EVALUATION OF THE PERFORMANCE OF THE BUCKET DRIP IRRIGATION (FAMILY DRIP SYSTEM) FED BY TREADLE PUMP FOR TOMATO PRODUCTION Isaac R. Fandika, Irrigation and Drainage Team, Kasinthula Agricultural Research Station, Department of Agricultural Research Services, P.O.Box 28, Chikwawa, Malawi, Tel: 265 1 420 207/265 9 336 212, Email: kasresearch@globe.mw.net or fandikai@yahoo.co.uk ABSTRACT An evaluation of the performance of the Drip Irrigation (Family Drip System) fed by Treadle Pump was conducted by Kasinthula Research Station in 2005/2006 to develop baseline information on the operation of drip irrigation, establish drip irrigation system testing and demonstration on the design, installation and management of drip kits, determine water use efficiency and yield response of tomatoes to drip irrigation within between seasons. The drip irrigation system consisting of a 1300 litres tank mounted 1.5 m above ground connected with a 32 mm mainland was completely designed basing on the soil and plant properties before the system was installed on the field. Eighteen drip lines of 43 m long each were connected midway to the mainland with drippers spaced at 60 cm apart each delivering 2 h -1. The drip lines consist of garden hose 15 mm in diameter laid out along each tomato row at 1m spacing. The irrigation water was being lifted to the tank kit using a treadle pump that was incorporated to the drip system at a distance of 10 m. each discharge manifold has removable end caps for flushing. Tomato (rodade and money maker varieties) was planted to two fields laid out in a 40 m by 40 m consisting of beds of 36 m each drip with furrow irrigated. Tomato spacing was 1 m by 0.6 m. One drip emitter was designed to irrigate one plant station. Fertilizer application for tomato was 180 kg N ha -1 applied in five phases through fertigation under drip and by dollop under furrow irrigation. It was split plot laid as CRBD with irrigation method as main plot and varieties as subplot. Three replicates which were determined by the distance from the water source to measure yield variation or irrigation uniformity between lateral or furrows. Irrigation water application and evapotranspiration determination were based on cumulative Class-A Pan Evaporation within irrigation interval of 4 days. The results showed that there were no significant differences in yields between irrigation though drip tomato yields outweighed furrow irrigated tomatoes in both varities. The average marketable yields for rodade (78.9; 45.2 t ha -1 ) outweighed money maker yields (60.3; 58.1 t ha -1 ) both under drip and furrow irrigation 1
respectively. There was no significant variation between yield from lateral lines placed far end and those close to the source that showed high irrigation uniformity within the design. Water use Efficiency under drip irrigation was high (26.1 and 20.6 kg m for rodade and money maker) as compared to furrow irrigation (8.7 and 11.1 kg m for rodade and money maker respectively), hence economic (labor saving, less pumping costs) and recommendable for smallholder farmers. INTRODUCTION Drip irrigation can be defined as a precise, slow application of water in the form of discrete drops, tiny stream, or miniature sprays that are achieved through pressure reducing paths and emitters. The emitters are located at prescribed points along the drip tubing, or tape, which correspond to required crop spacing. Most drip irrigation systems operate under high pressure heads, more than 1 bar (10 m water head). Although drip designed for high pressure operation, bucket drip can suit low head condition (approximately 1 m head) that makes it perfect for smallholder conditions. Local head can provide discharge without pumping for smallholder farmers, leaving the laborious component of filling the bucket unsolved. Incorporation of treadle pump in bucket irrigation system simplify the issue of water lifting to the bucket and simultaneously water usage is economized due to skipping of surface irrigation that treadle pump involve. Treadle pump as is a high capacity manual pump designed for small-scale irrigation suits bucket drip irrigation. The treadle pump technology is highly adopted and practiced in Malawi for it is appropriate for small scale farmers. While the bucket drip irrigation method was introduced in Malawi by some Non Governmental Organizations without proper operation information. In principle, it is better method of irrigation than the carry-and-irrigate method. However, it is required to be improved and evaluated under the prevailing climatic, edaphically and crop factors in Malawi. Therefore, research was carried out to establish the testing and demonstration site of the bucket drip irrigation technology adaptability to various crops and farmers needs, to identify problem that can be faced by farmers and their solutions and train farmers, extension staff on design, installation and management of drip kits in Malawi and finally to determine water use efficiency and yield response of various crops to drip irrigation. The essence of this research was promote micro gardens in dambo areas as well as in the backyard which supplement smallholder food supply during the dry period when food is in shortest supply. 2
