Use of saline water for tomato production in hydroponic greenhouse
NSTIP Project under Advanced and Strategic Technologies
Sub-Program / Technology Area
Agricultural Technology
Track
Hydroponic Techniques
Sub-Track
Water Relations
Project Duration
Nov 2015 – Nov 2017
Proposed Budget
1,868,975 Saudi Riyal
February, 2015
Precision Agriculture Research Chair (PARC).
College of Food & Agriculture Sciences,
King Saud University,
Riyadh, Saudi Arabia
Project Team
Principal Investigator:
Dr. Ranga Swamy Madugundu
Co-Investigator(s):
Prof. Dr. Khalid A Al-Gaadi
Prof. Dr. Abdulaziz R. Al-Harbi
Dr. Mahmoud A.E. Wahb-Allah
Research Associate(s):
Dr. ElKamil Tola
Masters Student(s):
Eng. Ahmad Mahmoud Hassan Zeyada
Eng. Ahmed Galal Ahmed Abd Elall Kaiad
External Consultant(s):
Prof. Nick Sigrimis (Agricultural University of Athens, Greece)
Prof. V. C. Patil (Former Chair Professor, PARC, KSU, Riyadh)
Overview
Hydroponic production technologies in greenhouses ensure increased food production, improve quality, conserve resources, and protect the environment.Hydroponic production systems can yield 10-20 times conventional farming systems, while using only 20% of the water.Tomato is one of the most important vegetable crops grown in Saudi Arabia. However, Saudi Arabia imported 190,000 metric tonnes of tomatoes worth US $ 62 million in 2009. In the Netherlands, tomato yields of up to100 kg m-2 per year under hydroponicshave been reported. The water use efficiency has been observed to be 60-70 kg of tomato per cubic meter of wateras compared to 12-15 kg of tomato per cubic meter of water observed in traditional agricultural practices.Hydroponics is an extremely efficient, environmentally friendly agricultural production system that is ideally suited to widespread adoption in Saudi Arabia, where water is becoming increasingly scarce.Saline water can be used for growing salt tolerant or moderately salt tolerant crops such as tomatoes in hydroponic greenhouses. However, investigations on the use of saline water without adverse effects on productivity and quality of crops are necessary.The proposed project envisages use of saline water in hydroponic tomato production. The main objectives of the project are 1. To study the effects of saline water on the yield and quality of tomatoes in hydroponicgreenhouses. 2. To determine the effects and Best Management Practice of conjunctive use of saline and non-saline water on the productivity of tomatoes in hydroponic green houses.3.To assess the impact of grafting on salt tolerant root stock, improved plant nutrition (elevated levels of P, K, Ca, Fe and Si) and mist cooling on salt tolerance in hydroponic tomatoes. 4. To provide training on hydroponic greenhouse technology to students and the farming community.Controlled polyethylene/glass greenhouses with Open and Closed hydroponic systems will be used in the study. One greenhouse will be earmarked for the Open system and the other one for the Closed system. Coco coir will be used as the growing medium.The experiments in both the Open and Closed system greenhouses will be laid out in split- split plot design with four replications. There will be two strips (main treatments): one for tomato seedlings and the other for grafted tomato plants. In these two strips, the following two sub-treatments will be allocated. 1. Nutrient solutions at different crop growth stages as recommended by Hochmuth and Hochmuth (2008). 