Short Term Effects of Crop Intensity, Surface Disturbance and Plant-Based Fertilizers on an Organically Managed Top Soil

Summary

As populations worldwide increase, greater pressure is exerted on agricultural systems to provide food, feed and fiber. Social pressure is also pushing for these systems to embody greater sustainability and organic integrity. This report investigates sustainable intensification in the cultivation of organic row vegetables and its effects on soil fertility and soil stability within the top soil (5-10cm). The study took place during the summer growing season of 2018. Management included complex crop rotations, cover crops, plant-based fertilizers, such as grass clover, and reduced tillage. This was in comparison to current organic practices like moldboard plowing and use of slurries and manures. Parameters measured for soil stability included clay dispersibility at two and ten minutes. Fertility parameters include arylsulfatase activity as a proxy for microbial activity, permanganate oxidizable carbon and total organic carbon. Differences between treatments in regards to stability and fertility were small. Grass clover under no till was found to have a positive influence on microbial activity, but was not found to significantly influence soil stability. Used as a plant-based fertilizer, grass clover could be a potential alternative to animal based fertilizers. Further research is needed to conclude how plant based fertilizers can be used for optimizing its potential for nutrient management. The effects of sustainable intensification showed no evidence to influence fertility or stability negatively or positively. This was largely due to a lack of greater heterogeneity between treatments of different intensifications. Treatments were thought to experience transient trends within the time span of the growing season, potentially effected by an unforeseen decline in rain during the start of the 2018 summer.