Table 1.

Summary of major research results reported on the effect of biochar application on plant nutrition and soil nutrient dynamics.

Study Location	Biochar		Soils characteristics		Crop and Study method	Application rate (Mg ha−1); Biochar pH	Crop yield/growth resp. over control		Nutrient and water retention & availability		Reference
	Feedstocks	(Pyrolysis Temp, 0C)	Description	pH
China	Wheat straw	350–550	Calcareous loamy and silty clay loam	NA¶	Maize and rice; Field	10, 20, 40 with and without N	Corn: 7-12% yield Rice: 8-14% yield		NA¶		(1)
	Wheat straw Maize straw	300–600 400	Upland Red soils (~Ultisols)	6.7	Rapeseed and potato; Field	0, 2.5, 5, 10, 20, 30 & 40	Rapeseed: 36% Potato: 54% yield		soil water stable aggregate soil organic carbon total N and C:N ratio		(2)
	Maize straw Wheat straw	400	Sandy loam and Calcic	NA¶	Rice and maize; Field	2.4	Rice & maize: 6% yield		NA¶		(2)
	Wheat straw	350–550	Hydroagric Stagnic Anthrosol	NA¶	Rice; Field	40	18.3% grain yield		NA¶		(3)
	Pig manure compost, peanut husk & biosolids	350–450	Entic Hydroagric Anthrosol	NA¶	Rice; Field	0.45	13.5%, 28.1% & 31.4% grain yield		NA¶		(4)
	Rice straw	NA¶	Gleyi–Stagnic Anthrosol	NA¶	Rice-wheat; Pot	4.5 & 9	14.8 & 21.3% grain yield				(5)
	Giant reed grass (Arundo donax)	300–600	Tropical sandy; 29.2% sand, 13.6% clay	6.02	Maize; Greenhouse column	0, 1, 2, 5% (w/w)	Growth		Reduce in ${\text{NH}}_4^{+}$-N, Increase in WHC, improve in N bioavailability		(6)
Japan	Chicken manure	402–528	Sandy: 47.5% sand, 11.7% clay	7.0	Brassica rapa; Field	10 (pH = 10.5)	90% growth		25% mineralization of the total N.		(7)
	Wood-based (Japanese cedar and cypress)	300	Sand-dune soils	6.9	Rice; Field	0, 20 & 40 (pH = 9.8)	Crop yield		20–30% to 50–60% increase in available water content		(8)
	Rice husk	350–400	Haplic Andosols	NA¶	Rice; Pot	0.02, 0.2 & 2 kg m−2	14% straw yield		NA¶		(9)
USA New York	Maize Stover	600	Kendaia silt loam and Lima loam.	7.36	Maize; Field	0, 1, 3, 12, and 30; + 108 kg N ha−1 (pH = 10.0)	No effects on yield		No improvement in crop N use efficiency; N uptake did not change; increased N retention		(10)
Florida	Peanut hull & Brazilian pepperwood	600	Sandy: sand: 94%, clay: 3.0%	5.9	Laboratory column	0.1 g char L−1 aqueous solution	Crop yield		Decrease in nitrate (34%), ammonium (35%) & phosphate (21%) leaching		(11)
Idaho	Hardwood biochar & dairy manure co-application	500	Calcareous; Portnuef soil	8.2	Lab incubation	0%, 1%, 2%, 10% by wt (pH = 6.8)	NA¶		Improve in soil water content; increase in soil NO3-N		(12)
Spain	Bamboo wood, Dairy manure, & mixed wood chip	NA¶	Sandy to silty clay loam	6.5	Lab incubation	2% (w/w; dry weight)	NA¶		Consistent decrease in N2O emissions by 10–90%		(13)
	Olive-tree prunings	450	Vertisol: 22% sand, 51% clay	8.2	Wheat; Field	2% by weight (pH = 6.6)	Crop yield		Increase in available N, P and C		(14)
Germany	Peanut hull	NA¶	Sandy	6.0	Quinua; Greenhouse	100 and 200 char (pH = 8.1)	Crop yield		Increase in leaf N; decrease in greenhouse gas emissions; increase in WHC		(15)
	Maize biochar used as hydro-biochar	600	Loamy sand	6.2	Wheat; Pot	0, 4, 12 (pH = 7.7)	Crop yield		No effect on N and Ca contents; decrease in plant tissue N		(16)
Denmark	Straw	730	Coarse sandy	6.5	Barley; pot	0, 8, 16, 32, 64 + (208 N+30 P) fertilizer	Yield: 6.0, 22, −12, −28, 10%		NUE was not prominent		(17)
Australia	Willow wood	550	Tropical Ferralsol	acidic	Maize; Field	0, 10, 25 + compost (co-composting)	10–29% yield		Increase in soil N, P, OC & water content		(18)
Bangladesh	Sawdust	300–350	“Alkaline”	8.0	Soybean; Pot	20 (pH = 5.21)	54% yield		Increase in available P		(19)
Finland	Spruce chips (Picea abies)	550–600	Boreal loamy sand 83% sand, 2% clay	4.65	Wheat; Field	0, 5, 10, 20, 30 + inorganic fertilizers	No effects on yield		Increase in soluble K & SOC; no effects on other soil nutrients (N, P); increase in plant-available water content		(20)
Indonesia	Bark of Acacia mangium	260–360	“Acidic” soil		Maize; Field	37	12% yield		NA¶		(21)
Philippines	Rice husk (Chimney charring process)	NA¶	Anthraquic gleysols Humic nitisols	6.55 4.3	Rice; Field	4.13 kg m−2	Both (16-35%) & in yield		NA¶		(22)

BC, biochar; C, Carbon; Ca, calcium; CUE, cation exchange capacity; K, potassium; N, nitrogen; NUE, nitrogen use efficiency; OC, organic carbon; P, phosphorus; WHC, water-holding capacity.

^¶NA, not available. The up arrows and down arrows represent, respectively, the increasing and decreasing responses of the parameters by biochar application.

References:

⁽¹⁾Zhang et al., 2016;

⁽²⁾Liu et al., 2014;

⁽³⁾Bian et al., 2014;

⁽⁴⁾Qian et al., 2014;

⁽⁵⁾Zhao et al., 2014;

⁽⁶⁾Zheng et al., 2013;

⁽⁷⁾Ishimori et al., 2017;

⁽⁸⁾Kameyama et al., 2017;

⁽⁹⁾Koyama and Hayashi, 2017;

⁽¹⁰⁾Guerena et al., 2013;

⁽¹¹⁾Yao et al., 2012;

⁽¹²⁾Ippolito et al., 2016;

⁽¹³⁾Cayuela et al., 2013;

⁽¹⁴⁾Olmo et al., 2014;

⁽¹⁵⁾Kammann et al., 2011;

⁽¹⁶⁾Reibe et al., 2015;

⁽¹⁷⁾Bruun et al., 2012;

⁽¹⁸⁾Agegnehu et al., 2016;

⁽¹⁹⁾Mete et al., 2015;

⁽²⁰⁾Tammeorg et al., 2014;

⁽²¹⁾Yamato et al., 2006;

⁽²²⁾Haefele et al., 2011.