Tomato is an important field crop, and nutritional imbalances frequently reduce its yield. Diagnosis and Recommendation Integrated System (DRIS), uses ratios for nutrient deficiency diagnosis instead of absolute concentration in plant tests. In this study, local DRIS norms for the field tomatoes were established and the nutrient(s) limiting tomatoes yield were determined. Tomato leaves were analyzed for nutrients, to identify nutritional status using the DRIS approach. One hundred tomatoes fields were selected from Chatter Plain Khyber Pakhtunkhwa and the Sheikupura Punjab Pakistan. The first fully matured leaf was sampled, rinsed, dried and ground for analyzing P, K, Ca, Mg, Cu, Fe, Mn and Zn using an Inductively Coupled Plasma Atomic Emission Spectrophotometer (ICP AES). Plant tissue N and S were measured by the combustion method. The tomatoes yields were recorded at each location. The data were divided into high-yielding (≥3.79 kg/10 plant) and low-yielding (<3.79 kg/10 plant) populations and norms were computed using standard DRIS procedures. High-yielding plant population had a statistically greater mean S and Fe than the low-yielding population. The average balance index, the sum of functions, for S and Fe were −11.04 and −5.17 which reflected deficiency of S and Fe. Plant nutrients norms established may optimize plant nutrition in field tomatoes for high yield.
Tomato (
Beaufils [
The DRIS approach has been used effectively as a diagnostic tool, and norms have been established for numerous ornamental and field crops internationally such as maize, potato, cauliflower, sugarcane, rice, lettuce, soybean, tomato, onion, banana, and cucumber [
The index tissue was sampled from 100 farmers’ fields from the Sheikhupura and Chatter Plain districts of Pakistan. The Chattar Plain lies between latitude 34°36’57.86″N and longitude 73°7’4.8″E with its warm and temperate climate where the mean annual temperature is 15.2°C and mean annual precipitation is 1144 mm. The sampling site of Sheikhupura lies at latitude 31°42’59.98″N and longitude 73°59’6.09″E, has extreme variations in temperature and mean annual precipitation is 635 mm.
The index tissue was the first early mature leave just before flowering (i.e., 25–35 days after planting). The index tissue was collected from several tomato plants and composited. The plant tissue was rinsed with distilled water, oven-dried at 70 ± 1°C for 2 days, and passed through a 60-mesh stainless steel strainer in a Wiley Mill. Tomato yield data per 10 plants was recorded during harvest from all one hundred farmers’ fields.
Phosphorus, K, Ca, Mg, B, Zn, Cu, Fe, Mn in first mature leaves of plants were determined by dry ashing. By taking 0.5 g leaf sample in a crucible, combusted at 485°C for 10 to 12 h until complete ashing and 5 mL of 20% HCl was added to the crucibles. Five mL of deionized water was mixed after 30 min and thoroughly swirled and allowed to stand for 180 min. The nutrients released were measured by an ICP-AES analyzer model ICap 7600 Duo ICP-OES [
The ratios of nutrient pairs were calculated from nutrient concentrations. The mean, and coefficient of variation were calculated for low and high yielders segregated based on the principles given by Walworth et al. [
where, f (A/B) through f (N/M) are functions of all the nutrient pairs. Function calculations depended upon whether A/B was greater than a/b, was equal to a/b, or was lower than a/b, where A/B was the nutrient ratio of low yielders and a/b was nutrient ratio of high yielders.
The coefficient of variation CV in the above equation was from norms. The index values were used for interpretation or diagnosis by the DRIS.
Further, the nutrient pairs, both indirect and reverse orders were added in the indices. The sum of nutrient indices (IA+IB+IC+ID+… = 0) is zero. Nutritional balance index (NBI), all the absolute values irrespective of their sign of nutrient indices of particular nutrient were added up.
The Average Nutritional Balance Index (NBIa) was calculated from NBI
NBIa = NBI/Z where Z was number of nutrients
The relationship of nutrient index with NBIa was used for the interpretation of nutrient status.
