Water Salinity Effect on Selected Date Palm Varieties and Management Options for This Problem in Arabian Peninsula Dr. Nazir Hussain, Salim Al-Rasbi, Prof. Helge Schmeisky, Ghanim Abdul Rehman Alghanim and Osman Ahmad El-Sharief Soil Research Section Department of Agricultural Affairs Ministry of Environment Government of Qatar

Date Palm—A traditional and major crop of GCC GCC 28% Other Countries 72% Dates production in the GCC countries and the World (FAOSTAT, 2004)

Comparison of dates production in GCC and the world World GCC countries GCC % of World

Dates fruit production (MT) in GCC Countries Saudi Arabia UAE Oman Bahrain Qatar Kuwait Yemen

The most probable causes of declining production  Water scarcity resulting in under irrigation  Consistent use of saline water  Gradual salt accumulation in the soil and consequent shift of soil EC beyond the tolerance of plant  Lack of monitoring of continuously changing soil and water salinity status  Increase in pests and diseases  Unavailability of more salt tolerant varieties which are capable of facing the changing conditions  Management problem (Lack of interest in farming)

Water demand and water balance in Arabian Peninsula Regional water demand was 6.6 billion cubic meter (BCM) in 1980This demand reached to 22.5 BCM in 1990 Water requirements are expected to reach 28.2 BCM by 2010, and 36.7 BCM by 2025 The water balance was -22,330 million rn3 in 2005 The water balance is expected to go as million cubic meter in 2015.

Some facts about salinity in Arab World and GCC countries  Arab land occupies 1402 mha area  Arable area is 197 mha (14.1%)  Actually cultivated 70 mha (5 %)  Irrigated land 9.5 mha  Salt affected area 82.7 mha (42 % of arable) Salt affected area in GCC countries Salt affected area in GCC countries  KSA 3641 mha  Oman mha  Qatar  Bahrain mha  Kuwait mha  Yemen mha

Date Palm Orchard Affected by Salinity in Oman

Categorization of water quality in Oman 1) EC > 3 dS m-1 = 48.3% 2) EC 3-5 dS m-1 = 12.1% 3) EC 5-10 dS m-1 = 9.5% 4) EC < 10 dS m-1 = 4.2% 5) Uncovered or mix quality = 25.9%

Demand of the day to face the changing conditions of soil, water and climate  Urgent need of research on all the related aspects  Monitoring of land and water resources and the date palm crop status  Surveys and mapping to pin point the problem sites where degradation is occurring  Very strong varietal evolution program  Establishment of data base at country and regional level

Methodology of the salt tolerance experiment A)Categories of irrigation water: ECiw 3 (Control), 6, 9, 12, 15 & 18 dS m-1 ECiw 3 (Control), 6, 9, 12, 15 & 18 dS m-1 B) Date palm varieties: Khalas, Khunaizy and Abunarenjeh  Statistical design: Split plot with four replications  Total number of plants was 72 (6 x 3 x 4 = 72)  A low ECe soil was selected, leveled and prepared for transplantation  Soil samples were collected just before transplantation and twice subsequently with one year interval  These samples were analyzed for ECe and pH

Methodology (Contd.)  The required levels of EC of water (ECiw) were synthesized through mixing of fresh water (EC 1.0 dS m-1) and the saline water (EC dS m-1) in appropriate ratios  Plants were maintained through proper irrigation, weeding and protection  Data were recorded annually for plant height, trunk girth, number of new fronds (leaves) and length of fronds  Leaf analysis was completed for N, P, K, Na, Ca, Mg and Cl

Analysis of the original soil ValuesUnitDeterminations 7.7-pHs 2.77 dS m-1 ECe 0.89 (m mol L-1)1/2 SAR 0.21% Organic matter 0.003% Total nitrogen 12.4 mg Kg-1 (ppm) Available phosphorus Loamy sand - Textural class

Analysis of irrigation water EC 18 dS m-1 EC 15 dS m-1 EC 12 dS m-1 EC 9 dS m-1 EC 6 dS m-1 EC 3 dS m-1 Parameters EC dS m SAR (mmol L-1)1/2 NilNilNilNilNilNil RSC mmolc L pH

Effect of water EC on date palm trunk height

Effect of water EC on number of fronds of date palm varieties

Effect of water EC on leaf length of date palm varieties

Effect of water EC on trunk girth of date palm varieties

Effect of water salinity on plant characters of date palm varieties

Percent decrease in growth parameters of date palm varieties due to overall effect of water salinity (EC 3-18 dS/ m) Trunk girth Leaf length Number of fronds Plant height Varieties Khalas Abunarenjeh Khunaizy

