Yield response of newly released cassava genotypes and hybrid maize to intercropping and inorganic fertilizers in Uganda

Abstract

This study determined the effect of intercropping the newly developed cassava (Manihot esculenta Crantz) genotypes with hybrid maize (Longe 6H) and NPK fertilizer appljcation on the growth and yield of the component crops. The specific objectives were to determine the effect of maize planting density in the cassava/maize inter crop on the growth and yield of the component crops, and to determine the effect of NPK fertilizer on the growth and yield of the newly released cassava genotypes. In experiment one, two newly released cassava genotypes NAROCASS 1 and NASE 14 inter cropped with Longe 6H maize were evaluated in different combinations including sole maize (SM), sole cassava (SC), one row of maize and cassava ( 1C:1 M), and two rows of maize and cassava (1C:2M). Inter cropping significantly influenced maize plant heights; cob length, the number of rows per cob and the maize grain weight when compared with sole cropping. The cob length and the number of rows per cob decreased in the order SM> 1C:1 M> l C:2M indicating that as the plant population density increases, the cob length and the number of rows per cob gradually decrease. In both NAROCASS I /Maize and NASE 14 /Maize intercrops, maize grain yield under the low plant density (1C:1 M) was comparable to sole cropping than those at the higher plant density (1 C:2M). Thus indicating that increasing maize plant population density (I C:2M) significantly reduced grain yields compared to grain yields at low plant population density (lC:lM). Similarly, cassava root yield decrease in the same order (SM> 1C:1M>1 C:2M) indicating that increased in population gradually reduced root yield. The land equivalent ratio (LER) values for intercrops were greater than one, indicating yield advantage of intercropping over sole cropping. In experiment two, the effects of NPK fertilizer on the growth and yield of the newly released cassava genotypes were assessed at three levels of 200, 400 and 600 kg/ha. Fertilizer application up to 400 kg/ha significantly (P<0.05) influenced the cassava root length, fresh