Effect of biochar derived from faecal matter on yield and nutrient content of lettuce (Lactuca sativa) in two contrasting soils

Environmental Systems Research

Table 2 Class means and contrasts of class for fresh yield and dry matter yield of lettuce grown in Soil 1 and 2 for two growing cycles

Class comparison	Soil 1				Soil 2
	Fresh yield		Dry matter yield		Fresh yield		Dry matter yield
	GC1^a	GC2	GC1	GC2	GC1	GC2	GC1	GC2
Classes	g/pot
Control	154	123	9.5	7.4	28	30	1.8	2.0
N alone	137	128	8.2	7.7	37	32	2.4	2.3
Biochar alone	198	163	11.7	9.7	115	87	7.0	5.5
Biochar with N	230	161	13.4	9.4	138	90	8.2	5.5
Contrasts^b
Control versus biochar alone	***	***	***	***	***	***	***	***
Control versus N alone	ns	ns	ns	ns	ns	ns	ns	ns
Biochar alone versus N alone	***	***	***	***	***	***	***	***
Biochar with N versus biochar alone	***	ns	***	ns	***	ns	***	ns
Biochar with N versus N alone	***	***	***	***	***	***	***	***

^aGC1 = Growing Cycle I and GC 2 = Growing Cycle II
^bClasses compared comprise the following treatments: control = control; biochar alone = biochar alone treatments (10, 20 and 30 t ha⁻¹)
N alone = N alone treatments (25, 50 kg N ha⁻¹); biochar with N = combination of the different biochar rates with the two N levels
ns, not significant (P > 0.05); * P < 0.05; ** P < 0.01; *** P < 0.001), n = 5