Optimizing combining green manures and pelletized manure for organic spring wheat production

Abstract

Well-planned crop rotations and targeted use of organic amendments are critical to success in organic wheat production. The impact of green manure (GMr) type, GMr termination timing, and “Acti-Sol” [pelletized dehydrated poultry manure (DPM); 5-2-3] on organic wheat productivity and quality was evaluated from 2014 to 2016 in Truro, NS, and Saint-Mathieu-de-Beloeil, QC. Crops prior to wheat were soybean or GMr of hairy vetch/oat (HVO), common vetch/oat (CVO), and red clover (RC) (NS site), and HVO, red clover/oat (RCO), and oat (QC site). Trials were split-split-plot designs with treatments of precrops, GMr termination (fall vs. spring), and DPM at 0, 40, 80, and 120 kg total N ha−1. Wheat yields ranged from 1500 to 1800 kg ha−1 if unfertilized with DPM and following soybean or oat precrops. All legume GMrs (HVO, CVO, and RC/RCO) and DPM applications increased grain yield (2000–4200 kg ha−1) and protein content (13%–16%), wheat total N uptake [49–60 kg N ha−1 (QC); 87–125 kg N ha−1 (NS)] and soil mineral N content mid-season and postharvest, and responses were consistently greatest following HVO. Timing of GMr incorporation largely had no impact. Applying DPM at 80 kg N ha−1 was an effective substitute for a GMr precrop.

Nitrogen content of pea‐based cover crop mixtures and subsequent organic corn yield

“…The high soil NO 3 –N content measured at corn planting might be explained by the mineralization of shoot and root cover crop biomass during winter and in early spring (Thorup‐Kristensen et al., 2003). Decomposition of cover crop residues with low C/N ratios, as in the present study (between 10 and 16 for shoot biomass), could result in a greater decomposition rate of those residues (Singh et al., 2020) and in net mineralization as compared to that of cover crop residues with greater C/N ratio (>30) (Alam et al., 2018; Sievers & Cook, 2018). Moreover, shoot C/N ratio was inversely correlated with soil NO 3 –N content at corn planting (Pearson correlation coefficient of −0.52, P < .001; data not shown).…”

“…For example, Alam et al. (2018) found greater N contribution from cover crops following fall rather than spring incorporation, in a clay loam. Moreover, the C/N ratio of the cover crop residues can impact the temporal synchronicity between N mineralization and N crop demand (Carr et al., 2019).…”

Soil Health and Biodiversity Is Driven by Intensity of Organic Farming in Canada

“…In Michigan, while clay content was a dominant driver of soil health, Tu et al (2021) found that crop diversification, regardless of composition-i.e., forages or cover crops, increased soil mineralizable C and aggregate stability, supporting the concept of overall spatial and temporal vegetative diversification being a key consideration. While agronomic benefits from cover crops to the following organic cash crops have been demonstrated (Alam et al, 2016(Alam et al, , 2018 their routine use varies with intensity of organic farm management. For organic farms weeds also may be a not insignificant contribution to the vegetative diversity benefiting soil health.…”

Green and animal manure use in organic field crop systems

“…Combining CGMs with pelletized PL improved organic wheat yields compared to only using CGMs in Nova Scotia and Quebec (Alam, Lynch, Tremblay, Gillis‐Madden, & Vanasse, 2018). In that study, more consistent yield improvements occurred following an oat + hairy vetch mixture than red clover, red clover + oat and oat CGM crops.…”

“…In that study, more consistent yield improvements occurred following an oat + hairy vetch mixture than red clover, red clover + oat and oat CGM crops. An application of 80 kg N ha −1 of pelletized PL could be substituted for the legume CGM crop without a change in wheat yield (Alam et al., 2018). Supplementing red clover and hairy vetch CGMs with municipal solid‐food waste composts consistently increased potato yield in a 3‐yr study conducted in Nova Scotia (Lynch et al., 2012).…”