Soil nutrient and nematode community changes in response to hardwood charcoal application

A one-time, large application of biochar (charcoal) could increase soil carbon (C) content and improve overall soil quality. It is known that nematodes have effects on soil organic matter and nutrient cycling and are plant diseases; moreover, nematodes affect nutrient mobilization in C-rich soil conditions; however, information is scant on the effect of biochar addition on nematode communities. Therefore, the objective of this field study was to evaluate the influence of sugar maple hardwood biochar on soil nematode communities and assess the relation among soil nematode communities and soil nutrient concentrations. Nematode communities were sampled and identified in soils without biochar application and soil amended with an application of 8% by weight (equivalent to 160 Mg ha(-1)). The application of 8% biochar did not change the abundance of nematodes but affected some nematode communities. Compared to the unamended soil, biochar-amended soil had lower plant-parasitic nematode populations and higher abundance of predatory nematodes. The Shannon diversity index (H') was lower, and the maturity index (MI) was higher with a mean value of 2.38 with biochar addition compared to 2.21 in unamended plots. Higher soil acidity and addition of substantial amounts of magnesium, calcium, potassium, and manganese in the biochar-amended soils were recorded after biochar application.