International Journal of Agriculture and Crop Sciences. Available online at www.ijagcs.com IJACS/2014/7-4/185-190 ISSN 2227-670X 2014 IJACS Journal Evaluation Of Comparative Water Use Efficiency Of And Irrigation Systems For Off-Season Vegetables Under Plastic Tunnel Mazher Iqbal 1, Fayyaz-ul-Hassan Sahi 2 Tamoor Hussain* 1, Nasrullah Khan Aadal 1, Muhammad Tariq Azeem 1 and Muhammad Tariq 1 1. Barani Agricultural Research Institute, Chakwal, Pakistan. 2. Department of Agronomy, PMAS- Arid Agriculture University, Rawalpindi, Pakistan. Corresponding author email: saleemkhansaleem90@gmail.com ABSTRACT: Three vegetables (tomato, cucumber and bell pepper) were grown in plastic tunnels as offseason crops for three years from 2009-10 to 2011-12 to evaluate comparative water use efficiency. A permanent tunnel of 80 x 27 x 10 ft was erected. Irrigation was applied though drip and furrow irrigation systems. Each crop was planted on 20 x 27 ft under drip irrigation and on 20 x 9 ft under furrow irrigation system. Water use efficiency was calculated as ratio of total yield (kg) to total water consumed by the crop (m 3 ). All three crops consumed less water under drip irrigation as compared to furrow irrigation system. Average water use efficiency increased by 250% for tomato, 274% for cucumber and 245% for bell pepper under drip irrigation system as compared to furrow system. On the contrary, the average fruit yield increased only by 2.05% for tomato, 3.32% for cucumber and 2.35% for bell pepper from furrow irrigated plots over those of drip irrigated plots. This suggested that drip irrigation has a greater scope for production of off-season vegetables especially in water scarce areas of Pakistan. Keywords: Off-season vegetables, drip irrigation, furrow irrigation, water use efficiency, plastic tunnel. INTRODUCTION Vegetable crops are the eminent source of human nutrition. These represent a dynamic segment of Pakistan s agriculture. These are short duration crops, which can be grown even in small spaces. Demand for fresh or canned vegetables is increasing in national and international market. Considering that the world population is estimated to increase by 65% (3.7 billion) by 2050, the demand for food will in crease strain on fresh water resources (Wallace, 2000). Increase in area under production of any crop is of no use until economic yield per unit area does not increase. Commercial production of vegetable is not possible without adequate water availability throughout the growing season. Due to expected scarcity of water in future, water use efficient crops can only cope with the increasing demand. Production of vegetable crops in greenhouses is steadily increasing throughout the world (Cantliffe and VanSickle, 2002). Every summer crop can be grown under plastic tunnels in winter season but tomato, cucumber and bell pepper got least attention by the researchers and farmers in Pakistan. Off-season vegetables can give 15 times higher net returns compared to produce of normal season vegetables. Moreover, improving vegetable productivity will put the prices of vegetables within the reach of urban and rural poor (Ali and Niaz, 2008). Novel high technological solutions in greenhouse production can lead the way to highly efficient water use production techniques. Adoption of more efficient water use techniques will contribute to sustainability, especially in highly populated urban areas. Moreover, efficient use of irrigation water in greenhouses allow flexibility in planting time, establishing a more uniform plant stand, influencing soil temperature, utilizing certain herbicides and soil fumigants more effectively, and assuring reliable yields (Amjad et al., 2007). In rainfed areas of Pakistan, more than 60% of the farmers are small land holders having less than 5 acres of land. Moreover, there is no continuous supply of water. Therefore, farmers should adopt such crops which return more profit from small piece of land, thus production of vegetables in tunnels is the answer. Production of summer vegetables in winter season under plastic
