Impacts of Spatial Zonation Schemes on Yield Potential Estimates at the Regional Scale

Simulations based on site-specific crop growth models have been widely used to obtain regional yield potential estimates for food security assessments at the regional scale. By dividing a region into nonoverlapping basic spatial units using appropriate zonation schemes, the data required to run a crop growth model can be reduced, thereby improving the simulation efficiency. In this study, we explored the impacts of different zonation schemes on estimating the regional yield potential of the Chinese winter wheat area to obtain the most appropriate spatial zonation scheme of weather sites therein. Our simulated results suggest that the upscaled site-specific yield potential is affected by the zonation scheme and by the spatial distribution of sites. As such, the distribution of a small number of sites significantly affected the simulated regional yield potential under different zonation schemes, and the zonation scheme based on sunshine duration clustering zones could effectively guarantee the simulation accuracy at the regional scale. Using the most influential environmental variable of crop growth models for clustering can get the better zonation scheme to upscale the site-specific simulation results. In contrast, a large number of sites had little effect on the regional yield potential simulation results under the different zonation schemes.

Spatial Zonation Model of Local Irrigation System Sustainability (A Case of Subak System in Bali)

This study was aimed at designing a spatial zonation model of a subak sustainability type based on the internal and external dimentions from 69 subaks in three districts in Badung regency. The internal dimention was measured based on subak capability index in implementing Tri Hita Karana (THK) philosophy. The external dimention was measured by using index of four variables, namely: road density, population density, social economic facilities, and number of nonfarmer families.The data were analyzed using descriptive quantitative technique and spatial analysis using Geographical Information System (GIS) software. The results found three zones of subak sustainability type, spatially follows the principle of distance decay of the growth of tourism and city center. Unsustainable - less sustainable subak zone dominates short distance zone, sustainable - less sustainable subak zone dominates transitional zone, while sustainable subak zone dominates long distance zone. To protect subak from destruction, less sustainable subaks have to be restored into sustainable ones and the sustainable subaks should be made eternal/exclusive subaks