Conclusion and Recommendation CHAPTER

Transcription

1 CHAPTER

2 7.1 GENERAL The present study was carried out to evaluate performance assessment of surface and subsurface drip irrigation methods, suitable for crops and fruit trees. Experiment base studies were carried out to evaluate the performance of the most advanced techniques of high efficiency irrigation system. Three field experiments were design under surface and subsurface drip irrigation system. One experiment was conducted on tomatoes vegetable crop, while the other two were on date palm trees. In both studies the latest self compensating emitter s pipes were used. Irrigation schedule was prepared in accordance with crop water requirement of respective crop/fruit tree for these experiments. A comparison has been made to see, which drip irrigation method, surface or subsurface, are the most effective and suitable method in respect of water consumption, yield, water use efficiency and cost analysis and applicable to crop as well as for fruit trees under different soil and climatic conditions. The study has been carried out on two different locations in the same hydrological region. 7.2 CONCLUSIONS In the following paragraphs the main conclusion of the two experiments of fruit tree, date palm and one experiment on vegetable crop, tomato are presented separately and an attempt is made to generalize the findings of these experiments Findings of Drip Irrigation Experiment under Crop The main conclusions of the study under vegetable crop are: This study examined the performance of a surface and subsurface drip irrigation system using drip pipes of low flexibility. Based on the experimental results, the following conclusions can be drawn from this investigation: 1 Low flexible drip pipe, having continues self-cleaning mechanism performed well under subsurface drip irrigation system due to their physical and hydraulic characteristics

3 2 Formation of bigger wetted volume of soil in the root zone was observed, in the case of subsurface drip irrigation method and smaller wetted volume of soil was found, in the case of surface drip irrigation method, which means that all volume of water consumed in subsurface drip irrigation system and also saved irrigation water due to non evaporation and wind effects. 3 Higher yield and yield to water ratio was obtained in subsurface drip irrigation method, regardless of their verities used under both drip irrigation methods, it is only due better water use efficiency of subsurface drip irrigation method. 4 Subsurface drip irrigation method proved, a feasible option for vegetable crop production under water limiting conditions. 5 Although fixed and capital costs of subsurface drip irrigation method was more but returns collected and gross margin in US$/ha/season under subsurface drip irrigation system was more as compared with surface drip irrigation system Findings of Drip Irrigation Experiment under Fruit Trees. The main conclusions of the study under fruit trees are: This study aimed to examine the performance of a surface and subsurface drip irrigation methods, by using drip pipes of varying flexibility, under surface and subsurface drip irrigation system. Based on the experimental results, the following conclusions can be drawn from these investigations: 1 Low flexible drip pipe performed well under subsurface drip irrigation system due to its better physical and hydraulic characteristics as compared to other medium and high flexible drip pipe types used. In addition to that low flexible drip pipes were equally efficient and better for surface drip irrigation system, than the other two, medium and high flexible drip pipe types. 2 Total quantity of water used in subsurface drip irrigation method was less as compared to surface drip irrigation method, under varying flexible drip pipe types used due to efficient utilization of all water applied. Low flexible drip pipe type consumed least water in peak period; for July and August due to its efficient working performance under subsurface

4 3 Under subsurface drip irrigation method, the yield of the fruit per tree for the area having low flexible drip pipe type was more, in comparison with surface drip irrigation system containing low flexible drip pipe type due to better physical and hydraulic properties of these drip pipe type, non evaporation and non wind effects. 4 The water use efficiency for low flexible drip pipes under subsurface drip irrigation method was more than surface drip irrigation method due to bigger wetted volume of soil in root zone and climatic factors. 5 Subsurface drip irrigation system eliminates the weed growth around the tree and prevents salt accumulation on the soil surface which was not in the case of surface drip irrigation system. 6 Subsurface irrigation facilitated the ease of mechanical field operation for fruit orchard, as all pipes were underground at recommended depth. 7 Fixed and capital costs of subsurface drip irrigation method was more but outcomes in the shape of revenue and gross margin in US$/ha/season under subsurface drip irrigation method was more as compared with the surface drip irrigation method. 7.3 OVERALL CONCLUSIONS 1 Hydraulic performance of the subsurface drip irrigation method was much better than that of surface drip irrigation method, because of non evaporation and wind effects. 2 The yield under crop and fruit trees from the subsurface drip irrigation method area was found to be more than that from the surface drip irrigation method area. 3 The water use efficiency of subsurface drip irrigation method is much more than that of surface drips irrigation method. As all water utilized by the plants, in case of subsurface drip irrigation method, while as for the surface drip irrigation method partly utilized by plants and partially evaporated

5 4 Bigger wetted volume of soil in root the zone was observed in the case of subsurface drip irrigation method, while it is smaller wetted volume of soil under surface drip irrigation method. 5 The analysis showed that subsurface drip irrigation method was more viable economically for both vegetable crop and fruit trees. 7.4 RECOMMENDATIONS Following recommendations are suggested. 1 Further investigation of subsurface drip irrigation method by using low flexible drip pipe type (self compensating dripper pipe type) needs to be undertaken for other crops and fruit trees to confirm the benefits of the use of low flexible drip pipe type under this irrigation method. 2 For efficient and successful system working performance, maintenance schedule as per recommended by the company/manufacturer must be followed, to get the optimum results for crop and fruit trees under this drip irrigation system. 7.5 REFERRED FUTURE STUDIES On the basis of experimental study s findings, under crop and fruit tree, following recommendations are suggested which can be made for future studies: 1 Further investigation of subsurface drip irrigation method, needs to be undertaken for other fruit trees like citrus to confirm the benefits of the use of low flexible drip pipe type under this irrigation system. 2 Further investigation of subsurface drip irrigation method, needs to be conducted for greenhouses planting of other vegetable crops to verify the features of the use of low flexible drip pipe type under this irrigation system