A nutrient was classified as deficient, adequate and excess when:
Adequate = |IA| ≤ NBIa
Deficient = IA < 0 and |IA| > NBIa
Excess = IA > 0 and |IA| > NBIa
On the basis of the plant nutrients’ reference concentration for tomatoes as suggested by Ulukapi et al. [
Overall | Chatter plain | Sheikhupura | |||||||
---|---|---|---|---|---|---|---|---|---|
Deficient | Sufficient | Excess | Deficient | Sufficient | Excess | Deficient | Sufficient | Excess | |
---Frquency (n/100)-- | ---Frequency (n/50)--- | ---Frequency (n/50)--- | |||||||
Nitrogen | 1 | 26 | 73 | 1 | 13 | 36 | 0 | 13 | 37 |
Phosphorus | 7 | 78 | 15 | 4 | 33 | 13 | 3 | 45 | 2 |
Potassium | 95 | 5 | 0 | 45 | 5 | 0 | 50 | 0 | 0 |
Calcium | 0 | 0 | 100 | 0 | 0 | 50 | 0 | 0 | 50 |
Magnesium | 0 | 16 | 84 | 0 | 35 | 15 | 0 | 1 | 49 |
Sulfur | 0 | 56 | 44 | 0 | 42 | 8 | 0 | 48 | 2 |
Zinc | 0 | 100 | 0 | 0 | 50 | 0 | 0 | 50 | 0 |
Iron | 0 | 21 | 79 | 0 | 8 | 42 | 0 | 13 | 37 |
Copper | 0 | 99 | 1 | 0 | 49 | 1 | 0 | 50 | 0 |
Boron | 31 | 69 | 0 | 1 | 49 | 0 | 30 | 20 | 0 |
Manganese | 0 | 99 | 1 | 0 | 46 | 1 | 0 | 50 | 0 |
Nitrogen was in the sufficient range in 26 tissue samples, and a vast number had N content in excess. Plant N in the index tissue ranged from 20.0 to 87.0 g kg−1. Phosphorus content in most plant tissues was in the sufficient range, and a few had P in excess (>6.5 g kg−1). Phosphorus in leaves ranged from 3 g kg−1 to 9 g kg−1. Potassium in the tomato index tissue was mostly in the low range (<35 g kg−1). Calcium and Mg were in excess in most of the plant tissue. Magnesium was in excess in many numbers of samples from Sheikhupura, while samples from Chatter plain had Mg in the sufficiency range. Sulfur was in excess (>2 g kg−1) and equally had S in the sufficiency range of 2 to 8 g kg−1. In Chatter plain, S was largely in sufficient range while in Sheikhupura both sufficient and excess levels were observed. Overall plant boron was in the deficient range, <30 mg kg−1 in almost one-third plants and a majority had boron in the sufficient range of 30 to 75 mg kg−1. Copper in tomato index tissue was mostly in sufficient range (5–30 mg kg−1) except for one sample. In the majority of samples iron was in excess (>300 mg kg−1), however, few samples had iron in the sufficient range within 45–300 mg kg−1. Overall, plant Mn was sufficient in the range from 30 to 300 mg kg−1. Zinc was also in the sufficient range from 18–75 mg kg−1 in plant tissue of Sheikhupura and Chatter plain.
The ratios of each nutrient with all nutrients were calculated. Mean, range and C.V of the nutrient pairs were calculated for both the high and low-yielding populations of tomatoes presented in
