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Alternative input data

How the Java results change when national maps are replaced by global datasets

The Java case study uses national data where it exists: the ATR/BPN rice field map (2024) as the crop mask and the Ministry of Agriculture irrigation map as the water regime. This page shows how the simulated results change when global datasets take their place, as they would in an area without national data. How each dataset is prepared is described in Input data.

Each run changes one input and keeps the others of the national run. All runs: Jawa, agricultural years , uniform calendar (wet season 15 November, dry season 1 April for irrigated rice), IR 58, 140 kg N, SLPF 1. SLPF 1 is the uncalibrated model, so the levels are higher than reported yields; the differences between runs are what this page shows. Crop outside a water regime map is rainfed (treatments > default_regime).

How much production changes

Mean simulated production per year (dry grain), each run against the national run:

  • Crop mask sets where rice is simulated and how much: .
  • Water regime sets the irrigated area, and only irrigated rice is planted in the dry season: .
  • Soil: .
  • Weather grid: .

Production per year

Simulated production of both seasons per agricultural year, the national run (grey) against the runs of each kind of input:

Where the difference is

Mean production per year in each weather cell, the selected run minus the national run (on the selected run’s own grid; for the 0.25° weather, the national run summed into its cells):

The input itself for the selected run, in the same cells: rice area for a crop mask, irrigated share of the rice for a water regime, and production per year for soil and weather:

The inputs compared

Crop mask

A general cropland class does not say which crop grows there: with WorldCover or MODIS, rice is simulated on all cropland. MODIS counts cropland/natural vegetation mosaics as well. MapSPAM is specific to rice, but it places reported areas with an allocation model on a 9 km grid.

Water regime

Rice area of the ATR/BPN map by class of the Ministry of Agriculture map and of the other two water regime maps, million ha:

Where LGRIP30 has cropland ( of the rice area), it agrees with the Ministry of Agriculture map on of the area. Neither map is ground truth, so this measures agreement, not accuracy; the LGRIP30 user guide reports 79.2% overall accuracy for Southeast Asia. LGRIP30 counts a cropland as irrigated with “at least one artificial irrigation during the crop growing period”.

Soil and weather

The soil runs replace the SoilGrids profiles of every cell: SoilGrids without the organic carbon factors fitted to WISE profiles, and one generic profile for all of Java (the IRRI soil of the template, or an HC27 loam). The weather run uses AgERA5 regridded to 0.25° (an area mean for rain), so a weather cell holds about six times the area and its soil is the crop-weighted mean of the larger cell.

Reproduce

python docs/scripts/run_alternatives.py --list    # the runs and the prepared inputs each needs
python docs/scripts/run_alternatives.py           # all runs
python docs/scripts/export_alternatives.py        # writes docs/java/data/alternatives/

Each run’s experiment file is written next to its results (<cache>/runs/alternatives/<run>.yml); the inputs are prepared as described in Input data.

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