Friday, 28 February 2014

Iraq Has a Great Capacity to Diversify and Boost its Agricultural Products

Iraq Has a Great Capacity to Diversify and Boost its Agricultural Products and Exports of N, P, and S Fertilizers
M.S. Berigari*
Iraq has a high capacity to diversify and boost its agricultural products as well as its exports of NPS fertilizers with its abundant phosphate, sulfur, and fossil fuel reserves to obtain surplus capital.  Thus, it can invest enough capital in developing the extensive arable land, water and human resources, and suitable climate and soils for multiple cropping systems annually. That should enhance its GDP (gross domestic product) and reduce drastically the currently high rate of unemployment.  By using up-to-date technology in intensive farming management it can increase its agricultural products of the essential grains, oils, legumes, vegetables, fruits, and forage crops as well as diverse animal products. Providing the essential nutrients in optimum amounts to various crops and optimizing other crop production parameters will ensure high crop yields and giving equal momentum to animal products will represent a giant step forward in achieving food security in Iraq as a strategic necessity.   Moreover, with proper soil drainage the number one soil problem (soil salinity) can be controlled in the soils of middle and southern Iraq.  It can, also, overcome water limitations for agriculture through efficient drip irrigation systems wherever applicable. Furthermore, to give a complete picture a list of inorganic fertilizers syntheses is included in this review.

Recent geological studies by the US Geological Survey and the Iraqi Geological Survey confirmed that after Morocco, Iraq has world’s largest phosphate rock reserves of 5.75 billion tons, in Akashat in the Anbar governorate (20).  And Iraq has large sulfur deposits in Mishraq in the Naynewa governorate. That is in addition to its abundant fossil fuel reserves in many parts of the country. Therefore, Iraq should plan for a large scale production of ammonia (N), phosphate (P), and sulfate(S) fertilizers to meet the increasing global and domestic demands for agriculture during the 21st century.  In fact it can become a major exporter of these fertilizers and their derivatives especially when the world demand for phosphate fertilizer has been and will be very high.
 Because phosphate is a major plant nutrient with distinct growth-limiting capacity in many soils where it is strongly bound to the soil solid phase and often becomes unavailable for plant root absorption but remains in soils. Therefore, global food production relies heavily on phosphate fertilization.   However, world phosphate reserves are limited and expected to be depleted before the end of the 21 st century (11). Consequently, world is facing great challenges to find solutions for this critical problem through intensive research on phosphate solubilization in soils to enhance its uptake by plant roots for higher crop yields and to cope with the increasing demand worldwide for food during 21 st century.
When the economic impacts of these fertilizers on agriculture of Iraq and their exports are added to that of petroleum exports, its gross domestic product (GDP) will increase significantly.  That should reduce the currently high unemployment rate remarkably, enhance the standard of living for its people, and consequently promote political stability as the absolute goal and necessity for the Iraqi society to have a brighter future.

