IV. COUNTRY REPORTS

1. Afghanistan
2. Cyprus
3. Iran
4. Iraq
5. Jordan
6. Lebanon
7. Libyan Arab Republic
8. Pakistan
9. Qatar
10. Saudi Arabia
11. Somali Democratic Republic
12. Sudan

1. Afghanistan

1.1. Introduction

Afghanistan is an interesting country, popularly called the land of mountains or the Switzerland of Asia. It lies between 29 and 38° north and the elevation varies from high mountains (up to 7 620 m) to arid desert plains, with the most general height being 1 200 m above sea level. The climate is cold in winter, hot and dry in the summer. Rainfall is scanty, nowhere more than 381 mm annually with much of the precipitation as winter snow and spring rains.

The total area is 653 000 km² with an estimated population of 17 million, 85 percent of which is classified as rural and 15 percent as urban. It is estimated that about 14 million hectares of land is cultivable, with 2.3 million hectares under wheat irrigation.

Afghanistan's economy is dependent on production and export of crops and livestock products. Principal exports are dried and fresh fruits, nuts Karakul pelts, raw cotton, wool, carpets and rugs.

1.2. Soils of Afghanistan

A detailed soil survey of the country is yet to be completed, however a generalized map of the soils of Afghanistan is presented in Fig. 1.

A study of the Genesis of Afghanistan soils indicate that these are developed predominantly from the influence of climate. Since moisture is low, physical weathering is more pronounced than chemical and soil formation has proceeded rather slowly. Most of the products of weathering are retained within the soil itself.

Calcification is the most dominant soil forming process in dry conditions. In areas of low rainfall there is a tendency to evaporation from the surface and replacement from the water table below. The groundwater which is drawn up often contains large amounts of dissolved calcium bicarbonate and on evaporation the calcium carbonate is deposited within the soil-body resulting in an accumulation of this substance. Leaching of the soluble materials from the surface downwards is minimal because of the absence of percolating water.

Horizons and features of three representative soil profiles are presented in Fig. 2. An examination of these shows that:

a) The profile of Kabul silt loam has a marked textural and structural B horizon. In the sub-soil there is an abundance of irregular calcareous nodules, less than 8 cm in diameter. A few calcite tubes, calcareous tubules and columnar Krotovinas, all about 2.5 cm in diameter were observed. A horizontal calcite plate 1 mm thick lay at a depth of 150 cm and was continuous except for the points at which it was pierced by calcite tubes.

b) The second profile at Nadi Ali, had a gravelly tertural II B horizon under a massive vesicular Ap, Pinkish white calcium carbonate nodules (7,5 yr 6/4 D) less than 1 cm in diameter are abundant in the II B 21. At a depth of 175 cm there is a petrocalcic horizon of unknown thickness.

c) The third profile is undisturbed Boast sandy loam, has a discontinuous desert pavement (Ar), and has the most cemented horizon. The II CICS between 58 and 82 cm contains more than 50% by volume of calcium carbonate and associated gypsum and salts. The weakly cemented III C6CS horizon does not effervesce with acid.

Figure -2- Horizonation and Features of Representative Soil Profile of Afghanistan

The soils of Afghanistan are alkaline in reaction. Most of the samples studied have a pH much higher than 7.0. It is estimated that nearly 50% of the soils of Afghanistan have a pH between 8 and 8.5, about 35% between 8.5 and 9.0 and about 10% between 9 and 9.5. It is also known that soils with a pH of 8.0 to 8.5 are generally rich in alkaline earth carbonates, except for the soils of Panjshir Ghorband Valley. All the soils studied so far have a calcium carbonate content of 10% or more; soils of the Ghazani area have in general 10 to 12% calcium carbonate, Kunduz soils show 10 to 15% Kabul and Katawaz 10 to 20%, Hari-Rud 15 to 20%, and Farah, Logar and Adras Kand areas show 20 to 25% calcium cargonate in the surface samples. Occasionally in some areas CaCO₃, content is more than 40%.

1.3. Response of Wheat, Corn and Sugarbeet grown on the Calcareous Soils of Afghanistan to Fertilization

The excess of calcium carbonate poses serious problems in plant nutrition, mainly because it influences the pH of soil and thus renders micro-nutrients unavailable to plants as well as the unavailability of phosphorus in calcareous soils.

During the FAO Project on soil fertility and fertilizer use, some simple fertilizer experiments were conducted in different provinces of Afghanistan (for details please refer to UNDP/FAO/Report No. TA 30/6).

The average mean yield of wheat as affected by fertilizer treatment is presented in Table 1. Corresponding yields for corn are given in Table 2 and for sugarbeet in Table 3. The average CaCO₃, is given for each province.

From these data it seems that, inspite of high CaCO₃ content, the response to application of N + P is uniformly high and statistically significant. However, more detailed experimentation is needed to draw valid conclusions about management of calcareous soils in Afghanistan.

REFERENCES

Salem, M.Z. and Hole, E.D. 1969, Soil Geography and Factors of Soil Formation in Afghanistan. Soil Science, Vol. 107, No.4.

UNDP/FAO T.A. Report No. 3016 - 1971, Soil fertility and fertilizer use in Afghanistan (based on work of Dr. Tamboli, FAO expert). FAO, Rome.

