Keywords

Drip fertigation-tomato-yield-quality-fertilizer use efficiency.

Introduction

Tomato (Solanum lycopersicum L.) is one of the most important fruit vegetable crop grown in the world. In India tomato is cultivated as an important cash crop in a larger area due to its wider adapatability and versatile use. Besides, the fruits of tomato are very useful for our health as they rich in vitamins like A and C and minerals like Ca. Tomato fruits are rich in lycopene which turns tomato fruits to red is a very powerful antioxidant that prevents the development of many forms of cancer. Tomato is a heavy feeder and responds well to the applied nutrients. However, indiscriminate use of chemical fertilizers in tomato cultivation, not only escalating the cost of cultivation but also the environmental hazards by leaching. Drip fertigation is a novel technology which saves water and nutrients by applying near to the root zone and ultimately increases the water and fertilizer use efficiency (10). In general, frequent applications of fertilizer through drip irrigation have improved the fertilizer use efficiency and the crop response to fertigation is very impressive. With this view, the present investigation was carried out to study the effect of fertigation on growth, yield and fertilizer use efficiency in tomato.

Materials and methods

A field trial on fertigation studies in tomato was conducted at the Department of Vegetable crops, Horticultural College and Research Institute, Coimbatore. Totally seven treatments viz., soil application of normal fertilizers at 100 percent RDF (T1), soil application of normal fertilizers at 100 percent RDF and drip irrigation (T2), drip fertigation with normal fertilizers at 100 percent RDF (T3), drip fertigation with normal fertilizers at 75 percent RDF (T4), drip fertigation with water soluble fertilizers at 100 percent RDF using MAP, Multi K and Urea (T5), drip fertigation with water soluble fertilizers at 75 percent RDF using MAP, Multi K and Urea (T6) and drip fertigation with water soluble fertilizers at 50 percent RDF using MAP, Multi K and Urea (T7). The experiment was laidout in a randomized block design and replicated thrice. Lakshmi a private hybrid obtained from Numhem seeds as used in the present study. Twenty five days old healthy seedlings were transplanted in the main field at a spacing of 60 cm X 45 cm. Normal fertilizers (NF) used in the experiment were Urea, single super phosphate and muriate of potash and water soluble fertilizers as mono ammonium phosphate (MAP), multi-K (KNO3) and Urea. The level of fertilizers adopted in the present experiment was 200: 250: 250 Kg NP&K per hectare. Half dose of nitrogen and full dose of phosphorous and potash were applied as basal dressing and remaining half dose of nitrogen was applied as top dressing after one month of transplanting. In fertigation the fertilizers were injected in weekly intervals through the drip line. Biometrical observations viz., plant height (cm), number of fruits per plant, fruit weight (g), yield per plant (kg), TSS (0brix), titrable acidity (percent), ascorbic acid content (mg per 100g of fruit pulp), leaf area index, dry matter production (g per plant) and total chlorophyll content (mg per g fresh leaf) were taken from randomly selected twenty plants from each treatment. Nutrient uptake was worked out by multiplying the NPK concentration in plant parts with respective dry weight of plant part, from which uptake per hectare was calculated based on plant population. Fertilizer use efficiency was worked out as a factor or total economic yield from all harvests by quantity of fertilizer applied and expressed in percentage. The data were subjected to statistical analysis and are presented in the Tables 1 and 2.

Table 1

Effect of fertigation on growth and yield characters in tomato

Trreatments Plant height (cm) Drymatter production (g/plant) Leaf area Index Total chlorophyll (mg/g) Number of fruits per plant Fruit weight (g) Yield per plant (kg)
T1 79..70 164.02 2.77 0.88 50.40 66.70 4.36
T2 89.40 178.40 3.12 1.33 52.00 74.20 4.85
T3 92.80 179.20 3.39 1.39 53.90 76.10 5.10
T4 81.87 164.70 3.19 1.29 50.74 68.93 4.53
T5 101.30 182.90 3.69 1.44 56.90 82.30 5.68
T6 100.60 182.10 3.48 1.41 55.10 80.10 5.41
T7 78.20 141.20 2.25 0.80 43.70 64.30 3.80
SED 4.14 7.91 0.14 0.05 2.41 3.40 0.22
CD (0.05) 9.02 17.24 0.31 0.12 5.26 7.42 0.48

