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B. RAMANJANEYA, K.S. KUMAR*, V. PRAVEEN RAO, V. RAMULU AND G. SHWETHA
College of Agriculture, Professor Jayashankar Telangana State Agricultural University, Rajendranagar, Hyderabad– 500 030.
Greenhouse tomato production in semiarid tropical climate suffers from sustainable yields due to lack of optimized irrigation and fertigation levels. The experiment was conducted in a naturally ventilated greenhouse with 3 levels of irrigation and fertigation in a randomized block design. The irrigation and fertigation levels are replicated thrice to keep the error degree of freedom in limits. The experimental soil was sandy clay loam in texture with low available nitrogen and high available phosphorous and potassium. The results of the study indicated that the highest lycopene content of tomato at initial and final pickings (3.47 mg 100 g-1 ), (6.57 mg 100 g-1) was recorded in GHC + Drip irrigation (1.0 Epan) + 125% N as compared to the rest of the treatments followed by lowest( 1.40 mg 100 g-1), (3.53 mg 100 g-1) in NGHC + Control (100% N + surface irrigation) = IW/CPE @ 5 cm. Total NPK uptake in tomato fruits and haulms at 30, 60 and 90 DAT and at harvest was significantly superior in GHC + Drip irrigation (1.0 x Epan) + 125% N, over the rest of treatments. The lowest NPK uptake was reported in the control (NGHC + Control (100% N + surface irrigation = IW/CPE @ 5 cm). From the study it is inferred that the existing green house micro climate and optimized irrigation and fertigation level are suitable for tomato production.
Dry matter, Fertigation, Greenhouse tomato, Nutrient uptake
Tomato (Lycoperiscon esculantum, L.) is a major vegetable crop that has achieved tremendous popularity in the greenhouse over the last century. Tomatoes, besides being tasty, are useful for maintaining health due to good source of vitamin A and C. Cooked tomatoes and tomato products are the best source of lycopene, which is a powerful antioxidant and helps in preventing the development of cancer. Hence, the crop is gaining importance both in developing and developed countries in general and India in particular. Efforts are being made to develop the quantity and quality of produce by adapting controlled environment, as the yield and quality are poor in open climate due to low winter temperatures and frost attack. In this direction, Greenhouse is the best alternative for maintaining the quantity, quality and uniformity of fruit size which is free from dust, insect, pest and diseases.
Water is an important input for greenhouse tomato, several researchers have concluded that drip irrigation can be used as an efficient input under protected cultivation system. The use of drip irrigation in the greenhouse not only saves water but also gives better plant
yield and quality with reduced humidity build up due to precise application of water to the root zone (Papadopoulos, 1992). In greenhouse tomato, due to indeterminate nature of the crop, both vegetative and reproductive stages overlap and hence, plant requires nutrients even up to fruit ripening stage for better growth and size. In this context, fertigation may be very effective for maintaining the sustainable yield.
Telangana state formed with periphery of ten districts is having a net cultivated area of 4.0 M ha, of which 60 per cent is rain fed. The state principally falls under semi-arid tropical climate. The soils are of predominantly red earths most suitable for the production of horticultural crops. With diversified three agro-climatic zones, horticultural production and productivity accounts to be 10.86 lakh ha and 121.57 lakh Metric tonnes, respectively. The average annual rainfall is 850 mm, receiving major share from South-West monsoon. With prevailing semi-arid tropical climate, there is a potential scope for greenhouse cultivation, especially for remunerative vegetable and export oriented crops. Keeping in view of the advantages of this technology, there is a need to develop a holistic development of horticulture in the state
by utilizing the financial assistance from the National Horticultural Mission, Government of India and also by earmarking sufficient funds from the state budget.
The field experiment was conducted during rabi 2014-2015 at Horticultural garden Department of Horticulture, College of Agriculture, Rajendranagar, Professor Jayashankar Telangana State Agricultural University, Hyderabad on a sandy clay loam soil, alkaline in reaction and non-saline, low in available nitrogen, high in available phosphorous and available potassium, the recommended dose of fertilizer 150-60-60 kg NPK ha-1, entire dose of P and K was applied as basal before sowing and N applied as fertigation in 6 splits of equal doses at 10 days interval from 15 days after sowing (DAT). The experiment was conducted in a randomized block design with ten treatments of drip irrigation schedules viz., drip irrigation GHC + Drip irrigation (0.75 Epan) + 100% N (T1), GHC + Drip irrigation(0.75 Epan) + 125% N (T2), GHC + Drip irrigation (0.75 Epan) + 150% N (T3), GHC+ Drip irrigation (1.0 Epan) + 100% N (T4), GHC + Drip irrigation (1.0 Epan) + 125% N (T5), GHC + Drip irrigation (1.0 Epan) + 150% N (T6), GHC + Drip irrigation (1.25 Epan) + 100% N (T7), GHC + Drip irrigation (1.25 Epan) + 125% N (T8) GHC + Drip irrigation(1.25 Epan) + 150% N (T9), NGHC + Control (100% N + surface irrigation = IW/CPE @ 5 cm) (T10). Where GHC (Greenhouse condition), NGHC (Non Greenhouse condition).