Table 1. Mean average yield of wheat as affected by fertilizer treatments (kg/ha)

Province	Lagman		Nangarhar		Kabul		Logar		Maidan
Treatment No.	1969 - 70		1969 - 70		1969 - 70		1969 - 70		1969 - 70
1.	1 167	1 719	1 087	1 835	1 655	2 012	1 378	1 691	1 089	1 628
2.	1 542	2 167	1 406	2 251	1 814	2 647	1 555	2 363	1 290	2 346
3.	1 800	2 339	1 710	3 205	2 031	2 768	1 727	2 482	1 441	2 408
4.	1 427	1 953	1 310	2 288	1 985	2 383	1 637	2 087	1 367	1 658
5.	1 540	1 806	1 398	3 094	2 148	2 379	1 721	1 982	1 469	1 991
6.	2 281	3 710	2 265	3 864	3 133	3 925	2 539	3 157	2 776	3 327
7.	2 052	3 273	1 954	2 704	2 590	3 327	2 024	2 787	2 418	2 671
8.	2 292	3 039	2 340	2 871	2 596	3 478	2 168	2 790	2 428	2 913
9.	3 197	4 522	3 304	4 382	5 420	4 781	4 769	3 909	4 900	3 980
10.	1 704	1 826	1 321	2 038	2 134	2 211	1 684	1 860	1 407	1 946
11.	2 354	3 814	2 319	4 026	3 158	4 018	2 591	3 322	2 487	3 379
12.	3 310	4 650	3 376	4 533	5 573	4 764	4 618	3 885	4 690	4 056
CaCO3 %	3.0		10.0		. 14		18		11

Province	Parwan		Kapisa		Ghazni	Baghlan	Kunar
Treatment No.	1969 - 70		1969 - 70		1970	1970	1970
1.	1 296	1 681	1 296	1 748	1 461	1 946	1 641
2.	1 574	2 202	1 574	2 400	1 997	2 350	2 485
3.	1 738	2 603	1 738	2 733	2 311	2 579	2 700
4.	1 570	1 963	1 570	2 156	1 894	2 225	1 833
5.	1 589	2 411	1 589	2 620	1 889	2 203	2 770
6.	2 499	3 643	2 499	3 615	2 781	3 791	3 876
7.	2 335	3 013	2 335	2 845	2 605	3 159	2 915
8.	2 332	3 127	2 332	3 136	2 233	3 000	3 491
9.	4 180	4 418	4 180	4 015	3 444	4 302	4 208
10.	2 029	1 943	2 029	2 551	2 066	2 280	2 100
11.	2 711	3 777	2 711	4 281	2 761	3 289	3 610
12.	3 968	4 486	3 968	4 603	3 411	4 333	4 441
CaCO3 %	3				15	17	3

Treatment
	N	-	P2O5	-	K2O
1.	0	-	0	-	0
2.	75	-	0	-	0
3.	150	-	0	-	0
4.	0	-	75	-	0
5.	0	-	150	-	0
6.	75	-	75	-	0
7.	75	-	150	-	0
8.	150	-	75	-	0
9.	150	-	150	-	0
10.	0	-	75	-	100
11.	75	-	75	-	100
12.	150	-	150	-	100

Table 2. Mean average yield of corn as affected by fertilizer treatment

Treatment	Fertilizers - kg/ha			Yield in kg/ha
No.	N	P2O5	K2O	Paktya1/	Logar2/
1.	0	0	0	1 967	1 905
2.	75	0	0	2 351	2 457
3.	150	0	0	3 859	3 900
4.	0	75	0	2 372	2 495
5.	0	150	0	2 499	2 676
6.	75	75	0	5 906	6 011
7.	75	150	0	3 973	4 035
8.	150	75	0	3 929	4 152
9.	150	150	0	6 844	6 995
10.	0	75	50	2 523	6 680
11.	75	75	50	5 988	6 087
12.	150	150	50	6 950	7 081

^1/ Soils with 15% CaCO₃
^2/ Soils with 18% CaCO₃

^1/ Soils with 17% CaCO₃

2. Cyprus

2.1. Physical. Morphological and Geological features of Cyprus

Cyprus is an island in the eastern Mediterranean sea lying between 34°33' to 35°41' North and between 32°20' to 34°35' East, 70 km from southern Turkey, 100 km west of Syria and 370 km north of Egypt.

Its maximum length is 225 km east to west and its greatest width is 96 km north to south. It covers an area of 9 250 km² of which some 47 percent is arable and about 25 percent under forests. Out of a total population of 640 000, 35 percent of the economically active population is presently engaged in agriculture.

The island is transversed by two mountain ranges, the high Troodos massif in the southwest with the highest peak, Olympus, at 2 000 m and the long narrow Kyrenia range rising to 900 m and bordering the northern coast. Between the two mountain systems lies the central plain, and along their seaward margins a more or less narrow coastal strip.

The Troodos massif consists of igneous rocks, while the Kyrenia range is hard crystalline limestone. Over almost half the central plain there are middle miocene and post middle miocene calcareous marine sediments, such as marls and limestone outcrops. The rest of the plain is covered by pleistocene calcareous of non-calcareous deposits, and by recent calcareous alluvium in some low lying areas. The coastal strips consist of upper miocene to upper pliocene limestones and marls in places, while the rest is covered by pleistocene calcareous or non-calcareous deposits and by recent calcareous alluvium.

