Responses of absolute and specific soil enzyme activities to long term additions of organic and mineral fertilizer

Abstract

• Acid phosphatase activity was negatively correlated with soil pH and P content.• βG, NAG, and LAP activities were positively correlated with SOC and Total N contents.• The four enzyme activities were significantly higher under manure than NPK fertilizer.• Enzyme activities were positively correlated with actinomycete and G + bacterium.• We recommend reducing P fertilizer application rates to subtropical paddy soils. G R A P H I C A L A B S T R A C Ta b s t r a c t a r t i c l e i n f o Long-term phosphorus (P) and nitrogen (N) applications may seriously affect soil microbial activity. A long-term field fertilizer application trial was established on reddish paddy soils in the subtropical region of southern China in 1998. We assessed the effects of swine manure and seven different rates or ratios of NPK fertilizer treatments on (1) the absolute and specific enzyme activities per unit of soil organic carbon (SOC) or microbial biomass carbon (MBC) involved in C, N, and P transformations and (2) their relationships with soil environmental factors and soil microbial community structures. The results showed that manure applications led to increases in the absolute and specific activities of soil β-1,4-glucosidase(βG), β-1,4-N-acetylglucosaminidase (NAG), and leucine aminopeptidase (LAP). The absolute and specific acid phosphatase (AP) activities decreased as mineral P fertilizer application rates and ratios increased. Redundancy analysis (RDA) showed that there were negative correlations between absolute and specific AP activities, pH, and total P contents, while there were positive correlations between soil absolute and specific βG, NAG, and LAP enzyme activities, and SOC and total N contents. RDA showed that the contents of actinomycete and Gram-positive bacterium PLFA biomarkers are more closely related to the absolute and specific enzyme activities than the other PLFA biomarkers (P b 0.01). Our results suggest that both the absolute and specific enzyme activities could be used as sensitive soil quality indicators that provide useful linkages with the microbial community structures and environmental factors. To maintain microbial activity and to minimize environmental impacts, P should be applied as a combination of inorganic and organic forms, and total P fertilizer application rates to subtropical paddy soils should not exceed 44 kg P ha −1 year −1 .

Effects of Pb, Cd, Zn, and Cu on Soil Enzyme Activity and Soil Properties Related to Agricultural Land-Use Practices in Karst Area Contaminated by Pb-Zn Tailings

“…Often, organic manure can increase the soil enzyme activities that usually show a positive and significant relationship with the C-N-P cycle [21]. Conversely, the C-N-P turnover and nutrient availability are reduced with the soil degradation processes [22].…”

Effects of inorganic and organic amendment on soil chemical properties, enzyme activities, microbial community and soil quality in yellow clayey soil

“…All fertilized treatments had decreased soil actinomycetes compared with the CK. This may be attributed to the enhanced acidity caused by N chemical fertilization, which is unfavorable for actinomycetes development [55]. …”

Responses of absolute and specific enzyme activity to consecutive application of composted sewage sludge in a Fluventic Ustochrept

“…Specific enzyme activity also gives information on the metabolic state of alterations in the microbial community, enzyme efficiency, and ecology-related information about activities of the immobilized extracellular enzymes [17]. In addition, specific enzyme activity can also serve as a functional indicator with direct ecological impacts and therefore could be more readily used as an indicator of alterations in soil microbial community composition [18].…”