पानी और नमी का नियंत्रण

01Pre-wetting is the first control point

Dry straw will not ferment. DMR wets straw on a platform for 24 to 48 hours until it reaches about 75 per cent moisture, and puts the water requirement at around 4000 litres per tonne of raw material. Run the leachate back over the heap instead of letting it drain away, because it carries nutrients with it.

Straw takes water slowly. A single soaking on the morning of stacking wets the outside and leaves the middle of each bale dry, and that dry core never joins the process. Give pre-wetting its own day in the schedule.

02One number per stage

Moisture is not a single target. DMR reports about 72 to 75 per cent at the end of Phase I, when drops appear between the fingers on squeezing, and 64 to 66 per cent after Phase II, when no liquid oozes even on firm squeezing.

Long method compost at spawning is different again: 68 to 72 per cent for synthetic compost and 65 to 67 per cent where horse manure was used. The farmer folder gives 68 to 70 per cent on the squeeze test on day 28. Always say which compost and which stage before quoting a moisture figure.

03How to measure it

The squeeze test is quick. Take a fistful, close the hand hard and read what happens: free running water means too wet, several drops between the fingers is Phase I level, a damp mass with no liquid is Phase II level.

If you have a balance, dry a known weight of compost until it stops losing weight and calculate the loss as a percentage. That is a real number, and it is the one to write down.

• Sample five points: both ends, both sides, centre.
• Take each sample from inside, not the dry surface.
• Use the same points every batch so readings compare.

04Too wet and too dry

Above 72 per cent at spawning, DMR reports that aeration fails, anaerobic conditions can kill the mushroom mycelium, and brown and white plaster moulds appear. Wet compost is also heavy and packs down, which blocks the air a blower is paid to deliver.

Dry compost fails the other way. NHB, reproducing ICAR guidance, links compost below 64 per cent moisture, under a wet casing layer, to weeper mushrooms. Correct water at a turning, where it can be mixed in, rather than pouring it on a filled bed later. Both faults cost the crop, and both are cheaper to prevent than to repair.