Middle miocene soft bedded limestones and chalks stretch from east to west of the southern part of the island over a distance of approximately 145 km. This stretch of land, frequently dissected by deep, narrow valleys, cut down by young rivers flowing to the sea, constitutes the southern flanks of the Troodos massif, and due to favourable climatic conditions, extensive vine plantations have been established on these extremely calcareous soils.

2.2. Climate

The climate of Cyprus has the characteristic features of the arid Mediterranean basin, with a cool wet winter followed by a hot and practically rainless summer. Cyprus, at the northeast corner of the Mediterranean sea and 3 200 km from the Atlantic ocean, is surrounded by much larger land masses and furthermore, these lands around Cyprus are of a dominant arid and semi-arid character. On account of its position Cyprus is influenced by modified continental air masses. Many travelling lows, however, are diverted at the southern corner of Turkey and leave Cyprus unaffected. In addition the major winter front, originating from the Icelandic low and covering most of Europe, seems to end in southern Turkey.

2.2.1 Precipitation and its distribution

Most of the rain falls between November and April, 50 percent of it in December and January. The average annual precipitation ranges according to elevation from 320 mm in the central plain and 500 mm in coastal areas to 800 mm at highest elevations. However, in dry years the central plains receive less than 200 mm of annual rainfall.

Winter rain is the most important element to the vegetative environment of the island as, in addition to the replenishment of the groundwater resources, it provides for the evapotranspiration requirements of dryland farming (cereals, carobs, olives and vines). Its distribution even in the rainy months is uneven and low precipitation in March-April affects adversely the performance of rainfed cereals during their critical physiological stage.

2.2.2 Temperature

The monthly mean maximum temperature in the central plain ranges from 15°C in January to about 35°C in July and August. The coolest areas are the most elevated, Olympus (2 000 m) having a mean maximum of 26°C in August.

The mean minimum temperature ranges from about 5°C to 20°C and frost, although infrequent, may happen unexpectedly.

2.2.3 Relative humidity

The average monthly relative humidity ranges from 40 to 80 percent in the inland plain with lowest in the summer, 50 to 85 percent in the coastal areas and 40 percent in the summer and 80 percent in January-February on the Troodos massif.

2.2.4 Evaporation and evapotranspiration

Evaporation (E pan) in the central plain and measured by USWB class 'A' pan reaches an annual total of 1 750 mm. In coastal areas annual cumulative pan evaporation is somewhat lower at around 1 500 mm. Evapotranspiration (ETp) calculated by Penman formula is about 70 percent of pan evaporation. Typical data obtained for Nicosia were as follows:

J	F	M	A	M	J	J	A	S	0	N	D	Year
37	45	85	143	206	269	285	260	196	119	61	39	1 745 mm E pan
31	41	68	108	142	181	192	184	130	87	46	28	1 238 mm ETp

2.3. Soils

From the pedogenic point of view the soils of Cyprus bear the strong impact of the aridity of the climate and the diversity of the topography, both of which seem to have acted dominantly on the parent material and to have subjugated to secondary importance the contribution of vegetation in the processes of soil formation.

The shallowness of the soil profile and the almost complete lack of well-defined diagnostic horizons indicate that the large soil moisture deficit created from low precipitation and high evapotranspiration has arrested the speed of the soil forming processes known to be active under more humid climates.

Essentially then the soils of Cyprus are typified by this Mediterranean character resulting in low organic matter, high calcium carbonate content in surface horizons, high pH, low mineral nitrogen, low phosphorus and high total and exchangeable potassium.

2.3.1 Soil surveys

Soil survey forms an important part of the activities of the Department of Agriculture under the Ministry of Agriculture and Natural Resources. A systematic soil survey designed to cover the whole island has been in progress since 1956. Until the present, over 300 000 hectares or 70 percent of the cultivated area of the island have been surveyed and covered by detailed soil maps.

In some watersheds land suitability surveys were carried out concurrently with detailed soil surveys in conjunction with proposed development projects, to propose the best land use based on soil properties, climate and availability of irrigation water.

2.3.2 Soil classification

Until 1970 the agricultural soils of Cyprus were classified as:

Rendzinas -	light-coloured calcareous soils formed on soft highly calcareous rock or calcareous colluvium and alluvium;
Terra Rossa -	red-coloured fine-textured soils on hard calcareous
	crust overlying soft mass of limestone;
Alluvial soils-	formed on recent water-borne deposits extensive in the central plain
Carbonate raw - soils	formed on calcareous parent material;
Silicate raw -soils	formed on igneous materials;
Brown earths -	formed on basic volcanic and plutonic rocks;
Bed soils (rotlehm)	formed on igneous conglomerates.

In 1970 the new system of soil classification introduced by the European Commission on Agriculture of the U.N. was adopted and a general soil map of the island at a scale 1:200 000 has been prepared. Under this system the soils of Cyprus fall into nine orders, namely, Lithosols, Solonchaks, Vertisols, Xerosols, Solonetz, Cambisols, Rendzinas, Luvisols and Rhegosol.

