Long-term fertilizer management in NERICA cultivated upland affects on soil bio-chemical properties

Figures & data

Table 1. Chemical properties of examined soils.

	TC (％)	TN (％)	C/N	NH4^+ (mgN kg^−1)	NO3^− (mgN kg^−1)	Soluble OC (mgC kg^−1)	POXC (mgC kg^−1)
Control	1.50	0.15	10.17	3.40 ± 0.39	0.62 ± 0.22	93.2 ± 1.0	351.8
N	1.50	0.16	9.65	3.60 ± 0.28	5.14 ± 0.94	143.1 ± 1.4	357.9
NP	1.47	0.15	9.80	3.82 ± 0.15	9.71 ± 0.94	96.2 ± 0.3	368.2
PK	1.53	0.16	9.87	3.86 ± 0.44	6.17 ± 0.37	125.1 ± 2.0	337.7
NK	1.32	0.12	10.57	3.73 ± 0.17	0.68 ± 0.09	96.0 ± 2.5	346.3
NPK	1.32	0.12	11.01	4.03 ± 0.26	11.19 ± 0.97	108.4 ± 2.2	366.4
NPK Compost	1.36	0.13	10.80	3.88 ± 0.29	8.00 ± 0.32	99.9 ± 3.1	422.0
Compost	1.50	0.14	10.91	3.32 ± 0.13	1.36 ± 0.22	70.6 ± 1.7	434.2

TC: total carbon, TN: total nitrogen, Soluble OC: soluble organic carbon, POXC: permanganate oxidizable carbon.

Figure 1. Soil pH and EC.

Figure 2. Correlation between soil pH and EC.

Figure 3. Microbial properties of examined soils.

Figure 4. Greenhouse gas production during aerobic (upper column) or flooded (lower column) incubation.

Figure 5. Ammonification under flooded condition and nitrification under aerobic condition.

Figure 6. Stable isotope ratio of soil organic matter in Uganda upland rice soil to compare with other ecosystems.

Figure 7. Correlation between available P and average yield of upland rice.

Figure 8. Correlation between nitrification and average yield of upland rice in the experiment.

Figure 9. Relation between nitrification and N₂O production after 4 weeks incubation.