Short‐Term Effects of Diverse Compost Products on Soil Quality in Potato Production

Abstract

Core Ideas Compost application increased soil organic matter content and improved soil quality. Compost products with greater C concentrations resulted in greater soil improvements. Particulate organic matter C was the index most responsive to compost addition. Mature composts with greater C concentrations and dry matter were most suitable. Soil quality has declined with intensive potato production practices in New Brunswick, Canada. Compost application may rapidly increase soil organic matter (SOM) and reverse declining productivity. This study assessed five diverse compost products for their short‐term effects on soil quality, and in particular SOM. Selected compost products derived from a range of forestry, marine, and municipal waste materials were compared with a non‐amended control. Treatments were applied to field plots at 45 Mg ha–1 dry weight in October of 2014 and 2015. Biological, chemical and physical soil properties under potato production in 2015 and 2016 (after one and after two consecutive applications) were used to evaluate soil quality. Compost application increased soil pH and concentrations of Mehlich‐3 extractable nutrients (K, Ca, Mg, and S). Compost reduced bulk density in the potato hill by 8% in both years. Particulate organic matter (POM) was the most sensitive indicator to compost‐application with twofold increases in POM‐C. Compost application increased soil organic carbon by 24% in 2016 and also increased permanganate oxidizable carbon, and soil respiration. Several soil properties were strongly correlated with compost composition, with better quality composts (i.e., more mature; greater in C, N, and other plant‐available nutrient concentrations) producing the greatest soil quality response. Overall, mature composts with greater C concentrations (i.e., low ash) and greater dry matter were most suitable for enhancing soil quality in New Brunswick potato production systems.