SEMAISENS CROP MODELS
Four crops. Four different ways of being healthy.
A number that means a good field in paddy means a dying one in pineapple. We built a separate model for each crop instead of one model with the crop name changed.
THE ARGUMENT
Most satellite tools would flag your rubber every February.
Mature rubber drops its leaves once a year. NDVI falls by up to 0.25 and sits in a trough for a month before climbing back. It is the most normal thing the tree does.
A tool that does not know this sends your team out to inspect a healthy block every single season. A tool that does know it suspends the health band entirely for those eight weeks and says nothing.
That is the difference between software built for Malaysian crops and software translated into them.
A healthy band can be suspended on purpose. The model refuses to call a seasonal leaf change a crop failure.
RICE · TWO SEASONS A YEAR · 120 TO 130 DAYS
Healthy at heading looks nothing like healthy at ripening.
Paddy climbs from about 0.20 after transplant to a peak of 0.90 at flowering, then drops back to 0.40 as the grain fills. The same reading means opposite things at different points in the season, so we track by growth stage, not by date.
Four ecosystems, each with its own bands: irrigated lowland, rainfed lowland, flood prone and rainfed upland. Direct seeded fields shift the whole window seven to ten days later.
WHAT MOST TOOLS GET WRONG
NDVI saturates above about 0.8 in every rice ecosystem, so at heading it stops telling you anything useful. We switch to NDRE. A high reading during ripening is not good news. It means the crop is late.
HEALTHY NDVI · IRRIGATED LOWLAND
Hide bands
Stage
Days after transplant
NDVI
Early vegetative
0 to 20
0.20 to 0.40
Tillering
20 to 45
0.40 to 0.65
Panicle initiation
45 to 70
0.65 to 0.80
Heading and flowering
70 to 95
0.75 to 0.90
Ripening
95 to 120
0.40 to 0.65
29 guides covering drought, salinity, submergence, poor soils, blast, bacterial leaf blight, tungro, sheath blight, brown planthopper, stem borers, leaffolder, gall midge, armyworm, six nutrient deficiencies and three weed groups.
OIL PALM · ONE PLANTING · 25 YEARS
After year six, NDVI goes blind.
The canopy closes and NDVI flattens out near the top of its range. A stressed prime block and a healthy one look almost the same. From year six we switch to NDRE or EVI, which keep working past the point NDVI gives up.
Four planting environments, because the ground underneath changes what healthy looks like. Peat is darker and reads lower at the same health. Reclaimed land closes canopy later.
WHAT MOST TOOLS GET WRONG
A mature block reading above its band is not an unusually good block. It is saturation, and it should not be treated as good news.
HEALTHY NDVI · 6 TO 15 YEARS
Hide bands
Environment
NDVI
Mineral upland
0.75 to 0.88
Coastal alluvial
0.72 to 0.85
Inland peat
0.68 to 0.82
Reclaimed or marginal
0.62 to 0.80
27 guides covering Ganoderma, upper stem rot, bud rot, Fusarium wilt, red ring, rhinoceros beetle, bagworms, nettle caterpillars, palm weevil, drought, waterlogging, peat subsidence, acid sulfate soils, wind and lightning, fire, and eight nutrient problems.
RUBBER · 25 TO 30 YEARS · TAPPING PANELS A TO D
The healthy band switches off for eight weeks a year.
Every February and March in Peninsular Malaysia, mature rubber drops its leaves and grows them back. NDVI falls 0.10 to 0.25, bottoms out around 0.55 to 0.70, and returns to normal within about eight weeks.
During that window the stand age band is suspended. A block is supposed to be out of band. We do not alert on it, and we do not let year on year comparison run through it either.
WHAT MOST TOOLS GET WRONG
They treat wintering as a crop failure. Or worse, they compare this February to last February on the calendar and report a decline that is really just a two week timing shift.
HEALTHY NDVI · MINERAL UPLAND
Hide bands
Stand age
NDVI
0 to 1 year
0.25 to 0.45
1 to 3 years
0.40 to 0.65
3 to 5 years
0.60 to 0.80
5 to 7 years, tapping opens
0.78 to 0.88
7 to 20 years, prime
0.80 to 0.90
20 to 25 years
0.75 to 0.88
24 guides covering white root, red root, brown root, Corynespora leaf fall, Pestalotiopsis, powdery mildew, black stripe, pink disease, termites, bark scale, tapping panel dryness, weeds, drought, waterlogging, wind and lightning, cold and haze, and five nutrient deficiencies.
PINEAPPLE · 14 TO 24 MONTHS · ROLLING BATCHES
A healthy pineapple block rarely goes above 0.75.
Low canopy, wide rows, and leaves that reflect differently to most crops. Healthy pineapple sits far below where healthy paddy or palm sits, so a generic threshold reads every good block as stressed.
Batches overlap and never line up. We track each one on its own clock instead of averaging a field that has three different crops standing in it.
WHAT MOST TOOLS GET WRONG
A block reading above 0.75 is almost certainly weeds before canopy closure, bright sand inflating the signal on coastal land, or silver mulch in the first three months. It is not an unusually good crop.
HEALTHY NDVI · MINERAL UPLAND
Hide bands
Phase
Months
NDVI
Establishment
0 to 3
0.12 to 0.25
Early vegetative
3 to 8
0.22 to 0.42
Late vegetative
8 to 12
0.42 to 0.62
Forcing
12 to 14
0.52 to 0.70
Fruit development
14 to 18
0.58 to 0.75
Ripening
18 to 22
0.48 to 0.65
28 guides covering heart rot, root rot, fusariosis, black rot, mealybug wilt, nematodes, mealybugs, thrips, mites, symphylids, scale, weeds, drought, waterlogging, sunburn, chilling, wind and lodging, salinity, and seven nutrient problems.
PUBLIC DOCUMENTATION
Over a hundred guides. All of them public.
Every band on this page comes from our crop guides, and every guide names the research behind it. You can read the lot before you talk to us, and you can tell us where we are wrong.