High-yielding population | Low-yielding population | ||||||||
---|---|---|---|---|---|---|---|---|---|
Variable | Mean | C.V(%) | Range | Mean | C.V(%) | Range | |||
Yield | 4.15 | 11.67 | 3.79 | 5.35 | 2.86 | 17.64 | 1.37 | 3.75 | 0.000 |
N/P | 11.57 | 26.00 | 7.71 | 18.77 | 11.64 | 27.47 | 2.94 | 20.89 | 0.506 |
N/K | 2.31 | 24.65 | 1.67 | 4.00 | 2.26 | 26.64 | 1.00 | 4.31 | 0.659 |
N/Ca | 1.43 | 17.22 | 1.02 | 1.93 | 1.41 | 25.26 | 0.56 | 2.68 | 0.870 |
N/Mg | 4.93 | 30.47 | 3.08 | 8.88 | 5.44 | 35.82 | 2.81 | 12.21 | 0.815 |
N/S | 5.37 | 15.69 | 4.01 | 7.21 | 7.07 | 29.33 | 3.11 | 11.34 | 0.041 |
N/Zn | 1875 | 32.28 | 1277 | 3582 | 1600 | 30.02 | 384 | 2700 | 0.541 |
N/B | 1807 | 24.95 | 1136 | 2948 | 1596 | 27.10 | 528 | 2402 | 0.081 |
N/Cu | 2963 | 27.50 | 1993 | 4820 | 2989 | 25.71 | 1418 | 5149 | 0.732 |
N/Fe | 122 | 50.28 | 59.46 | 261 | 139 | 38.43 | 35.82 | 272 | 0.873 |
N/Mn | 968 | 35.35 | 477 | 1509 | 704 | 47.69 | 151 | 1457 | 0.170 |
P/N | 0.09 | 25.71 | 0.053 | 0.12 | 0.09 | 38.99 | 0.04 | 0.34 | 0.000 |
P/K | 0.20 | 24.42 | 0.135 | 0.32 | 0.20 | 36.58 | 0.08 | 0.56 | 0.003 |
P/Ca | 0.12 | 16.33 | 0.102 | 0.18 | 0.13 | 40.77 | 0.05 | 0.35 | 0.000 |
P/Mg | 0.46 | 45.80 | 0.248 | 0.96 | 0.52 | 55.36 | 0.17 | 1.27 | 0.266 |
P/S | 0.49 | 30.46 | 0.295 | 0.77 | 0.68 | 58.74 | 0.21 | 3.23 | 0.016 |
P/Zn | 166 | 27.43 | 103 | 237 | 147 | 36.90 | 37.09 | 286 | 0.863 |
P/B | 159 | 19.80 | 111 | 215 | 145 | 34.36 | 56.36 | 271 | 0.558 |
P/Cu | 268 | 31.44 | 150 | 420 | 287 | 47.03 | 96.95 | 686 | 0.653 |
P/Fe | 10.54 | 37.16 | 4.48 | 19.29 | 12.76 | 45.77 | 4.87 | 31.37 | 0.393 |
P/Mn | 86.52 | 39.04 | 46.13 | 170 | 66.17 | 54.92 | 9.85 | 155 | 0.604 |
K/N | 0.45 | 20.00 | 0.24 | 0.59 | 0.47 | 28.69 | 0.23 | 0.99 | 0.233 |
K/P | 5.10 | 24.63 | 3.12 | 7.38 | 5.47 | 39.43 | 1.76 | 12.04 | 0.744 |
K/Ca | 0.64 | 24.32 | 0.42 | 0.95 | 0.65 | 27.97 | 0.30 | 1.50 | 0.904 |
K/Mg | 2.19 | 34.55 | 1.57 | 4.44 | 2.51 | 39.21 | 1.26 | 5.40 | 0.757 |
K/S | 2.42 | 25.59 | 1.38 | 3.61 | 3.34 | 39.01 | 1.33 | 6.08 | 0.094 |
K/Zn | 803 | 13.52 | 610 | 1036 | 732 | 27.61 | 174 | 1176 | 0.555 |
K/B | 788 | 17.16 | 584.5 | 1048 | 726.7 | 25.31 | 316 | 1036 | 0.000 |
K/Cu | 1346 | 40.07 | 791 | 2775 | 1433 | 43.13 | 561 | 3179 | 0.870 |
K/Fe | 52.49 | 38.65 | 26.35 | 86.20 | 64.47 | 40.76 | 21.46 | 139 | 0.674 |
K/Mn | 417 | 29.16 | 238 | 635 | 314 | 43.13 | 62.17 | 633 | 0.063 |
Ca/N | 0.71 | 18.265 | 0.51 | 0.97 | 0.75 | 91.01 | 0.37 | 1.76 | 0.081 |
Ca/P | 7.99 | 14.65 | 5.49 | 9.72 | 8.75 | 39.17 | 2.84 | 18.89 | 0.615 |
