Evaluation of soil biological properties as potential bioindicators of soil health

Abstract

Two long-term field trials in South Australia were used to detect and characterise changes in soil biological properties that were a consequence of different agricultural management. The properties examined were total bacteria, fungi, and actinomycetes; total pseudomonads; cellulolytic bacteria and fungi; mycorrhizal fungi; plant root pathogens (Gaeumannomyces graminis var. tritici, Rhizoctonia solani, Pythium irregulare); bacterial-feeding protozoa; soil mesofauna (collembola and acari); earthworms; microbial biomass; C and N mineralisation; in situ CO2 respiration; cellulose decomposition; and soil enzyme activity (peptidase, phosphatase, sulfatase). The sensitivity of these biological properties was assessed to tillage (no-tillage v. conventional cultivation), stubble management (stubble retained v. stubble harvested), crop rotation (continuous wheat v. wheat-sown pasture), and N fertilisation (nil v. 80 kg N/ha applied during the crop phase). Tillage, stubble management, crop rotation, and N fertilisation significantly (P<0.01) affected C mineralisation and microbial biomass. Tillage with stubble management significantly affected root pathogenic fungi, protozoa, collembola, earthworms, and cellulose decomposition. Crop rotation affected mycorrhizal fungi, protozoa, and soil peptidase activity, and N fertiliser had a significant effect on mycorrhizal fungi, protozoa, and cellulose decomposition. As these biological properties are responsive to agricultural management, they may have potential as bioindicators. Total bacteria, fungi, and actinomycetes, cellulosedecomposing bacteria and fungi, soil phosphatase and sulfatase activity, and N mineralisation were less affected by these treatments and may therefore have limited potential as bioindicators.

Impacts of management on soil biota in Vertosols supporting the broadacre grains industry in northern Australia

“…Additionally, these constraints do not appear to be consistently affected by management, other than a suggestion that effects are greater in cropped soils. This is contrary to the findings for major diseases like crown rot (Wildermuth et al 1997), take-all (Rovira 1990), Pythium root rot (Pankhurst et al 1995), and Rhizoctonia bare patch (Neate 1987).…”

Biomass and catabolic diversity of microbial communities with long-term restoration, bare fallow and cropping history in Chinese Mollisols

“…Soil microbial biomass is defined as an indicator of soil fertility and quality, which is easily influenced by soil managements (Pankhurst et al 1995). Wang et al (2004) reported that an application of chemical fertilizers (NPK) increased the black soil MBC compared with no fertilization, and reached the same level as the natural restoration in soil layer of 0-20 cm.…”

Alterações nas frações do carbono em um neossolo quartzarênico submetido a diferentes sistemas de uso do solo Edicarlos Damacena de Souza

“…Como possuem relação direta com as condições de solo, qualquer alteração no ecossistema afetará a densidade, diversidade e a atividade das populações microbianas do solo (Pankhurst et al, 1995). O carbono na biomassa microbiana é o destino inicial do carbono que será transformado no solo e funciona como energia armazenada para processos microbianos e, por responder rapidamente às alterações no solo, pode ser usado como identificador de alterações na matéria orgânica do solo em curto prazo (Rice et al, 1996). A relação entre o carbono da biomassa e o carbono orgânico total demonstra processos importantes relacionados com aportes e transformações da matéria orgânica, assim como a eficiência de conversão do carbono desta em carbono microbiano (Sparling, 1992).…”