Lecture 7 - Crop Rotation Glossary

Allelopathy

Chemical suppression of one plant’s growth by another through the release of allelochemicals into the environment.

Biological drilling

Planting a deep-rooted crop to form biopores in soil that enhance soil structure and aeration.

Break crop

Lower income crop introduced into the rotation (e.g. legume into cereal rotation) to interrupt disease cycles and improve soil health.

Disease-suppressive

Soil microbiome that can decrease levels of a soilborne disease or pest through enhanced microbial activity or competition.

Exudation

The release of carbon-containing compounds from the root system into the soil, which can enhance nutrient availability and support beneficial microbial communities.

Methyl Bromide

Highly effective (now illegal) soil fumigant that controls soilborne diseases and pests by killing pathogens and insects in the soil.

Microbiome

Assemblage of microbes either in bulk soil, rhizosphere or plant (if endophytic) that plays a crucial role in soil health, nutrient cycling, and plant disease suppression.

Minirhizotron

A plastic or glass-sided tube placed into soil to observe root growth and soil processes over time without disturbing the soil structure.

Mucilage

Cells sloughed off the root tip that aid root penetration through the soil and help in the absorption of water and nutrients by forming a gel-like substance.

N offtake

Nitrogen removal in the crop yield (=crop yield x grain Nitrogen concentration)

N sparing

Nitrogen remaining in the soil that a legume hasn’t taken up

Residual Moisture

Moisture remaining in the soil after the crop has been harvested and may influence subsequent planting and growth.

Smothering

Physical suppression of weeds by (cover) crop by intercepting light and competing for resources, thereby limiting their growth.

Yield Decline

Decreased yield when the same crop planted year on year in the same field due to nutrient depletion and increased pest pressures.