effect of subsurface irrigation with porous clay capsules on quantitative and quality of grape plant

introduction: maintaining soil moisture content at about field capacity and reducing water loss in near root zone plays a key role for developing soil and water management programs. clay pot or porous pipe is a traditional sub-irrigation method and is ideal for many farms in the world’s dry land with small and medium sized farms and gardens and is still used limitedly in dry lands of india, iran, pakistan, the middle east, and latin-america. clay capsule is one of porous pipes in sub irrigation that is able to release water in near root zone with self- regulative capacity. watering occurs only in amounts that the plants actually need (this amount is equal to field capacity) and released water in near root zone without electricity or use of an automatic dispenser. materials and methods: a study was carried out in 2013 on the experimental field of agriculture faculty of tarbiat modares university, to study the effect of two irrigation types on qualitative and quantitative characters in grape production (vitis vinifera l.). in order to provide the water requirement of grape plant were used porous clay capsules for sub irrigation with height and diameter of 12 cm and 3.5 cm and dripper with neta film type for drip irrigation, respectively. porous clay capsules provided from soil science group at tarbiat modares university. in this research, the volume of water delivered to grape plants during entire growth period in two different irrigation methods was measured separately with water-meters installed at all laterals. the water consumption, yield production and water use efficiency were evaluated and compared in two drip and porous clay irrigation systems at veraison phonological stages. in the veraison stages, cluster weight, cluster length, solid solution and ph content were measured in grape fruits. leaf chlorophyll content and leaf water content were also measured in two irrigation systems. results and discussion: the results of fruit quality characteristics showed that cluster weight, cluster length, solid solution and ph content has not significant different at 5% level in two system irrigation. also, the foliar analysis showed that chlorophyll content and relative humidity of leaf has not been affected in two irrigation systems. meanwhile, irrigation types were significantly effect on water consumption and water use efficiency. the average water consumption and yield production with buried clay capsules and drip irrigation methods on grapevine plant were 4050 and 6668 m3.ha-1 and 14.2 and 14.8 ton.ha-1 respectively. the reducing water consumption with buried clay capsules irrigation method in related to drip irrigation was 39% on grapevine plants. meanwhile, the average yield production with buried clay capsules and drip irrigation methods on grapevine plant was 14.2 and 14.8 ton.ha-1 respectively. also, the statistics analysis show that the yield and component yield have not significant different at 5% level in the surface and subsurface irrigation. according to the water consumption and yield production, using buried porous clay capsules created a better water use efficiency than drip irrigation method. in other words, iran has been localized at arid and semi arid and have huge water consumption in agriculture, and therefore it is necessary to optimize water consumption especially in agriculture using new technology. according to the results of this research, using buried porous clay capsules is recommended in order to optimize water consumption for grape plants in different place in arid and semi-arid regions of iran. conclusion: the purpose of an efficient irrigation system is to apply the water in such a way that the largest fraction thereof is available for beneficial use by the plant. according to the experimental results reported here, it could be concluded that the reducing water consumption with buried clay capsules irrigation method in related to drip irrigation was 39% on grapevine plants. meanwhile, the average yield production with buried clay capsules and drip irrigation methods on grapevine plant was 14.2 and 14.8 ton.ha-1 respectively. also, the statistics analysis show that the yield and component yield have not significant different at 5% level in the surface and subsurface irrigation. the final result, it could be concluded that the porous clay capsules have a good ability to providing water requirement of grape plant. the grape irrigation in huge area of iran is doing with a traditional method and the authors of this work believe that porous clay capsules have a high water saving potential and good capability for irrigation of various types of crops.