Authors:
Austin T. Phiri
, Ray R. Weil
, Jerome P. Mrema
, Enerst Semu
, G.Y. Kanyama-Phiri
,
Julie Grossman
and Rebbie Harawa |
Abstract:
A study aimed at the assessment of the contribution of pigeon pea roots to N yield for the pigeon
pea was conducted at Chitedze Agricultural Research Station (S 130
59' 23.2", E0330
38' 36.8"),
Malawi in the 2012/2013 cropping season. Ten treatments, replicated three times were laid in a
randomized complete block design. Two pigeon pea varieties, long (ICEAP 04000) and medium
duration (ICEAP 00557) and groundnut (CG 7) were grown as monocultures and intercrops. The
intercrops involved planting either of the pigeon pea varieties with groundnut. Some of the plots
were treated with triple super phosphate (TSP) at the rate of 25 kg P ha-1
. Analysis of soil
samples collected in all treatment plots indicate that the soil had low fertility, having; low
organic carbon (1.4 %), low cation exchange capacity (CEC) (NH4OAc) (3.5-3.6 cmol (+) kg-1
soil) and low N (0.12%), while plant available phosphorus (Mehlich 3) was marginally adequate
both in the top and sub soil (u=21.5 mg P kg-1
and 22.1 mg P kg-1
). Assessment of pigeon pea root biomass indicated a mean yield range of 507-605 kg ha-1
. Phosphorus yields in the roots
ranged from 0.3 kg ha-1
to 0.5 kg ha-1
while N yield of 5.7 kg N ha-1
to 7.7 kg N ha-1
, a modest contribution to the soil N pool. Though
modest the contribution by roots of N to the soil cannot be overlooked since the nutrient even
after immobilization, a temporally state, largely is available for uptake by succeeding crops in a
rotation system as it does not get complexed in the soil as is the case with phosphorus |
