B P International

The major objectives of this study were to identify spectral characteristics associated with rice yield and to establish their quantitative relationships. Field experiments were conducted at Shi-Ko experimental farm of TARI’s Chiayi Station, during 2001 to 2005. Rice cultivar Tainung 67 (Oryza sativa L.), the major cultivar grown in Taiwan, was used in the study. Various levels of rice yield were obtained via nitrogen application treatments. Canopy reflectance spectra were measured during entire growth period and dynamic changes of characteristic spectrum were analyzed. Relationships among rice yields and characteristic spectrum were studied to establish yield estimation models suitable for remote sensing purposes. Spectrum analysis indicated that the changes of canopy reflectance spectrum were least during booting stages. Therefore, the canopy reflectance spectra during this period were selected for model development. Two multiple regression models, constituting of band ratios (NIR/...

Unfavorable ecosystems in Bangladesh are under intense pressure of crop production and climate change impact; although the relationships of indigenous soil nutrients ratios with crop performance are yet to be fully explored. Experiments were conducted under submergence and cold prone areas (agricultural ecological zone, AEZ-3), drought and cold prone areas (AEZ-26), non-saline tidal flood ecosystem (AEZ-13), char and saline prone ecosystem (AEZ-18) and haor ecosystem (AEZ-21) for evaluating rice grain yield with native nutrients ratios. Synergistic and antagonistic relationships were observed in different AEZ depending on indigenous nutrient ratios. The K:Ca and K:Mg ratios were playing significant negative role in AEZ-18 for wet season rice yield; but K:Ca played synergistic role in AEZ-3 and AEZ-26. In dry season, K:Ca ratio was acting antagonistically in AEZ-3 and AEZ-13 and K:Mg in AEZ-13. The ratio of K to Ca was acted positively for dry season Boro rice production in AEZ-18 an...