Impacts of Sewage Sludge in Tropical Soil: A Case Study in Brazil

Table 2

Franca sewage sludge (FS), Barueri sewage sludge (BS), and mineral fertilizer (NPK) amounts applied in six corn cultivations.

Treatment	Sewage sludge (kg ha^−1 dry matter)						N (cultivation + coverage) + P2O5(kg ha^-)						K2O (kg ha^-)
	Cropping						Cropping						Cropping
	1°	2°	3°	4°	5°	6°	1°	2°	3°	4°	5°	6°	1°	2°	3°	4°	5°	6°
C	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
NPK	—	—	—	—	—	—	16+34	18+72	18+82	20+70	20+80	20+50	64	72	72	56	70	50
							80	90	90	70	70	70
F1N	3014	3504	3766	4432	4300	5720	—	—	—	—	—	—	28	33	58	96	63	39.1
F2N	6028	7008	7533	8863	8700	11450	—	—	—	—	—	—	25	29	45	90	54	29.1
F4N	12057	14017	15065	17726	17400	22890	—	—	—	—	—	—	17	23	18	75	36	6.1
F8N	24113	26033	30131	35452	34800	45790	—	—	—	—	—	—	—	11	—	42	3	—
C	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—
NPK	—	—	—	—	—	—	16+34	18+72	18+82	20+70	20+80	20+50	64	72	72	56	72	50
							80	90	90	70	70	70
B1N	8095	3995	5315	5295	3200	3880	—	—	—	—	—	—	3	28	40	87	57	35.6
B2N	16190	7991	10631	10591	6500	7770	—	—	—	—	—	—	—	19	8	69	45	21.2
B4N	32381	15981	21262	21182	12900	15530	—	—	—	—	—	—	—	4	—	33	21	—
B8N	64762	31962	42524	42363	25800	31060	—	—	—	—	—	—	—	—	—	—	—	—

FS: sewage sludge from the Franca Wastewater Treatment Plant. BS: sewage sludge from Barueri Wastewater Treatment Plant. C: control; NPK: mineral fertilization recommended for the crop; F1N, F2N, F4N, and F8N: SS from Franca based on the nitrogen concentration that provides the same amount of N as in the mineral fertilization, one, two, four, and eight times the N recommended sewage sludge dosage, respectively; B1N, B2N, B4N, and B8N: sewage sludge from Barueri based on the nitrogen concentration that provides the same amount of N as in the mineral fertilization, one, two, four, and eight times the N recommended sewage sludge, respectively.