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Int.J.Curr.Microbiol.App.Sci (2019) 8(9): 282-292 International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 8 Number 09 (2019) Journal homepage: http://www.ijcmas.com Original Research Article https://doi.org/10.20546/ijcmas.2019.809.034 Soil Moisture Distribution under Different Emitters and Fertigation Levels and Its Effect on Tomato Yield P.C. Pradhan* and B. Panigrahi Odisha University of Agriculture and Technology, Bhubaneswar, Odisha-751003, India *Corresponding author ABSTRACT Keywords Pressure compensating emitter, Nonpressure compensating emitter, Emission uniformity Article Info Accepted: 15 August 2019 Available Online: 10 September 2019 Field experiments were conducted in sandy clay loam soils to assess the effect of different levels of fertigation and emitter types on hydraulics of drip irrigation, movement of soil moisture distribution and yield of tomato. The three levels of fertigation i.e. fertigation with 100% recommended dose of fertiliser (RDF), 80% RDF and 60% RDF and four types of emitters viz. online pressure compensating (online pc), online non pressure compensating (online npc), inline pressure compensating (inline pc) and inline non pressure compensating (inline npc) emitters were tried in split plot design with three replications. The fertigation levels were allocated to main plots and the emitter types were assigned to sub plots. Water soluble fertilisers viz. urea, urea phosphate with SOP and sulphate of potash were used for fertigation. The emission uniformity test showed better results for pc emitters over npc emitters. The soil moisture distribution under various emitters indicated the highest moisture content below the emitters and it decreases as distance from emitter increases both horizontally and vertically. The treatment with 100% fertigation through online pc emitter based drip system results the maximum fruit tomato yield of 59.8 t/ha since this treatment maintained higher soil moisture contents both in horizontal and vertical direction below the emitter than all other treatments. Further the said treatment had the highest value of emission uniformity (99.04%) amongst all the treatments that have caused uniform distribution of water in the root zone resulting higher yield. Introduction The availability of water for irrigation is diminishing day by day throughout the world due to increasing demand from other sectors viz. industrial, urban and domestic uses. This has resulted in an increased threat to food security. Hence, irrigation methods are vital for efficient utilisation of this increased scar resources. Deficit irrigation may become unavoidable in future due to scarcity of irrigation water. Though India has been expanding the irrigated area since independence but the irrigation efficiency has not achieved more than 40%. The surface irrigation practices such as check basin, furrow are inefficient, causing various problems including salinity, runoff and 282 Int.J.Curr.Microbiol.App.Sci (2019) 8(9): 282-292 contamination of water bodies. Therefore there is urgent need of maximising production per unit of water by adopting advanced method of irrigation like micro irrigation. Amongst different types of micro irrigation, drip irrigation has proved its superiority over other methods of irrigation due to direct application of water and fertiliser in root zone area of crop. In India the potential of drip irrigation is about 27 million ha as per report of task force on micro irrigation. Water saving and fertiliser saving in drip irrigation is to the tune of 39-100% and 40-60%, respectively. Drip irrigation is an advanced method of irrigation in which water is applied in the crop root zone in order to meet the crop water requirement and maintain optimum soil moisture around the plants (Devi Aruna and Selvaraj, 2013). Water is applied directly at the crop root zone without wetting the entire surface area. This causes considerable saving of irrigation water (Bafna et al., 1993). In addition to saving irrigation water, drip irrigation has other added advantages like better crop survival, higher yield and improved crop quality (Martin et al., 1994; Prasad et al., 2003; Kumar et al., 2005; Sharma and Kumar, 2007). Drip irrigation has been practised in a number of vegetables. Field experiment was conducted with drip irrigation in okra crop by Tiwari et al., (1998) who reported higher fresh yield and benefit cost ratio (1.77) under drip irrigation as compared to