The distribution of most of the Cyprus soils classified according to the above-mentioned orders and sub-orders is approximately as follows:

 

Order	Sub-order		Area, km2
Lithosol	calcaric		2 280
	eutric (igneous, lavas)		137
Solonetz	orthic
		saline and alkaline	283
Solonchaks	gleic
Xerosols	haplic	Kythrea formations
			770
Lithosols	calcaric	marls and sandstones
Vertisols	chromic (mamonia)		103

 

Order	Sub-order				Area km2
Vertisol	calcaro pellic
				central plain alluvials of low EC	269
Lithosols	calcaric
Cambisols	vertic				291
Cambisols	calcaro chromic (reddish brown)				1 142
Cambisols	eutric (igneous)				1 434
Rendzinas	orthic
		limestones			832
Lithosol	calcaric
Rhegosols	calcaric				269
Rhegosols	calcaric
		alluvial			229
Vertisols	verlic
Luvisols	rhodo chromic				317
	rhodo calcic

2.3.3 Calcareous soils and their distribution

Soils in Cyprus are calcareous with the exception of those developed on hard igneous rocks of the Troodos massif, on non-calcareous swelling clays outcropping to the southwest and on some pleistocene non-calcareous deposits of the central plain and the coastal strip which could be termed as non-calcareous. It is worth noting here that the vast majority of soils in Cyprus contain free calcium carbonate, they have a predominantly Ca-saturated clay and their pH determined in a 1:5 soil to water suspension is above 7.5.

Soils referred to as "calcareous" vary in lime content from those having a small concentration somewhere in the profile to those containing an appreciable amount of lime throughout the profile. The term "calcareous soils" is used here to designate soils in which the lime content is sufficiently high to affect adversely the nutrition of crops, reduce productivity of the soil and narrow the choice of crops that could be grown on such soils.

The following calcium carbonate classes if adopted could be used for separating calcareous soils associated with properties that may adversely affect plant nutrition, from the rest of calcareous soils:

	CaCO3 Content
Calcium Carbonate Classes	%
(1) Non or almost non-calcareous soils	<5
(2) Slightly calcareous soils	5-15
(3) Moderately calcareous soils	15-35
(4) Calcareous soils	35-55
(5) Very calcareous soils	55-75
(6) Extremely calcareous soils	>75

The distribution of Cyprus soils according to the above system of classification and the proposed calcium carbonate classes may be summarized as follows:

soils developed on the Troodos massif are practically non-calcareous Eutric Cambisols and Eutric Rhegosols;

soils developed on the Kyrenia range are on the majority calcareous and have been classified as Calcaric Lithosols and Mollic Rendzinas;

over the central plain the soils occurring extensively are classified as Calcaric Lithosols and Orthic Rendzinas which are very calcareous; Xeric Vertisols, Calcaric Cambisols and Calcaric Rhegosols which are calcareous; and Rhodic Vertisols, Pellic Vertisols and Vertic Cambisols which are moderately calcareous;

in the northern coastal strip the soils are Pellic Vertisols which are moderately calcareous and Calcaric Cambisols which are calcareous;

soils on the southern coastal strip are Calcaric Cambisols and Calcaric Rhegosols which are calcareous; Chromic Vertisols and Pellic Vertisols which are moderately calcareous; and Gleyic Solonchaks which are very calcareous;

soils developed on the marls, limestones and chalks on the southern flanks of the Troodos massif are Calcaric Lithosols and Ochric Rendzinas which are very or extremely calcareous.

Preliminary results obtained recently from X-ray defraction analysis of clay minerals from a limited number of soils indicate that throughout a 120 cm profile of an alluvial Calcaric Rhegosol, 2:1 lattice minerals predominate with abundant montmorillonite and beidellite and some illite. The predominant minerals in two Rhodo Chromic Luvisols were illite and Kaolinite with some montmorrillonite.

2.3.5 Soil fertility and nutrient availability

As mentioned earlier the agricultural soils of Cyprus in their natural state are poor in nitrogen (0.1 %), poor in organic matter (around 1 59, poor in available phosphorus and rich in total and exchangeable potassium.

Although magnesium is generally in good supply, especially in soils developed on igneous rocks, it may be short in some others.

Lime - induced chlorosis is observed under conditions of high calcium carbonate content coupled with high moisture regimes and on calcareous soils where the surface horizon has been removed in the process of land levelling.

Zinc deficiency is by far the most prevalent micro-nutrient disorder especially in tree crops such as citrus and deciduous.

From leaf analyses manganese seems to be in short supply for some crops but this may not at present be of economic importance.

In spite of the adequate supply of soil potassium, application of potassic fertilizers does not improve the uptake of this element by irrigated tree crops, presumably because of excessive Ca⁺⁺ in the soil solution and possibly due to fixation by clay minerals.

2.3.6 Fertilizer consumption

Whereas in 1960 agriculture in Cyprus used 6 500 t of N, 7 500 t P₂O₅ and 500 t of K₂O, in recent years fertilizer consumption rose to 13 500 t N, 10 000 t P₂O₅ and 1 900 t of K₂O. Thus the value of all fertilizer imports is over £2 million a year. It is estimated that more than 50% of the fertilizer import is consumed by irrigated crops, such as citrus, potatoes and other vegetables representing only 12% of the total cultivated area.

2.3.7 Crop responses

Crops in general respond to fertilizer nitrogen applications and to a lesser extent to phosphorus. Responses of crops to soil application of potassium are an exception rather than the general rule.

