Effect of Chicken Manure Fermentation Extract as an Alternative to Chemical Fertilizer on Cucumber Growth and Soil Microbiome Environment

Abstract

ABSTRACT In recent years, the destruction of the soil environment caused by excessive application of chemical fertilizers has attracted attention to using organic fertilizers to replace chemical fertilizers. Previous studies have shown that chicken manure fermentation extract (CMFE) as an organic fertilizer may also directly influence soil nutrient availability from the soil native pool and fertilizer application. However, it is unclear whether application CMFE can partially replacing chemical fertilizer to reduce the amount of chemical fertilizer without reducing cucumber yield. Therefore, an experiment was conducted in Yantai Agricultural Science Academy of Shandong Province in 2018 and 2019. In 2018, five fertilization combinations were set up, namely CK (900 kg·ha−1 chemical fertilizer), T1 (750 kg·ha−1 chemical fertilizer +150 L·ha−1 CMFE), T2 (675 kg·ha−1 chemical fertilizer +225 L·ha−1 CMFE), T3 (600 kg·ha−1 chemical fertilizer +300 L·ha−1 CMFE) and T4 (525 kg·ha−1 chemical fertilizer +375 L·ha−1 CMFE). Selected the optimal combination T3 for testing in 2019. The yield, quality, photosynthesis and growth indicators of cucumber, as well as soil nutrients and microbial content were determined. The results showed that the fertilization combination of 600 kg·ha−1 chemical fertilizer +300 L·ha−1 CMFE (T3) can minimize the amount of chemical fertilizer used without reducing yield. Compared with conventional fertilizer application, CMFE partially replacing chemical fertilizer did not reduce cucumber yield, but significantly increased cucumber vitamin C and protein content. CMFE partially replacing chemical fertilizer increased the root to shoot ratio as well as the fresh and dry weight of vegetative organs in cucumber, optimizing the growth and development of cucumber. Compared with conventional fertilizer application, CMFE partially replacing chemical fertilizer increased the content of soil organic matter, improved the composition structure of soil microbial community, increased the relative abundance of Actinomycete and Acinetobacter, and reduced the relative abundance of Bacteroides, Ascomycota, and Basidiomycetes. Overall, CMFE partially replacing chemical fertilizer optimized the growth and development of cucumbers, increased the root to shoot ratio, increased soil organic matter content, increased microbial abundance and diversity, and improved the composition structure of soil microbial communities. Therefore, in order to reduce the use of fertilizers, it is recommended to partially replacing chemical fertilizers with CMFE, with the optimal combination of 600 kg·ha−1 chemical fertilizer +300 L·ha−1 CMFE (T3).