furrow irrigation. Tiwari et al., (2003) also conducted field experiments with drip and furrow irrigation in cabbage crop and reported 54% higher yield and 40% saving of costly irrigation water through drip irrigation compared to furrow irrigation. Antony and Singhdhupe (2004) tested the impact of drip irrigation on growth and yield of capsicum and found the maximum yield and growth of the crop in drip irrigation at 100% evapotranspiration rate in loamy soil of humid sub tropical region. Field experiment with drip and furrow irrigation in brinjal and capsicum were conducted by Mohanty et al., (2016) and Paul et al., (2013), respectively in Odisha, India. It was reported that drip system gave the maximum fruit yield, yield attributing parameters and water use efficiency as compared to furrow irrigation. They reported considerable saving of irrigation water with yield improvement in drip irrigation as compared to conventional furrow irrigation. In drip irrigation, the type of emitter plays a crucial role in uniform application and distribution of water in the crop root zone. Field experiment conducted by Capra and Scicolone (2004) with different types of emitters and filters for use of waste water by drip irrigation revealed that inline emitters and gravel filter were good combination over vortex emitter and screen filter. Tayel et al., (2013) tried eight different types of emitters with reclaimed water and recommended pressure compensating emitters of short flow path for getting higher hydraulic performance of drip irrigation. Pei et al., (2014) conducted study with online pressure compensating and online non-pressure compensating emitters and recommended online pressure compensating emitters for practical utilisation. Drip irrigation system can easily be used for fertigation through which crop nutrient can be applied in real time. In drip fertigation, the water soluble fertilisers are applied to the root zone of plants which enhances application efficiency due to small quantity of fertilisers applied in frequent intervals. Fertigation reduces the fertiliser requirement and at the same time increases the yield in most of the vegetables. Drip fertigation on Assam lemon in alluvial sandy loam soils of Jorhat gave the maximum benefit cost ratio of 4.17 (Barua and Hazarika, 2014). Works on fertiliser use efficiency (FUE) in drip-fertigation system have been done by several researchers. Increase of FUE was observed with decrease 283 Int.J.Curr.Microbiol.App.Sci (2019) 8(9): 282-292 of fertigation level in the research works conducted by Rajan et al., (2014) and Gupta et al., (2014). Rajan et al., (2014) recorded highest FUE when fertigation was done at 50% of recommended dose in tomato whereas Gupta et al., (2014) recorded maximum FUE in tomato when fertigation was maintained at 60% of recommended dose. Water and nutrient movement in soil under drip irrigation is influenced by the type of soil and nutrient application (Thabet and Zayani, 2008). The moisture distribution patterns in the soil profile in drip fertigation are also governed by design parameters viz. location of drippers, application rates, frequency and amount of irrigation water which need to be investigated properly. The field study by Moncef et al., (2011) in tomato and watermelon plots irrigated through drip irrigation with different emitter discharge rates inferred that wetting front depth was highly correlated with lateral spread of wetting front. Wetting front or wetted bulb coordinates in soil under surface drip irrigation were measured by Molavi et al., (2012) for loamy and sandy loam soils with 2 different emitter discharges of 2 and 4 lph by using the trenching method. Kumar et al., (2015) investigated the effect of dripper discharge at different system operating pressures on spatio-temporal soil moisture movement. The value of moisture contents varied significantly under different operating pressure and at different locations below and away from the dripper. The present study was undertaken (i) to assess the hydraulics of different types of emitters/drippers, (ii) to study the moisture distribution pattern below the emitters and (iii) to find out the impact of soil moisture distribution on yield of tomato. Materials and Methods Details of experimental site The field experiments were conducted at farmer’s field for two consecutive winter seasons of 2014 and 2015. The study site (200 15’N latitude and 860 10’E longitude) is located in Jagatsinghpur region of the state of Odisha, India. The