Abstract
Sowing maize (Zea mays) and sorghum (Sorghum bicolor) in furrows of tied ridges (tied furrows) was compared with the traditional tillage system of sowing on flat land at five levels of applied N at two sites; one on sandy-loam and the other on a clay soil (Eutric Eutrchrept), in the 1996-97 rainy season in semi-arid Zimbabwe. Grain yield from tied furrow plots was about four times greater than from flat plots at the site with the sandy-loam soil and experienced a long dry spell after sowing. At this site, maize in tied furrows took up 99 kg ha-1 N compared to 48 kg ha-1 N on flat land. At the site with the clay soil, plants in tied furrows and on flat plots took up similar amounts of N. Nitrogen uptake was not affected by N application on sandy-loam soil, but uptake was more on clay soils when 80 kg ha-1 was applied compared to 0 and 40 kg ha-1 N. Apparent recovery of applied N was generally greater in tied furrows than on flat land. Grain produced per unit of applied N was up to four times greater with tied furrows than with flat cultivation. It was concluded that N application in areas with mean annual rainfall of about 500 mm or less was more effectively used with tied furrows.