MATERIALS AND METHODS Experimental Site The study was conducted at Kasinthula Research Station in Chikwawa, located at latitude 16 south, longitude, 34 5 s and altitude of 70 m above sea level. According to the long term data, the annual average minimum and maximum temperature, annual precipitation, relative humidity, wind speed and evaporation are 18.6, 35.6, 520 mm, 70%, 4.7 km day -1 and 8.6 mm day -1 respectively. The soil of this site is sandy loam textured. The total available water within the soil depth and the mean bulk density varies as shown in table 1 below Table 1 Soil properties of the experimental site. Soil Depth Soil Texture Field Capacity (0.3 Bars) Wilting Point (15 Bars) Available Water Bulk Density Infiltration Rate (mm hr -1 ) 0-15 SL 13.58 5.56 8.02 1.31 15 15-30 SL 12.28 5.59 6.69 1.31 30-45 SL 13.12 6.03 7.09 1.31 45-60 SL 14.19 6.68 7.81 1.45 60-75 SCL 14.18 8.53 5.65 1.46 75-90 SCL 22.07 11.22 11.34 1.52 90-105 SCL 22.07 11.69 10.49 1.73 Drip Irrigation System Design, Field Layout and Crop The drip irrigation system consisting of a 1300 liters tank mounted 1.5 m above ground connected with a 32 mm mainline was completely designed basing on the soil (Table 1) and plant properties before the system was installed on the field. Eighteen drip lines of 43.2 m each with seventy two drippers (thirty six drippers per drip line of 21.6 m each side were connected midway to the mainline) spaced at 60 cm apart each delivering 2L h -1. The drip lines consisted of garden hose 15 mm in diameter laid out along each tomato row at 1 m spacing. The irrigation water was being lifted to the tank kit using a treadle pump that was incorporated to the drip 3
system at a distance of 10 m. Each distance manifold had removable end caps for flushing (figure 1). Fig 1: front view showing drip main line from the drip tank raised 1.5 m on concrete. Fig 2: Drip Irrigation system side view showing drip lateralines. Tomato (rodade and money maker varieties) were planted to two fields one drip irrigated and another furrow irrigated laid out in a 43.2 m by 40 m (0.34 ha) consisting of beds of 43.2 m each. Tomato spacing was 1 m by 0.6 m. One drip emitter was designed to irrigate one plant station. Fertilizer application for tomato was 180 kg N ha -1 applied in five phases through fertigation for drip irrigation and by drop for furrow irrigated tomatoes. The experiment was RCBD with three 4
replicates which were determined by the distance from the water source to measure yield variation or irrigation uniformity between lateral lines and furrows. Irrigation Water Application and Evapotranspiration Determination Irrigation water was applied based on cumulative Class-A Pan Evaporation within irrigation interval. In the study amount of irrigation water was determined using the following equation: I=A*Ep*Kpc*P (Equation 3.1) Where: I equals amount of irrigation water (l), A equals plot area (m 2 ) Ep equals cumulative evaporation amount considering irrigation intervals (mm). Kpc equals coefficients (including pan coefficient, kp crop coefficient kc and application efficiency) and p equals wetted area %. Wetted area was determined to be 30% by tables for determining values of % of soil wetted by various discharge and spacing for a single row of uniformity spaced distributors in a straight line. The drip system was placed on the plots immediately following transplanting. The initial amount was based on the soil moisture deficit that would need to bring a 90 m layer of soil to field capacity. Subsequent irrigation was applied considering intervals and coefficients of kpc. Plant and soil water measurements and observation started 10 days after transplanting and were terminated on the last harvest date. Data on uniformity of application along the drip line; discharge per dripper; infiltrated depth; wetted area; water quality and quantity, time and labour gain or loss on a treadle pump lifting, length of lateral frequency of irrigation and amount of water required per irrigation in each case and tomato yields were recorded. Yield was determined by hand harvesting and weighing. Quantity of tomato was assessed whether it deteriorated as drip line deviates the main line to measure irrigation uniformity impact. Water use was estimated (Appendix 1) on a cumulative Class-A Pan Evaporation. Water use was the total of seasonal cumulative Class-A Pan Evaporation plus rainfall. Water use efficiency (WUE) was computed as the ratio of tomatoes yield to water use. 5
