Research Article
The Effect of Minjingu Phosphate Rock and Triple Superphosphate on Soil Phosphorus Fractions and Maize Yield in Western Kenya
Table 5
Sequentially extractable soil P fractions (mg kg−1) at Nyabeda in the second season.
| | Treatment | Resin-Pi | NaHCO3-Pi | NaOH-Pi | HCl-Pi | NaHCO3-Po | NaOH-Po | Sum of fractions |
| | (1) Control | 5.4 | 9.6 | 77 | 9 | 44 | 308 | 453 | | (2) Tithonia | 7.1 | 9.2 | 79 | 10 | 45 | 327 | 477 | | (3) TSP + urea (50 kg P ha−1) | 9.8 | 11 | 91 | 11 | 46 | 324 | 493 | | (4) TSP + tithonia (50 kg P ha−1) | 8.1 | 10 | 84 | 9 | 44 | 317 | 472 | | (5) MPR + urea (50 kg P ha−1) | 9.0 | 10 | 85 | 10 | 41 | 322 | 477 | | (6) MPR + tithonia (50 kg P ha−1) | 9.6 | 10 | 93 | 10 | 43 | 324 | 490 | | (7) TSP + urea (250 kg P ha−1) | 33 | 21 | 143 | 11 | 44 | 333 | 585 | | (8) TSP + tithonia (250 kg P ha−1) | 40 | 23 | 135 | 10 | 44 | 331 | 582 | | (9) MPR + urea (250 kg P ha−1) | 20 | 17 | 116 | 11 | 43 | 313 | 520 | | (10) MPR + tithonia (250 kg P ha−1) | 28 | 19 | 127 | 12 | 45 | 320 | 551 | | s.e.d. | 3.2 | 1.7 | 7.1 | 1.4 | NS | NS | 13 | | CV | 9 | 10 | 11 | 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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