Comparison of three land suitability evaluation depth scenarios for irrigated paddy fields (case study: North of Iran)

Abstract

ABSTRACT Improving agricultural sustainability and increasing production are the most important goals for the near future especially for developing countries. Accordingly, in these countries, a land suitability evaluation (LSE) study based on the FAO framework is recommended, whereas the high cost caused a dramatic reduction in LSE studies particularly in irrigated paddy fields. Therefore, in this study two depth scenarios (scenario2: 0–50cm and scenario3: 0–25cm) were compared to the FAO framework depth scenario (scenario1: 0–100cm) to investigate the ability of the two new scenarios in qualitative and quantitative LSE classification for irrigated paddy fields. The study was conducted in Guilan province, Iran. Seventy-seven soil profiles were described, soil samples from genetic layers and 30 yield samples were collected. The results showed that, in both qualitative and quantitative LSE, the calculated values for both new scenarios were significantly correlated to the values in scenario1. Moreover, the coefficient of determination, the paired t-test, and the kappa coefficient showed very strong agreements between the two proposed scenarios and senario1. Overlaying three scenarios maps also didn’t reveal notable differences. Although the use of scenario1 is preferred, scenario2 due to very close results to scenario1 and being time-and-cost-saving, will be recommended.