RESULTS AND DISCUSSIONS The study has shown that the average time for pumping water into the 1300 litres tank raised 1.5 m using the treadle pump placed 10 m away taking 14-16 minutes for two people and 19-22 minutes for one man. Irrigation using such amount lasts 43 minutes and during this time people rests or do other work. The number of tank used per irrigation depended on the crop water requirement that varied with crop stage and weather. The results showed time and labour or energy saving using drip incorporated by treadle pump. Wetted Diameter and Wetted Depth The wetted diameter and wetted depth from the mainline did not correlate (Fig. 1(a-b) with drippers positions whether placed close to the mainline or to the far end as explained by linear regression equations. Wetted diameter = -0.2188x+26.921, R 2 =0.15 Wetted depth +-0.004x+23.282 R 2 =0.0001 6
There was no correlation between tomato yield per plant or dripper as they deviate from the mainline with wetted diameter or wetted depth (Figure 2a-b) as expressed by the equations: For Wetted Depth Y =3.2072x+ 717.93 R 2 =0.001 For Wetted Diameter Y =9.0126x+ 570.38 R 2 =0.008 This means that dripper or plant position had no effect on tomato yields, which shows that the design did not cause pressure variation that resulted into uniform water distribution and uniform yield as well as tomato quality. This is because the wetted depth (20-25mm) is greater than the designed net irrigation depth of 10.8 mm day -1 and the gross irrigation depth of 12 mm which shows that the head of 1.5 m can irrigate more than 0.02 ha (figure 1-2) with a tank of 1300 liters. Yield and Crop Water Use Efficiency The results of irrigation water amounts applied and marketable fruit yields obtained in the experiments are in Table 2. Yield between drip irrigation and furrow irrigation was not 7
significantly different (P>0.05) though tomato yields under drip were higher Table 2 (b). Rodade variety yield outweighed money maker under drip (78.9, 60.3 t ha -1 ) and under furrow irrigation, money maker out yielded rodade 45.2,58.1 t ha -1. The average fruit yield of tomatoes in Shire River during winter is 45 t ha for rodade and 60 t ha for money maker (Kumwenda R. 2005) where more than 500 mm was is used. The fruit yield and water use from drip irrigation study was higher and lower than the average yield and water use respectively for the region. This collate with other scientists who found that drip irrigation considerably increase marketable tomato yields compared to yields under average farming conditions (Kadam, 1993) where highest tomato yield of 150-166 t ha -1 were reported under drip irrigation. Tomato yields under drip irrigation are higher than other irrigation method due to the fact that the nature of drip irrigation, which applies irrigation slowly and frequently, soil water content in a portion of the plant root zone remains fairly constant compared to furrow irrigation. Therefore, the plant use fertilizers and water more efficiently. Some studies carried out in other region have also proved that higher yields are obtained by drip irrigation compared to other irrigation methods but their results were double of this study possibly due to differences in tomato varieties (Van der Gulik, B.C, 1999). Therefore, there is need to further study various tomato varieties response to drip irrigation. Table 2: Tomato yield t ha -1 and water use efficiency (kg mm 3 ) for drip and furrow irrigation. Irrigation system Variety Tomato Total Yield (t ha -1 ) Water Use (mm) Water Use Efficiency (kg m -3 ) Drip Irrigation Money Maker 60.3 302 20.6 Rodade 78.9 302 26.1 Furrow Irrigation Money Maker 58.1 520 11.1 Rodade 45.2 520 8.7 CV% 15.6 LSD 32.58 Sig. NS 8
