Soil health in organic grain cropping systems as influenced by green manure management and weed presence

Abstract

From 2016-2018 two experiments in Bible Hill, Nova Scotia were conducted where GMr of red clover, hairy vetch or common vetch grown two years prior to soybeans with current season presence or absence of weeds (Exp. 1) or one year prior to wheat with different tillage intensities incorporating GMrs (Exp 2). Soil biological, physical and chemical properties were examined following the Cornell Soil Health Assessment (CSHA) protocol. Phospholipid fatty acid analysis (PLFA) measured soil microbial biomass and community composition. GMr or tillage treatments did not affect weed biomass production nor most measures of soil health or microbial community. Non-mycorrhizal weed species withstood tillage practices better. High residue soil input over the last 10+ years may have masked treatment effects. Weed presence improved soil respiration and fungal PLFA, but not overall soil health. Temporal soil sampling resulted in differences in microbial measurements with significantly more fungi observed later in the season.