31 March 2000

Measuring light to enlighten growers

MEASURING the light reflected from a cereal crop in early spring could be the key to unlocking the big, but so far elusive, yield benefits that enthusiasts say growers could achieve by managing crop canopies more precisely.

The difficulty for many farmers with the canopy management approach is assessing canopy size early in the season, explains Rosie Bryson of ADAS Boxworth.

Now a major MAFF LINK/HGCA levy-funded project is developing a system which will use a sophisticated approach to automatically measure the light reflected from a crop to guide management decisions across individual fields.

"Unlike other sensing systems which measure a few wavelengths of light reflected from a crop, we use hyper-spectral reflectance, which measures a wide-range of wavelengths.

"That should allow us to separate out different effects, such as reflectance from the soil, disease levels and nutrient disorders," she explains.

"There is a lot more to it than simply measuring chlorophyll levels. We have compared reflectance measurements of canopy size with yield maps and have found a good relationship."

The technique also offers the potential to assess crop development and adjust management much earlier in the season.

A system could be on the market within a few years, operating from in-field equipment, low flying aircraft or even satellites. &#42

Detecting differences in crop development automatically could aid canopy management, says ADASs Rosie Bryson.