Soil fertility studies were the first agricultural research activity embarked upon, long before the establishment of the Agricultural Research Institute in 1962. Since then experimental work in soil fertility has been expanded considerably to include fertilizer field experiments and plant nutrition studies of the most important irrigated and rainfed crops such as citrus, potatoes, carrots, vines, wheat and barley.

From the results of long term experiments the responses of individual crops is summarized in the following paragraphs.

a) Fertilizer Use by Major Crops

Potatoes: previous and recent experiments on fertilizer requirements by potatoes of the commonly cultivated varieties, Arran Banner and Up-to-Date, have established that high yields are attainable with only 110 kg of N applied as sulphate of ammonia and 90 kg P₂O₅ as single superphosphate per hectare per year all applied at planting. This has been re-established from recent work on the fertilization of potatoes in the main growing areas of Terra Rossa. In these experiments close planting at 18-20 cm in rows corresponding to 70 000 plants per hectare irrigated by sprinkling could produce up, to 50 tons of Arran Banner and 45 tons of Up - to-Date. Doses of nitrogen above 150 kg of N per hectare always tended to decrease production. Phosphorus on the other hand, even used at higher rates, had no ill-effect on production. Most of the fields sampled in a survey showed that they had acquired high levels of available phosphorus by the continuous use of high rates of phosphatic fertilizers. Potassium, on the other hand, has never increased yields or improved the quality of potatoes. These findings come in sharp contrast to the practice of potato growers who firmly insist on fertilizing with high doses and up to 2.8 tons/ha of the mixed types of fertilizer 14-22-0 or 14-22-9. On the basis of the present area cultivated with potatoes, it is estimated that the potato growers could save up to £250 000 per year if they were to adopt the recommended fertilizer rates.

Carrots: experiments on the fertilization of carrots grown on Rhodo Chromic Luvisols developed on igneous pebbles have shown that very high exportable yields of 75 - 80 tons/ha of the variety Chantenay could be achieved when fertilized with only 110 kg N/ha as sulphate of ammonia and 90 kg P₂O₅/ha as single superphosphate, all applied at planting. Mechanical triple-row planting and sprinkler irrigation have been used and the high yields are not only attributed to the right combination and amount of fertilizers used but also to the mechanical triple-row planting and the Sprinkler irrigation for maintaining high moisture regimes.

Citrus: within the objectives of the Agricultural Research Institute's crop programme, the study of all aspects of citrus production is of paramount importance. Nutrition and fertilizer requirements of citrus are major aspects of citrus management. Two experiments on the fertilization of Valencia oranges at Morphou (Calcaric Rhegosols) were established in 1962. The results of these experiments so far indicate that 14-year old Valencia orange trees require up to 0.75 kg N/tree as sulphate of ammonia applied in February and 0.25 kg N/tree as nitrate applied in early July to supplement the nitrogen requirements of Valencia growing in light textured soils. The phosphorus requirement under the same conditions was found to be 0.2 kg P₂O₅/tree triple superphosphate per year. Potassium, on the other hand, has not been found to affect either yields or quality of the fruit inspite of the fact that the potassium leaf levels have dropped from 1.15 - 0.65 % since 1962, However, the present levels of potassium in the leaves are considered "low" and current studies are directed towards finding ways and means to increase potassium content in the leaves. In connection with the serious problem of the creasing of Valencia oranges in the Morphou area, which causes serious losses in certain years, a number of experiments have been set up with a view to finding the cause and a remedy for this symptom.

Apples: production is important in certain regions of the island where the climate is sufficiently cold to allow the cultivation of this crop. In addition, the expansion of apple culture makes it necessary to carry out experimental work to determine the fertilizer requirements. An experiment was initiated in 1962 on a Rendzina where the nitrogen, phosphorus and potassium requirements of apples are being studied. So far, although no conclusive results can be cited, it is indicative that apples require 1 kg Nitrogen, 0.3 kg P₂O₅ phosphorus and, interestingly enough, no potassium. In another small experiment initiated at Saittas on the Lord Lambourne variety of apples, it has been shown from leaf analysis at intervals that N, P and K are continuously on the decline from the beginning of July until harvest of the apples.

Lucerne: This has been used as a test crop in a long-term field experiment at Morphou whereby the interest was to find out the direct and residual effects of phosphate fertilization and at the same time exhaust the phosphorus and the potassium of the soil. So far, it has been found that lucerne will require up to 200 kg P₂O₅/ha/year in order to maintain high production of up to 120 tons of green matter/ha/year. This is equivalent to about 24 tons of dry matter containing roughly about 5 tons of crude protein. In rotation with lucerne, potatoes have been grown and it was found that they too responded to direct application and to residual phosphorus in the soil.

Application of increasing rates of potassium to lucerne resulted in the reduction of the magnesium content. Similarly zinc was reduced from 30 ppm to 20 ppm with the application of 200 kg P₂O₅/ha.

Olives: a long-term experiment on olives in a Calcaro Chromic Cambisol was carried out in Kyrenia in which the nitrogen, phosphorus and manure requirements of olives was studied. The results over the years have shown that the best combination under trial conditions for maximum olive production was 0.75 kg N as sulphate of ammonia and 0.2 kg P₂O₅ of single superphosphate per tree per year applied in early February.

