Research Article
The Effect of Minjingu Phosphate Rock and Triple Superphosphate on Soil Phosphorus Fractions and Maize Yield in Western Kenya
Table 2
Olsen extractable soil P (mg kg−1) at Nyabeda and Khwisero.
| Treatment
| Nyabeda | Khwisero | | Season 1 | Season 2 | Season 1 | Season 2 |
| | (1) Control | 3.8 | 4.4 | 3.6 | 5.8 | | (2) Tithonia (6 kg P ha−1) | 4.0 | 4.9 | 4.3 | 6.1 | | (2) TSP + urea (50 kg P ha−1) | 4.8 | 5.4 | 5.7 | 7.7 | | (3) TSP + tithonia (50 kg P ha−1) | 5.2 | 5.4 | 6.8 | 7.5 | | (4) MPR + urea (50 kg P ha−1) | 3.9 | 5.0 | 4.2 | 7.1 | | (5) MPR + tithonia (50 kg P ha−1) | 4.8 | 5.6 | 4.8 | 6.9 | | (6) TSP + urea (250 kg P ha−1) | 21 | 12 | 22 | 24 | | (7) TSP + tithonia (250 kg P ha−1) | 18 | 14 | 20 | 28 | | (8) MPR + urea (250 kg P ha−1) | 7.7 | 9.0 | 9.4 | 16 | | (9) MPR + tithonia (250 kg P ha−1) | 8.0 | 11 | 10 | 16 | | s.e.d | 2.3 | 0.9 | 1.7 | 1.9 | | CV. | 11 | 8 | 13 | 10 |
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TSP: triple superphosphate; MPR: Minjingu phosphate rock; s.e.d.: standard error of difference between means; CV: coefficient of variance.
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