The results on water use efficiency (WUE) showed that the relationship between yields and irrigation water depends on the quality of water applied, the irrigation method used as well as the tomato variety. Drip irrigation water use efficiency (Table 2) was very high within the range of 13.0 56.9 kg m -3 reported by Kadam, 1993. The results of WUE prove that tomatoes under drip irrigation use water more efficiently. WUE might not only depend on the amount of irrigation water applied but also the method of fertilizer application, in this case drip used fertigation while furrow used dollop method. Fertigation facilitated efficient tomato utilization of fertilizer other than dollop method. The results of yield which were also measured per plant as they deviate from the main lateral line to determine change of pressure head effect on the water distribution. The yield (Table 3 a-b) showed that there was no significant variation between yield from lateral lines placed at the far end and those close to the source. This also showed high irrigation uniformity and distribution uniformity within the design. The variation of water use efficiency between drip as the deviate from the mainline were minor and might have been caused by other factors (e.g. clogging) other than pressure variation since many drips have high WUE (fig 3) as well. Table 3(a): Water Use Efficiency (WUE) data for drip irrigated Money Maker as measured per planting station along the lateral line. Plant No Tomato yield/plant (g) Seasonal irrigation (mm) Water use (mm) Water use efficiency (g mm -1 ) Irrigation efficiency (g mm -1 ) 1 823.49 302 302 2.73 2.73 2 551.70 302 302 1.83 1.83 3 708.10 302 302 2.34 2.34 4 808.41 302 302 2.68 2.68 5 1033.78 302 302 3.42 3.42 6 460.10 302 302 1.52 1.52 7 224.36 302 302 0.74 0.74 8 548.50 302 302 1.82 1.82 9 944.87 302 302 3.13 3.13 9
10 788.38 302 302 2.61 2.61 11 928.21 302 302 3.07 3.07 12 933.02 302 302 3.09 3.09 13 535.38 302 302 1.77 1.77 14 720.55 302 302 2.39 2.39 15 1002.00 302 302 3.32 3.32 16 397.10 302 302 1.31 1.31 17 1204.39 302 302 3.99 3.99 18 682.30 302 302 2.26 2.26 Mean 2.45 2.45 Table 3(a): Water Use Efficiency (WUE) data for drip irrigated Rodade as measured per planting station along the lateral line. Plant No Tomato yield/plant (g) Seasonal irrigation (mm) Water use (mm) Water use efficiency (g mm -1 ) Irrigation efficiency (g mm -1 ) 1 953.45 302 302 3.16 3.16 2 606.00 302 302 2.01 2.01 3 905.40 302 302 3.00 3.00 4 938.60 302 302 3.11 3.11 5 1443.76 302 302 4.78 4.78 6 671.00 302 302 2.22 2.22 7 804.20 302 302 2.66 2.66 8 520.94 302 302 1.72 1.72 9 1143.80 302 302 3.79 3.79 10 1181.80 302 302 3.91 3.91 11 864.46 302 302 2.86 2.86 12 1074.10 302 302 3.56 3.56 13 1348.10 302 302 4.46 4.46 10
14 947.15 302 302 3.14 3.14 15 835.36 302 302 2.77 2.77 16 1238.50 302 302 4.10 4.10 17 1592.35 302 302 5.27 5.27 18 1242.10 302 302 4.11 4.11 Mean 3.37 3.37 Drip irrigation information dissemination and recommendations to small scale farmers and partners. Since drip irrigation installation at Kasinthula, the project has undertaken training of Extension Officers and NRC students on the installation and management of the drip kits and also established drip system as a testing and demonstrating site for various crops and farmer needs. During this period of experimentation, opportunities and challenges ranging from technical, management, supply and availability emerged. The technology is of interest to farmers and NGOs an there is urgency for further field testing to addressing on farm problems that can undermine the potential for adoption and diffusion. Drip irrigation is a recommendable irrigation system for Malawian farmers for they can gain advantages without suffering from the disadvantages only if attention on how to select and 11
manage a drip irrigation system can be followed. Therefore it is firstly, recommended that farmers make decision on water cost, water quality, crop value, crop life, cost of energy, cost of alternative irrigation system and irrigation management. Secondly, the system design need to be properly designed to provide precise amounts of water directly to the plant frequently be enough and adequate quantities for proper growth. Thirdly, operation of the drip need to maintain soil moisture at higher level so that the stress encountered by the plants is reduced. Management of Drip Irrigation In planning drip irrigation, installation the drip emitter needs to be sufficiently near the plant station surface to germinate seed, if necessary soil and the system should be designed to meet 80% distribution uniformity (DU). Secondly, flow rate and emitter spacing of drip needs to match with the soil conditions. Therefore, the use of both measurements of soil water and estimates of crop water use called crop evapotranspiration or ET is highly encouraged to irrigate only to replace the soil moisture deficit in the top 30 cm of soil. It is usually not necessary to exceed ET. Irrigation needs to be managed closely to meet plant water needs and reduce nitrogen fertilizer because nitrate leaching is reduced or nearly eliminated. Experience has shown that if fertilizer nitrogen applications are not reduced, crop under drip irrigation