Summary of negative effect of saline water on plant parameters (% decrease over control) Trunk girth Leaf length Number of fronds Plant height Water EC ds/ m

Correlation of water salinity (ECiw) with different parameters Significa nce Slope Coefficient of Cor. (r2) Parameter ** Leaf Na ** Leaf K/ Na NS Leaf Ca ** Leaf Mg NS Leaf Cl ** Soil EC

Correlation of water salinity (ECiw) with different plant nutrients Signific ance Slope Coefficient of Cor. (r2) Parameter NS Leaf N * Leaf P NS Leaf K NS Leaf Fe * Leaf Mn ** Leaf Zn NS Leaf Cu

Effect of water salinity on soil EC after two years

Experiment No. 2: Managing saline water for growing date palm The objective of this experiment was to standardize some management practices that are effective to minimize the deleterious effects of saline groundwater.Treatments: A) Categories of irrigation water: EC 6 & 9 dS m-1 A) Categories of irrigation water: EC 6 & 9 dS m-1 B) Management practices B) Management practices 1.Control (No leaching fraction and no organic matter) 2.Application of irrigation water including leaching fractions of Application of irrigation water including leaching fractions of Application of organic matter (crop residues) 10 kg/ plant/ year 5.Leaching fraction Organic matter (Treatments 1 + 3) 6.Leaching fraction Organic matter (Treatments 2 + 3)

Role of leaching fractions in improvement of growth character of date palm seedlings when irrigated with saline water

Effectiveness of leaching fractions in controlling increase in soil EC during irrigation with saline water

Efficiency of organic matter application in maintaining plant growth parameters during saline water irrigation

Effectiveness of organic matter application for controlling increase in soil EC during irrigation with saline water

CONCLUSIONS  The growth of the three date palm varieties (Khalas, Khunaizy and Abunarenjeh) was decreased significantly during irrigation for two consistent years with saline water (6-18 dS m-1) when compared with 3 dS m-1 even in sandy soil with good drainage.  However, 50 % decline was recorded only at water EC 18 dS m-1. Therefore, date palm could be regarded as highly salt tolerant.  Much difference between salt tolerance potential of three varieties was not recorded, only Khunaizy showed a little edge over the other two.  Leaf ionic concentration of date palm changed with saline water irrigation. There was a significant increase in Na, decrease in K while Cl remained unchanged.

CONCLUSIONS  The physiological basis of salt tolerance in date palm was a strict control on Na and Cl concentration in leaves and keeping up the K content with narrow K/ Na ratio.  Applying more water in the form of Leaching Fractions (LF 0.15 and 0.22) proved partially useful because its effectiveness decreased at water EC of 9 dS m-1, especially in the second year.  Similar was the usefulness of organic matter (10Kg plant-1 year-1). However, coupling of both proved more effective.

RECOMMENDATIONS 1.Date palm plants (seedlings during vegetative growth) can be irrigated with saline water when good quality water is not available. However, significant decline in growth will be expected when the EC of irrigation water exceeds 9 dS m-1 that may reach up to 50% in case of EC 18 dS m-1, used on sandy soil with very good drainage 2.Three varieties; Khalas, Khunaizy and Abunarenjeh revealed a good salt tolerance potential and can be grown with saline water of EC up to 18 dS/ m 3.In the absence of any other option Leaching Fractions (LF) can be regarded useful technique to check deleterious effects during irrigation with saline water but may not be adopted blindly. This technique can usefully be used when water EC is not too high (Exceeds 9 dS m-1) and texture is light with good soil drainage 4.Application of organic 10 kg/ plant/ year is another useful management practice to mitigate deleterious effects of saline water. Its combination with LF can prove more effective provided that EC of water is not beyond 9 dS/ m

Future research required in this field  The investigations on irrigation with saline water will be required on later stages of growing date palm; the reproductive, fruit setting and maturity stages.  Data have to be generated under medium and heavy soil textures with relatively restricted drainage.  The percentage losses for the whole life cycle of date palm have yet to be finalized through long-term studies (5- 10 years).  Some more management techniques have to be brought out through different investigations so that negative effects on plants and soil can be avoided and minimized.  Studies on fertilizer application including N, P, K and micronutrients during irrigation with saline water at later stages of plant growth will be required.  Experimentation on some more varieties can be undertaken to prepare a long list of salt tolerant cultivars of date palm.