The agriculture capacity of Iraq is very large considering:
 1) Extensive areas of arable land suitable for growth of all types of arid and semi- arid- zone crops with mechanization along proper soil drainage under irrigation,
 2) Adequate water resources for efficient drip irrigation systems wherever applicable to overcome the limited water supply from the two rivers (Tigris and Euphrates),
 3) A long growing season with excellent sunshine duration for growth of multiple crops annually,
 4) Long term availability of the macronutrients N, P, and K from fertilizers and possibly K, Ca, Mg, and S presence in the soil minerals, and
 5) Enough human resources.
Therefore,  a great potential exists for agriculture development in Iraq when taking all these factors together and adopting vigorous plant breeding, certified seeds ,  plant protection, soil fertilization, comprehensive extension program for up- to- date crop production managements, and adapting new plants. For example, soybean is an excellent source of protein and cooking oil, canola an excellent source of high quality cooking oil, and jojoba with its unique liquid wax for many industrial uses.  Jojoba wax resembles in many ways the sperm whale oil (liquid wax).  However, sperm whale (Physeter catodon) is an endangered species, its hunting is forbidden and jojoba oil (wax) is an excellent substitute for its oil (wax).  Further, cherry plants should be grown in the Kurdistan Region where the climate and soils are suitable for their growth instead of importing this fruit from neighboring countries.  Add to the list pecan plant that is expected to do well in the Kurdistan Region since it is very much like walnut, a good source of omega-3 fatty acid, and its nut is favorable in terms of its good taste and thinner shell.
 It is equally important to focus on animal production by a vigorous program for animal breeding, nutrition, and protection from diseases and pests. Moreover, there is a definite need for diversification including cattle, sheep, goat, poultry, fish, and honey bees. The country should introduce and adapt high quality animals in terms of high milk, meat, and other animal products.  For example, Holstein cow with its high milk production can grow in Kurdistan Region where the climate is more suitable.  In fact Kurdistan Region has the advantage of specializing in animal production because of the suitable climate, availability of good quality water resources, natural pastures, and other cultivated forage crops.
It is clear that Iraq can create an intensive and diverse agriculture to reach self- sufficiency within a ten year period in most essential grains, oil crops, legumes, vegetable crops, and fruit trees.  That is in addition to various forage crops for feeding a diverse group of livestock and poultry for their meat (white, and red), milk and other products, and including fish especially those with high omega-3 fatty acid content.  
The soils of Iraq in general are slightly to moderately weathered and are high in potassium supplying power as is the case with other soils of arid and semiarid regions (11), thus, the need for potassium fertilizer import is not great despite the fact that K+ is subject to fixation under wet and dry soil conditions by 2:1 type clays which are abundant in soils of Iraq (3).  NH4+ ion has the same ionic size as K+ ion and is subject to fixation similarly under wet and dry soil conditions by 2:1 type clays (2).  Fixation of both NH4+ and K+  results in equivalent reduction in soil cation- exchange capacity(CEC), a very important soil fertility property in retaining cations from leaching(2,3).   ln general soils of Iraq are, also, calcareous, hence, are very high in Ca and Mg contents as calcite (CaCO3) and dolomite ( CaCO3.MgCO3) minerals.
