Prospective study of the technology for evaluating and measuring in-row seed spacing for precision planting: A review

Corn is the most cultivated and consumed cereal in the world. The overall objective of this review was to study the methodologies to measure and evaluate the in-row seed spacing for precision planting as well as to determine the technological alternatives that would allow obtaining information about seed mapping for corn crop planting in precision agriculture applications. As a conceptual synthesis about the electronic measurement system, there are two strategies for determining in-row seed spacing in the precision planting. Indirect methods correspond to the measurement before the seeds reach the furrow, while direct methods correspond to the measurement with the seeds placed in the furrow. The indirect measurement strategy is the most widely used in research publications and commercial planter monitors. Within this method, the seed spacing measurement systems use optical or radio wave type seed sensors. Corn seed counting accuracy through electronic measurement systems with optical-type seed sensor is at least 96%. The microwave seed sensor is used commercially by a few companies whose technologies are patented. The direct measurement strategy is under development and requires further research. The main limitation of these technologies is the seed detection in the furrow, which limits the planter travel speed and the equipment cost. The conceptual proposal for the term ‘seed mapping’ is to provide integrated and geo-referenced information on in-row seed spacing and depth for precision planting.