Fundamentally, I disagree with digging low quality organics into the soil. To become hummus and give back to your plants they need to suck in everything that life needs- nitrogen, phosphorous, potassium and the rest. They will give it back when they become hummus but until then they will out compete your plants. This stuff may help your mychorizia but until that develops its also a nutrient vacuum. Amendments to me means something else- ashes, composted compost , manure epsum salt et al. This is a long term development that you did, not expected to do well at first and not worth doing in my climate and soil.