tunnels is a valuable technique to get more profit from small piece of land. Plants are grown vertically in plastic tunnels. That is why they occupy less space when grown in tunnels compared with those grown in field. Despite high returns, non-availability of irrigation water is hindering expansion of area under vegetables (Baksh and Ahmad, 2004). or micro irrigation is an expensive, but efficient system of irrigating high value crops such as vegetables. Combined use of such systems with mulches and row covers for added efficiency should be taken into consideration (Amjad et al., 2007). Review of literature regarding the use of drip irrigation system showed irrigation efficiency with drip systems ranges from 75-95% compared to 25-50% for surface (furrow); 70-80% solid set sprinklers and 65-75% for portable sprinkler systems (Smajstrla, et al., 1988; Sanders, 1990). Similarly, Maisiri et al., (2005), Mahajan and Singh (2006) and Ngouajio et al., (2007) also reported increased irrigation water use efficiency (IWUE) by using drip irrig ation system in case of tomato. Malash et al., (2005) and Mahajan and Singh (2006) recorded higher yield of tomato under drip irrigation than surface irrigation system while Maisiri et al., (2005) observed no significant difference in vegetable yield between the irrigation systems. Yields of bell pepper increased from 12 ton acre -1 to 19 ton acre -1 by using drip and plastic mulch culture together (Crespo-Ruiz, 1988). Palada et al., (2003) reported high water use efficiency of drip system in combination with plastic mulch in case of bell pepper; however, drip irrigation improved marketable yield and fruit quality in case of tomato. Keeping above results in mind, this study was undertaken to determine water requirements by off-season tomato, cucumber and bell pepper irrigated through drip and furrow systems sown under plastic tunnel and to estimate the comparative water use efficiency of both these irrigation systems for the off-season crops in rainfed areas of Pakistan. MATERIAL AND METHODS The studies pertaining to the comparative water use efficiency in drip and furrow irrigation systems for offseason vegetables sown under plastic tunnel were carried out at Groundnut Research Station, Attock (Pakistan) for three years from 2009-10 to 2011-12. Attock is situated at 33 0 46 / North and 72 0 22 / East. The soil was sandy loam with Ece 0.20-0.18 dsm -1, ph 7.6-7.7, organic matter 0.60-0.45%, Olsen-P 4-2.5 mg kg -1 soil at 0-15 and 15-30 cm depth, respectively. The methodology of nursery raising and transplanting of the nursery for tomato, cucumber and bell pepper is given in (Table 1). Nurseries of tomato, cucumber and bell pepper were sown in plastic bags having mixture of soil, farmyard manure and sand in equal quantities, which were irrigated and were protected from diseases and insects. A permanent tunnel of 80 x 27 x 10 ft was erected. The tunnel was divided into four equal parts. On three parts (20 x 27 ft each), tomato, cucumber and bell pepper were planted under drip irrigation while the fourth part was again divided into three parts (20 x 9 ft each). On these three parts, the three crops were planted as to provide them irrigation in furrows. The water requirement of plot measuring 20 x 27 ft and 20 x 9 ft was transformed into that of a tunnel measuring 190 x 27 ft. Then, it was calculated on the basis of seven tunnels measuring 190 x 27 ft each for one acre. The tunnel was covered with plastic sheet. The plants were irrigated with the help of drip and furrow (as flood) systems as per requirement. The data of water applied through each drip and furrow irrigation was recorded through water meters. Two gram of each Urea, DAP and Potash were applied to each plant of tomato, cucumber and bell pepper at fortnight interval. Plant protection measures were adopted to avoid insect and disease attacks as and when needed. Temperature data inside the tunnel was recorded on daily basis (Fig 1). Data regarding total water used per acre, number of irrigations, water used per irrigation, water used per plant per irrigation, water used per plant per day and total yield (kg acre -1 ) were recorded from all vegetable crops on per unit area basis. After the harvesting of the crops water use efficiency of each irrigation system was calculated according to the following formula (Hillel, 1997): Total Marketable Yield (kg) WUE Total Water Used (m3) RESULTS AND DISCUSSION Tomato Tomato exhibits indeterminate growth habit with simultaneous vegetative and reproductive growth. The life span of tomato crop ranges between 6 and 7 months inside the plastic tunnel which is much higher than the crop grown under normal summer season (4 to 5 months). This led to the expansion of production period which in turn, resulted in more productivity. On an average of three years, 116 irrigations as drip and 100 irrigations in furrow as flood were applied to tomato crop sown in tunnel (Table 2). Although the tunnel was covered with tarpaulins to 186