2. Modified nutrient solutionsat different crop growth stages with elevated levels of P, K, Ca, Fe(40% higher than in treatment 1) and Si@ 2.25 mg L1, coupled with mist cooling. In these strips, ten saline water irrigation treatments with constant EC levels of 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, and differential EC levels with mid-day reductions in EC to 2.5 dsm-1 (2.5/7.5, 2.5/10.0, 2.5/12.5 and 2.5/15.0 dsm-1 ) will be superimposed as sub-sub treatments.The nutrient solutions will be supplied through drip-irrigation system. The drip fertigation system will be designed to deliver 100 mL of nutrient solution per plant using drippers/capillary tubes. One dripper/capillary tube will be provided to each plant. The irrigation frequency will be based on the crop growth stage, plant transpiration demands and solar radiation. Drainage will be through a gutter system placed along each row. The minimum percent drainage of EC nutrient solution of 10-15 %, will be adopted and it will be adjusted by manipulating irrigation frequency through the automatic irrigation scheduler. A programmable irrigation timing controller will be used to schedule and control the fertigation cycles and the midday reduction of EC. However, same amounts of water will be delivered in both the Open and Closed systems. This fertigation system will also have the capacity to operate automatically to adjust the irrigation frequency when we plan future experiments to target a specific “drain EC & pH”. Drainage water will be recycled to increase water and nutrient-use efficiency in hydroponic greenhouses and reduce the environmental impact of the drainage water discharge. The pH, and EC of the influx and efflux of nutrient solutions will be monitored constantly. Environmental data inside both the greenhouses will be collected using sensors and climate control systems. Periodic data on crop growth and yield parameters will be recorded in all the treatments. Fruit trusses will be harvested weekly based on colour of fruits. A truss in which at least 80% of the fruits attain red ripeness stage will be harvested.Harvested fruits will be graded, weighed and properly stored for fruit quality assessment. Fruit quality parameters such as lycopene, chlorophyll and total soluble solid (TSS) concentrations of fruits will be measured every week for all harvested tomatoes. Data collected in the experiment will be analyzed using SAS software. Significance among individual treatments will be analyzed by analysis of variance (ANOVA) and least significant difference (LSD) test.The salient findings of the project will be documented in the form of bulletins, booklets and folders. The relevant photographs, graphs, tables will be included in these extension education materials. The findings will also be documented in multi-media format which will all be utilized for periodic on-site training of farmers and students.
استخدام المياه المالحة لإنتاج الطماطم في البيوت المحمية المائية
ملخص
تقنيات الانتاج في البيوت المحمية المائية ضمان لزيادة الإنتاج الغذائي، وتحسين الجودة، والحفاظ على الموارد وحماية البيئة. يمكن لنظم الزراعة المتحكم بها بيئيا ان تزيد من العائد 10-20مرة من النظم الزراعية التقليدية، في حين تستخدم20 ٪ فقط من المياه. يعتبر الطماطم احد أهم محاصيل الخضروات التي تزرع في المملكة العربية السعودية. ومع ذلك استوردت السعودية 190000طن منه‘ اي ما يمثل ما قيمته 62 مليون دولار في عام 2009. في هولندا، انتاجية الطماطم تتجاوز100كجم /م2 في السنة باستخدام الزراعة المائية. وقد لوحظ أن كفاءة استخدام المياه تكون 60-70 كجم من الطماطم لكل متر مكعب من المياه بالمقارنة مع 12-15 كجم من الطماطم لكل متر مكعب من المياه باستخدام الطريقة التقليدية بالزراعة المفتوحة بالحقل. الزراعة المائية هي فعالة للغاية ونظام انتاج زراعي صديق للبيئة والذي يعتبر مثاليا لاعتماده على نطاق واسع في المملكة العربية السعودية، حيث أن المياه أصبحت نادرة بشكل متزايد. يمكن استخدام المياه المالحة لزراعة نباتات تتحمل بشكل عالي او معتدل مثل الطماطم في البيوت المحمية المائية. ومع ذلك، فالابحاب المتعلقة باستخدام المياه المالحة من دون آثار سلبية على إلانتاجية وجودة المحاصيل ضرورية. يتوخى المشروع المقترح استخدام المياه المالحة في إنتاج الطماطم دون تربة. الأهداف الرئيسية للمشروع هي : 1. لدراسة الآثار الناجمة عن استخدام المياه المالحة على انتاجية وجودة محصول الطماطم في البيوت المحمية المائية. 