Carobs: the results obtained from a long-term experiment carried out at Paphos, have shown that fertilization with 0.75 kg N as sulphate of ammonia and 0.2 kg P₂O₅ as single superphosphate per tree per year increased yields on the average by about 30%, in addition to the increase of N and P in the leaves.

Wheat: in a recent four-year cycle of experiments on wheat fertilization in the main wheat belt of Mesaoria (Calcaro Pellic Vertisols) the nitrogen and phosphorus requirement of both Kyperounda (durum) and Pitic 62 (soft) were studied. It was found that under most conditions Pitic outyielded Kyperounda by 40 percent and that it also responded to higher rates of nitrogen fertilization. On the other hand, Kyperounda responded very markedly to the application of nitrogen as indicated by higher levels of nitrogen in the grain.

In a parallel experiment in 1968/69 on the effect of nitrogen fertilization and of supplementary irrigation at critical stages of the growth of three wheat varieties: Kyperounda, Pitic 62 and 8156, it was again verified that Pitic was superior in grain yield compared to the other two varieties. Generally, nitrogen fertilization increased yields but at the same time high rates of nitrogen were found to induce lodging of Kyperounda. On closer examination of the statistical interaction of varieties and nitrogen levels, it became clear that Pitic continued to respond at the higher levels of nitrogen applied. The corresponding yield of grain in tons/ha for 1969 at Athalassa were as follows:

With respect to supplementary irrigation no striking differences were obtained because of the high rainfall in the winter of 1968/69.

Vines: from long-term NPK experiments with rainfed vines growing on Orthic Rendzinas it has been established so far that vines respond to nitrogen application up to 150 kg N/ha as sulphate of ammonia producing on the average 7 tons of fresh grapes per hectare. However, there has been some indication that significant losses of nitrogen as ammonia may occur from application of ammonium sulphate.

Response to phosphorus application has been observed in one location (available soil P 12 ppm, Olsen 25°C).

No responses have so far been observed from potassium applications.

In a sultana table grape experiment on a Chromic Vertisols irrigated once in early May there were marked linear responses to nitrogen up to 200 kg N/ha applied as sulphate of ammonia (N_o 10 tons fresh grapes/ha, N₃ 15 tons fresh grapes/ha). °

No phosphorus or potassium responses were obtained so far.

In order to complement and to evaluate meaningfully the results obtained in field fertilizer experiments extensive and detailed analytical work is carried out on soil and plant material.

Concurrently nutrient status surveys, especially of high cash tree crops such as citrus and deciduous, are undertaken from time to time in order to establish the effect of current fertilizer practices on yield and quality and to compare the results of these surveys with the norms of macro- and micronutrients obtained from long-term experiments.

In the case of Valencia oranges we have established that the norms for N, P and K, Zn, B, Mn and Cu in six-to-seven month old leaves from non-bearing growth suggested by Californian workers are, in the main, applicable to Cyprus conditions as well.

From nutrient status surveys we have also found that in citrus high leaf nitrogen levels were prevalent as a consequence of excessive amounts of nitrogenous fertilizers used by the growers which had resulted in the deterioration of fruit quality.

2.4. Water Resources

The Government of Cyprus, recognizing the urgent need to implement an overall water policy and a masterplan for the utilization and development of the island's scarce water resources, received UNDP assistance in instituting the Cyprus Hater Planning Project with the main object to take an inventory of the island's water resources and to identify viable development projects. The conclusions of this survey were:

(a) the total available water was estimated around 960 × 10 m per year of which some 400 × 106m³ are being used at present for various purposes.

(b) even when full development of the water resources has taken place by the end of this century, it is estimated that water utilization will be around 600 × 106m³ per annum or about 60 percent of the potential water, and

(c) the additional water available to agriculture will be insignificant.

Thus future projections for increasing the irrigable land do not seem promising. However, in view of the importance of irrigated agriculture, which contributes over 55 percent of the value of agricultural production, the urgency for the most economic and efficient use of the presently available water resources is pressing.

2.4.1 Water use research

Given this state of realities, apart from the various measures taken by Government for promoting the most efficient use and conservation of the available water resources, water use field studies have commended a high priority in the overall programme of the Agricultural Research Institute since its establishment. A major part of the activities in the soils and water use field is devoted to the determination of the water requirements of irrigated crops such as citrus, potatoes, vegetables and table grapes, including comparison and evaluation of methods of irrigation. In parallel, microclimatological data are collected for calculating evapotranspiration for comparison with values determined in the field.

Salinity studies are undertaken in conjunction with each irrigation field study with the object of supplementing crop water requirements with those of leaching. The results obtained so far from this work are summarized below.

2.4.2 Water requirements of crops

Citrus

Even with good quality irrigation water (EC-1 mmho/cm) and inherently good drainage, salinity tended to build up within the root zone when low amounts of water were applied which did not permit leaching.

The experiment has now been modified to allow a wider range of amounts of water to be applied in order to determine the additional field leaching requirements.

Potatoes

Table Grapes

Method of Irrigation	Water applied m3/ha.				Mean method
	0	1500	2400	3800	± 0.86
	± 1.22
Sprinkler	9.50	9.77	12.92	13.13	11.33
Border	7.72	10.54	12.91	12.79	10.99
Mean amount ± 0.86	8.61	10.16	12.92	12.96

From soil moisture measurements with a neutron probe it was observed that moisture moved down to 60 cm when irrigated with 1 500 m³/ha and to 90 cm and 120 cm for 2 400 m³/ha and 3 800 m³/ha respectively.

