Marmonix MGM-740 Portable Grain Moisture Meter

The Marmonix MGM-740 is a portable digital grain moisture meter for farmers, traders, and inspectors who need fast moisture readings on up to 14 grain types (rice, wheat, corn, barley, soybean, and more). Using the electrical resistance method, it covers roughly 7.5%–55% (grain-dependent) with 0.1% resolution, limit setting, deviation correction, and a backlit LCD for field use.

Browse related instruments in the moisture meters category, and compare crop vs building meters in our 2026 moisture meter buyer’s guide.

MGM-740 grain moisture tester key features

What the MGM-740 gives you at the silo or buying point:

• Moisture testing for 14 grain / crop codes including rice, wheat, corn, barley, and soybean
• Measuring range about 7.5%–55% depending on species
• 0.1% resolution with electrical-resistance sensing
• Moisture limit setting, deviation correction, and data hold
• Backlit LCD for barns, stores, and low-light docks
• Powered by 4 × 1.5 V AA with auto power-off and low-battery alert

Where teams use the MGM-740 moisture meter

Typical jobs where the MGM-740 fits include:

• Farm harvest & storage — check grain before binning to reduce spoilage risk
• Grain trading — verify moisture at intake against contract limits
• Food / feed inspection — quick field checks across multiple crop codes
• Quality control — hold and correct readings for repeatable sample notes

MGM-740 typical specifications

MGM-740 grain moisture meter questions

Which grains can the MGM-740 measure?

The MGM-740 includes 14 grain/crop codes such as paddy, wheat, corn, barley, rice, sorghum, rapeseed, soybean, peanut, and related species — select the matching code before testing.

What moisture range and resolution does it offer?

Depending on the grain code, readings typically span about 7.5% to 55% with 0.1% resolution using the electrical resistance method.

When should I choose the MGM-740 instead of a hay or building moisture meter?

Choose the MGM-740 for crop-calibrated grain trading and storage checks; choose a hay probe (e.g. MHM series) for bales, or a pin/pinless building meter for wood and construction materials.

Related: Moisture meters · Buyer’s guide