2. لتحديد الجدول الزمني الأمثل لإدارة الاستخدام المشترك للمياه المالحة وغير المالحة في البيوت المحمية المائية لإنتاج الطماطم. 3. لتقييم التاثير المحسن للتغذية النباتية الجيدة (مستويات مرتفعة من الفوسفور والبوتاسيوم و الكالسيوم والحديد والسيلكيا) إلى جانب نظام التبريد الضبابي على تأثيرات كفاءة استخدام المياه المالحة و 4. لتوفير التدريب على تقنية الزراعة المحمية المائية المسببة للطلاب والمجتمع الذي يعمل بالزراعة. سيتم استخدام البيوت البلاستيكية البولي ايثيلين مع أنظمة التحكم المائية المفتوحة وشبه المفتوحة في الدراسة. كما سيتم تخصيص أحد البيوت المحمية للنظام المفتوح والآخر للنظام شبه المفتوح. سيتم استخدام بقايا الكوكا باعتباره بيئة جبدة للنمو. تصميم التجارب بتصميم وحدات منفصلة شريطية مع أربعة مكررات. وسيتم تخصيص المعاملتين الرئيسيتن احدها للشتلات والاخرى للنتات المطعمة. وتحت كل معاملة رئيسية ستقام معاملتين فرعيتين هما1. استخدام محلول مغذي Hochmuth and Hochmuth (2008)بطول موسم النمو في البيت المحمي2. محلول غذائي معدل مع رفع مستويات عناصر P ، K ،Ca، Fe 40%و Siالى 2,25ملجم/لتر، إلى جانب التبريد الضبابي. في هذه الشرائط، عشرة معاملات من مياه الري المالحة مع مستويات ثابتة من االتوصيل الكهربي للماء ECw2,5 ، 5,0 ، 7,5 ، 10,0 ، 12,5 ، 15,0ديسمنس/م، ومستويات من EC مع منتصف النهار مخفضة إلى قيمة2,5 ديسمنس/م بالنسب التالية (2,5/7,5 ، 2,5/ 10,0 ، و2,5/12,5 2,5/15,0ديسمنس/م) وهي قيم للمعاملة الفرعية بالتصميم. سيتم تصميم نظام الرسمدة بالتنقيط لاعطاء 100 مليلتر من المحلول المغذي للنبات باستخدام الضغط والأنابيب الشعرية (3 مم من الداخل)، بواقع منقط لكل نبات. تكرار الري اعتمادا على الاحتيا جات المائية للنبات ومراحل النمو والظروف المناخية الخارجية. سيتم التخلص من الصرف منها بشكل سليم من خلال إنشاء نظام صرف يوضع على طول كل صف ومن ثم إلى المجاري الصحية. الحد ألادنى من الصرف للمحلول المغذي 10-15٪ ، وهي نسبة تمارس على نطاق واسع في إنتاج الطماطم المائية وسيتم تعديله من خلال التحكم في تكرار الري من خلال جدولة الري الآلي. سيتم برمجة الري الياُ باستخدام وحدة التحكم لجدولة دورات الرسمدة وانخفاض قيم التوصيل الكهربي في منتصف النهار، مع الحرص على ان تصل نفس كميات المياه إلى النظم المفتوحة وشبه المفتوحة. نظام الرسمدة هذا له القدرة على العمل تلقائيا في ضبط تكرار الري عندما نخطط في المستقبل لتجارب محددة الهدف "لقيم EC و pH". سيتم اعادة استخدام مياه الصرف لزيادة كفاءة استخدام المياه والمغذيات في البيوت المحمية المائية والحد من التأثير البيئي لتصريف مياه الصرف. سيتم رصد الرقم الهيدروجيني ، و التوصيل الكهربي من تدفق المواد الغذائية إلى النباتات او الصرف من وسط بيئة النمو باستمرار باستخدام عدادات الرسمدة. سيتم جمع البيانات البيئية داخل البيتين المحميين على حد سواء باستخدام أجهزة الاستشعار واجهزة قياس المناخ. سيتم تسجيل البيانات الدورية على نمو المحاصيل وعناصر الانتاج في جميع المعاملات. سوف تحصد الثمار بناء على لون الفاكهة عموما مرة واحدة كل أسبوع. سيتم حصادها عندما تصل80٪ من ثمار مرحلة النضج الحمراء. سوف توزن الفواكه وتدرج على الفور بعد الحصاد وتخزينها تحت التبريد لتقييم معايير الجودة لاحقا في غضون24ساعة. وسوف يقاس تركيزات كل من الليكوبين، الكلوروفيل، والمواد الكلية الذائبة(TSS) من الفواكه كل أسبوع لجميع طماطم المعاملات. وسيتم تحليل البيانات التي تم جمعها في التجربة باستخدام البرمجيات (SAS) ، وسيتم تحليل دلالات وأهمية المعاملة بين المعاملات الفردية عن طريق تحليل التباين (ANOVA) ، واختبار الفرق الأقل معنوية (LSD)، على التوالي. وسيتم توثيق هذه النتائج البارزة للمشروع في شكل كتيبات ونشرات وابحاث منشورة. الصور ذات الصلة، والرسوم البيانية والجداول سوف تدرج في هذه المواد المنشورة. كما يتم توثيق النتائج في شكل وسائط متعددة والتي سوف يتم استخدامها كافة لتدريب المزارعين والطلاب.
