Effect of plant population density on the growth and yield of sorghum varieties grown on a <I>vertisol </I>

Abstract

Code Number: cs02004 ABSTRACT Sorghum (Sorghum bicolor (L.) Moench) is an important crop that is usually grown on the Vertisols of north eastern Nigeria during the dry season. The crop is grown on soils with residual moisture, and thus exposing it to terminal drought stress. Improvement of resource use efficiency and yields is probably possible through the use of appropriate plant densities. Field trials were therefore conducted to study the effects of four plant densities, varying from 2.0 to 12.5 plants m -2 on water and radiation use and performance of two Masakwa sorghum varieties grown on a Vertisol under residual soil moisture conditions. At higher plant densities the locally adapted Nigerian variety, Bulwalana produced higher grain yields than the selection from Cameroun, Bourgouri-28. It also had more efficient water use and better light interception. At low plant densities, Bourgouri-28 yielded higher than Bulwalana. Leaf area index and radiation interception increased with increasing plant density. Stem borer incidence decreased with increasing plant density. More stem borer holes and stem tunnelling were recorded in Bulwalana than in Bourgouri-28. Covered kernel smut [Sporisorium sorghi (Ehrenberg) Link] appeared to be a potentially serious disease of the crop. The study showed that the performance of the crop can be improved through manipulation of plant population and use of early maturing cultivars. pour étudier les effets de quatre densités des plantes, variant entre 2.0 et 12.5 plantes m -2 sur l'utilisation de l'eau, de la radiation et sur la performance de deux variétés de sorgho Masakwa cultivées sous des conditions d'humidité résiduelle. A des densités de plantes élévées, la variété Nigériane localement adaptée, Bulwalana a produit un rendement en grains plus élévé que la sélection du Cameroun, Bougouri-28. Elle avait aussi une utilisation plus efficace de l'eau et une meilleure interception de la radiation. Aux densités basses, Bougouri-28 a eu un rendement plus élévé que celui de Bulwalana. La surface foliaire et l'interception de la radiation ont augmenté avec la densité des plantes. L'incidence des foreurs des tiges a diminué avec l'augmentation des densités des plantes. Un plus grand nombre des trous des foreurs des tiges et des percements des tiges ont été enregistrés sur Bulwalana que sur Bourgouri-28. Le charbon couvert [Sporisorium sorghi (Ehrenberg) Link] apparait comme une maladie potentielle sérieuse de ce sorgho. Cette étude a montré que la performance de ce sorgho peut être améliorée en manipulant la densité des plantes et en utilisant des cultivars adaptés et précoces.

Water harvesting techniques and supplemental irrigation impact on sorghum production

“…That is because TRwSI conserves more moisture within the root zone and also assists in even distribution of retained rain water. These results agree with Tabo et al and Elbasri et al findings.…”

“…There was no significant difference between RoSI and BoSI in the first season but showed significant difference in the second season. This result could be attributed to the fact that the TRwSI gave the highest plant population by the concentrated organic matter and fertiliser present near the soil surface in the tied‐ridge, which was found to be 0.54% and 1.2% for the first and second season, respectively, which was clearly reflected in increasing the grain productivity of sorghum …”

Competition of sorghum cultivars and densities with Japanese millet (Echinochloa esculenta)

“…1989; 1990) and pest and disease incidence (Delobel 1982; Harvey & Thompson 1988; Pande et al . 1990; Tabo et al . 2002).…”

“…However, a high sorghum density of >100 000 plants per ha has an adverse effect on the grain yield, especially under severe water stress conditions (Thomas et al 1981;Wade & Douglas 1990). Increases in sorghum density also could have a potential impact on lodging (Pande et al 1989; and pest and disease incidence (Delobel 1982;Harvey & Thompson 1988;Pande et al 1990;Tabo et al 2002).These biotic and abiotic factors should be kept in mind when adopting a high sorghum density for improved weed management. Fig.…”

The role of supplemental irrigation to crop water use under rainwater harvesting

“…This result could be attributed to the fact that the T1 w gave the highest plant density by the concentrated organic matter and fertilizer present near the soil surface in the tiedridge, which was found to be 0.54 and 1.2 % for the first and second season, respectively. This, clearly reflected in increasing the grain productivity of sorghum (TABO et al, 2002;REDDY et al, 2011). The lowest values may be refer to that water deficits affected grain yield primarily through effect on number of grain when it occurred during the period from emergence to time after floral initiation (ABDEL-MOTAGALLY, 2010).…”