Carrington Research Extension Center
North Dakota State University
NDSU Extension Service
North Dakota Agricultural Experiment Station

Ag Alert

August 12, 1999


Canola swathing has been in progress the last 1 to 3 weeks in south-central North Dakota and combining has begun south of I-94. The following are general points to consider with canola harvest:

Additional canola swathing and harvest details may be obtained in the NDSU Extension Service circular A-1171 'Swathing and harvesting canola'.


With a significant percentage of cropland not planted this year due to excessive soil moisture, farmers planning to grow corn next year on this year's 'involuntary' fallow ground should be aware of a potential concern called 'fallow syndrome'. The basic problem with fallow syndrome is insufficient soil phosphorus (P) availability for corn grown on fallow ground, even though a soil test may indicate an adequate level present for corn production. Early-season corn growth is delayed and ultimately maturity may be delayed 10 to 15 days, which may result in reduced grain yield and wetter corn.

The source of fallow syndrome can be found around the corn root system. Mycorrhizae soil organisms naturally infect or colonize corn roots and obtain necessary nutrients to live. In return, the fungal infection of the corn root system helps the plant increase uptake of P which enhances early root and shoot growth. The problem with fallow preceding corn production is that the mycorrhizae have no living-root host relationship and are believed to go into a resting (spore) stage. The year after fallow, with little mycorrhizal activity or root infection, the ability of corn roots to absorb soil P is reduced.

A general recommendation to minimize or avoid fallow syndrome in corn is a banded placement (2 inches below and 2 inches to the side of the seed) of 20 to 25 pounds of P per acre.

Greg Endres, Area Extension Specialist/Cropping Systems, Email:
1999 Ag Alert Archive * Carrington R&E Center Home Page * NDSU Agriculture