TY  - JOUR
N2  - A field study was conducted on a sandy soil in Niger to evaluate the agronomic effectiveness of various P fertilizers for millet production during 1985 to 1987. The P fertilizers tested were two finely ground phosphate rocks (PR) indigenous to Niger (Tahoua and Parc W rocks), PR partially acidulated with H2SO4 at 50% acidulation level (PAPR), single superphosphate (SSP), and triple superphosphate (TSP). In 1985, application rates were 0, 6.5, 13.0, and 19.5 kg P ha?1 for each of the P fertilizers. In 1986, half of the plots received the same rates of P as in 1985 and half of the plots received no additional P. In 1987, P additions were repeated only in half of the plots that received P during 1986. A significant (P = 0.05) millet response to P was observed in all the trials. The major findings of this study were: (i) finely ground Tahoua PR was more effective than Parc W PR because of its higher reactivity and was 82 to 91% as effective as SSP for millet production in both the initial and two subsequent seasons; (ii) partial acidulation of Parc W PR can significantly increase its agronomic effectiveness in the first year, but not in terms of residual effect; (iii) partial acidulation was not a desirable technology for increasing the effectiveness of Tahoua PR, because its high Fe2O3 plus Al2O3 content resulted in a product containing relatively low amounts of water-soluble P; and (iv) over a period of 3 yr, one initial application of a large dose of P fertilizer was found to be more effective than three small annual applications in terms of total grain production
AV  - restricted
A1  - Chien, S H
A1  - Henao, J
A1  - Christianson, C B
A1  - Bationo, A
A1  - Mokwunye, A U
TI  - Agronomic evaluation of two unacidulated and partially acidulated phosphate rocks indigenous to Niger
UR  - http://dx.doi.org/10.2136/sssaj1990.03615995005400060045x
JF  - Soil Science Society of America Journal
SP  - 1772
Y1  - 1990///
ID  - icrisat7097
EP  - 1777
SN  - 0361-5995
VL  - 54
PB  - Soil Science Society of America
IS  - 6
ER  -