| dc.description.abstract | The influence of three leaf mulches from three
tree species on soil nutrients, maize performance and
yield and N concentration of maize at various growth
stag£~ was studied for two. very contrasting seasons
(ven dry 1987 "short rains" and wet 1988 "long
rains") in the semi-arid district of Machakos, Kenya.
Fresh leaf mulches of Leucaena leucocephala, Cassia
siamea and Terminalia brownii were burried in the
soil at a depth of 15cm at 1 and 2kg/m 2 rates. The
mulching materials were burried in furrows 90cm
apart. The design of the experiments was randomised
complete block replicated four times. After burying
the mulches, KaLumani maize was planted on ridges
(above the mulch layers ), at a spacing of 90x30cm.
Analysis of the leaf mulches for their nutrient
composition showed that Leucaena leucocephala had the
highest concentration of nutrients while Terminalia
brownii had the lowest concentrations but highest C
content. I n terms of C/N rati 0 Terminal i e brown i i had
the highest (average of 38.4) while Leucaena
letlcocephala had the lowest (Average of 15.4) ,
indicating a lower ..decomposition of the former.
Soil analysis showed that the mulches increased
soil pH,organic carbon, exchangeable bases, lolal
nitrogen and phosphorus during their decomposition
xi
and even cumulative over the trials. There was a
progressive decline in the soil nutrient status in
the unmulched plots, which is likely to be due to
nutrient removal by the maize crop and leaching.
Results on the mulched influence on maize
indicated that mulch application significantly
increased n i t r-o gen concentration of maize ear leaves
(cobbing stage). Maize grain yield was higher In the
mulched plots compared to the unmulched, however the
differences were not significant (p=O.05). Maize
grain yield w a s significantly and positively
cor re 1ate d w iLh p 1ant he j gh t, p La n t bas e diarneter ,
leaf area index, cob weight, and grain
size in the second trial. | en |
