RA 00048.pdf - OAR@ICRISAT

Aspects of Nitrogen Fertilization of Sorghum
J. T. Moraghan, T. J. Rego and Sardar Singh
Abstract
Nitrogen deficiency is a constraint to high sorghum yields in India. Soil nitrogen dynamics in the region are complex.
Four separate situations are considered: (a) kharif production on Vertisols; (b) kharif production on Alfisols; (c) rabi
production on Vertisols after a kharif fallow; and (d) rabi production on Vertisols after a kharif crop. Denitrification and
nitrate leaching losses are likely problems in (a) and (b), respectively. Split applications of banded nitrogen fertilizer
under high rainfall conditions have increased fertilizer efficiency in (a) and (b). Positional availability of fertilizer, due to
dry soil zones, is a possible constraint in (c) and (d). Deep placement of fertilizer is needed in such situations. Pertinent
research involving the isotope N 16 and soil nitrogen mineralization will be discussed.
Insect Pests of Sorghum in West Africa
K. F. Nwanze
Abstract
Three species of insect pests are considered important in West Africa: the shoot fly, mainly Atherigona soccata:
sorghum midge, Contarinia sorghicola; and stem borers, mainly Busseola fusca. Over 20 species of shoot fly have
been recorded in Upper Volta. Infestations are usually low to insignificant except on very late sown crops. Midge
attack varies between seasons; it is usually low in the dry Sahelian zone but severe south of latitude 13°N. It is
generally insignificant in Nigeria and Mali while "hot spots" have been identified in central and southern Upper Volta.
Stem borer infestation is caused primarily by B. fusca; however, Eldana saccharina and Sesamia calamistis are also
found. Severe infestations occur in Nigeria as far north at 12°6' latitude, being most severe at Samaru and Funtua. In
Upper Volta, B. fusca infestations occur below latitude 11°30'N where annual rainfall exceeds 900 m m . The late crop is
most severely infested.
Damage by head bugs and head worms is increasing particularly on introduced sorghums with compact
panicles—they are not a problem on local cultivars with loose panicles.
A Comparison of Three Methods for Grain Mold Assessment in Sorghum
V. M. Canez, Jr. and S. B. King
Abstract
Eleven grain sorghums believed to represent a range in susceptibility to grain mold were field grown in Mississippi
with and without aerial misting during seed development. At physiological maturity and harvest maturity, threshed
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