Guano Production and Crop Fertilization

🌱 Guano Production & Farmland Crop Fertilization

Parameter	Specification Details
NBT Persistence Tag	betterbats:guano_ticks (Integer)
Default Timer Threshold	12000 ticks ($600\text{ seconds} / 10\text{ minutes}$)
Speed GameRule Key	better-bats:bat_guano_threshold
Item Drop GameRule Key	better-bats:bat_drop_guano_item (Default: false)
Crop Target Interface	net.minecraft.world.level.block.BonemealableBlock
Farmland Search Depth	Up to 20 blocks vertically below roost position
Fertilizer Particles	HAPPY_VILLAGER (Success) / MYCELIUM (Soil drop)
Item Entity Drop	minecraft:bone_meal (When item drop enabled)

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⌛ Guano Accumulation Mechanics

When a bat rests (isResting() == true), its internal NBT guano counter (betterbats:guano_ticks) increments once per tick inside BatMixin.betterbats$onTick:

                  ┌────────────────────────┐
                  │    Bat is Resting      │
                  └───────────┬────────────┘
                              │
                    guano_ticks++
                              │
                 guano_ticks >= threshold?
                     ┌────────┴────────┐
                    YES                NO
                     │                 │
           Scan up to 20 blocks        Wait for next tick
           down for farmland/crops
                     │
         ┌───────────┴───────────┐
      Crop Found?             Soil / Block Only?
         │                       │
 🌾 Bonemeal Crop         ✨ Spawn Mycelium particles
 ✨ Spawn Happy Villager   📦 Drop Bone Meal Item
    particles                 (If bat_drop_guano_item is true)

$$\text{Guano Timer Progress} = \frac{\text{guano_ticks}}{\text{bat_guano_threshold}} \times 100%$$

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🌾 Farmland Crop Bonemealing Logic

The bat scans vertically downwards up to 20 blocks below its roosting position:

1. Farmland Crop Target: If a block below is FarmlandBlock and the block directly above it implements BonemealableBlock:
   • Checks crop.isValidBonemealTarget(level, cropPos, cropState).
   • Executes crop.performBonemeal(level, level.getRandom(), cropPos, cropState).
   • Plays bone meal sound (levelEvent(2005, cropPos, 0)).
   • Spawns 5 HAPPY_VILLAGER particles around the crop.
2. Soil / Physical Item Drop: If no bonemealable crop is present:
   • Spawns 3 MYCELIUM particles on the soil surface.
   • If better-bats:bat_drop_guano_item is set to true, drops a physical ItemStack(Items.BONE_MEAL) item entity at the block location.

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💾 Save & Load Persistence

The guano counter is preserved across game saves using modern MC 26.2 ValueOutput and ValueInput mixin hooks:

@Inject(method = "addAdditionalSaveData", at = @At("TAIL"))
private void betterbats$onAddAdditionalSaveData(ValueOutput output, CallbackInfo ci) {
    output.putInt("betterbats:guano_ticks", this.betterbats$guanoTicks);
}

@Inject(method = "readAdditionalSaveData", at = @At("TAIL"))
private void betterbats$onReadAdditionalSaveData(ValueInput input, CallbackInfo ci) {
    this.betterbats$guanoTicks = input.getIntOr("betterbats:guano_ticks", 0);
}

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🔗 Related Pages

• Bat Ecology, Photophobia & Daytime Roosting
• Dynamic GameRules Reference Table
• Sound Effects & Visual Particles Reference