Effects and optimization of different NPK ratios on yield and quality of soilless cultivated cherry tomatoes

Peidong Li; Lili Zhang; Shanxing Zhao; Lifu Zhao; Biao Gong; Dan Zhao; Peidong Li; Lili Zhang; Shanxing Zhao; Lifu Zhao; Biao Gong; Dan Zhao

doi:10.48130/tihort-0026-0009

Figures (2) Tables (8)

Figure 1.
Response surfaces showing the effects of N × K₂O and N × P₂O₅ interactions on single-plant yield. (a) Response surface of N and P interaction on yield per plant at a fixed K level of 315 mg L⁻¹. (b) Response surface of N and K interaction on yield per plant at a fixed P level of 120 mg L⁻¹.
Figure 2.
Response surfaces showing the effects of N × K₂O and N × P₂O₅ interactions on total soluble solids.(a) Response surface of N and P₂O₅ for TSS at a fixed K₂O level of 315 mg L⁻¹. (b) Response surface of N and K interaction to soluble solids content when P level is fixed at 120 mg L⁻¹.
Coded level N (mg L⁻¹) P₂O₅ (mg L⁻¹) K₂O (mg L⁻¹)

+α 350 170 400

1 290 120 315

0 180 70 207.5

−1 70 20 100

−α 50 10 80

Table 1.
Factor levels and coded values used in the central composite design (CCD).

Run type	Factorial point								Center point				Axial point
Treatment (mg L⁻¹)	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17
N	70	70	70	70	290	290	290	290	180	180	180	70	290	180	180	180	180
P₂O₅	20	20	120	120	20	20	120	120	70	70	70	70	70	20	120	70	70
K₂O	100	315	100	315	100	315	100	315	207.5	207.5	207.5	207.5	207.5	207.5	207.5	100	315

Table 2.

Nutrient-solution compositions (Yamazaki-based) used in the CCD optimization experiment.

Run	Yield (g plant⁻¹)	Sugar/acid ratio	Lycopene (mg 100 g⁻¹)	Soluble sugars (mg 100 g⁻¹)	Total soluble solids (°Brix)	Vitamin C (mg 100 g⁻¹)	Citric acid (mg g^-−1)	Titratable acidity
1	1,216 ± 137	8.5 ± 0.17	3.2 ± 1.47	52 ± 1.38	5.1 ± 0.26	17.5 ± 1.12	2.1 ± 0.14	2.8 ± 0.25
2	1,634 ± 109	12.5 ± 0.25	5.8 ± 2.14	62 ± 2.05	6.3 ± 0.38	18.5 ± 1.63	2.5 ± 0.16	3 ± 0.30
3	1,292 ± 165	9 ± 0.25	4.5 ± 2.91	54 ± 2.61	5.4 ± 0.33	17.8 ± 1.47	2.2 ± 0.15	2.9 ± 0.28
4	1,862 ± 151	15.2 ± 0.33	7.2 ± 1.44	68 ± 1.92	6.9 ± 0.41	19 ± 1.81	2.6 ± 0.17	3.4 ± 0.37
5	1,406 ± 204	10.5 ± 0.22	3.8 ± 3.32	55 ± 3.36	5.6 ± 0.34	18 ± 1.44	2.4 ± 0.17	3 ± 0.30
6	1,938 ± 114	16.5 ± 0.32	8.5 ± 1.55	78 ± 1.59	7.7 ± 0.54	20.2 ± 2.14	2.7 ± 0.22	3.6 ± 0.45
7	1,140 ± 107	7.6 ± 0.29	3.5 ± 3.20	50 ± 3.35	4.9 ± 0.27	17 ± 1.19	2 ± 0.13	2.7 ± 0.24
8	2,090 ± 152	15.8 ± 0.28	7.8 ± 1.92	74 ± 1.60	7.4 ± 0.52	19.5 ± 2.04	2.85 ± 0.24	3.8 ± 0.49
9	1,786 ± 236	15.2 ± 0.36	6.5 ± 2.28	66 ± 2.63	6.6 ± 0.46	19 ± 1.71	2.6 ± 0.19	3.4 ± 0.39
10	1,808 ± 192	15.5 ± 0.32	6.6 ± 2.26	67 ± 2.36	6.7 ± 0.41	19.1 ± 1.86	2.62 ± 0.20	3.4 ± 0.41
11	1,763 ± 109	14.9 ± 0.28	6.3 ± 3.44	65 ± 3.90	6.4 ± 0.38	18.9 ± 1.70	2.58 ± 0.19	3.3 ± 0.38
12	1,520 ± 184	11 ± 0.24	4.8 ± 1.31	58 ± 1.35	5.7 ± 0.31	18.2 ± 1.28	2.3 ± 0.16	3.1 ± 0.31
13	1,900 ± 167	16.2 ± 0.28	7.5 ± 4.18	72 ± 3.70	7.3 ± 0.51	19.6 ± 2.06	2.72 ± 0.23	3.6 ± 0.47
14	1,672 ± 195	13.5 ± 0.30	5.5 ± 1.94	61 ± 1.83	6 ± 0.36	18.5 ± 1.57	2.5 ± 0.18	3.2 ± 0.35
15	1,862 ± 183	16.8 ± 0.36	8.2 ± 2.70	76 ± 2.72	7.6 ± 0.53	19.8 ± 2.08	2.68 ± 0.23	3.7 ± 0.48
16	1,254 ± 177	9.5 ± 0.22	3.6 ± 1.43	53 ± 1.74	5.2 ± 0.26	17.6 ± 1.23	2.15 ± 0.15	2.9 ± 0.26
17	1,884 ± 102	17 ± 0.28	8 ± 3.43	75 ± 3.18	7.5 ± 0.53	20 ± 2.10	2.75 ± 0.24	3.7 ± 0.48

