Standard Operating Procedure (SOP) for Maize Harvesting and Seed Handling

The determination of the grain yield potential is the ultimate goal of most maize variety trials. Harvesting marks the end of the field work for each trial. In most cases, all ears in a designated portion of the plot (for example, the two middle rows in a 4-row plot) are dehusked and removed from the stalk manually. All the harvested ears from a plot are packed in front of the plot for the determination of relevant ear data, such as number of ears, weight of harvested ears, number of rotten, diseased, and insect-damaged ears, ear aspect, shelling percentage, and ear or grain moisture at harvest. Harvesting is normally done by a large number of casual laborers, mostly unskilled and with little or no education. Consequently, harvesting must be supervised thoroughly to ensure that the plots are cleanly harvested and ears from one plot are not mixed with those from nearby plots. The latter is particularly important for single- and 2-row plots. Similarly, the determination of ear weight, shelling percentage, and grain moisture requires careful handling. Balances used in the field are usually mounted on a tripod placed on uneven surfaces. The field assistants in charge of weighing must ensure that the pointer on the balance is at the exact starting point (e.g., zero point) for each plot to be weighed; otherwise some bias would be introduced into the data inadvertently. This should also be done for the grain to be used for moisture determination by the oven method. Ideally,