Research note on investigation on the poor performance of rain fed maize (<i>Zea mays</i>) at Morogoro Tanzania

Abstract

A study was undertaken to find out the cause of poor performance of maize in some parts of  Morogoro District, Tanzania. Rainfall (R) and Reference crop evapotranspiration (ETo) data were organized on 10-day basis for a period of 20 years from 1974 to 1993. Corresponding values of the two parameters for each I0-day period were then matched and used to determine the duration of rain seasons, appropriate planting dates and to detect the occurrence of dry spells. Findings indicate that, long rains are marked by a period of moisture sufficiency (R> ETo) lasting 60 days beginning March 12th. The average long-term rainfall amount during long rains is 360mm, which is inadequate for optimum yields for late maturing cultivars of maize. Storage of surplus moisture in the profile would extend the period of moisture sufficiency by 20 days during long rains. However, this is unlikely because soils are coarse textured and low in organic matter. Further more, poor agronomic practices encourage the loss of up 30% of rainwater as runoff. Short rains are characterized by a period of general increase in the supply of moisture beginning November 71th reaching a peak in December. During the entire short rain season, rains do not attain a level of sufficiency (R/ETo 1) in any of the ten day periods. Thus, moisture supply for the crop is sufficient during long rains but only to short maturing maize cultivar Kito/Katumani. There is a deficit in the supply of moisture throughout the short rains ruling out a successful production of a maize crop. The current study has however failed to detect the frequently experienced dry spells (during long rains) which adversely affect the maize crop. On the strength of the results obtained, the following can be concluded. During short rains, neither short (Kilo/Katumani) nor long maturing (Staha/IIonga Composite) maize cultivars can be successfully grown. Short maturing Kito/Katumani is recommended for planting during long rains instead of Staha/llonga. Composite as is currently practiced. Dry planting should be done before March 10th so as to make full use of the first rains.

Keywords: Rainfed maize, rainfall chacteristics, poor performance

Tanzania J. Agric., Sc. (2900) Vol. 3, No. 2, l57-164