Gray en la solubilidad de rocas fosfóricas: experimento de incubación de laboratorio
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Date
2004Author
Karanja, NK
Gachene, CKK
Savini, I
Type
ArticleLanguage
enMetadata
Show full item recordAbstract
A 16-week laboratory incubation experiment was
conducted to evalua
te the effect of
Tithonia
diversifolia
leaves on the dissolution of Minjingu
(MPR) and Busumbu (BRP) rock phosphates in a
Kenyan Oxisol. Triple superphosphate (TSP) fertilizer
was included as a positive control. Soil samples were
extracted with anion exchange resin (AER) and mixed
anion-cation exchange resin (ACER) after 1, 7, 14, 28,
56 and 112 days to estimate plant available P. Soil P
fractionation was carried out using solutions of 0.5M
NaHCO
3
, 0.1M NaOH and 1M HC
l. The highest mean
AER-extractable P concentrations for BRP and MPR
treatments were 6.0 and 20 mg kg
-1
respectively; while
that of the TSP treatments was 24 mg kg
-1
. The AER-
extractable P concentrations were in the order TSP >
MRP > BRP. The ACER-extractable P concentrations
were higher than those of AER. Application of tithonia
at 10 tons ha
-1
in combination with MPR caused a
significant (P<0.05) depression in AER-extractable P.
The TSP treatments had the highest NaHCO
3
-P
i
and
NaOH-P
i
(labile and moderately labile inorganic P)
fractions which ranged from 22 to 32% and 45 to 59%
of total added P, respectively; followed by MPR
treatment which had NaHCO
3
-P
i
and NaOH-P
i
fractions ranging from 13 to 22% and 26 to 34% of the
total added P, respectively. Addition of tithonia
decreased the NaHCO
3
-P
i
and NaOH-P
i
fractions from
the MPR treatments by 2 to 8%. The RP treatments
had the highest HCl-P
i
(undissolved RP) fraction
Citation
Karanja, N. K., Gachene, C. K. K., Savini, I., & Smithson, P. C. (2004). GRAY EN LA SOLUBILIDAD DE ROCAS FOSFÓRICAS: EXPERIMENTO DE INCUBACIÓN DE LABORATORIO. Tropical and Subtropical Agroecosystems, 4, 75-83.Publisher
University of Nairobi, college of agriculture and veterinary sciences,