protect the crops from severe cold at night inside the tunnel but the temperature remained uncontrolled from mid December to mid January. Therefore, irrigation frequency was increased in both irrigation systems during this period due to severe cold wave (below 5 ºC inside the tunnel) as high irrigation frequency resulted in retrieving of the crop to normal growth in case of high frost (Ali and Niaz, 2008). Due to very low temperature, tops of the plants were burnt and the growth was ceased for about 20-25 days. However, the plants revived within 20-25 days and started flowering again. Amount of water used per plant per irrigation ranging from 10.33-13.91 litres and water used per plant per day ranging from 3.26-7.27 litres in furrow was much higher than that used per plant per irrigation ranging from 1.99-3.44 litres and that used per plant per day ranging from 0.90-2.14 litres in case of drip irrigation (Table 2). Consequently, total amount of water used per acre in furrow was 9.04 millions litres (9040 m 3 ), which was much higher than that of drip irrigation i.e. 2.53 millions litres (2530 m 3 ). On an average of three years, 257 % more water (ranging from 159-332%) was applied to the crop in furrow system compared with that through drip system (Table 3). On the contrary, the fruit yield increased only by 2.05 % (ranging from 0.82 to 3.26%) from furrow irrigated plots over those of drip irrigated plots (Table 5). Hence, average water use efficiency (Table 4) was higher in drip irrigation (6.50 kg m 3 ) than that of furrow irrigation system (1.86 kg m 3 ). It showed that water use efficiency (Table 4) was enhanced by 250% (ranging from 157 to 319%) in drip irrigation system compared with furrow system (Smajstrla, et al., 1988; Sanders, 1990). In drip irrigation system, water is applied drop by drop only to the root zone of the plants. Thus, a large amount of water away from root zone could be saved. Palada et al., (2003) reported high water use efficiency of drip system in combination with plastic mulch. The results of present investigation also revealed improved marketable yield and fruit quality in case of tomato through drip irrigation. Ngouajio et al., (2007) also reported increased irrigation water use efficiency (IWUE) by using the drip irrigation system in case of tomato. Maisiri et al., (2005) reported no significant difference in vegetable yield between drip and surface irrigation systems. On the contrary, Malash et al., (2005) and Mahajan and Singh, (2006) observed higher fruit yield of tomato under drip irrigation than surface irrigation system. Cucumber Cucumber belongs to Cucurbitaceae family with spreading and climbing type of growth habit. Its life span ranges from 3 to 4 month normally. On an average of three years, 76 irrigations as drip and 71 irrigations in furrow were applied to cucumber crop sown in tunnel (Table 2). Irrigation frequency increased in both irrigation systems from mid December to mid January due to severe cold wave ( below 5 ºC inside the tunnel) to cope with frosty temperature (Ali and Niaz, 2008). As regards amount of water used per plant per irrigation, water used per plant per day and total amount of water used per acre in cucumber, a similar trend was observed to those of tomato (Table 2). On an average of three years, 287 % more water (ranging from 188-235%) was applied to the crop in furrow system compared with that through drip system (Table 3). This resulted in higher water use efficiency in case of drip irrigation (7.12 kg m 3 ) by saving 287% of water (Table 3,4) as compared to furrow irrigation system (1.90 kg m 3 ) (Smajstrla, et al., 1988). It showed enhanced