region is characterised by hot and humid climate. The normal annual rainfall of study site is 1514 mm distributed over 66 rainy days. The rainfall occurs mainly due to South –West monsoon from mid June to mid October. The average maximum and minimum temperatures of the area are 32.5 and 23.40C, respectively and average relative humidity varies from 67 to 84%. The experimental site had well drained sandy clay loam (75.8 % sand, 2% silt and 22.2% clay) soil having pH of 6.08. The bulk density of soil was 1.32 gm/cc and electrical conductivity was 0.05 dS/m. The soil of the site had available N of 288.5 kg/ha (medium), P of 13.05 kg/ha (medium) and K of 132.9 kg/ha (medium). The field capacity and permanent wilting point of soil was found to be 24.6% and 7.4%, respectively on weight basis. Experimental design The field experiment was laid out in split plot design with twelve treatment combinations replicated thrice. The three fertigation levels viz.F1 =100% recommended dose of fertilisers (RDF), F2 = 80% RDF and F3 = 60% RDF were allocated to main plots and four types of emitters viz. E1 = online npc, E2 = online pc, E3 = inline npc and E4 = inline pc were allocated to sub plots. Based on soil test report and regional recommendations, the recommended dose of fertiliser (RDF) was fixed at 125, 75 and 100 kg/ha N, P2O5 and K2O, respectively. The drippers/emitters were spaced equally i.e. 40 cm apart in all four types of emitters. The discharge capacity of each emitter was 2 lph. The various treatments are defined in Table 1. 284 Int.J.Curr.Microbiol.App.Sci (2019) 8(9): 282-292 Drip fertigation system The drip irrigation system was installed in a plot of 65 m x 32 m. The drip irrigation system had one hydrocyclone filter, one disk filter and ventury injector. The main plot was divided into 3 sub-plots catering to need of three replications. Each subplot was again divided to 12 plots of size 10 m x 5 m each. PVC pipes of 50 mm and 40 mm were used as main pipe and sub-main pipe and 12 mm lateral pipes were used for distribution network Tomato seedlings of 30 days old were planted on 4 January 2014 and 3 January 2015. Gross and net plot sizes were 10.0 m x 4.8 m and 8.4 x 2.4 m, respectively. The crop in all treatments had row to row spacing of 1.2 m and plant to plant spacing of 0.4 m. The single lateral lines of 12 mm diameter low density polyethylene (LDPE) pipes were laid along the crop rows. The spacing between two adjacent laterals within plot was 1.2 m and spacing between emitters in each lateral were 0.4 m. The fertigation was applied in four growth stages of the crop i.e. crop establishment (20 days), crop development stage (30 days), mid season (30 days) and late season (30 days). Fertigation was done using water soluble grades of urea (46:0:0), urea phosphate with SOP (18:18:18) and sulphate of potash (0:0:50) through ventury injector at weekly intervals as shown in Table 2. The amount of water (lit/day) applied through drip irrigation system to each plant was calculated using following equation (Pawar et al., 2013) V = ETo× Kc× Ls× Es× Ws/ η (1) Kc = crop coefficient; Ls and Es = lateral and emitter spacing taken as 1.2 and 0.4 m, respectively, Ws = percentage wetted area factor and η = water application efficiency of the system assumed as 90% for all treatments and so in Eq. (1), while calculating the value of V, we use η as 0.90 for all treatments. The values of Kc of tomato for various growth stages were taken as 0.45, 0.75, 1.15 and 0.8 and values of Ws were assumed as 0.3, 0.45, 0.6 and 0.8 for crop establishment, crop development, mid season and late season stages, respectively (Panigrahi et al., 2011). Volume of water so calculated was divided by the emitter/dripper discharge and the time of operation of drip system was then calculated. In drip system water was applied on alternate day. Hence while calculating values of V of a particular day, sum of two previous days ETo values was taken as ETo value in Eq. (1) and the amount of water so given as irrigation by drip system was used for plant consumption for 2 days. Weather parameter during crop growing period Daily values of maximum and minimum temperature (C), maximum and minimum relative humidity (%), pan evaporation (mm) and wind speed (km/h) during the crop growth period in 2014 and 2015 are shown in Figure 1(a) and (b), respectively. There was no rainfall during the crop growing period in 2014 and 2015. Emission uniformity (Eu) The emission uniformity was studied to find out the