 However, there are numerous gypsic soils (4) containing significant amounts of sparingly- water soluble gypsum (CaSO4.2H2O) which can release more available Ca2+ than either calcite or dolomite (1) but require special management due to sinkhole problems. Therefore, there will be sufficient quantities of macronutrients preferably in the order N≥K>Ca>Mg≥ P>S to meet the plant requirement (15) during the coming decades for agriculture in Iraq. However, soils are less likely to be deficient in Ca, Mg and S than the other three N, K, and P that are added as fertilizer elements to soils (15).   It is very important to apply these fertilizers to soils in balanced forms in terms of the ratio of N: P: K and to other essential plant nutrients for optimum crop yields keeping in mind the nutritional requirement of each crop or each family of crops(14  ) .
 Soil tests and diagnostic plant symptoms should help in revealing any deficiencies in the macronutrients and micronutrients. The micronutrient deficiencies can be corrected by their small scale incorporation with NPK fertilizer and direct addition to soils or more effectively through fertigation or as foliar spray applications when soil pH limits their availability (18).  Because soils in Iraq are dominantly calcareous i.e. are slightly alkaline,  soil pH ˃ 7 which may limits available micronutrients boron, H3BO3, iron, Fe2+, copper Cu2+, manganese Mn2+, and zinc Zn2+ but increases that of molybdenum,MoO42- ( 14 ).   Plants are not likely to show deficiencies in chloride, Cl-, from soils or irrigation water.  In fact there is no shortage of Cl- but a problem of salinity which exists in most cultivated soils mainly as water soluble NaCl in the middle and southern Iraq where soils need adequate drainage
If soils contain enough solid phase reserves of the essential nutrients, plant roots normally exudates enough organic acids to modify the pH of the rhizosphere where microorganisms, plant roots, and soil components are actively involved in enhancing the availability of these micronutrients and other nutrients to crops with few exceptions (5). Moreover, there is a good possibility that root exudates could chelate various divalent cations, thus, make them more available.  Plant roots must exudate equivalent quantity of H+ ions  to that of nutrient cations taken up by plant roots and of course equivalent amounts of anions for uptake of nutrient anions such as NO3-, HPO42-, and SO42- to balance the overall electrical charge of soil solution. However, substituting H+ ions for basic cations causes a certain drop in the pH of the rhizosphere which enhances availability of the nutrient cations K+, Ca2+, Mg2+, Fe2+, Cu2+, Mn2+, and Zn2+ whereas soil pH may have variable effects on availability of H3BO3, Cl- , MoO42-, PO42-,3- , and SO42- depending on the concentrations of the divalent cations and soil composition especially Fe and Al oxides (14). It is important to note that plants vary in relation to the level of each micronutrient required and, also, to the levels of their toxicity to various plants (14).
 There is ample evidence that the processes of plant development are controlled by internal signals that depend on adequate supply of mineral nutrients by soil to plant roots (5).   An earlier study (12) revealed that equilibration of some calcareous soil samples of Iraq with citric acid and orthophosphate (P) enhanced available (P) whereas both oxalic and tartaric acids rendered P relatively unavailable in the soil samples.  A more recent study (11) confirmed that phosphate availability and uptake by the young root system of oilseed- rape was enhanced by exudation of organic acid anion citrate, and also, facilitated rapid transport of the two anions citrate and phosphate in soil.
It is clear that Iraq and Kurdistan Region in particular can adopt a modern system for agricultural products to fully meet the nutritional requirement of its population.  That is by providing the essential nutrients in optimum amounts to various crops and optimizing other parameters for high crops yields as well as the optimum parameters for animal products.  That will represent a giant step forward in achieving food security as an essential strategy for the country.

