. 2021 May 25;11:10845. doi: 10.1038/s41598-021-89221-4

Table 1.

Effect of planting density on soil fertility status.

Treatments	2015–16	2016–17	2017–18	2018–19	2019–20
Organic carbon (%)
Control	1.10^c	1.21^c	1.26^c	1.30^b	1.34^d
HDP-1	1.28^abc	1.42^b	1.54^b	1.60^a	1.64^c
HDP-2	1.25^bc	1.48^a	1.52^b	1.65^a	1.68^bc
UHDP-1	1.35^ab	1.50^a	1.64^ab	1.72^a	1.75^ab
UHDP-2	1.48^a	1.58^a	1.70^a	1.80^a	1.82^a
Available nitrogen (kg ha⁻¹)
Control	309.3^b	341.9^c	363.7^b,c	385.2^c	380.4^c
HDP-1	325.0^a,b	366.0^b	353.7^c,d	374.1^d	382.1^c
HDP-2	310.0^b	375.4^a,b	342.0^d	365.7^e	370.1^c
UHDP-1	332.1^a,b	383.0^a	379.2^b	401.9^b	405.3^b
UHDP-2	347.7^a	399.0^a	402.9^a	422.9^a	430.1^a
Available phosphorus (kg ha⁻¹)
Control	21.5^b	32.8^b	33.1^d	34.1^c	34.5^c
HDP-1	22.1^b	42.8^a,b	42.6^b,c	44.0^b	45.6^b
HDP-2	20.4^b	40.5^a,b	41.1^c	42.6^b	46.4^b
UHDP-1	23.6^b	44.8^a	45.3^b	46.0^a,b	48.7^a,b
UHDP-2	26.6^a	48.9^a	49.5^a	51.1^a	54.6^a
Available potassium (kg ha⁻¹)
Control	291.9^c	504.6^c	495.2^c	715.4^b	720.1^c
HDP-1	315.0^b	542.3^b	563.6^b	800.8^a	810.2^a
HDP-2	310.1^b,c	510.4^c	572.8^b	621.3^c	628.7^e
UHDP-1	330.0^a,b	560.2^a,b	596.4^a	681.8^b	690.2^d
UHDP-2	345.1^a	574.3^a	575.8^a,b	770.0^a	775.4^b

Means with at least one letter common are not statistically significant using TUKEY's Honest Significant Difference at 5%

Control: Planting at 6 m (row to row) × 6 m (plant to plant) spacing (tree density—277 plants ha⁻¹), HDP-1: Planting at 6 m (row to row) × 3 m (plant to plant) spacing (tree density—555 plants ha⁻¹), HDP-2: Planting at 4 m (row to row) × 4 m (plant to plant) spacing (tree density—625 plants ha⁻¹), UHDP-1: Planting at 4 m (row to row) × 2 m (plant to plant) spacing (tree density—1250 plants ha⁻¹), UHDP-2: Planting at 2 m (row to row) × 2 m (plant to plant) spacing (tree density—2500 plants ha⁻¹).