emitter flow variation along the drip pipe line (Keller and Karmeli, 1974) which is defined as: where, V = volume of water applied (lit/day/plant), ETo,= reference crop evapotranspiration (mm/day) calculated by Penman-Monteith method (Allen et al., 1988), 285 (2) Int.J.Curr.Microbiol.App.Sci (2019) 8(9): 282-292 where, Eu = emission uniformity, Cv = manufacturer’s coefficient of variation, n = number of emitters per plant (taken as 1 in this study), qmin = minimum emitter discharge rate for the minimum pressure in the section and qavg = average emitter discharge rate. Discharge from each emitter was collected in plastic beaker (catch can) for 30 minutes interval. The volume of water so collected was measured with help of measuring cylinder. These measured quantities were used for calculation of discharge which are used in Eq. (2) for computation of Eu. The values of Eu so calculated along with the statistical test (ANOVA) are shown in Table 3. Hydraulics of drip emitters and soil moisture movement with the statistical analysis for all treatments is shown in Table 4. Results and Discussion Different fertigation levels failed to cause significant variation in emission uniformity. However, dripper/emitter types differed significantly for Eu values. The online pc emitter recorded the maximum emission uniformity of 98.42 % followed by inline pc emitters with Eu value of 95.73 %. Online pc emitters recorded 2.8% more Eu value over inline pc emitters. Similarly online npc emitters recorded 4.9% more emission uniformity value than inline npc emitters. Pressure compensating emitters performed better than npc emitters (Table 3). Spatial soil moisture distribution Field experiment were done to study hydraulics of emitters and soil moisture movement under drippers for various treatments and finally to study their effect on tomato yield. The soil moisture movement was observed at operating pressure of 0.8 kg cm-2.The wetting front was recognised by the colour difference of wetted zone and surrounding soils. The horizontal and vertical wetting distances on the wetted face were recorded by measuring scale. However, the soil moisture contents were measured by a digital soil moisture meter at 0, 10, 20, 30, 40 cm distance away from the dripper and at different depths (10 cm interval upto 40 cm) below the dripper after 1 hour of operation. The readings were taken after 24 hours of drip operation. Yield of tomato Spatial distribution of soil moisture was significantly different at different locations in horizontal and vertical direction from the dripper. The highest value of soil moisture content (24.5%) was observed below the dripper which decreased as the distance increased from the dripper. The soil moisture distribution under different emitters for various treatments were plotted taking into consideration the moisture content at 10 cm interval in both horizontal and vertical direction and using the SURFER software. It is observed that there is more uniform distribution of moisture under pc emitters as compared to npc emitters. The soil moisture distribution for different treatments under different types of emitters is shown in Figure 2. Effect of fertigation and emitters on soil moisture distribution and impact on yield Yield of tomato were recorded for each treatment. The ripe tomatoes were harvested on alternate day during 2nd to 4th week of April of each year. The pooled data of yield along Both fertigation level and emitter types exerted significant influence on fruit yield of tomato. 286 Int.J.Curr.Microbiol.App.Sci (2019) 8(9): 282-292 Table.1 Notations of various treatments adopted in the study Symbol for treatment combination F 1 E1 F2 E1 F 3 E1 F 1 E2 F 2 E2 F3 E2 F 1 E3 F 2 E3 Sl. No. 1 2 3 4 5 6 7 8 9 10 11 12 Treatment details 100% RDF with online npc emitters 80% RDF with online npc emitters 60% RDF with online npc emitters 100% RDF with online pc emitters 80% RDF with online pc emitters 60% RDF with online pc emitters 100% RDF with inline npc emitters 80% RDF with inline npc emitters 60% RDF with inline npc emitters 100% RDF with inline pc emitters 80% RDF with inline pc emitters 60% RDF with inline pc emitters F3E3 F1 E4 F 2 E4 F 3 E4 F- Fertigation, E - Emitters Table 2. Fertigation schedule in tomato Stage of Crop Duration Fertilizer Grade Crop establishment Crop development Mid season 20 days 18:18:18 Weekly scheduled per ha (kg) 55.70 30 days Late season 30 days 18:18:18 46:0:0 18:18:18 46:0:0 0:0:50 31.25 16.25 31.25 11.00 50.00 30 days Table.3 Emission