will become excessively leafy. Fertilizers containing sulfate, phosphate, calcium, or anhydrous or aqua ammonium can lead to solid chemical precipitation inside the drip tape. The precipitates can block emitters therefore farmers should seek expertise or chemical analysis of irrigation water and competent technical advice before injecting chemical fertilizers into drip tape. Quality of water is crucial in drip irrigation management, therefore, choice of filters need to much with the water quality and filters must be properly managed. In spite of filtration, drip tape must be flushed, with a frequency that is dependent on the amount and kinds of sedimentation in the tape. In extreme cases, chlorine or other chemicals need to be added periodically to the drip to kill bacteria and algae in the drip lines that may clog the drippers. Rodents must be controlled, especially where drip tape is buried to provide irrigation for a number of years because they may damage the drip tape or clog the system. 12
Benefits and challenges of drip irrigation observed during the experiment Proper management of tomatoes under drip system can be able to repay itself in a short period. Drip irrigation saved water as compared to furrow irrigation since only small area around plants was irrigated, application of water was very slow that improved water penetration, reduced weed growth and precise water control allows injection of fertilizer directly into the irrigation water. Yield was improved as compared to other irrigation method. The benefits was further significantly evidenced by the experienced advantages of its adaptable to fields with odd shapes or uneven topography; and the precise water application that reduced evaporation, runoff, deep percolation. Irrigation uniformity and nutrients utilization improved so it was no longer necessary to over water parts of a field to adequately irrigate the more difficult parts. Lastly, a timely application of herbicides and insecticides was possible and incorporation of treadle pump that increased reduction of pumping costs experienced in automated system. The challenges of drip irrigation on initial cost $500 to $1,200 per hectare, drip plugging by algae in the tape and chemical deposits at the emitter are outweighed by the benefits of the system. ACKNOWLEDGEMENTS I wish to thank The National Research Council of Malawi (NRCM) for funding this study in 2004/2005 financial year. I would also like to thank Irrigation and Drainage Technical Staff at Kasinthula Research Station namely; Mr D. Kadyampakeni, Mr Henry Mapwesera, H. Kakhiwa and Ms C. Bottomani for assistance they made in data collection, compilation and trial management. Finally, but not least, I would like to thank the Malawi Government, especially the Department of Agriculture Research Services in the Ministry of Agriculture and Food Security for financial and technical support to the project. 13
REFERENCE Barak, E. (1986), In Service Training Irrigation Research Project, December 1981 to November 1986. Final activity available. Ministry of Agriculture. Department of Agriculture Research. Malawi. Burt, O Connor, and Ruehr (1995) Fertigation, California Polytechnic State University. Order from the Irrigation Training and Research Center, California Polytechnic State University (Cal Poly), San Luis Obispo, CA 93407, telephone (805) 756-2434. Chanson, Schwankl, Grattan, and Prichard, (1994). Drip Irrigation for Row Crops. University of California, Davis. Order from Cooperative Extension Office, Department of LAWR, 113 Veihmeyer Hall, University of California, Davis, CA 95616, telephone (530) 752-1130. Hassan, Farouk A Fresno, CA, (1998) Microirrigation Management and Maintenance. Agro Industrial Management, 1998. The book is available from Farouk A. Hassan, Ph.D. Irrigation & Soil Consultant, Agro Industrial Management, P.O. Box 5632, Fresno, California 93755, U.S.A. Phone: (209)224-1618, Fax: (209) 348-0721, E- mail:fahassan@aol.com Kadam J.R (1993), Evaluation of different irrigation methods for growth and yield of tomatoes. Annals of plant Physiology: 1993, 17:1.78-84. Kumwenda R (2005). Evaluation of AVRDC tomato varieties for adaptability and yield. In Horticulture In-House Proceedings held at Andrews Holiday Resort in Mangochi. Department of Agricultural Research Services, Malawi. Malawi Government (1996), Guide to Agriculture Production Manual. Ministry of Agriculture. Van der Gulik, B.C, (1999) Trickle Irrigation Manual. Ministry of Agriculture and Food Resource Management Branch. Order from Irrigation Association of British Columbia, 2300 Woodstock Drive, Abbotsford, B.C., Canada, V3G 2E5, telephone (604) 859-8222. 14