Ca/K | 1.63 | 23.23 | 1.05 | 2.34 | 1.65 | 28.43 | 0.80 | 3.23 | 0.195 |
Ca/Mg | 3.60 | 45.11 | 1.93 | 8.67 | 3.87 | 25.72 | 2.17 | 7.72 | 0.773 |
Ca/S | 3.88 | 29.86 | 2.69 | 7.04 | 5.23 | 38.25 | 2.17 | 7.72 | 0.043 |
Ca/Zn | 1325 | 29.54 | 806 | 2043 | 1182 | 34.147 | 564 | 2107 | 0.796 |
Ca/B | 1272 | 21.87 | 809 | 1648 | 1143 | 22.30 | 754 | 2117 | 0.068 |
Ca/Cu | 2102 | 28.55 | 1359 | 3280 | 2221 | 33.14 | 1000 | 4452 | 0.683 |
Ca/Fe | 85.32 | 45.95 | 35.85 | 174 | 101 | 37.62 | 42.04 | 183 | 0.452 |
Ca/Mn | 682.2 | 35.64 | 358 | 1123 | 496 | 44.42 | 125 | 1059 | 0.334 |
Mg/N | 0.21 | 24.52 | 0.11 | 0.32 | 0.20 | 31.39 | 0.08 | 0.35 | 0.028 |
Mg/P | 2.52 | 35.18 | 1.04 | 4.02 | 2.44 | 47.08 | 0.78 | 5.82 | 0.807 |
Mg/K | 0.49 | 22.52 | 0.22 | 0.63 | 0.45 | 33.05 | 0.18 | 0.78 | 0.160 |
Mg/Ca | 0.31 | 32.60 | 0.11 | 0.51 | 0.27 | 26.50 | 0.12 | 0.45 | 0.505 |
Mg/S | 1.14 | 23.66 | 0.71 | 1.63 | 1.35 | 25.12 | 0.57 | 2.75 | 0.041 |
Mg/Zn | 395 | 27.17 | 162 | 580 | 326 | 41.16 | 92.83 | 713 | 0.828 |
Mg/B | 386 | 27.61 | 177 | 573 | 320 | 38.53 | 152 | 643 | 0.088 |
Mg/Cu | 648 | 43.19 | 311 | 1316 | 592 | 33.93 | 288 | 1398 | 0.647 |
Mg/Fe | 25.87 | 47.43 | 12.38 | 46.06 | 27.21 | 40.51 | 10.34 | 55.90 | 0.852 |
Mg/Mn | 208 | 36.65 | 53.68 | 332 | 140 | 56.87 | 30.78 | 55.90 | 0.204 |
S/N | 0.19 | 15.82 | 0.13 | 0.24 | 0.15 | 31.25 | 0.08 | 10.32 | 0.066 |
S/P | 2.20 | 46.80 | 0.30 | 4.58 | 1.83 | 46.91 | 0.30 | 4.58 | 0.173 |
S/K | 0.44 | 27.8 | 0.27 | 0.72 | 0.34 | 39.25 | 0.16 | 0.74 | 0.890 |
S/Ca | 0.27 | 24.37 | 0.14 | 0.37 | 0.21 | 32.36 | 0.05 | 0.38 | 0.989 |
S/Mg | 0.92 | 25.66 | 0.61 | 1.39 | 0.78 | 27.25 | 0.36 | 1.73 | 0.334 |
S/Zn | 356 | 34.70 | 200 | 645 | 254 | 49.46 | 40.28 | 705 | 0.239 |
S/B | 338 | 23.35 | 234 | 531 | 248 | 41.46 | 55.37 | 465 | 0.011 |
S/Cu | 558 | 28.05 | 394 | 884 | 446 | 27.68 | 148 | 803 | 0.089 |
S/Fe | 22.82 | 46.91 | 10.21 | 47.21 | 20.78 | 41.66 | 3.75 | 43.85 | 0.458 |
S/Mn | 182 | 33.70 | 66.12 | 271 | 110 | 60.79 | 16.78 | 255 | 0.078 |
Zn/N | 0.000 | 24.84 | 0.0002 | 0.007 | 0.0006 | 40.46 | 0.0003 | 0.002 | 0.000 |
Zn/P | 0.006 | 30.55 | 0.004 | 0.009 | 0.007 | 46.13 | 0.0034 | 0.027 | 0.000 |
Zn/K | 0.001 | 13.49 | 0.000 | 0.001 | 0.001 | 46.06 | 0.0008 | 0.005 | 0.000 |
Zn/Ca | 0.000 | 30.45 | 0.000 | 0.001 | 0.0009 | 35.05 | 0.0004 | 0.001 | 0.000 |
Zn/Mg | 0.002 | 39.60 | 0.001 | 0.006 | 0.003 | 49.11 | 0.001 | 0.01 | 0.000 |
Zn/S | 0.003 | 31.14 | 0.001 | 0.004 | 0.005 | 63.46 | 0.001 | 0.02 | 0.000 |
Zn/B | 1.008 | 26.42 | 0.67 | 1.48 | 1.05 | 30.97 | 0.49 | 1.89 | 0.481 |