uniformity of emitters as affected by emitters and fertigation Treatment 100% RDF (F1) 80% RDF (F2) 60% RDF (F3) Mean SEm() CD (P=0.05) Online npc (E1) 93.51 93.47 93.52 93.50 Online pc (E2) 99.04 98.40 97.82 98.42 Inline npc (E3) 89.78 89.15 88.67 89.20 F 0.39 NS E 0.26 0.78 F×E 0.64 NS F x E = Fertigation levels in same or different types of emitters E x F = Emitter types in same levels of fertigation 287 Inline pc (E4) 94.66 96.82 95.71 95.73 E×F 0.45 NS Mean 94.25 94.46 93.93 94.21 Int.J.Curr.Microbiol.App.Sci (2019) 8(9): 282-292 Table.4 Effect of fertigation levels and emitter types on fruit yield (t/ha) of tomato (pooled over two years) Treatment Online npc(E1) Online pc Inline npc (E2) (E3) Fruit Yield, t/ha Inline pc (E4) Mean 57.14 59.82 55.22 57.72 57.47 55.04 57.74 54.31 56.26 55.84 46.48 48.64 45.78 47.62 47.13 52.89 55.40 51.77 53.87 53.48 F E F×E E×F SEm() 0.15 0.09 0.23 0.17 LSD (P=0.05) 0.58 0.27 0.81 0.46 100% RDF (F1) 80% RDF (F2) 60% RDF (F3) Mean Minimum Temp. Minm. Relative Humidity Pan Evaporation 12 80 10 60 8 40 6 20 4 2 Wind Velocity, km/h and Pan Evaporation, mm Maximum Temp. Maxm. Relative Humidity Wind Velocity 0 1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93 97 101 105 109 0 Temperature, 0Cand Relative Humidity,% 100 Fig.1 (a) Variation of meteorological parameters during crop growth period in 2014 Days after planting Fig. 2(a) Variation of meteorological parameters during crop growth periods in 2014 Fig.1(b) Variation of meteorological parameters during crop growth period in 2015 288 Int.J.Curr.Microbiol.App.Sci (2019) 8(9): 282-292 Fig.2 Soil moisture distribution under different emitters and fertigation level Online npc dripper with 100% R Online npc dripper with 100% RD Online pc dripper with 100% RDF F Online pc dripper with 100% RDF D Online pc dripper with 100% RD Online pc dripper with 100% RDF Inline npc dripper with 100% RDF F F Inline pc dripper with 100% RDF Online npc dripper with 80% RDF Inline npc dripper with 80% RDF Inline pc dripper with 80% RDF Online pc dripper with 60% RDF Inline npc dripper with 60% RDF 289 Online pc dripper with 80% RDF Online npc dripper with60% RDF Inline pc dripper with 60% RDF Int.J.Curr.Microbiol.App.Sci (2019) 8(9): 282-292 Among fertigation levels, 100% RDF fertigation recorded maximum fruit yield of 57.47 t/ha and proved significantly superior to 80 and 60% RDF levels (Table 4). Fertigation at 100% RDF level recorded 2.9 and 21.9% higher fruit yield over 80 and 60% RDF levels, respectively. The results are in conformity with findings of Rajput and Patel (2002), Hebbar et al., (2004) and Rajaraman et al., (2013) who reported the maximum fruit yield of onion, tomato and okra, respectively at 100% RDF with drip irrigation at New Delhi, Bangalore and Thoppur (Tamil Nadu), respectively. emission uniformity among four types of emitters showed that online pc emitters recorded 5.3% more value over online npc emitters. Similarly inline pc emitters recorded 4.35% more emission uniformity value over inline npc emitters. It was observed that highest soil moisture content was recorded below emitters and decreased horizontally and vertically as distance from drippers increases. The maximum soil moisture content of 24.5% observed in case of treatment F1E4 followed by F3E2. The maximum fruit yield of 59.8 t/ha was also recorded in case of 100% fertigation through online pc emitters (F1E2). Hence, the drip fertigation through online pressure compensating emitters is recommended for tomato for maximum productivity. Among emitter types online pc proved the best with fruit yield of 55.4 t/ha and superior to all other emitter types. It recorded 2.8, 4.7 and 7.0 % higher fruit yield than inline pc, online npc and inline npc, respectively. The interaction effect of fertigation levels and emitter types on fruit yield of tomato was found significant. The 100% fertigation levels applied through online pc proved the best with fruit yield of 59.82 t/ha and proved superior to other combinations of fertigation levels and emitter types. In all fertigation levels, online pc proved the best with fruit yield of 59.82, 57.74 and 48.64 t/ha at 100, 80 and 60% fertigation levels (Table 4). The increase in yield for pressure compensating emitters was due to better emission uniformity of dripper which consequently resulted uniform application and uptake of water and fertilizer at root zone area of each plant. References Allen, R.G., Pereira, L.S., Raes, D and Smith, M. (1988). Crop evapotranspirationGuidelines for Computing Crop Water Requirement, FAO Irrigation & Drainage Paper 56. Antony, E. and Singhdhupe, R.B. (2004). Impact of drip and surface irrigation on growth, yield and WUE of capsicum (Capsicum annum L.). Agric. Water Mgt., 65:121-132. Anonymous, (2013). Orissa Agricultural Statistics, Directorate of Agriculture and Food Production. Bafna, A.M., Daftardar, S.Y., Khade, K.K., Patel, P.V. and Dhotre, S.