1. Methane Gas, CH4:  It is released abundantly from oil wells and upon its immediate contact with air it is burned wastefully. However, it can be harnessed and used as a clean source of energy and, also, to generate H2 gas for the Haber-Bosch process.  That process yields ammonia which is a very important source of nitrogen fertilizers and played a major role in the green revolution of agriculture during 20 th century.
Therefore, chemical engineers can widen the scope of manufacturing plants for N, P, and S fertilizers to increase their export capacities for a diverse economy to take place in addition to heavy reliance on fuel oil exports. Alternatively, the Kurdistan Regional and the Federal Iraqi Governments could obtain economically sound contracts from industrial countries to built large scale factories at various economically suitable sites. The route to infrastructure is clear and should be used in addition to its merits in reducing the unemployment rate of Iraqi population which is a high priority and is currently too high for any form of political stability.
The following outline is presented as a short-cut guide and the details are left for the chemical engineers to implement.
2. Hydrogen Production:   The primary technology currently used for direct production of H2 gas is steam reforming from hydrocarbons.  Many other alternative methods are available including electrolysis and thermolysis of water, H2O(9).
2.1 Steam Reforming:   Fossil fuels are the main source of industrial H2 which is generated from natural gas at approximately 80% efficiency or from other hydrocarbons to a varying degree of efficiency.  Most hydrogen production, however, is obtained by steam reforming of methane or natural gas (9):
a) At high temperatures (700- 1100 ᴼC = 973-1373 ᴼK) H2O steam reacts with CH4 to yield CO, H2 and large quantity of heat in an exothermic reaction:               
CH4(g) + H2O(g) ---------->  CO + 3H2 + energy                           (∆H = -191.7 kJ/mol)
b) At a second stage, additional H2 is produced by the lower temperature steam shift reaction at (130 ᴼC = 403 ᴼK) which is also, an exothermic reaction:
CO(g) + H2O(g) --------->  CO2(g)  + H2(g)  + energy                                  (∆H= -40.4 kJ/mol)
3. Ammonia Synthesis by the Haber-Bosch Reaction: Fritz Haber, a German chemist, pioneered synthesis of ammonia from nitrogen and hydrogen gases in 1904, then obtained a patent for his work in 1908, and was awarded a Noble prize in 1918.    The H2 gas produced from the above reactions can be chemically combined with nitrogen gas from the air through the Haber-Bosch process to produce ammonia which is the basic source of commercial N fertilizer (21) and the reaction is not as simple as it looks but the overall reaction occurs by a series of steps, with hydrazine,N2H4(g), produced at an intermediate stage (13):        
3H2(g) + N2(g) --------˃  N2H4(g) + H2(g) ------> 2NH3(g) + energy               (∆H = -92.22k J/mol) 
KC = [NH3]2/ [N2] [H2]3
At (300 ᴼC = 573 ᴼK), KC has a value of 9.6, indicating that at this temperature, a considerable quantity of NH3 forms from H2 and N2 reaction. Since the reaction is exothermic increasing temperature will shift the reaction to the left according to the Le Châtelier principle (13, 17).  Thus, increasing temperature will decrease KC (14, 20)However, at low temperatures the speed of the reaction is slow.  Therefore, for commercial production of NH3 a catalyst consisting of a mixture of Fe2O3 and Fe3O4 promoted with K2O,, and Al2O3 is used to speed up the Haber-Bosch reaction at temperature between 400-600 ᴼC = 673-873 ᴼK while maintaining a pressure of 200 atmosphere or 2.03 x 104 k Pascal (Pa) during the course of the reaction(8, 13).
 Moreover, for an efficient reaction to proceed the NH3 and heat generated must be constantly removed from reaction system and stored.  And, also, increasing the pressure is the best choice to favor the forward reaction because there are 4 moles of reactants for every 2 moles of the product and at a constant temperature the volume is reduced to 2/4 or 1/2 according to Boyle’s Law. Thus, the forward reaction is favored based on the Le Châtelier principle (17) yet the entropy, extent of randomness as a universal law, decreases by converting 4moles of the reactant gases to two moles of the gas product.  Once anhydrous ammonia is produced it can be used to make other forms of nitrogen fertilizer such as urea, ammonium phosphate, ammonium nitrate, and ammonium sulfate (8).  For example:
4. Urea Synthesis:  Ammonia is a gas at room temperature under one atmosphere = 101.3 kPascal of pressure and is easily compressed into a liquid that can be stored and transported.  In the anhydrous form it is applied directly to soils as fertilizer. When ammonia is reacted with CO2 yielding urea, an organic compound, which is solid at room temperature and easier to transport and handle by unskilled workers and when applied to soils it slowly releases nitrogen to crops (14).
2NH3(g) + CO2(g) ---------->  NH2 +  CO + NH2(s) + H2O(l)                              
5. Ammonium Nitrate: This is highly soluble in water and disassociates into ammonium and nitrate ions (equation b) both of which are taken up from soil solution by plant roots. 
a)  NH3(g, l) +  HNO3(l) -----------˃  NH4 NO3(s)                                                                                                   (6)
b) NH4NO3(s) + H2O(l) -----------> NH4+(aq) + NO3-(aq)                                     
6. Ammonium Sulfate:  Ammonia reaction with sulfuric acid yields this fertilizer which supplies both nitrogen and sulfur elements when it dissolves in water or soil solution:
a) 2NH3(g)  +  H2SO4(l) ---------->  (NH4 )2SO4(s)                                                                       (6)
b) (NH4)2SO4(s) + H2O(l) -----------> 2NH4+(aq) + SO42-(aq)
7. Ammonium Phosphate:  Reaction of ammonia with phosphoric acid will produce this compound as a source of nitrogen and phosphorus nutrients for plant growth:
a) 3 NH3(g) + H3PO4(l) -----------˃ (NH4)3PO4(s)
b) ( NH4)3PO4(s) + H2O(l------------->3NH4+(aq) + PO43-(aq)
8. Sulfur Dioxide Production:  Sulfur element from its ores or as a byproduct from oil refineries is melted, filtered off impurities, and then oxidized with oxygen in the exothermic reaction:
S(s)  + O2(g) -----------˃ SO2(g)   +  energy                                                        (∆H = -300 kJ/mol)               
9. SO2 Conversion to Sulfur Trioxide:  The SO2 is reacted with O2 in the presence of a catalyst, V2O5, to yield SO3 in the exothermic reaction:
2SO2(g) + O2(g) ----------> 2SO3(g)  + energy                                            (∆H = -100 kJ/mol)
10. Sulfuric Acid Formation:  The SO3 is then absorbed into counter-current flow of H2SO4  to give more H2SO4 by the exothermic reaction:
SO3(g) + H2O(l) -----------˃ H2SO4(l)  + energy                                                           (∆H = -200 kJ/mol)
11. Superphosphate Production:
a) The phosphate rock must be ground until at least 75% is ≤ 75 µ (micron) in diameter, and then perform its composition analysis. The proportions of various minerals present are amended to give the desired composition.
b) Phosphate ground rock, sulfuric acid and water are mixed and allowed to dry and react to yield superphosphate-a mixture of CaSO4 and Ca(H2PO4)2.H2O (6):
Ca3(PO4)2(s) + 2H2SO4(l)  + 2 H2O  ----------˃ Ca(H2PO4). 2H2O(s) +   2CaSO4(s
The underlined compounds represent more soluble superphosphate in soil solution (6) that supplies crops with P, S, and Ca nutrients.
c) Granulation is achieved by grinding the superphosphate cake to give particles less than 6 mm in diameter.
12. Triple Superphosphate Reaction:  The compound is a fertilizer produced from reaction of concentrated phosphoric acid with ground rock phosphate (10): 
4H3PO4(aq) + Ca3(PO4)2(s) ----------> 3Ca (H2PO4)2(aq)------------˃  3Ca2+(aq) + 6H2PO41-(aq)
The active ingredient of the product, monocalcium phosphate is identical to that of superphosphate except for the absence of calcium sulfate as the case when sulfuric acid is reacted with ground rock phosphate instead of phosphoric acid as reactant (8).
13. Monoammonium Phosphate (MAP):  This fertilizer is produced by the reaction of ammonia as a weak base with concentrated phosphoric acid.  The product is soluble in water yielding NH4+ as a source of nitrogen nutrient and H2PO42- as a source of phosphorus nutrient (7).
NH3(g) + H3PO4(aq) ---------˃ NH4H2PO4(aq) ----------> NH4+(aq)  + H2PO4-(aq)                
 14. Diammonium Phosphate (DAP):  Using two moles of ammonia to react with one mole of concentrated phosphoric acid will produce this form of N and P fertilizer.  When it dissolves in water, it produces two NH4+ ions for every one HPO42- ion (7).
2NH3(g) + H3PO4(aq) ------------> (NH4)2HPO4(s)         
(NH4)2HPO4(s)  + H2O(l) ----------˃ 2NH4+(aq)  + HPO42-(aq)