Zn/Cu | 1.72 | 45.25 | 0.95 | 3.77 | 2.01 | 35.15 | 0.83 | 4.15 | 0.854 |
Zn/Fe | 0.06 | 38.39 | 0.03 | 0.10 | 0.09 | 41.38 | 0.03 | 0.18 | 0.000 |
Zn/Mn | 0.53 | 35.39 | 0.32 | 0.85 | 0.44 | 43.14 | 0.11 | 0.99 | 0.741 |
B/N | 0.000 | 23.22 | 0.000 | 0.000 | 0.0006 | 34.22 | 0.0004 | 0.001 | 0.000 |
B/P | 0.005 | 19.53 | 0.004 | 0.008 | 0.007 | 38.08 | 0.003 | 0.0177 | 0.000 |
B/K | 0.001 | 17.40 | 0.000 | 0.001 | 0.001 | 31.81 | 0.0009 | 0.0031 | 0.000 |
B/Ca | 0.000 | 25.33 | 0.000 | 0.001 | 0.0009 | 21.43 | 0.0004 | 0.001 | 0.000 |
B/Mg | 0.002 | 39.12 | 0.001 | 0.005 | 0.003 | 36.07 | 0.0015 | 0.006 | 0.000 |
B/S | 0.003 | 21.50 | 0.001 | 0.004 | 0.002 | 36.49 | 0.001 | 0.006 | 0.000 |
B/Zn | 1.05 | 24.93 | 0.67 | 1.47 | 1.04 | 32.67 | 0.52 | 2.001 | 0.017 |
B/Cu | 1.716 | 35.48 | 1.04 | 3.23 | 2.04 | 41.4 | 0.98 | 4.64 | 0.233 |
B/Fe | 0.06 | 41.44 | 0.02 | 0.12 | 0.09 | 36.79 | 0.03 | 0.17 | 0.000 |
B/Mn | 0.53 | 26.12 | 0.28 | 0.79 | 0.43 | 35.51 | 0.08 | 0.78 | 0.526 |
Cu/N | 0.000 | 23.73 | 0.0002 | 0.0005 | 0.0003 | 25.91 | 0.0001 | 0.0007 | 0.000 |
Cu/P | 0.004 | 31.02 | 0.0023 | 0.006 | 0.004 | 44.14 | 0.0014 | 0.010 | 0.000 |
Cu/K | 0.000 | 28.43 | 0.0003 | 0.001 | 0.0008 | 36.68 | 0.0003 | 0.001 | 0.000 |
Cu/Ca | 0.0005 | 27.41 | 0.0003 | 0.0007 | 0.0004 | 30.17 | 0.0002 | 0.0009 | 0.000 |
Cu/Mg | 0.001 | 35.44 | 0.0007 | 0.003 | 0.001 | 30.98 | 0.0007 | 0.003 | 0.000 |
Cu/S | 0.001 | 24.71 | 0.0011 | 0.002 | 0.002 | 39.49 | 0.0012 | 0.006 | 0.000 |
Cu/Zn | 0.66 | 23.67 | 0.26 | 1.04 | 0.564 | 38.24 | 0.94 | 1.20 | 0.811 |
Cu/B | 0.64 | 29.53 | 0.30 | 0.96 | 0.566 | 35.37 | 0.21 | 1.01 | 0.723 |
Cu/Fe | 0.04 | 53.46 | 0.02 | 0.10 | 0.048 | 39.1 | 0.01 | 0.09 | 0.000 |
Cu/Mn | 0.35 | 44.81 | 0.11 | 0.68 | 0.247 | 53.83 | 0.04 | 0.56 | 0.913 |
Fe/N | 0.009 | 41.10 | 0.003 | 0.01 | 0.008 | 44.74 | 0.003 | 0.02 | 0.000 |
Fe/P | 0.10 | 41.73 | 0.05 | 0.22 | 0.095 | 43.63 | 0.030 | 0.20 | 0.013 |
Fe/K | 0.02 | 39.15 | 0.01 | 0.03 | 0.01 | 45.05 | 0.007 | 0.04 | 0.000 |
Fe/Ca | 0.01 | 41.31 | 0.005 | 0.02 | 0.01 | 39.34 | 0.005 | 0.02 | 0.000 |
Fe/Mg | 0.04 | 44.89 | 0.02 | 0.08 | 0.04 | 38.75 | 0.017 | 0.09 | 0.000 |
Fe/S | 0.05 | 42.24 | 0.02 | 0.09 | 0.05 | 52.89 | 0.02 | 0.26 | 0.000 |
Fe/Zn | 17.43 | 37.81 | 9.14 | 28.0 | 13.03 | 47.61 | 5.26 | 32.38 | 0.718 |
Fe/B | 17.47 | 46.31 | 8.03 | 37.0 | 12.09 | 46.71 | 5.65 | 31.47 | 0.149 |
Fe/Cu | 28.12 | 37.55 | 9.17 | 45.6 | 24.07 | 38.48 | 10.76 | 54.08 | 0.627 |
Fe/Mn | 9.41 | 52.38 | 4.06 | 18.5 | 5.9 | 69.77 | 0.001 | 17.19 | 0.264 |
Mn/N | 0.001 | 39.24 | 0.0006 | 0.002 | 0.001 | 69.78 | 0.0006 | 0.006 | 0.000 |