2.4.3 Methods of irrigation

A preliminary study initiated in late 1971 and continued in 1972 aimed at comparing the conventional method of furrow irrigation with the sprinkler and trickle methods.

The test crop used was sweet peppers. The evaluation of these methods, the moisture movement and the salinity profiles as well as the practical and economic problems involved are to be assessed.

2.4.4 Field water balance studies

Two studies initiated in 1972 are continuing with the main objective of evaluating the drainage component in the field water balance equation for a more precise determination of crop water requirements.

Soil moisture changes are followed by neutron probe and tensiometry in order to establish the hydraulic gradient and calculate the hydraulic conductivity of the profile at different depths.

Data obtained so far indicate that the unsaturated hydraulic conductivity varies widely from layer to layer due to textural difference and the sequence of the soil horizons making the evaluation of the drainage component rather difficult. This complicating situation is likely to occur in most irrigated soils of the island.

2.5. Concluding Remarks

The present character of the soils of Cyprus is the result of the strong effect of aridity on the parent material in a slow process of soil formation and horizon development resulting in the omnipresence of calcium carbonate throughout the profile. Aridity is the dominant feature also of lands in the Mediterranean basin.

In general the agricultural soils of Cyprus are poor in nitrogen and phosphorus and rich in potassium.

The high calcium carbonate contents with attendant high pH impose restricting conditions on the uptake of micronutrients especially zinc, iron and manganese.

The fertility of the soil can be easily restored by the application of the main nutrient elements in the form of fertilizers and of foliar sprays of micronutrients.

A basic requirement for the most efficient use of fertilizers and soil nutrients in general is the continuous supply of moisture to the soil. Prolonged moisture deficits created by the semi-arid climatic conditions have to be supplemented by irrigation whenever possible. However, the scarcity of water resources imposes a further restriction in bringing more land under irrigation and at the same time it underlines the necessity for the meticulous use of water and fertilizer in order to increase crop yields, maintain a high quality of agricultural produce and lower production costs.

Thus the necessity for applied research on the fertility of calcareous soils and on the most efficient use of the scarce water resources available is of paramount importance, not only for Cyprus, but for the Region as a whole.

The Government of Cyprus in perpetuating an effective programme in the development and utilization of the island's land and water resources will lend its active support to regional projects under the Near East Regional Applied Research Programme.

3. Iran

3.1. Introduction

Iran, or historic Persia, is situated between 25 and 39.45° N and 44 to 63° E, covering 165 million hectares of lands with wide ranges of:

Climate:	- Humid to Subhumid in the north
	- Semi-arid in the north-west and west
	- Arid to hot desertic in the east, south-east and central Iran
Geology:	- Basic Sedimentary rocks, ultras-basic igneous and acid extrusive rocks of the Precambrian era, up to present time sediments
Vegetation:	- Deciduous forests in the north and west
	- Shrubs and Scrubs in the north-west and south-west
	- Steppe and salt tolerant bushes in arid and desertic areas
Physiography or Geomorphologic Land Types:
	- High altitude mountains (up to 6 000 m)
	- Hills, piedmont plains, river alluvial plains
	- Saline flood plains and low lands.

Iran is one of the countries with most parts affected by dry or arid conditions which account for the formulation and accumulation of calcareous materials in some soils as well as salt in some others.

3.2. Calcareous Soils in Iran

According to the studies on soils carried out since 1953, it is clear that with the exceptions of the Caspian Zone, where CaCO₃ has been leached from the soil by high rainfall, the central and south-eastern deserts which are affected by salt and a few small areas of non calcareous origins, the soils of the rest of the country are affected by or combined with lime comprising from 10 to 60% of the soil constituents and/or up to 100% of the calcareous stones.

According to "The Soils of Iran" the areas and the association of calcareous soils are as follow:

Soil Association		Area in 1 000 ha
	I - Soils of the plains and valleys
1	Fine textured alluvial soils (mainly calcareous)	4 750
2a	Coarse textured alluvial and colluvial soils and Regosols	4 500
	II - Soils of the plateaux
7	Brown soils	6 000
8	Chestnut soils (calcareous horizon below 50 cm)	1 000
5-2a	Desert soils - Regosols	8 000
6.2	Sierozem soils - Regosols	9 000
7-15	Brown soils - Lithosols	2 000
	III - Soils of the Caspian Piedmont
11	Brown forest (mainly calcareous in sub-soil)	300
	IV - Soils of the dissected slopes and mountains
12	Brown soils - Rendzinas	400
13	Calcareous Lithosols, desert and Sierozem	35 000
14	Calcareous Lithosols from saliferous, gypsiferous materials	12 000
15	Calcareous Lithosols, Brown and Chestnuts	24 000
	Total	106 950

The figures show that around 65% of the soils of the country are calcareous.

