Bull. Spec. CORESTA Congress, Lisbon, 2000, p. 100, A13

Short and long-term effects of applying lime in fractions of the full required amount on soil features and on yield and quality of tobacco

ARET, Agricultural Research and Extension Trust, Lilongwe, Malawi
The fact that most soils in Malawi are acidic has been known for some time and such soils have detrimental effects on tobacco production. Correcting soil acidity is achieved by proper liming regimes with the aim of increasing soil pH and the availability of phosphate factors which are considered to be desirable features for tobacco yield and quality. Although, the importance of liming tobacco fields is now well known, due to financial constrains, a number of smallholder farmers, who are keen to apply lime, may not afford to procure the whole amount that has been recommended for a specific field in order to correct the soil pH to values between 5.5 and 6.0, which is ideal for tobacco production. This work was initiated with the aim of establishing whether farmers sould achieve similar benefits by applying lime in various fractions of the total amount recommended. Results of this work show that application of lime in proportions less than that recommended does not raise the soil pH to the same level as in the case where the full lime requirement is applied. Even in cases where the full lime requirement is fully applied having been split over a period of a number of years, the desired for soil pH is not attained. In light of these observations, it would still be recommendable to apply the whole amount of lime determined by the analysis the soil pH to be corrected. Results also show that within a season there was an increase in the amount of available phosphorus as soil pH increased and there was a drastic increase in available phosphorus from the first season to the third season after application of the correct amount of lime. Any effect liming had on soil characters did not affect the yield and quality of tobacco grown in these soils.