Altaf Ali Siyal

Rice yield estimation using Landsat ETM+ Data

Abstract. Paddy rice areas in Larkana district in Sindh province, Pakistan, were mapped over eight years. Landsat 7 ETM+ satellite imagery was classified for rice areas using training data collected through visual interpretation and using a bagged decision tree approach. Within the rice areas, we estimated yield for the 2013 season using regression models based on Landsat-derived normalized difference vegetation index (NDVI) and ratio vegetation index (RVI) values against historic, reported yield values. The annual cropped rice area estimated from satellite imagery was between 19% and 24% lower than the area reported by the Crop Reporting Service, Sindh. A positive and strong relationship with coefficient of determination (R2) of 0.94 was observed between the reported rice crop yield and NDVI at the peak of the growing season for the years 2006 to 2013. A fair relation (R2=0.875) between rice crop yield and RVI was observed for the same years. A strong relationship between observed and predicted rice production with model efficiency=0.925, mean bias error=−85,016 t, and RMSE=80,726 t was obtained. Thus, Landsat ETM+ has a high potential for estimating rice yield and production at the district level in Pakistan and elsewhere.

Effect of Irrigation Methods and Plastic Mulch on Yield and Crop Water Productivity of Okra

Abstract: A field experiment was conducted during 2014-15, aiming to observe the efficiency of irrigation methods and plastic mulch on the yield and crop productivity of Okra. Okra seeds (cv. Subzpari) were grown on ridges with plastic under two different irrigation methods i.e. Every Furrow Irrigation (EFI) and Alternate Furrow Irrigation (AFI). The soil physical properties of ridges being affected by plastic mulched were analyzed before sowing and after harvesting. The results revealed that dry density of soil decreased by 0.03 g cm -3 and 0.04 g cm -3 for AFI and EFI methods, respectively. The total volume of irrigation water applied under AFI method (2169.70 m 3 ha -1 ) was calculated to be half of the total irrigation water applied to EFI method (4340.91 m 3 ha -1 ). Yield obtained under EFI method was 8518 kg ha -1 which was 10.5% greater than yield obtained under AFI method (7621 kg ha -1) and 31.40% when compared with traditional method. The crop water productivity (CWP) for AFI method (3.51 kg m -3 ) was calculated to be greater than CWP obtained under EFI method (1.96 kg m -3 ). The study concluded that both EFI and AFI methods, under plastic mulched ridges practices were beneficial to increase the crop yield with improved crop water productivity.Â