1.     Berigari, M.S. and F.M. Al-Ani.  1994.  Gypsum determination in soils by
conversion to water soluble sodium sulfate.  Soil Sci.Soc.Amer.J.58:  1624-1627.   
2.     Berigari, M.S.; F.M. Al-Ani; M.A.Umran and L.H.Ibrahim. 1987.  Ammonium
fixation in relation to characteristics of some Entisols and Aridisols of Iraq.  J.Agric.Water   Resour.Res., Baghdad, 6(3):65-81   .

3.     Berigari, M.S.; F.M. Al-Ani and M.A.Umran.  1985.  Potassium fixation by some calcareous soils of Iraq.  J.Agric.Water Resour.Res., Baghdad, 4(4): 89-107.

4.      Buringh, P.  1960.  Soils and Soil Conditions in Iraq (with Soil Maps).   Publ. Ministry of Agriculture, Baghdad.

5.     Dakora, F.D. and D.A.Phillips.  2002.  Root exudates as mediators of mineral    
acquisition in low nutrient environments.  Plant and Soil 245:  35-47.
6.     Hill, J.W.  1992.  Chemistry for Changing Times. 6th ed. Macmillan Publishing    
Company, New York.  Maxwell Macmillan Canada, Toronto:  512-519.            
  12.  Karim, M.I.; M.S.Berigari: F.M.Al-Ani; and L.H.Ibrahim.  1989.  Effect of citric,
          oxalic, and tartaric acids on phosphate sorption by some calcareous soils of
          Iraq.  J. Agric.Water  Resour. Res., Baghdad, 8(1): 51-67.               
  13.  McMurry, J. and R.C.Fay.  2004.  Chemistry.  4 th ed.  Prentice Hall: 841-2.
  14.  Olson, R.A.; T.J.Army; J.J.Haway; and V.J.Kilmer (eds.).  1973.  Fertilizer Technology & Use. 
  15. Plaster, F.J.  1992.  Soil Science and Management.  2nd ed.  Delmar Publ., Inc.  Soil  Sci. Soc. Amer., Madison, Wisconsin
  16.  Reese, M. and Marquart, C.  2010.  Modeling the cost of production of            
        nitrogen fertilizers produced from wind energy:  Presented to the Minnesota        
       Corn Research and Promotion Council, Morris, MN. 

*Dr. Mohammed Sa’id Berigari, Senior Soil and Environmental Chemistry Scientist
5733 Nordeen Oak Court, Burke, Virginia 22015-2209 USA.  

للعراق قدرة عاليه على تنويع وزيادة الانتاج الزراعي وصادراته لاسمدة النتروجين والفسفور والكبريت                                                       
محمد سعيد بريكاري                                                                                                           

لدى العراق قدرة  فائقة  على زيادة الانتاج الزراعي كما ونوعا وكذلك صادراته من الاسمدة النتروجينية والفوسفورية والكبريتية باستغلال موارده الضخمة من النفط  (البترول)  والغاز الطبيعي  والفوسفات والكبريت وتحويلها الى راسمال فائض.   وبذلك يمكن استثمار مبالغ كافيه في تنمية الاراضي الزراعية الواسعة والمصادر  المائية والبشرية وزراعة عدة محاصيل سنويا على نفس القطعة من الارض لملائمة المناخ والتربة في اكثرمناطق العراق.   وهذا ما سيمكنه من مضاعفة الانتاج او الدخل الوطني الشامل والحد من معدل البطالة العالية حاليا الى ادنى مستوى.  وبتطبيق التكنولوجيا الحديثة في الزراعة الكثيفة يستطيع العراق زيادة الانتاج الزراعي لمحاصيل الحبوب , الزيوت, البقوليات , الخضروات , الفواكه , والعلف للحيوانات بانواعها المختلفة.  وبتوفير مقادير مثالية من عناصر تغذية النبات الضرورية والعوامل الاساسية الاخرى لنمو المحاصيل لاجل تحقيق اعلى انتاج,  وباتباع نفس المعايير في الانتاج الحيواني سيخطو العراق خطوة عملاقة باتجاه تحقيق الامن الغذائي كاستراجية ضرورية له.   وتعتبر ملوحة التربة في وسط وجنوب العراق اهم مشكلة تواجه الزراعة فيه.  ويمكن حل هذه المشكلة بتطبيق نظام صرف ملائم وكفوء.  اما بالنسبة للموارد المائية المحدودة الى حد ما فيمكن تفاديها باتباع انظمة الري الكفوءة وخاصة الري بالتنقيط .  ولاعطاء صورة كاملة البحث فقداضيفت اليه قائمة لصناعة مختلف الاسمدة غير العضوية.    

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