In this study, we have attempted to develop a land suitability model for saffron, an agronomic crop, which is economically viable, environmentally bearable and socially equitable at Khost Province of Afghanistan. The objective was to determine different land suitability classes for saffron cultivation using AHP and GIS. A decision tree was developed encompassing physical, economic and social criteria. We used the secondary data (meteorological, remote sensing) from available sources and also substantial primary data generated from soil survey, interviews and experts' opinion. A total of 30 physical and socio-economic factors were included in the analysis. The final land suitability result showed that out of the total land area of Khost Province, 1.5, 4.5, 8.6 and 85.4% area were highly suitable, moderately suitable, Downloaded by [Mount Allison University 0Libraries] at 23:15 09 October 2015A c c e p t e d M a n u s c r i p t marginally suitable and not suitable, respectively. This modeling approach can be applied to determine the suitability of land for other crops covering a wider geographical region of Afghanistan.

This study investigated the relationship between backscattering coefficients of a synthetic aperture radar (SAR) and the four biophysical parameters of rice crops—plant height, green vegetation cover, leaf area index, and total dry biomass. A paddy rice field in Miyazaki, Japan was studied from April to July of 2018, which is the rice cultivation season. The SAR backscattering coefficients were provided by Sentinel-1 satellite. Backscattering coefficients of two polarization settings—VH (vertical transmitting, horizontal receiving) and VV (vertical transmitting, vertical receiving)—were investigated. Plant height, green vegetation cover, leaf area index, and total dry biomass were measured at ground level, on the same dates as satellite image acquisition. Polynomial regression lines indicated relationships between backscattering coefficients and plant biophysical parameters of the rice crop. The biophysical parameters had stronger relationship to VH than to VV polarization. A disadvantage of adopting polynomial regression equations is that the equation can have two biophysical parameter solutions for a particular backscattering coefficient value, which prevents simple conversion from backscattering coefficients to plant biophysical parameters. To overcome this disadvantage, the relationships between backscattering coefficients and the plant biophysical parameters were expressed using a combination of two linear regression lines, one line for the first sub-period and the other for the second sub-period during the entire cultivation period. Following this approach, all four plant biophysical parameters were accurately estimated from the SAR backscattering coefficient, especially with VH polarization, from the date of transplanting to about two months, until the mid-reproductive stage. However, backscattering coefficients saturate after two months from the transplanting, and became insensitive to the further developments in plant biophysical parameters. This research indicates that SAR can effectively and accurately monitor rice crop biophysical parameters, but only up to the mid reproductive stage.

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