Mn/P | 0.013 | 35.73 | 0.005 | 0.02 | 0.02 | 89.88 | 0.006 | 0.10 | 0.000 |
Mn/K | 0.002 | 28.68 | 0.001 | 0.004 | 0.004 | 68.38 | 0.001 | 0.01 | 0.000 |
Mn/Ca | 0.001 | 37.94 | 0.0008 | 0.002 | 0.002 | 58.59 | 0.0009 | 0.007 | 0.000 |
Mn/Mg | 0.005 | 67.52 | 0.0030 | 0.01 | 0.01 | 60.28 | 0.003 | 0.05 | 0.000 |
Mn/S | 0.006 | 48.02 | 0.003 | 0.01 | 0.01 | 73.37 | 0.003 | 1.29 | 0.000 |
Mn/Zn | 2.08 | 31.89 | 1.16 | 3.03 | 2.81 | 54.66 | 1.005 | 8.80 | 0.164 |
Mn/B | 2.00 | 28.58 | 1.26 | 3.54 | 2.87 | 67.85 | 1.27 | 11.17 | 0.717 |
Mn/Cu | 3.60 | 58.49 | 1.45 | 8.46 | 5.71 | 67.27 | 1.78 | 23.37 | 0.498 |
Mn/Fe | 0.13 | 51.53 | 0.05 | 0.24 | 0.26 | 74.6 | 0.05 | 1.0008 | 0.010 |
Nitrogen, P, K, Ca, Mg and S ratios with other nutrients were statistically similar in both populations except P/Ca ratio which was wider in the low-yielding population than the high-yielding population and K/B which was wider in the high-yielding population than the low-yielding population. Zinc, B and Mn ratios with other nutrients were statistically wider in the low-yielding population than the high-yielding population except for the micronutrients which were similar in both the populations. Copper and iron ratios with other nutrients were wider in the high-yielding population than the low-yielding population except for micronutrients which were similar in both the populations.
DRIS functions were calculated to estimate sufficiency or deficiency of a specific nutrient against other nutrients individually given in
Function | Value | Function | Value | Function | Value |
---|---|---|---|---|---|
N/P | 0.24 | Mg/N | −2.44 | Cu/N | −2.44 |
N/K | −0.94 | Mg/P | −0.97 | Cu/P | −0.97 |
N/Ca | −0.82 | Mg/K | −3.85 | Cu/K | −3.85 |
N/Mg | 3.40 | Mg/Ca | −4.45 | Cu/Ca | −4.45 |
N/S | 20.09 | Mg/S | 7.64 | Cu/Mg | 7.64 |
N/Zn | −5.31 | Mg/Zn | −7.79 | Cu/S | −7.79 |
N/B | −5.32 | Mg/B | −7.54 | Cu/Zn | −7.54 |
N/Cu | 0.31 | Mg/Cu | −2.20 | Cu/B | −2.20 |
N/Fe | 2.80 | Mg/Fe | 1.09 | Cu/Fe | 1.09 |
N/Mn | −10.61 | Mg/Mn | −13.30 | Cu/Mn | −13.30 |
P/N | 0.96 | S/N | −14.57 | Fe/N | 4.30 |
P/K | 0.28 | S/P | −6.78 | Fe/P | −3.62 |
P/Ca | 2.12 | S/K | −9.44 | Fe/K | −4.83 |
P/Mg | 3.08 | S/Ca | −11.75 | Fe/Ca | −5.33 |
P/S | 12.61 | S/Mg | −6.74 | Fe/Mg | −2.47 |
P/Zn | 10.11 | S/Zn | −11.56 | Fe/S | 2.26 |
P/B | −6.70 | S/B | −15.68 | Fe/Zn | −8.94 |
P/Cu | 0.00 | S/Cu | −8.98 | Fe/B | −7.54 |
P/Fe | 2.28 | S/Fe | −2.09 | Fe/Cu | −4.47 |
P/Mn |
4.44 |
S/Mn |
−19.27 |
Fe/Mn |
−11.35 |
The nutrient’s functions involving S were highly positive and with Mn highly negative.
