Impact of agricultural inputs on soil organisms—a review

Abstract

External agricultural inputs such as mineral fertilisers, organic amendments, microbial inoculants, and pesticides are applied with the ultimate goal of maximising productivity and economic returns, while side effects on soil organisms are often neglected. We have summarised the current understanding of how agricultural inputs affect the amounts, activity, and diversity of soil organisms. Mineral fertilisers have limited direct effects, but their application can enhance soil biological activity via increases in system productivity, crop residue return, and soil organic matter. Another important indirect effect especially of N fertilisation is soil acidification, with considerable negative effects on soil organisms. Organic amendments such as manure, compost, biosolids, and humic substances provide a direct source of C for soil organisms as well as an indirect C source via increased plant growth and plant residue returns. Non-target effects of microbial inoculants appear to be small and transient. Among the pesticides, few significant effects of herbicides on soil organisms have been documented, whereas negative effects of insecticides and fungicides are more common. Copper fungicides are among the most toxic and most persistent fungicides, and their application warrants strict regulation. Quality control of organic waste products such as municipal composts and biosolids is likewise mandatory to avoid accumulation of elements that are toxic to soil organisms.

Combined effects of nitrogen deposition and biochar application on emissions of N2O, CO2and NH3from agricultural and forest soils

“…1c), which is consistent with the results of Yoo and Kang (2012). These findings can be partly explained by the following facts: right after the incorporation of biochar into soils, volatile biochar compounds (aliphatic compounds) may act as decomposable organic C sources in soil and thus provide a readily available substrate for denitrifying microorganisms (Blagodatskaya and Kuzyakov 2008;Ameloot et al 2013); due to the priming effect (soil microbial community has been stimulated due to the addition of various organic amendments), biochar incorporation with a high C/N ratio may stimulate soil microorganisms to decompose SOM (Kuzyakov et al 2000;Bünemann et al 2006;Smith et al 2010;Nelissen et al 2012).…”

“…As for the agricultural soil, biochar incorporation increased CO 2 emissions at the rate of 0 kg N ha −1 yr −1 (Table 3), which was in agreement with Augustenborg et al (2011) that CO 2 emissions increased in the low-SOM soil. Generally due to the priming effect, biochar incorporation may stimulate soil microorganisms to decompose SOM (Bünemann et al 2006;Smith et al 2010;Nelissen et al 2012) and provide readily available substrate for denitrifying microorganisms (Blagodatskaya and Kuzyakov 2008;Ameloot et al 2013) and mineralize the labile biochar C fraction by biotic or abiotic ways (Kolb et al 2009;Zimmerman et al 2011) in agricultural soil thus enhance CO 2 emissions. Therefore, the relative responses of CO 2 emissions to biochar amendment were affected by the soil type with different levels of SOM.…”

Impacto de herbicidas na biomassa microbiana e nos microrganismos solubilizadores de ortofosfato do solo rizosférico de cana-de-açúcar

“…Segundo Bunemann (2006), os herbicidas pouco afetam os organismos do solo. Entretanto, tem sido relatado que alguns desses produtos podem desequilibrar os ecossistemas edáficos e aquáticos (Das et al, 2003).…”

Early Changes in Soil Metabolic Diversity and Bacterial Community Structure in Sugarcane under Two Harvest Management Systems

“…Assessment of the structure of microbial communities in the soil can also be useful for detecting possible impacts of crop management systems on soil microbiota (Jansa et al, 2002;Oehl et al, 2003;Baumgartner et al, 2005;Bünemann et al, 2006;Chen et al, 2008;Smith et al, 2008;Wallis et al, 2010). Determination of significant shifts in the structure of the bacterial community, based on the profiles of 16S rRNA gene amplicons after denaturing gradient gel electrophoresis (PCR-DGGE), were observed in soils under forest, pasture, organic, and conventional management systems (Cookson et al, 2007;Liu et al, 2007;Cenciani et al, 2009;Rachid et al, 2012).…”