DETERMINATION OF MOISTURE CONTENT OF MAIZE SEED: COMPARISON OF TWO MOISTURE METERS WITH THE OVEN METHOD

Abstract

Accurate estimate of seed moisture content is important in the determination of the harvest date of seed crops, the physiological quality of seeds as well as grain price. Therefore. an accurate determination of this parameter is important. Usually. secondary methods of seed moisture determination like seed moisture meters are calibrated against the ground oven method. However, the oven method is cumbersome and time consuming. Faster methods involving moisture meters are now available commercially. The performance of moisture meters relative to the oven method in the determination of harvest moisture in maize (Zea mays L.) has not been investigated in sub-Saharan Africa. The objectives of this study were to (i) investigate the accuracy of two moisture meters; HE 90 and the multi-grain (ii) establish prediction equations for maize kernel moisture from the reading of the two meters. The overall and group mean values for each method were significantly different (P<0.05). Seed moisture content as determined by oven method was the highest (P<0.05) and the multi-grain gave the least (P<0.05). Both meters underestimated the overall mean seed moisture content by 2 and 52% respectively. Multi-grain consistently underestimated seed moisture content by 20-62% of the oven method value and the degree of underestimation increased with increase in seed moisture content. Similarly, HE 90 underestimated samples in the range 12.51-15.00 and >15.00 were by 2%. The prediction equations obtained from the regression analyses had no practical and physiological relevance. The margin of loss of precision associated with the determination of seed moisture content using multi-gram far outweighed the gain associated with the non- destructiveness, rapidly and simplicity of the method. The HE 90 will be useful for a rapid estimation of the moisture content of maize seed samples that had been determined a priori to fall in the range 12.5 - 15%