ISSN: 0041-3216 (Online), 0041-3216 (Print)
Volume 52 Number 1
Leaching of nitrate under maize at Samaru, Nigeria
As part of a study into the effect of planting date on maize yields, soil mineral nitrogen was measured weekly at depths down to 75cm under maize crops, both with and without fertilizer, planted at four different dates spanning two months. a consequence of heavier rains in the second half of the season, fertilizer nitrogen applied to the seedbed was more rapidly lost from the topsoil under late planted than under early planted crops, but the availability of native soil mineral nitrogen did not decrease with lateness of planting. Nitrate leaching appeared to play, at most, only a minor role in the decline of yields with lateness of planting. The rate of leaching of native soil nitrate was estimated to be 0·2 to 0·3cm/cm rainfall, but that of fertilizer nitrate may have been somewhat greater.