The nutrient balance indices were calculated and presented in
Nutrient | Index | Diagnosis |
---|---|---|
Nitrogen | −0.70 | Adequate |
Phosphorus | −0.56 | Adequate |
Potassium | −0.85 | Adequate |
Calcium | 0.33 | Adequate |
Magnesium | −3.19 | Adequate |
Sulphur | −11.04 | Deficient |
Zinc | 5.23 | High/Excess |
Boron | 3.47 | Adequate |
Copper | −0.59 | Adequate |
Iron | −5.17 | Deficient |
Manganese | 13.07 | High/Excess |
Sum of imbalances | 44.24 | |
Mean imbalance | 4.02 |
Nitrogen balance index was −0.7 while P balance index was −0.562. The K balance index was −0.856 while its ratios with macronutrients (N, P, Ca, Mg, S) and micronutrients (Fe, Cu) were almost similar in the high and low-yielding population. The Ca balance index was 0.338 and the Mg balance index was −3.193. Tissue Mg concentration was higher than the critical value; with 34% in the sufficiency range and 66% in the excessive range. The S balance index was −11.043 and the iron balance index of −5.176% and 79% plants had an excess of iron and the remaining in the sufficiency level. The copper balance index of −0.595. The boron index was 3.47. The DRIS index for zinc and the Mn index was 13.074.
The reference nutrient concentrations for tomatoes, following suggested by Ulukapi et al. [
Boron concentration in plant generally remains within sufficient range, except, one-third plants, showing deficiency. Reported range of boron is 10–39 mg kg−1 in the tomato index tissue [
Tomato yields were subdivided into two groups, a high-yielding population of ≥3.79 kg/10 plants and a low-yielding population of <3.79 kg/10 plants. The P/Ca ratio was wider in the low-yielding population than the high-yielding population and K/B was wider in the high-yielding population than the low-yielding population. Nitrogen balance index was −0.7, indicated the adequate N was present in plants of the low-yielding population. Nitrogen index that showed slight deficiency of nitrogen in tomato crop was reported [
However, the nitrogen index value −0.7 suggested that N may become deficient when other more deficient nutrients are applied. The P balance index was −0.562 that also showed nearly adequate level of P in the low-yielding population. Reported P index IP was −37 and −9 for tomatoes grown on different media showing severe deficiency of P [
Phosphorus ratios with macronutrients except for K and S and micronutrients (Zn and Mn) were almost similar in the high and low-yielding populations. Again, we concluded that P may become deficient once additional nutrients are applied. Minor deficiency of K in the low-yielding population was indicated by NBI for K, −0.856. Potassium balance index (IK) of −20 [
The iron balance index of −5.176 indicated Fe deficiency in the low-yielding population and 79% plants had an excess of iron, while remaining plants had sufficient level. Iron deficiency was also reported in peanut and chickpea [
The DRIS index for zinc and manganese were 5.23 and 13.07, showed greater quantity of respective nutrients in tomato index tissue. This may be due to more response to fertilizer application. DRIS indices identified sulfur −11.04 as the most deficient nutrient in the tomato crop in this study. However, N, P, and K may also deficient when sulfur is applied. Commercial growers may consult the established norms on plant nutrients to optimize plant nutrition in field crop for high yield.
The authors extend their appreciation to Taif University for supporting current work by Taif University Researchers Supporting Project No. (TURSP–2020/288), Taif University, Taif, Saudi Arabia.