a1 Agricultural Research Council of Malawi, Makoka Research Station, Thondwe, Malawi
a2 Chikwawa Cotton Development Project, Malawi Government
Yield response to a range of plant densities (0·7–7·2 plants m.−2) achieved by uprooting plants at random was curvilinear, with an optimum plant density of 3·3 plants m.−2 at which fertilizer increased the yield at Makoka by over 1000 kg. ha.−1 to 2227 kg. ha.−1. There was no interaction between fertilizer and plant density. At Ngabu there was no response to fertilizer. Top dressing was effective on unfertilized cotton at Makoka, but filling in was ineffective at both sites. A method of partitioning components of yield is described which illustrates the stages of plant development which benefitted or were adversely affected by the different agronomic practices.
(Accepted April 09 1971)
* Seconded fom Imperial College, London to Foreign and Commonwealth Office (Overseas Development Administration).
† Seconded from Agricultural Research Council, U.K. to Foreign and Commonwealth Office (Overseas Development Administration).