Soil organisms are affected by the presence of predatory protists. However, it remains poorly understood how predatory protists can affect plant disease incidence and how fertilization regimes can affect these interactions. Here, we characterise the rhizosphere bacteria, fungi and protists over eleven growing seasons of tomato planting under three fertilization regimes, i.e conventional, organic and bioorganic, and with different bacterial wilt disease incidence levels. We find that predatory protists are negatively associated with disease incidence, especially two ciliophoran Colpoda OTUs, and that bioorganic fertilization enhances the abundance of predatory protists. In glasshouse experiments we find that the predatory protist Colpoda influences disease incidence by directly consuming pathogens and indirectly increasing the presence of pathogen-suppressive microorganisms in the soil. Together, we demonstrate that predatory protists reduce bacterial wilt disease incidence in tomato plants via direct and indirect reductions of pathogens. Our study provides insights on the role that predatory protists play in plant disease, which could be used to design more sustainable agricultural practices.

In this study, we empirically investigate whether and to what extent corporate social responsibility (CSR) may affect firm liquidity risk. We define liquidity risk as the covariance between market-wide liquidity shocks and individual firms’ stock returns and employ two methods to estimate firm liquidity risk. We find a negative association between CSR and firm liquidity risk after controlling for various firm characteristics, i.e., year and industry fixed effects. Our results are robust to possible endogeneity issues when we adopt two-stage lease square estimator and dynamic GMM estimator. In addition, we document that the negative relation between CSR and firm liquidity risk is more pronounced when firms have higher reliance on external financing.

This article examines the concept of quality as a factor commonly used in portfolio management. Although value and momentum are fairly well-established constructs, the third major factor in many models, quality, is not so well articulated. This research aggregates the most common components of quality into a parsimonious, well-defined factor (QAL) using the data reduction technique known as partial least square. The authors show that their factor has power independent of the other factors and significant return in excess of common risk models. Moreover, their QAL factor possesses favorable downside risk properties and works as a superior hedge during turbulent market performance periods, which they contend is the main feature one would expect of assets with high quality. Additionally, adding the authors’ QAL to an opportunity set consisting of other factors, as well as a traditional 60/40 equity/fixed income portfolio, increases the Sharpe ratio and improves downside protection simultaneously because of its diversifying effect.