Table 2

Effect of fertigation on quality characters and nutrient uptake in tomato

Trreatments TSS 0brix Titrable acidity (%) Ascorbic acid content (mg 100-1) Nutrient uptake (Kg per ha.) Fertilizer use efficiency (Kg yield per Kg NPK)
N P K
T1 4.02 0.40 16.67 140.50 12.69 92.30 177.88
T2 4.15 0.43 17.67 150.70 13.30 100.70 204.13
T3 4.22 0.44 18.00 160.30 14.40 105.20 217.04
T4 4.06 0.40 17.04 141.70 12.80 92.73 188.19
T5 4.28 0.46 19.33 165.70 15.40 113.50 247.77
T6 4.25 0.45 19.00 163.40 15.30 110.60 233.54
T7 3.95 0.40 16.00 109.30 9.50 69.10 148.62
SED NS 0.01 0.82 6.88 0.62 4.57 9.48
CD (0.05) 0.04 1.79 15.03 1.36 9.96 20.67

Results and discussion

Growth characters

From the results it was observed that the fertigation treatments showed significant difference for all the characters studied. Higher leaf area index of 3.69 was observed by drip fertigation with water soluble fertilizers at 100 percent RDF using MAP, Multi-K and Urea (T5) and 3.48 by drip fertigaion with water soluble fertilizers at75 percent RDF using MAP, Multi-K and Urea (T6). The lowest leaf area index values of 2.25 and 2.77 were recorded by drip fertigation with water soluble fertilizers at 50 percent RDF using MAP, Multi-K and Urea (T5) and control (T1). Total chlorophyll content was significantly higher (1.44 mg per g of fresh leaves) with drip fertigation with water soluble fertilizers at 100 per cent RDF using MAP, Multi-K and Urea (T5) and it was followed by drip fertigation with water soluble fertilizers at 75 percent RDF using MAP, Multi-K and Urea (T6- 1.41 mg per g of fresh leaves) and drip fertigation with normal fertilizers at 100 percent RDF using Urea, Single super phosphate and muriate of potash (T3- 1.39 mg per g of fresh leaves). The lowest total chlorophyll content of 0.80 mg and 0.88 mg per g of leaves were noticed with T7 (drip fertigation with water soluble fertilizers at 50 percent RDF using MAP, Multi K and Urea) and T1 (Soil application of normal fertilizers at 100 percent RDF). These results are in line with the findings of (6).

Significantly higher plant height of 101.30 cm at the of final harvest was recorded by drip fertigation with water soluble fertilizers at 100 percent RDF using MAP, Multi-K and Urea (T5). It was closely followed by the treatment T6 (drip fertigation with water soluble fertilizers at 75 percent RDF using MAP, Multi K and Urea) and T3 (drip fertigation with normal fertilizers at 100 percent RDF) which recorded 100.60 cm and 92.80 cm respectively as plant height. It was also observed that the treatments T5, T6 and T3 were on par with each other. While the lowest plant height values of 78.20 cm and 79.70 were registered by T7 (drip fertigation with water soluble fertilizers at 50 percent RDF using MAP, Multi K and Urea) and T1 (control). Total dry matter production is an important economic character highly correlated with yield. In the present study it was found that the fertigation treatments had significant influence on dry matter content. The highest dry matter production of 182.90 g per plant and 182.10g per plant at the time of final harvest was recorded by the treatments T5 (drip fertigation with water soluble fertilizers at 100 percent RDF using MAP, Multi-K and Urea) and T6 (drip fertigation with water soluble fertilizers at 75 percent RDF using MAP, Multi K and Urea) and these treatments were on par with each other. The lowest dry matter production of 141.20 g per plant was observed when the plants were treated with water soluble fertilizers using MAP, Multi-K and Urea at 50 percent RDF through drip irrigation (T7). Higher plant height and dry matter production observed in the present investigation might be due to higher leaf area index which contributed for more photosynthesis and carbohydrate production which resulted in increased plant height and drymatter production. These results are in line with the findings of (3).

Yield characters

Fetigation treatments showed significant increase in yield attributing characters viz., number of fruits per plant, fruit weight (g) and yield per plant (kg). among the different treatments T5 (drip fertigation with water soluble fertilizers at 100 percent RDF using MAP, Multi K and Urea) and T6 (drip fertigation with water soluble fertilizers at 75 percent RDF using MAP, Multi K and Urea) registered higher values for number of fruits per plant (56.90 and 55.10), fruit weight (82.30 g and 80.10 g) and yield per plant (5.68 kg and 5.41 kg). It was also observed that the treatments T5 and T6 were on par with each other.it was closely followed by T3. The lowest number of fruits per plant (43.70 and 50.40), fruit weight (64.30 g and 66.70 g) and yield per plant (3.80 kg and 4.36 kg) were recorded by T7 (water soluble fertilizers using MAP, Multi-K and Urea at 50 percent RDF through drip irrigation) and T1(soil application of normal fertilizers at 100 percent RDF). Higher yield obtained with drip fertigation might be due to maintenance of favourable soil water status in the root zone, which inturn helped the plants to utilize moisture as well as nutrients more effectively from the limited wetted area. Similar reports were also made by (11), (8) and (2). The above results also supported higher fertilizer use efficiency and nutrient uptake observed by the same treatment.