الاستماع
قراءة صوتية للكلمات
القاموس
1. Introduction
The Kingdom of Saudi Arabia lies in the tropical and sub-tropical desert region of the Middle East. The oil resources of the Kingdom have enabled it to be one among the highest per capita GDP nations in the world. Agriculture is an important sector in the economy of the Kingdom. It assumes strategic significance not only in attaining food security but also in generating gainful employment to the rural people. The agriculture sector witnessed an impressive annual growth rate of 10.9 per cent as compared to GDP growth of 11.6 per cent between 1969 and 2004. This was possible due to private sector investment in agriculture, adoption of modern technologies and substantial financial support by the Government. As a result, the country not only achieved self-sufficiency in wheat, milk, and vegetables, etc., but also exported wheat for some time. The rapid progress witnessed in agriculture sector was at the cost of the fast dwindling non – renewable underground water resources. Thus, the country is now faced with a formidable challenge of adopting a sustainable agricultural policy to meet food requirements of a population of 27 million people, growing at the rate of 2.9 per cent annually. This challenge necessitatesstriking a delicate balance between Food Security and Water Security. Soil and water resources coupled with use of fertilizers determine the production potential of agricultural ecosystems. Increased crop yields are associated with increased water and fertilizer use and modern research is focused on maximizing the Water and Fertilizer Use Efficiency (WFUE). The fast dwindling global fresh water and renewable water resources coupled with increased demands for water from agricultural sector are threatening the food and water security of nations around the world. As a result, approaches to water resources management are also changing dramatically. This “Changing Water Paradigm” has many components: a shift away from reliance on finding new sources of supply, a growing emphasis on ecological values, a re-emphasis on meeting human water needs and a conscious breaking of the ties between economic growth and water use (Gleick, 2000).
Agricultural situation in Saudi Arabia:The nation’s cultivated area in 2007 was 1.074 million hectares (m.ha) with a production of 2.967 million tons (m.t.) of grains, 2.6 m.t. of vegetables and 1.581 m.t. of fruits including 982,000 tons of dates. Saudi Arabia imported 190,000 metric tonnes of tomatoes worth US $ 62 million in 2009.The soils in Saudi Arabia are sandy in nature, with low organic matter content and poor water and nutrient holding capacities. The long term annual precipitation of the country has been estimated at 114 mm per year. The annual water demand has been steadily increasing due to comprehensive development in all sectors coupled with high growth rates in population and living standards. Agricultural sector utilizes around 80 per cent of the total quantity of water used in the Kingdom (Abderrahman 2001). The available surface and ground water resources are limited, precipitation rates are low and evaporation is high. Such eco-physical conditions pose significant challenges to agricultural activities. The sustainability of agro-ecosystems of Saudi Arabia depends heavily on conservation of natural resources such as soil and water. However, steady decline in finite water resources and continued degradation of soil resources make the task much more challenging. Besides, the external inputs required for agricultural production are becoming scarcer and costlier. Thus there is an urgent need to conserve the natural resources and to increase the input use efficiencies to achieve sustainability of agriculture in the kingdom.Greenhouse construction and protected cultivations alter microclimate conditions to favour plants’ productivity but they also predominantly reduce transpiration and increase water productivity (litres of water per Kg of production) by a factor of 3-5.
