Manure induced transformations in soil nutrient stocks, microbial activity and multifunctional diversity: A six year long study in Chernic Phaeozem

Abstract Manure amendment is a viable strategy to counteract declining soil fertility and degradation. However, existing studies often fail to comprehensively evaluate how different manure types and application methods affect soil health and crop yields. To address this gap, a six‐year‐long field experiment was conducted on Chernic Phaeozem soil, examining the effects of manure amendments in four experimental variants: a control field with only mineral fertilizers (NPK) and three fields treated with poultry, cattle and swine manure in combinations with NPK. Soil biochemical properties such as carbon (C) and nitrogen (N) contents, dehydrogenase activity (DHA), basal respiration (BS) and substrate‐induced respirations (SIR) were assessed at two depth intervals (0–10 cm and 10–20 cm). All manure treatments significantly increased C and N contents in the 0–10 cm as compared to the control. Both poultry and swine manures increased C, N contents in 0–10 cm and 10–20 cm by approximately +24%, +22% and 13%, 10%, respectively, while the effect of cattle manure was rather intermediate (+10%, 11% and + 1%, 4%, respectively). In the 0–10 cm, DHA was higher in plots treated with the poultry (+80%) and cattle (+125%) manures, as compared to the swine manure treatment. In the 10–20 cm, poultry manure resulted in higher C (+6%) and N (+12%) contents, compared to swine manure, while the contents in cattle manure‐treated plots were similar to the control. Swine manure showed the highest increase in manure‐related C and N stocks across both depth intervals (+18% and 69%, respectively), despite no significant effects on soil biological activity (DHA, BR and SIR). Over the entire experiment period, all manure treatments significantly increased crop yields by 0.5 t cereal units ha −1 year −1 The poultry and swine manure amendments of soil biochemical properties and crop yields emphasize their value for sustainable soil management. We emphasize the need for site‐specific strategies to maximize the benefits of manure amendments for sustainable agriculture.