Nondestructive estimation of rice plants' nitrogen status
2000
Malabayabas, M.D. | Takabashi, S. | De Dios, J.L. | Corton, T.M. (Philippine Rice Research Inst., 3119 Maligaya, Munoz, Nueva Ecija (Philippines))
The study was conducted to determine the relationship (1) between the N concentration of rice plants and SPAD values, (2) relationship between dry matter weight and plant height and tiller number, (3) the time-course of N uptake at different rice straw management, and (4) N recovery efficiency. The SPAD values were highly correlated with leaf nitrogen concentration. Likewise, dry matter weight of aboveground parts was correlated with plant height and tiller number. The nitrogen recovery efficiency (NRE) decreased with higher N rate. Furthermore, the percentage of NRE of basal N calculated using the N content at 33 days after transplanting (DAT) was 20-30%. This calculation leads to extra high % NRE (90%) of the topdressed N. The results showed that nitrogen status of rice could be determined nondestructively by using chlorophyll meter (SPAD-502) and plant parameters like height and tiller number
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