Dry matter and nitrogen accumulations and partitioning in two potato cultivars

Potato plant dry matter and nutrient accumulation and partitioning patterns into various parts of the plant are important to fine tune management practices that optimize the nutrient uptake efficiency and tuber production. Accumulation and partitioning of dry matter and nitrogen (N) during the growing period were evaluated in this four year study for two potato cultivars in high yielding production conditions in the Columbia Basin production region in Washington, under irrigated farming. Studies were conducted on a Quincy fine sand, which represents a typical potato production soil in this region. A full season indeterminate potato cultivar (Russet Burbank) and an early maturing determinate cultivar (Hilite Russet) were used in this study. Partitioning of assimilates into the tuber was similar for both cultivars. The tuber weight accounted for 76 to 87% of total plant weight, while that of stem and leaf weight accounted for 3 to 11, and 9 to 13%, respectively. Tuber weight increased rapidly during 60 to 100 days after planting. Nitrogen content in the tuber, in relation to the total N in the plant, accounted for 81 to 86, and 83 to 89%, for the Hilite Russet and Russet Burbank cultivars, respectively. Nitrogen in the leaves comprised 6 to 18%, and in the stem 3 to 5% of the total plant N. Prior to senescence of the vines, total N in the plants (excluding roots) accounted for up to 350 kg ha(-1). At this growth stage, the N in tubers, leaves, and stems represented 68.6, 19.4, and 12.0%, respectively. The above information is useful for N management with the knowledge of soil residual N and availability of N from mineralization of crop residue during the crop growing season.