Biochar amendment of soil improves resilience to climate change

Abstract

Because of climate change, insufficient soil moisture may increasingly limit crop productivity in certain regions of the world. This may be particularly consequential for biofuel crops, many of which will likely be grown in drought-prone soils to avoid competition with food crops. Biochar is the byproduct of a biofuel production method called pyrolysis. If pyrolysis becomes more common as some scientists predict, biochar will become more widely available. We asked, therefore, whether the addition of biochar to soils could significantly increase the availability of water to a crop. Biochar made from switchgrass (Panicum virgatum L.) shoots was added at the rate of 1% of dry weight to four soils of varying texture, and available water contents were calculated as the difference between field capacity and permanent wilting point water contents. Biochar addition significantly increased the available water contents of the soils by both increasing the amount of water held at field capacity and allowing plants to draw the soil to a lower water content before wilting. Among the four soils tested, biochar amendment resulted in an additional 0.8-2.7 d of transpiration, which could increase productivity in drought-prone regions or reduce the frequency of irrigation. Biochar amendment of soils may thus be a viable means of mitigating some of the predicted decrease in water availability accompanying climate change that could limit the future productivity of biofuel crops.

Effects of Biochar Application on Winter Wheat (Triticum aestivum L.) Roots Under Long-term Drought Conditions

“…al., 2009), improvement of the physical properties of soil, such as increase in the pH level and cation exchange capacity as well as reduction in tensile strength (Chan et al, 2007;Lehman et al, 2011). The addition of biochar also significantly increases the content of available water in the soil by increasing the amount of water retained in the soil (field water capacity) and allowing plants to draw the soil water content and lower it before wilting (Koide et al, 2015). This is caused mainly due to increasing capillary water capacity of the soil after application of biochar.…”

Engineered biochar from microwave-assisted catalytic pyrolysis of switchgrass for increasing water-holding capacity and fertility of sandy soil

“…In addition, many soils are becoming less suitable for food crops and bioenergy plants cultivation because of water deficiency and low soil fertility (Basso et al, 2013;Zhang and You, 2013;Koide et al, 2014). Increase in drought conditions also poses severe negative impacts on sandy soils through water loss by evaporation and facilitates the degradation of organic matter.…”

“…Increase in drought conditions also poses severe negative impacts on sandy soils through water loss by evaporation and facilitates the degradation of organic matter. Furthermore, water drains rapidly through sandy soils, leaching soluble nutrients and contaminating groundwater (Cai et al, 2011;Zhang and You, 2013;Koide et al, 2014). To reduce the competition between crop productions for bioenergy and food, bioenergy crops should be cultivated in low productivity areas or marginal lands.…”

“…One of the major reasons for improving soil fertility is to address the issue of food security, particularly in South Asia and sub-Saharan Africa, with malnutrition in 22 and 32% of the total population, respectively (FAO, 2006). Increasing the ability of soil to retain water and nutrients is a crucial need for achieving higher growth of bioenergy raw materials in desert land, arid and semi-arid areas and to provide enough food for the soaring population (Cai et al, 2011;Basso et al, 2013;Zhang and You, 2013;Koide et al, 2014;Agegnehu et al, 2016). Biochar application to soil may mitigate some of the portended deficiency in water as a consequence of climate change effects in order to retain the future productivity of bioenergy crops (Mulcahy et al, 2013;Koide et al, 2014;Agegnehu et al, 2016).…”

“…Increasing the ability of soil to retain water and nutrients is a crucial need for achieving higher growth of bioenergy raw materials in desert land, arid and semi-arid areas and to provide enough food for the soaring population (Cai et al, 2011;Basso et al, 2013;Zhang and You, 2013;Koide et al, 2014;Agegnehu et al, 2016). Biochar application to soil may mitigate some of the portended deficiency in water as a consequence of climate change effects in order to retain the future productivity of bioenergy crops (Mulcahy et al, 2013;Koide et al, 2014;Agegnehu et al, 2016). Biochar, a co-product of thermochemical conversion of biomass into valuable biofuel, can be applied to soil as an amendment to improve the sustainability of biomass and crop production, enrich fertility and quality of agricultural soils (Laird et al, 2010;Novak et al, 2012;Zhang and You, 2013;Koide et al, 2014).…”