(1993). Utilisation of nitrogen and water by tomato under drip irrigation system. Water Management, 1(1):1-5. Barua, P. and Hazarika, H. (2014). Studies on fertigation and soil application methods along with mulching on yield and quality of Assam Lemon. Indian J. Horticulture, 71 (2):190-196. Capra, A. and Scicolone, B. (2004). Emitter and filter tests for waste water reuse . Moreover, the pc emitters maintained higher soil moisture contents in the root zone of plant than npc which might have caused higher tomato yield. In conclusions, the use of an appropriate drip irrigation system, fertigation, better emission uniformity and after all uniform soil moisture distribution give better yield of tomato. The 290 Int.J.Curr.Microbiol.App.Sci (2019) 8(9): 282-292 Agric Water Manag, 68:135-149. Devi Aruna K. and Selvaraj, P.K. (2013). Moisture distribution and fertiliser mobility under drip fertigation in mulberry. Journal of Soil and Water Conservation, 12: 123-129. Gupta, A.J., Chatoo, M.A. and Singh, L (2014). Drip irrigation and fertigation technology for improved yield, quality, water and fertiliser use efficiency in hybrid tomato. J. Agri Search (2):94-99 Hebbar, S.S, Ramachandrappa, B.K., Nanjappa, H.V. and Prabhakar, M. (2004). Studies on NPK drip fertigation in field grown tomato (Lycopersicon esculentum Mill).. Europe J Agron. 21: 117–127. Keller, J. and Karmeli, D. (1974). Trickle irrigation design parameters. Trans ASAE 17(4)687-684. Kumar, S., Sharma, I.P., and Raina, J. N. (2005). Effect of levels and application methods of irrigation and mulch materials on strawberry production in north-west Himalayas. J. Indian Soc. Soil Sci. 53: 60-65. Kumar, M., Rajput, T.B.S and Patel, N. (2015). Effect of dripper discharge on spatio-temporal movement of water in soil under drip irrigation. Journal of Soil & Water Conservation 14(2): 141-145. Martin, G.C., Ferguson, L. and Palito, V.S. (1994). Flowering, pollination, fruiting, alternate bearing and abscission . Olive Production Manual.pp. 33-54. Moncef, H., Hedi, D. and Abdessatar, H. 2011. An empirical concise approach to predict the maximal wetted soil depth under trickle irrigated crops. AmericanEurasian Journal of Agriculture and Environment Science. 11 (3): 334-340. Molavi1, A., Sadraddini, A., Nazemi, A.H. and Fakheri, F.A. 2012. Estimating wetting front coordinates under surface trickle irrigation. Turk J Agric For. 36: 729-737 Mohanty, B., Senapati, S.C., Sahu, A.P. and Panigrahi, B. (2016). Yield, water use efficiency and economic evaluation of drip irrigated brinjal (Solanum melongena l.) as affected by single and double inlet laterals and sub main sizes. International Journal of Agriculture Sciences, Vol. 8, Issue 48: 2030-2032. Prasad, R. N., Bankar, G. J. and Vashishtha, B. B. (2003). Effect of drip irrigation on growth, yield and quality of pomegranate in arid region. Indian J. Hort. 60: 140-42. Panigrahi, B., Ray, D.P. and Panda, S.N. (2011). Water use and yield response of tomato as influenced by drip and furrow irrigation . International Agricultural Engineering Journal, Vol. 19 (1): 19-30. Paul, J.C., Mishra, J.N., Pradhan, P.L. and Panigrahi, B. (2013).Effect of drip and surface irrigation on yield, water use efficiency and economics of capsicum under mulch and non-mulch conditions in Eastern Coastal India. European Journal of Sustainable Development, 2(1): 99-108. Pawar, D., D, Dingre, S.K, Shinde, M.G and Kaore, S.P, (2013). Book on ‘Drip Fertigation for Higher Productivity’, pp120, MPKV, Rahuri, Maharashtra. Pei, Y., Li, Y., Liu, Y., Zhou, B., Li, Y. and Jiang, Y. (2014). Eight emitters clogging characteristics and its suitability under on site reclaimed water. Irrigation Science, 32: 141-157. Rajput, TBS., Patel, N. (2002). Water and nitrate movement in drip-irrigated onion under fertigation and irrigation treatments. J Agric Water Management. 79: 293–311. Rajaraman, G. and Pugalendhi, L. (2013). Potential impact of spacing and fertiliser level on flowering, productivity and economic viability of hybrid Bhendi (Abelmoschus esculentus L.) under drip fertigation system. 291