Table 3.

Yield and fruit-quality responses of cherry tomato under different nutrient-solution treatments in the CCD experiment.

Source	df	Yield		Soluble solids
		F-value	p-value	F-value	p-value
Model	9	23.19	0.0002**	5.56	0.0171*
A-(N)	1	14.42	0.0067**	4.92	0.0621 ns
B-(P)	1	2.31	0.1726 ns	0.9	0.3735 ns
C-(K)	1	153.5	< 0.0001**	37.01	0.0005**
AB	1	3.49	0.1040 ns	1.81	0.2202 ns
AC	1	4.87	0.0630 ns	1.81	0.2202 ns
BC	1	6.49	0.0383*	0.25	0.6351 ns
A²	1	0.59	0.4669 ns	0.46	0.5202 ns
B²	1	0.17	0.6941 ns	0.09	0.7676 ns
C²	1	13.59	0.0078**	1.37	0.2807 ns
Residual	7
Lack of fit	5	16.91	0.0568 ns	14.54	0.0656 ns
Pure error	2
R²		0.9676		0.8772
R² adj R²		0.9258		0.7193
CV%		4.8		7.83
** indicates p < 0.01; * indicates p < 0.05; ns indicates not significant.

Table 4.

ANOVA for the quadratic regression models of single-plant yield and total soluble solids.

Term	Yield model			Soluble solids model
	Coefficient	Std error	p-value	Coefficient	Std error	p-value
Intercept	1,763.68	33.86	< 0.0001**	6.65	0.21	< 0.0001**
A-(N)	95	25.02	0.0067**	0.35	0.16	0.0621 ns
B-(P)	38	25.02	0.1726 ns	0.15	0.16	0.3735 ns
C-(K)	310	25.02	< 0.0001**	0.96	0.16	0.0005**
AB	−52.25	27.97	0.1040 ns	−0.24	0.18	0.2202 ns
AC	61.75	27.97	0.0630 ns	0.24	0.18	0.2202 ns
BC	71.25	27.97	0.0383*	0.09	0.18	0.6351 ns
A²	−37.18	48.34	0.4669 ns	−0.21	0.3	0.5202 ns
B²	19.82	48.34	0.6941 ns	0.09	0.3	0.7676 ns
C²	−178.18	48.34	0.0078**	−0.36	0.3	0.2807 ns
** indicates p < 0.01; * indicates p < 0.05; ns indicates not significant.

Table 5.

Estimated regression coefficients and significance tests for the yield and total soluble solids models.

Growth stage	Treatment	Plant height (cm)	Stem diameter (mm)	Leaf number	Total dry mass (g)	SPAD	Yield (g plant⁻¹)	Seedling vigor index
Seedling stage	T_Q	34.77 ± 2.68^b	4.82 ± 0.23^b	8.50 ± 0.22^b	1.85 ± 0.12^b	33.14 ± 0.51^b	−	0.23 ± 0.10^b
	CK	35.05 ± 2.88^b	4.95 ± 0.15^b	9.25 ± 0.42^ab	1.98 ± 0.24^b	34.19 ± 0.22^b	−	0.29 ± 0.04^ab
	T_B	38.90 ± 1.26^a	5.11 ± 0.18^a	9.55 ± 0.25^a	2.25 ± 0.17^a	35.62 ± 0.35^a	−	0.33 ± 0.02^a
Harvest stage	T_Q	124.88 ± 2.14^b	10.51 ± 0.29 b	18.68 ± 0.58^b	153.43 ± 6.52^b	43.26 ± 2.15^b	1,850 ± 45^b	−
	CK	126.13 ± 2.55^b	10.60 ± 0.17^b	18.70 ± 0.46^b	158.08 ± 3.55^b	44.54 ± 1.67^b	1,811 ± 52^b	−
	T_B	131.25 ± 1.47^a	10.94 ± 0.30^a	19.50 ± 0.32^a	160.91 ± 3.89^a	48.88 ± 2.14^a	2,022 ± 42^a	−
Different lowercase letters within a column indicate significant differences among treatments (Duncan's multiple range test, p < 0.05); '−' indicates not measured.

