The APSIM Mucuna Module

The APSIM Mucuna Module – (Mucuna)

Introduction

The mucuna module was developed Michael Robertson. The reader is referred to the science document for the plant module for a comprehensive description of the processes simulated by APSIM-Mucuna. The paper by Robertson et al. (2004) outlines the science content of the module, and some testing in Malawi. This document outlines some mucuna-specific issues that are not covered by the plant science document.

Notable features of APSIM-MUCUNA

The module simulates the main variety grown in southern Africa - Kalagonda
The module does not simulate production from second and further flushes of flowers and pods.
APSIM-Mucuna is not phosphorus-responsive, this is currently under development.
Crop growth is not sensitive to waterlogging.

Cultivars and crop classes

There is one crop class.

There is one cultivar able to be simulated: mucuna_gen. This cultivar is typical of that found growing under smallholder conditions in southern Africa.

Validation

APSIM-Mucuna has received testing in Malawi only, with factors such as sowing date and soil types. Table 1 summarises module performance reported by Robertson et al (2004).

Table 1: Observed (O) and simulated (S) biomass at flowering and maturity and grain yield for velvet bean crops used for model testing. All variables are in kg/ha.

Location	Season	DAS^a	Grain yield		Biomass N at maturity		Grain N at maturity		Biomass at flowering			Biomass at maturity
			O	S	O	S	O	S	O	S	O		S
Chitala^b	1998-9	72							848	1623
Chitedze	1998-9	202	2126	2382	256	221	96	102	2374	1791	6848		8609
Chitedze	1997-8	202	2820	2752	314	270	NM^c	NM	7640	4747	10420		9189
Lisasadzi	1998-9	182	2187	1851	163	211	98	83	2401	2628	5418		6268
Makoka	1998-9	181	1343	2352	117	NM	60	105	2610	923	5925		8364
N'gabu	1998-9	173	1852	1643	257	277	83	85	2135	1017	8651		5893

^a days after sowing of maturity harvest

^b crop at Chitala suffered late leaf diseases, therefore only sampling at flowering is recorded

^c NM = not measured

IN Which environments THIS MODULE should be used with confidence?

APSIM-Mucuna can be used with most confidence in southern Africa. No testing has been done elsewhere.

References

MJ Robertson, Sakala W, Benson T, Shamudzarira Z (2004) Simulating response of maize to previous velvet bean (Mucuna pruriens) crop and nitrogen fertiliser in Malawi. Field Crops Research (in press).