water use efficiency by 274% (ranging from 171 to 323%) in drip irrigation system as compared to furrow system (Table 4). On the contrary, average fruit yield increased only by 3.32 % (ranging from 0.29-6.21%) from furrow irrigated plots over those of drip irrigated plots (Table 5). Maisiri et al., (2005) also reported no significant difference in vegetable yield between drip and surface irrigation systems. Bell Pepper It is a sun loving crop and completes its life cycle within 7 to 8 months. It is very sensitive to frost. It was irrigated 113 times in case of drip irrigation and 97 times in case of furrow irrigation (Table 2). Similar was the case with bell pepper to those of tomato and cucumber during frosty nights. As regards amount of water used per plant per irrigation, water used per plant per day and total amount of water used per acre in bell pepper, a similar trend was observed to those of tomato and cucumber (Table 2). On an average of three years, 253 % more water (ranging from 165-311%) was applied to the crop in furrow system compared with that through drip system (Table 3). This resulted in higher water use efficiency in case of drip irrigation (3.07 kg m 3 ) by saving 253% of water (Table 3,4) as compared to furrow irrigation system (0.89 kg m 3 ) (Smajstrla, et al., 1988). It showed enhanced water use efficiency by 245% (ranging from 153 to 303%) in drip irrigation system as compared to furrow system (Table 4). On the contrary, the average fruit yield increased only by 2.35 % (ranging from 0.20 to 4.76%) from furrow irrigated plots over those of drip irrigated plots (Table 5). These results are in agreement with those of Crespo-Ruiz, (1988) and Palada et al., (2003) who reported high irrigation efficiency of drip irrigation in combination with plastic mulch in case of bell pepper. Similarly, Maisiri et al., (2005) reported no significant difference in vegetable yield between drip and surface irrigation systems. 187
It was further observed that much higher amount of water was used by the crops sown under furrow system as compared to those sown under drip system due to sandy loam soil. In drip irrigation system, water is applied drop by drop only to the root zone of the plants. Thus, a large amount of water away from root zone could be saved. Overall, cucumber used less amount of water per acre under both irrigation systems compared with tomato and bell pepper (Fig 2). Likewise, higher water use efficiency was observed for cucumber compared with other crops (Fig 3). CONCLUSION It may be concluded that all crops consumed much less amount of water under drip irrigation as compared to furrow system, while no considerable yield differences between two irrigation systems were observed. Higher water use efficiency was observed for crops sown under drip irrigation compared to those sown under furrow system. This suggested that drip irrigation system has a greater scope for the production of off-season vegetables grown under plastic tunnel especially in water scarce areas of Pakistan. REFERENCES Ali MA, Niaz S. 2008. Crop management in frosty conditions. The Daily DAWN, Pakistan, Economic and Business Review, 18 February, 2008. Amjad M, Jahangir MM, Iqbal Q. 2007. Drought stress in vegetable production. The Daily DAWN, Pakistan, Economic and Business Review, 02 July 2007. Baksh K, Ahmad B. 2004. Constraints in vegetable production. The Daily DAWN, Pakistan, Economic and Business Review, 13 September 2004. Cantliffe DJ, Vansickle JJ. 2002. A sleeping giant: Can Florida compete with the Spanish and Dutch greenhouse industries? Practical Hydroponics and Greenhouses. 