Hydroponics: Increasing demand for food and rising food prices have created a dire need for adoption of sustainable food production strategies. In recent times, skyrocketing of food prices have led to social unrest in many parts of the world. Production of crops inhydroponic greenhouses results in increased food production, improved quality, conservationof resources, and protection of the environment.Hydroponicsmeans cultivation of plants without soil.Itis also referred to as nutrient-solution culture,soilless culture, water culture, gravel culture and nutriculture (Marr, 1994).Soil is medium of plant growth that offers mechanical support to the plant, stores water and provides plants with the required nutrients. However, continuous and intensive use of soil in greenhouses has led to infestation by plant pathogens and deficiency of essential nutrients. This has resulted in the use of soil disinfections leading to pollution of the environment and damage to fertigation systems. Hydroponics is a viable system that overcomes these problems. Growing of plants in nutrient solutions (water and fertilizers) with or without the use of rooting medium (e.g., rock wool, perlite, peat, vermiculite, gravel, coir, sand, gravel, and sawdust) is known as hydroponics.There are two types of hydroponic systems:1. Open System, where in, nutrient solution that is fed to plants is drained out andnot reused 2.Closed System where in the excessnutrient solution is reused.In hydroponics, either organic substrates or inert substrates are used as mediaor there could be total absence of substrate. In the latter, there will be a thin water filmwhich is known as Nutrient Film Technique (NFT). The substrates used in hydroponics, act as anchorage to plantsand have a very low cost of replacement; and there will be no need for costly disinfections. Extensive research on plant nutrition in hydroponic systems has been carried out.Hydroponic systems that are automateduse considerably less water and yield much higher than the conventional agricultural systems. The ecological footprint is improved and this leads to “zero emissions” greenhouse or the “green” greenhouse. Saline water can be used for growing salt tolerant or moderately salt tolerant crops such as tomatoes in hydroponic greenhouses. In Saudi Arabia, water is not only scarce but also precious. In such a situation, studies on the use of saline water without sacrificing onyield and quality of crops are very much necessary to determine appropriate water management practices. The various options that facilitate for the use of saline water are: conjunctive use of saline water with non-saline water, improved plant nutrition,mist coolingandelevated levels ofCO2. However, in Closed systems the salinity build up that occurs due to recirculation of excess nutrient solution can be dealt with by practicing a ‘run-to-waste’ system. Hydroponic production of vegetable crops is possible throughout the year without any problems of soil salinity, adversaries of climate, infestation by weeds, pests and diseases.Since hydroponic production is possible throughout the year and the quality of the produce is also better, premium rates can be obtained for the produce obtained during off-season. Tomato yields of 100 kg m-2 per year under hydroponicshave been reported from The Netherlands. The water use efficiency of 60-70 kg of tomato per cubic meter of waterin hydroponics has been reported as compared to 12-15 kg of tomato per cubic meter of water obtained through traditional agricultural practices.Hydroponics is an extremely efficient, environmentally friendly agricultural production system and ideally suited to widespread adoption in Saudi Arabia, where water is becoming increasingly scarce. The country is faced with a difficult situation of meeting the food needs of a growing population by reducing the dependence on imported fresh food produce. At the same time, increasing productivity per drop of water even under extremely high temperature conditions is really a challenge.Therefore farmers are looking for sustainable agricultural technologies that also result in conservation of resources. Hydroponic production technology meets most of these specific requirements.
2. Project Objectives:
- To study the effects of saline water on the yield and quality of tomatoes in hydroponicgreenhouses.
- To determine the effectsand Best Management Practice of conjunctive use of saline and non-saline water on the productivity of tomatoes in hydroponic greenhouses.
- To assess the impact of grafting on salt tolerant root stock, improved plant nutrition (elevated levels of P, K,Ca, Fe and Si) and mist cooling on salt tolerance in hydroponic tomatoes.
- To provide training on hydroponic greenhouse technology to students and the farming community.
3. Review of Literature
Types of Hydroponic System: Two types of hydroponic system are exists namely i) Closed and open/semi open systems
Closed System: The nutrient solution is recirculated in closed systems (Donnan, 1994a). There are two types of closed systems: Nutrient film Technique (NFT) with continuous recirculation and, flood and drain system with intermittent recirculation. In NFT, there will be reduced consumption of water and fertilizers and the environmental pollution that is generally associated with over irrigation of soil- or soilless-grown greenhouse crops. Closed systems are compulsory in the Netherlands.The systems are leached at a threshold level of 8 mol m-3Na+ in tomato (Baas and Berg, 1999). In closed systems, water and nutrient efficiencies are improved but the EC of nutrient solution increases (Conversa et al, 2003). Lopez et al (2003) reported negative effect of recirculation of the nutrient solution on the fruit yield and quality of greenhouse grown tomato. Donnan (1994b) while comparing open and closed systems, reported that irrigation water and EC management are usually easier in recirculating systems while nutrient management is difficult; hence, currently no more than 10% of the world’s commercial hydroponic crop production uses these systems. According to the conclusions of a simulation study carried out by Stanghellini et al. (2005), closed systems are not financially viable. Anastasiou et al (2009) has concluded that in closed systems the critical process is the balancing of nutrient solution whereas in open systems irrigation scheduling is more critical to save water and fertilizers.