Table 6.

Effects of model-derived nutrient solutions on cherry tomato growth and yield in the validation experiment.

		Leaf			Stem			Fruit			Root
		N	P	K	N	P	K	N	P	K	N	P	K
Content (g kg⁻¹)	T_Q	31.63 ± 0.14^c	4.89 ± 0.12^b	49.65 ± 0.93^b	20.47 ± 0.22^b	6.62 ± 0.18^b	31.17 ± 0.54^b	19.76 ± 0.35^b	5.05 ± 0.06^b	37.15 ± 0.46^b	19.50 ± 0.50^b	6.80 ± 0.30^b	29.5 ± 1.00^a
	CK	32.66 ± 0.22^b	5.11 ± 0.16^a	50.12 ± 0.52^b	21.18 ± 0.67^a	6.72 ± 0.22ab	32.17 ± 0.56^a	20.25 ± 0.25^b	5.06 ± 0.08^b	37.52 ± 0.24^b	20.20 ± 0.40^a	7.00 ± 0.20ab	30.5 ± 0.80^a
	T_B	33.51 ± 0.32^a	5.25 ± 0.14^a	52.15 ± 1.30^a	21.97 ± 0.36^a	6.88 ± 0.42^a	33.55 ± 0.23^a	21.55 ± 0.16^a	5.16 ± 0.06^a	38.14 ± 0.27^a	21.00 ± 0.60^a	7.30 ± 0.40^a	31.5 ± 1.20^a
Uptake (mg plant⁻¹)	T_Q	1.77 ± 0.11^b	0.29 ± 0.11^b	3.18 ± 0.18^b	0.68 ± 0.10^b	0.21 ± 0.02^b	0.97 ± 0.06^b	1.09 ± 0.09^b	0.28 ± 0.11^b	2.00 ± 0.10^b	0.52 ± 0.05^b	0.18 ± 0.02^b	0.78 ± 0.06^b
	CK	1.89 ± 0.12^b	0.32 ± 0.13ab	3.32 ± 0.22ab	0.71 ± 0.06^b	0.23 ± 0.02ab	1.01 ± 0.02ab	1.12 ± 0.10^b	0.29 ± 0.06^b	2.03 ± 0.20^b	0.58 ± 0.04^b	0.20 ± 0.02^b	0.87 ± 0.05^b
	T_B	2.22 ± 0.15^a	0.36 ± 0.13^a	3.45 ± 0.17^a	0.81 ± 0.08^a	0.28 ± 0.02^a	1.10 ± 0.05^a	1.18 ± 0.04^a	0.32 ± 0.03^a	2.11 ± 0.15^a	0.65 ± 0.06^a	0.23 ± 0.03^a	0.97 ± 0.08^a
Different lowercase letters within a column indicate significant differences among treatments (Duncan's multiple range test, p < 0.05). TQ, quality-optimized formulation; CK, Yamazaki formula (control); TB, comprehensive optimum (yield + quality).

Table 7.

N, P, and K contents and uptakes in different organs of cherry tomato under different nutrient-solution treatments.

Treatment	Firmness (kg cm⁻²)	Total soluble solids (°Brix)	Soluble total sugars (mg 100 g⁻¹)	Citric acid (mg g⁻¹)	Malic acid (mg g⁻¹)	Lycopene (mg 100 g⁻¹)	Sugar/acid ratio	Vitamin C (mg 100 g⁻¹)
T_Q	5.25 ± 0.35^b	7.65 ± 0.28^a	78.50 ± 2.20^a	2.65 ± 0.45^a	0.61 ± 0.15^b	8.08 ± 1.68^a	16.5 ± 0.24^a	22.5 ± 0.85^a
CK	5.18 ± 0.45^b	6.67 ± 0.39^b	70.14 ± 1.78^b	2.05 ± 0.03^b	0.64 ± 0.11^b	7.15 ± 1.56^b	15.2 ± 0.22^b	18.7 ± 0.89^b
T_B	5.71 ± 0.31^a	7.48 ± 0.32^a	76.80 ± 2.05^a	2.60 ± 0.25^a	0.75 ± 0.17^a	8.25 ± 2.88^a	16.0 ± 0.18^a	23.0 ± 0.82^a
Different lowercase letters within a column indicate significant differences among treatments (Duncan's multiple range test, p < 0.05).

Table 8.

Fruit quality of cherry tomato under different nutrient-solution treatments in the validation experiment.

Coded level	N (mg L⁻¹)	P₂O₅ (mg L⁻¹)	K₂O (mg L⁻¹)
+α	350	170	400
1	290	120	315
0	180	70	207.5
−1	70	20	100
−α	50	10	80