Both irrigation and nitrogen levels significantly influenced the dry matter production of tomato (Table 1). Maximum dry matter production was recorded with GHC + Drip irrigation (1.0 Epan) + 125% N and it was significantly superior over all other treatments. Dry matter production at 30 DAT was found to be on par with GHC
+ Drip irrigation (1.0 Epan) + 150% N. At all growth stages, the lowest dry matter production was recorded in NGHC + Control (100% N + surface irrigation = IW/ CPE @ 5 cm). The higher dry matter with GHC + Drip irrigation(1.0 Epan) + 125% N could be attributed to increase in plant height coupled with more leaf area resulted in enhanced carbohydrate synthesis which ultimately lead to higher dry matter accumulation. These results corroborate with findings of Viswanatha et al.,
(2000) and Tiwari et al., (1998), and Hebbar et al., (2004) who reported that the total dry matter production in tomato was higher in drip irrigation (165.8 g plant-1) over furrow irrigation (140.2 g plant-1).
Data pertaining to nitrogen uptake at 30, 60, 90 DAT and at harvest as influenced by different Drip irrigation and fertigation levels (Table 2). The analysis of nutrient uptake was partitioned into haulm and fruit separately as the nutrients translocate at the time harvest.
At all the crop growth stages, significant differences were observed with regard to nitrogen uptake due to different irrigation and fertigation levels. Maximum uptake of nitrogen was observed with GHC + Drip irrigation (1.0 x Epan) + 125% N and it was significantly superior over the rest of the treatments due to more production of dry matter. GHC+ Drip irrigation (1.0 x Epan) + 150% N resulted in on par with GHC + Drip irrigation (1.0 x Epan) + 125% N. The lowest N uptake was obtained in NGHC + Control (100% N + surface irrigation) = IW/CPE @ 5 cm. This might be due to frequent application of irrigation with fertigation, N was readily available and effectively utilized by the crop as a result of direct contact with the root system. Moreover, negligible N loss through leaching in drip irrigation treatments might have taken place, where in the applied nutrients did not move beyond 30 cm soil depth. The results are in agreement with the studies on optimum N uptake in tomato fruits under drip irrigation by Singandhupe et al., (2003).
Data on Phosphorous uptake at 30, 60, 90 DAT and at harvest as influenced by different treatments was tabulated in Table 3. Uptake was divided into haulm and fruit at harvest. There were significant differences in Phosphorous uptake due to different irrigation and fertigation levels at all the crop growth stages. Among the various treatments, significantly highest uptake was recorded in GHC + Drip irrigation (1.0 x Epan) + 125% N. However, GHC+ Drip irrigation (1.0 x Epan) + 150% N, found to be on par with GHC + Drip irrigation (1.0 x Epan) + 125% N. Lowest Phosphorus uptake was obtained in NGHC + Control (100% N + surface irrigation) = IW/ CPE @ 5 cm at all the crop growth stages. The higher uptake of P with GHC + Drip irrigation (1.0 x Epan) + 125% N when compared to other treatments might be
due to maintenance of optimum soil moisture for bacterial growth, increased availability of nutrients which in turn enhanced dry matter production, higher yield and more nutrient uptake (Locascio et al. 1989).
Data related to potassium uptake at 30, 60, 90 DAT and at harvest as influenced by different treatments was tabulated in Table 4. At harvest, the uptake was divided into haulm and fruit.
Potassium (K) uptake differed significantly among the treatments at all the crop growth stages due to different irrigation and nitrogen levels. Highest uptake of potassium was observed with GHC + Drip irrigation (1.0 x Epan) + 125% N and it was significantly superior over rest of the treatments. The lowest K uptake was obtained in NGHC
+ Control (100% N + surface irrigation) = IW/CPE @ 5 cm.
Better uptake of N, P and K under GHC + Drip irrigation (1.0 x Epan) + 125% N might be due to higher dry matter production. This could be attributed to the synergistic effects of higher water content and available nutrients in the soil and crop growth. These results are is conformity with the findings of Gupta et al. (2010), where in similar trend.
• Drip irrigation scheduled at 1.0 E pan with 125% N in the greenhouse is recommended for tomato production in southern agro-climatic conditions of Telangana as it maintained high dry matter and high nutrient uptake.
• GHC + Drip irrigation (1.0 Epan) + 125% N shows better results when compared with surface irrigation.