Hello garden friends, let’s discuss agronomy. 

First of all, what is agronomy?

Agronomy is the study of soil conservation, the study of plant breeding and study of fertilizer. In this article, we will concentrate on soil science and organic fertilizer. 

I can’t stress enough about soil conservation especially when it comes to plant life. This would include crop rotation, mulching and cover cropping. The whole idea is organic or ecological growing of crops; eliminating synthetic fertilizers, pesticides, herbicides; and nurturing rich, long term balanced soil. 

What does crop rotation mean? It basically means a farmer shouldn’t continuously plant the same crop year after year in the same plot of ground. The soil eventually gets depleted of beneficial nutrients and allows pest and invasive weeds to take over. A good example is tumbleweed. 

It’s ideal before the crops are growing to incorporate weed free manure and or organic mulch. The mulch would include finely ground wood shavings such as almond or any other hardwood. Additionally, crop rotation will improve soil structure, reduces soil erosion, and increases farm system resilience. 
Finally, let’s discuss cover crops. What are cover crops and why do we plant them? 

Cover crops cover the soil to prevent erosion and improve the soil. They are planted in between cash crops or after harvest of cash crops. Cover crops might include, alfalfa, vetch, white and crimson clover, and many types of legumes. The cover crops are allowed to mature and eventually disked into soil. This replenishes fertility in soil. 

Leguminous cover crops are especially important to increase nitrogen to the soil through biological processes (nitrogen fixation) along with atmospheric nitrogen (N2) and (NH+4) ammonium nitrogen. I find here in the Central Valley only wine grapes might have cover crops. The fields are not planted with a cover crop such as in the Midwest. Here most crops are allowed to wilt and fall.

Mark Koehler

Mark Koehler of Los Banos is an arborist and master gardener, who has degrees in Landscape Architecture and Landscape Horticulture from UC Berkeley and Northeastern University.