Soils of the western hills of Nepal are shallow, light textured, acidic in nature, and therefore need good management practices. The objectives of these studies were to manage the marginal maize production system with the use of organic manures, inorganic fertilizers, residue incorporation and inclusion of grain legumes in the cropping system; to synchronize nitrogen requirement through organic and inorganic sources; to identify limitations of nitrogen, phosphorus and potassium nutrients and to select acid tolerant maize germplasm for the acid soil areas. The results showed that under the acidic, low fertility and marginal rainfed upland soils of Lumle with excessive rainfall, even high doses of balanced chemical fertilizer gave very poor yields of maize and fingermillet. Application of 120 kg N/ha through organic manure or a combination of 60 kg N/ha through organic manure plus 60:30:20 N:P2O5:KO/ha through inorganic sources produced 1.68 to 1.71 ton maize grain/ha. Organic manure alone or a combination of organic and inorganic fertilizer produced better yield of relayed fingermillet grain (0.57 - 0.69 t/ha) in maize than inorganic fertilizer alone (0.36 -0,44 ti ha). Application of 3 ton lime/ha in the second year increased soil pH in all treatments in the third year. Similarly total N and available P contents slightly increased while exchangeable K and organic carbon decreased with the use of lime. The result of synchronizing nitrogen requirement showed that 5 ton farmyard manure (FYM) at planting plus 60 kg nitrogen/ha at earthing-up or 20 ton FYM at planting plus 30 kg N at knee high plus 30 kg N/ha at silking, or 10 ton FYM/ha at planting plus 3 splits of N (20 kg at planting, 20 kg at knee high and 20 kg/ha at silking), or 10 FYM plus 60kg N/ha at knee high gave similar high yields of maize grain (5.00 - 5.32 kg/ha) with high carbon, total N and available P but low exchangeable K on the acidic soil. Significant response of 100 kg N, 100 kg N + 100 kg P 20/ha, 100 kg N + 100 kg P 205 + 100 kg ~0/ha was not observed when compared with farmers' practice. But above doses of NPK plus 5 ton lime/ha gave significantly higher yields as compared to farmers' practice or 100 kg N/ha. Out of 28 genotypes in acid soil V -yellow set, 10 genotypes (570/0) produced similar maize grain yields (5.83-7.99 t/ha). Out of 20 genotypes acid soil VI-yellow set 5 genotypes produced 5.00 to 6.97t maize grain/ha. In acid soil X white set, 3 genotypes produced 7.0 to 9.Ot maize grain/ha. indicating that these genotypes could tolerate acidic soil conditions. These genotypes should be made available to the farmers of acid soil areas for increasing maize production.

English

0304|AGRIS 0301|AL-Maize Program|R01PROCE

Juan Carlos Mendieta

CIMMYT Publications Collection