Some maize production parameters for KwaZulu

Abstract

As part of a farming systems research project in KwaZulu, a range of agronomic variables (hybrid and open‐pollinated seed, frequeincy of weeding and fertilizer rates) were evaluated for small‐scale subsistence and commercial maize (Zea mays L.) production.

Not all hybrids performed well but a group of adapted cultivars outyielded the open‐pollinated cultivars consistently. The grain yield regression equation of a leading hybrid (PNR6549) on the best open‐pollinated cultivar (Kalahari Early Pearl) was y = 0,32 + l,2x (yield range: 1 t ha‘¹ to 8 t ha^‐1). The large‐grained Hickory King and a traditional cultlvar (Maputaland), while giving lower grain yields than other open‐pollinated and hybrid culttvars, were preferred for consumption as green mealies (corn‐on‐the‐cob).

Weed control was a major determinant of yield. At the lowest level of purchased input (open‐pollinated seed, no fertilizer), increasing the number of weedings from one to three raised the mean grain yield over two seasons from 1,1 t ha^‐1 to 2,0 t ha^‐1, and from 2,2 t ha‘¹ to 3,8 t ha‘¹ in the treatment incorporating a hybrid cultivar and the highest fertilizer level.

Production objectives and labour and cash constraints in KwaZulu differ between subsistence farmers and semi‐commercial and commercial farmers. The data presented here provide guidelines to the selection of suitable options for the various categories of farmer.

Notes

An abridged version of this paper was read at the Annual Congress of the South African Society of Crop Production, University of Stellenbosch, January 1991.

Institute of Natural Resources. University of Natal, Pietermaritzburg. The authors are indebted to Professor M F Dutton, Department of Biochemistry, University of Natal, Pietermaritzburg, for mycotoxin assays and gratefully acknowledge financial assistance from the South African Sugar Association and Premier Food Industries.