Development of critical K dilution curves for diagnosing sweetpotato K status

Scientific and reasonable application of potassium fertilizer is an important agronomic measure to achieve high yield quality sweetpotato, it great significance determine the appropriate amount in field. For this we constructing a model critical K dilution curve (CKDC) sweetpotato under different N levels crop nutritional statuses. In study, 3-year field experiment was conducted Zhejiang Province China, using two nitrogen (N0: 0 kg ha −1 N1: 120 ) five fertilization rates (K0: 0, K1: 75, K2: 150, K3: 225, K4: 300 for cultivars ‘Shang 19’ ‘Yan 25’. Plant dry matter first increased then decreased concentration continuously with increase rate. The required maximum conditions greater than that low conditions. A new CKDC based on created assess nutrition sweetpotato. At levels, expressed by negative power function equation, aboveground: c(N0) = 5.30W -0.463 , R 2 0.79, c(N1) 4.23W -0.298 0.78, under-ground: 1.38W -0.125 0.81, 1.32W -0.132 0.72;whole-plant: 4.31W -0.421 0.80; Kc (N1) 3.89W -0.415 0.79. There no significantly whole-plant underground between N0 N1 while there aboveground levels. can strengthen effect concentration, its whole-plant. Then, indexes were constructed identify status could be used as reliable indicator diagnosis results provide theoretical basis improve management sustainability