Potential of sun hemp residue to provide potato with adequate nitrogen

ABSTRACT

Sun hemp (Crotalaria juncea L.) residue as a proper nitrogen (N) source for a potato crop (Solanum tuberosum L.) was investigated. Leaf nutritional indices (LNI), i.e, SPAD (SPAD-502, Minolta, Japan), total chlorophyll (CHLT), and N-total content, and their validity to predict tuber yield and N recovery were estimated. Moreover, comparison with mineral N fertilization was conducted. The estimated variables exhibited linear increase patterns to sun hemp N rates. Moreover, correlation coefficients between LNI and yield components were significant. Comparison of sun hemp N-amounts with mineral nitrogen showed lower SPAD values, similar CHLT, N-total, and N recovery. However, the elevated application produced superior yields to mineral one. Sun hemp residue incorporation prior to potato accounted for adequate N supply. Additionally, LNI are appropriate tools to determine potato N status and enable yield prognoses.

KEYWORDS:

• Legumes
• N nutrition status
• Solanum tuberosum
• yield forecast