Phosphorus and nitrogen deficiencies limit production of maize ( Zea mays
L.) in many soils of western Kenya.
Considerable amount of work has been done on N nutrition of maize in the region. There is, however, paucity of
information on which to base fertiliser P recommendations for increased maize production considering potential
differences in responses due to varieties, soil type, and climate. External and internal P requirements, and P
utilisation efficiencies of two open pollinated varieties (Ababari
) and one hybrid (H513) were
examined at four P-deficient on-farm sites (2 Ferric Alisol, 1 Haplic Ferralsol, and 1Ferric Acrisol) in western
Kenya. The varieties were grown under P fertilisation rates of 13, 26, 39, 52 kg P ha-1
and a check (no P
application). Maize performance varied with site, rate of P application, and variety. The highest grain yields
(15% moisture content) at the sites varied from 2,732 to 6,479 kg ha-1
for Ababari, 2,350 to 5,835 kg ha-1
H513, and 2,299 to 4,459 kg ha-1
. Internal P requirements ranged from 7 to 24 kg P ha-1
4 to 18 kg P ha-1
, and 5 to 18 kg P ha-1
for H513. Internal P requirements depended on both variety and
environment, but more on environment than on variety. Phosphorus physiological efficiency (kg grain kg-1
ranged from 111 to 314 for Ababari
, 145 to 277 for Oking'
, and 127 to 390 for H513. Ababari
performed as well
as did H513, and the two were better than Oking'
is, therefore, recommended for the region since it is
open pollinated and, hence, the peasant farmers do not have to buy the seeds every season. Row application of
P is inappropriate in case determination of crop external P requirement is required.