Spatial and temporal variability in rice yield collected from multiple small-sized paddy fields in multiple years

摘要

Using descriptive statistical method, yield information of different field areas were analyzed to examine their field variability according to examining year, analysis method as well as field size and variety. Semivariogram and Kriged maps of geo-statistical analysis were also adopted to examine their within field spatial dependence. The results obtained were as follows. Descriptively statistical results of the yield showed that the yield and the difference of yield ranged from 100 to 946kg/10a and from 372 to 653kg/10a, respectively within a field. The coefficient of variation also ranged from 11.9 to 22.4%. Over 90% of yield information was placed between 350 to 850kg/10a of its frequency distribution. The results indicated that the appropriative design of the grain flow sensor considering the range of yield measurement was at least 0.34 to 0.82kg/s when the working velocity of 4 rows head-feed combine was assumed 0.8m/s. The results of yield showed a high spatial dependence within paddy field. The Q values ranged from 0.20 to 0.94, and the range of spatial dependence was from 6.9 to 52m. From this result, the rational sampling interval for yield investigation was estimated 6.9m. The results also showed that the spatial variability of yield was clearly distributed evenly in the paddy field. To apply precision agriculture in a paddy field, the field test should be continued to build a solid data-base including meteorological data, blight damage and insect damage.