Open and Semi Open Systems: In open systems the nutrient solution is not recirculated (Donnan, 1994a). Also known as run to waste systems, they use dripper irrigation of soilless media in containers. In open hydroponic systems, since solution is not recovered and recycled, the quality of the irrigation water is less critical. In Semi open systems, solution is recirculated and drained occasionally. A content of up to 500 ppm of extraneous salts is easily tolerated, and for tomatoes even higher salinities are permissible. The drainage should be collected and tested periodically for total dissolved salts and if salinity of the drainage reaches 3,000 ppm or above, the bags must be leached free using plain water in the irrigating system.Given the fact that hydroponic systems allow for drainage sampling and on-line measuring of pH and EC, Sigrimis et al (2001) achieved control of watering at high precision of drainage percentage and fertilizer injection at target EC of drainage solution, irrespective of changes in transpiration conditions.
Media and irrigation scheduling in hydroponics: Root anchorage and plant support must be supplied in solution hydroponics systems. Media such as sand, peat gravel, scoria, and mixtures of vermiculite, bark, sawdust, peat, and perlite, have been used successfully(Cotter and Corgan 1974; Johnson 1985) to support the plants in a manner similar to that of soil. A complete plant nutrient solution is regularly added to these media. Medium solution retention may be limited (particularly with the coarse aggregate materials), and this requires frequent rewetting throughout the day. Conventional greenhouse and nursery systems usually deliver nutrient solutions in appropriate quantities and times so that the medium is fully wetted and a small amount leaches away (about 10-30 percent). In hydroponic culture the nutrient solution can be recycled or used only once. Frequently one-time use of a solution is convenient. Even more recently, techniques that deliver complete nutrient solutions to the roots in a continuous nutrient film (Cooper 1979, 1985; Edwards 1985) have been described and used successfully. Regardless of the system, the availability of adequate oxygen (O2) in a root zoneis essential. The nutrient film technique (NFT) innovation reported by Cooper (1985) includes the use of a split root technique that alternately provides dissolved nutrients to one half of the root system at a time. In the other half, root O2 exchange is enhanced. Donnan (1992) recommended recirculating NFT or flood and drain gravel channels for short term crops such as lettuce, and non-recirculating, media-based systems for longer term crops or those very vulnerable to root disease. He further observed that recirculating systems aren’t suitable for water with high dissolved salts. The level of salts which can be tolerated in the water depends on their composition and the type of crop is to be grown. Even 50 ppm of sodium can be toxic to plants such as lettuce, straw berry and rose. In contrast tomato could cope with over 200 ppm (Donnan, 1994a).The optimum supply of water and nutrients is crucial in hydroponic growing systems in order to use water efficiently, avoid stress situations and improve production. Adaptive and learning techniques, based on Solar Radiation (Sigrimis et al 2001) for prediction of system response have attained a drain regulation accuracy of better than 3%.Lizarraga et al (2003) evaluated two irrigation scheduling techniques for hydroponic tomato production in Navarra, northern Spain. The results showed that irrigation scheduling by time clock was not flexible enough to satisfy the varying crop water requirements through the day and during the season. With constant irrigation intervals and volumes, water and fertilisers were wasted during the morning (excessive irrigation) whereas during the afternoon, the plants suffered water stress. Their recommendation of scheduling of irrigation at a radiation level of 0.81 MJ m−2, with some supplementary time clock irrigation applications during the hours of darkness (in order to keep the growing medium wet) has come in to practice. Hochmuth and Hochmuth (2008) reviewed the nutrient solution formulations designed by them in 1990, for hydroponic tomato production systems. They reported that the media (perlite, rock wool or NFT) required frequent irrigations during the day, ranging from 10 to 20 cycles per day, depending on the weather and greenhouse environment, in order to maintain about 20% solution leach.