67:30-36. Crespo-Ruiz M. 1988. Nutrient uptake and growth characteristics of peppers under drip irrigation and plastic mulch. Journal of Agricultural University Puerto Rico 72:575-584. Hillel D.1997. Small scale irrigation for arid zones: Principles and options. FAO document repository. Natural Resources management and environment department. W3094/E. Mahajan G, Singh KG. 2006. Response of green house tomato to irrigation and fertigation. Agricultural Water Management 84:202-206. Maisiri N, Senzanje A, Rockstrom J, Twomlow SJ. 2005. On farm evaluation of the effect of low cost drip irrigation on water and crop productivity compared to conventional surface irrigation system. Physics and Chemistry of the earth, part A/B/C. 30:783-791. Malash N, Flowers TJ, Ragab R. 2005. Effect of irrigation systems and mater management practices using saline and non-saline water on tomato production. Agricultural Water Management 78:25-38. Ngouajio M, Wang G, Goldy R. 2007. Withholding of drip irrigation between transplanting and flowering increases the yield of field-grown tomato under plastic mulch. Agricultural Water Management 87:285-291. Palada MC, Davis AM, Kowalski JA, Crossman SMA. 2003. Yield and irrigation water use of vegetables grown with plastic and straw mulch in the U.S. Virgin Islands. International Water and Irrigation 23:21-25. Sanders DC. 1990. Using plastic mulches and drip irrigation for vegetable production. North Carolina Cooperative Extension Service Leaflet 33.13. Smajstrla AG, Boman BJ, Clark GA, Haman DZ, Harrison DS, Izuno FT, Pitts DJ, Zazueta FS. 1988. Efficiencies of Florida agricultural irrigation systems. University of Florida Cooperative Extension Services, Bulletin, 247. Wallace JS. 2000. Increasing agricultural water use efficiency to meet future food production. Agriculture, Ecosystems & Environment 82:105-119. Table 1. Sowing methodology of off-season vegetables grown in plastic tunnel. Crops Nursery Sowing Transplanting Harvesting Plant x Row Variety Date Date Date Spacing (cm) Tomato 15.09.2009 21.10.2009 20.05.2010 40 x 90 NSX-6658 11.10.2010 17.11.2010 05.06.2011 40 x 90 NSX-6658 15.09.2011 20.10.2011 28.05.2012 40 x 90 NSX-6658 Cucumber 15.09.2009 11.10.2009 20.03.2010 40 x 90 H6-01 25.09.2010 18.10.2010 07.03.2011 40 x 90 Primo 15.09.2011 06.10.2011 13.03.2012 40 x 90 Byblos F1 Bell Pepper 15.10.2009 25.11.2009 20.06.2010 40 x 90 Capistrano 26.09.2010 07.11.2010 11.06.2011 40 x 90 Capistrano 28.09.2011 06.11.2011 28.05.2012 40 x 90 Capistrano 188
Table 2. Water requirement of off-season vegetables grown in plastic tunnel (3-year average). Crops Irrigation No. of Water used Water used Water used system irrigation plant -1 irrigation -1 plant -1 day -1 acre -1 (litres) (litres) (million litres) Tomato 116 1.99-3.44 0.90-2.14 2.53 100 10.33-13.91 3.26-7.27 9.04 Cucumber 76 1.96-3.56 0.90-2.68 1.44 71 10.41-13.39 3.52-6.99 5.58 Bell Pepper 113 1.99-4.08 0.88-2.28 2.74 97 10.26-13.21 3.55-7.00 9.69 Table3. Water increase in furrow over drip irrigation system applied to off-season vegetables grown in plastic tunnel. Crops Years Water used acre -1 (m 3 ) Water increase in furrow over drip irrigation system (%) Tomato 2009-10 1800 7784 332 2010-11 2927 11922 307 2011-12 2863 7413 159 Average 2530 9040 257 Cucumber 2009-10 1461 6354 335 2010-11 1700 7026 313 2011-12 1169 3366 188 Average 1443 5582 287 Bell Pepper 2009-10 2222 9099 311 2010-11 2903 11716 304 2011-12 3114 8260 165 Average 2743 9692 253 Table 4. Water use efficiency of off-season vegetables grown in plastic tunnel. Crops Years Water used efficiency (kg m -3 ) WUE increase in drip over furrow irrigation system (%) Tomato 2009-10 9.09 2.17 319 2010-11 5.70 1.43 299 2011-12 5.68 2.21 157 Average 6.50 1.86 250 Cucumber 2009-10 9.12 2.16 323 2010-11 4.46 1.08 312 2011-12 8.48 3.13 171 Average 7.12 1.90 274 Bell Pepper 2009-10 4.52 1.12 302 2010-11 2.74 0.68 303 2011-12 2.35 0.93 153 Average 3.07 0.89 245 Table 5. Yield increase of off-season vegetables grown under furrow over drip irrigation system. Crops Years Yield (kg acre -1 ) Yield increase in furrow over drip irrigation system (%) Tomato 2009-10 16359 16892 3.26 2010-11 16673 17020 2.08 2011-12 16276 16409 0.82 Average 16436 16774 2.05 Cucumber 2009-10 13317 13702 2.89 2010-11 7584 7606 0.29 2011-12 9909 10524 6.21 Average 10270 10611 3.32 Bell Pepper 2009-10 10001 10231 2.30 2010-11 7964 7980 0.20 2011-12 7332 7681 4.76 Average 8432 8631 2.35 189
50 40 30 20 10 0 Nov Dec Jan Feb Temp. ( o C) Mar Apr May Min. Temperature Max. Temperature Figure1. Weekly temperature inside tunnel (3-year average) 10000 Water used acre -1 (m 3 ) 7500 5000 2500 0 Tomato Cucumber Bell Pepper Figure2. Comparison of water used by vegetables (3-year average) 8.00 WUE (kg m -3 ) 6.00 4.00 2.00 0.00 Tomato Cucumber Bell Pepper Figure3. Comparison of water use efficiency of vegetables (3-year average) 190