systems simulator (APSIM) was developed in order to assess the nitrogen (N) and yield benefits of velvet bean green manure crops, when grown in rotation with maize in small holder situations in Malawi. The velvet bean module was able to simulate maturity biomass from six contrasting sites in Malawi over an observed range of 847-10,420 kg/ha with a root mean squared deviation (RMSD) of 1562 kg/ha. APSIM was then tested for its ability to simulate the response of maize crops to fertiliser N in two seasons, to previous velvet bean green manure crops in one season, or both in combination in one season. With no previous velvet bean crop, the response to fertiliser N varied across sites from a non-significant increase to an eight-fold increase in maize yield. Where a velvet bean crop was grown in the previous season, the response to applied N varied from non-significant to slight. Simulated yields were within one standard error of the observed in the majority of cases. A sensitivity analysis for key parameters in the velvet bean module highlighted, that those governing the N content of crop root and shoot residues had greatest impact on maize yield response. Parameters controlling production and partitioning of root or shoot biomass were less important.
  • To our knowledge this is the first reported case of a cropping systems simulation model being tested for its ability to simulate the production of a green manure legume followed by a cereal. (C) 2004 Elsevier B.V. All rights reserved.

publication date

  • 2005
  • 2005
  • 2005