Significantly higher fertilizer use efficiency was recorded when the plants were supplied with drip fertigation with water soluble fertilizers at 100 percent RDF using MAP, Multi-K and Urea (247.77 percent).and it was followed by drip fertigation with water soluble fertilizers at 75 per cent RDF using MAP, Multi-K and Urea (233.54 per cent) and drip fertigation with normal fertilizers at 100 percent RDF using Urea, single super phosphate and potash (217.04 percent). Water soluble fertilizers using MAP, Multi-K and Urea at 50 percent RDF through drip irrigation (T7) and soil application of normal fertilizers and furrow irrigation (T1) registered the lowest fertilizer use efficiency of 148.62 percent and 177.88 percent respectively. Higher fertilizer use efficiency noticed with drip fertigation might be due to higher availability of moisture and nutrients throughout the growth peiod in drip fertigation system results better uptake of nutrients and production of tomato fruits (7). Similarly, drip fertigation with water soluble fertilizers at 100 percent RDF using MAP, Multi-K and Urea and drip fertigation with water soluble fertilizers at 75 percent RDF using MAP, Multi-K and Urea recorded higher nutrient upake. The treatments T5 and T6 registered a nutrient uptake of 165.70, 15.40 and 113.50 kg NPK per hectare and 163.40, 15.30 and 110.60 kg of NPK per hectare respectively. It was followed by drip fertigation with normal fertilizers at 100 percent using Urea, single super phosphate and muriate of potash (160.30, 14.40 and 105.20 kg of NPK per hectare). The lowest nutrient uptake of 109.30, 9.50 and 69.10 kg of NPK per hectare and 140.50, 12.69 and 92.30 kg of NPK per hectare was registered by water soluble fertilizers using MAP, Multi-K and Urea at 50 percent RDF (T7) and soil application of normal fertilizers and furrow irrigation (T1). The increase in nutrient uptake by the fertigation treatments might be due to better availability of nutrients in root zone as a result of frequent application of fertilizers through drippers and reduced loss of nutrients through leaching by precise application of nutrients near to the root zone in fertigation compared to soil application (12).

Quality characters

Present study showed significant difference in titrable acidity and ascorbic acid content of tomato fruits. While, non-significant difference was noticed by TSS of tomato fruits. Higher titrable acidity (0.46 per cent and 0.45 per cent) and ascorbic acid (19.33 mg per 100g of fruit pulp and 19.00 mg per 100g of fruit pulp) were recorded by T5 (drip fertigation with water soluble fertilizers at 100 percent RDF using MAP, Multi K and Urea) and T6 (drip fertigation with water soluble fertilizers at 75 percent RDF using MAP, Multi K and Urea). It was followed by drip fertigation with normal fertilizers at 100 percent RDF using Urea, single super phosphate and muriate of potash (T3-18.00 mg per 100g of fruit pulp). The lowest titrable acidity of 0.40 percent and 0.40 percent and ascorbic acid content of 16.00 mg per 100 gram of fruit pulp and 16.67 mg per 100 gram of fruit pulp were recorded by water soluble fertilizers using using MAP, Multi-K and Urea at 50 percent RDF through drip irrigation and soil application of normal fertilizers and furrow irrigation (T1). The results revealed that the higher acidity and ascorbic acid content observed in tomato fruits might be due to better availability of K to the plants (1). Among the different treatments T5 (drip fertigation with water soluble fertilizers at 100 percent RDF using MAP, Multi-K and Urea), T6 (drip fertigation with water soluble fertilizers at 75 percent using MAP, Multi-K and Urea) and T3 (drip fertigation with normal fertilizers at 100 percent using Urea, single super phosphate and muriate of potash) registered the highest TSS value of 4.28 0 birx, 4.25 0 birx and 4.22 0 birx. The lowest TSS values of 3.95 0birx and 4.02 0birx were registered by water soluble fertilizers using MAP, Multi-K and Urea at 50 percent RDF through drip irrigation (T7) and soil application of normal fertilizers and furrow irrigation (T1). Higher TSS content observed by fertigation treatments might be due to when water was applied in lesser amount through drip system, sugar imported by fruits via., phloem become concentrated which help in increasing TSS content of fruits (4,5).

From the results it was inferred that when the fertilizers were frequently applied through drip irrigation fertilizer use efficiency has greatly increased. Increased fertilizers use efficiency prevents nutrient loss through leaching and application of fertilizers in small quantity by several split doses encourage more efficient nutrient uptake. Higher fertilizer use efficiency and nutrient uptake by the plants ultimately results in increased vegetative vigour and yield.