Mulch and planting depth influence potato canopy development, underground morphology, and tuber yield

The response of potato (Solanum tuberosum cv Haryeong) to mulching and different planting depths was evaluated during 2010-2013. Two different plastic mulches, black and clear polyethylene (PE) were compared with the unmulched control and seed tubers were planted at 5-, 10-, 15-, and 20-cm depths in each treatment. The objectives were to determine how mulching and planting depth affected the canopy development, underground morphology, and tuber yield. Early emergence, canopy development and tuber growth rate were improved in the mulched treatment; while delayed or decreased as the depth of planting increased. The number of stems per plant increased as seed pieces were planted closer to the soil surface in two of the four seasons, but was not affected by mulches except for 2012. Stolon length was longest in black mulches, especially on upper part of underground stem, but it was long on lower part of the stem in unmulched potatoes. Percent tuber bearing stolons were increased in the mulches and deep (10-20 cm) planted potatoes. Particularly, on the lower part of underground stem, a higher percentage of tubers were formed irrespective of mulches and planting depth. Harvest index was significantly higher in clear PE mulches in two of the four seasons while it was not affected by planting depth. Mulching potatoes produced higher total and >80 g yields, while varying the depth of planting affected the total yield which was lower in the deepest (20 cm) planted potato.