3.3. The Management and Land Use

Calcareous soils are productive under semi-arid to subhumid conditions or with irrigation in the following circumstances:

(i) when water is available and slope and topography of the land are suitable; these soils are used mainly for irrigated, annual crops or fruit trees;

(ii) when precipitation is sufficient for dry farming (300-600 mm/h) nearly all the slopes and even the tops of the hills in some places are under dry farming (wheat or barley);

(iii) when the rainfall is 150-300 mm/a, or yearly distribution is not suitable for cropping, or when rainfall is well above 300 am but there is no suitable topography for cropping, the main land-use is pasture or forest;

(iv) in the Caspian zone, on cretaceous and jurassic limestones with very shallow to very deep soil cover of rendzina to brown forest soils there are highly productive forests;

(v) when rainfall is lower than 150 mm/a, and the evaporation is also high, the lime or gypsum is concentrated immediately below the surface and occurs mostly together with salt; these areas are naturally seasonal or occasional grazing lands or waste lands and deserts, with no vegetation;

	million ha
Occasional grazing	58
Deserts, waste, urban	43
Marginal grazing	25
Productive range	19
Fallow	12
Dry farming	4
Irrigated cropping	3
Forest	1

3.4. Research and Studies

Different organizations in the Ministry of Agriculture and Natural Resources have various activities on the reclamation or management of lands and soils. Within these organizations the Soil Institute plays the major role in research and studies on soils and has many experimental fields throughout the country.

During the past few years the Soil Institute, which consists of various divisions, has carried out the following activities among many others:

(i) Land Resources Inventories: various land resources of the country and their potentiality or capability for different land uses have been defined. In this respect more than 40 million ha were surveyed and mapped in the last four years by the Land and Soil Evaluation Division.

(ii) Soil and Land Classification: this activity was started in 1952 and a great deal of work has been done on the classification of lands for irrigation and on the soil classification of Iran.

(iii) Soil Fertility Research and Soil and Water Management: many studies, combined with experimental field work all over the country, have been carried out on soil fertility, soil and water management and salt leaching in the last 10 years by the Soil and Water Management Division. This same Division has also done plant nutrition studies in relation to CaCO₃ content and iron and zinc deficiencies in calcareous soils.

(iv) Soil and Water Conservation: soil conservation on a country-wide scale has been done by the Natural Resources Organization and includes such activities as: afforestation of many degraded forests, dune stabilization, plantation of drought resistant plants in desertic areas etc. Conservation of agricultural soils, however, comes under the Division of Soil and Water Conservation and includes such work as the installation of large scale experimental stations in areas of calcareous soils, e.g. Quin (160 km west of Teheran) and on the basic igneous soils of Tickmeh-Dash (500 km north-west of Teheran) and many other stations in the Provinces.

4. Iraq

4.1 Introduction

At present the main problem for agricultural development in Iraq is salinity. Other problems, including the presence of between 15 and 35 percent CaCO₃, are of lesser importance. Recently, studies were started on the effect of CaCO₃ on the physical, chemical and nutritional characteristics of calcareous soils in Iraq. The effect of CaCO₃ on phosphorus fixation and that of teaching and cropping on CaCO₃ content have been studied but more work is needed in order to obtain definite and clear information on the behaviour of these soils.

4.2. Physiographic Regions of Iraq

The physiographic formation of Iraq is composed of five zones, namely: mountain ranges, undulating low hills, desert land, the Jezira and the Mesopotamian Plain.

4.3. Parent Material of Soils

Most of the parent material in the mountain ranges is limestone; in the undulating low hills it is gravels, conglomerate, sandstone or mudstone; in the Jezira gypsum is dominant, while in the desert land it is limestone. The parent material of the alluvial Mesopotamian Plain is formed by sediments of the Tigris and Euphrates rivers and is generally calcareous containing 15 to 35 percent CaCO₃ in the top metre.

4.4. Distribution of Lime in Iraqi Soils

Most Iraqi soils contain from 15 to 35% lime with few having less than 15% or more than 35%. In the plains of the mountain ranges some soils have only 2-7% in the surface but more than 50% in the sub soil. In the low hills, the soils have more than 25% lime content throughout the profile. The Jezira soils generally contain more than 6% CaCO₃ while those of the desert lands have more than 25% in the surface and up to 50% in the subsurface layers. The calcareous soils of the Mesopotamian Plain contain from 15 to 35% lime mainly as CaCO₃ (90%) and MgCO₃ (10%).

Generally, the soils of the coarse textured levee contain less carbonate than those of the fine textured basins which could be caused by:

i) better drainability of the levees; consequently leaching of carbonates would be more than in other soils;

ii) the decrease in size of the lime particles as they move in the water stream before being deposited on the fine textured soils of the basins.

4.5. Distribution of Lime in the Soil Profile

The lime distribution is usually homogenous within the soil profile, but in recent sediments the top metre has a higher lime content which increases with depth and with the age of these sediments. In the old soils of northern regions, the lime content also increases with depth.

In the calcareous soils of Iraq, lime can be found in the following forms: fine calcite, calcite intercalary crystals, calcite crystal chambers, calcite crystal tubes, calcite crystal sheets, calcitan lining some pores, neocalcitans deposited around some pores, amorphous deposits as a result of high groundwater levels in southern Iraq, soft lime nodules, Petrocalcic layer and Lithorelics.

The lime in the soil of the Mesopotamian Plain originates from the limestone rocks of the mountain ranges. Due to soil erosion, lime is transported in the rivers' streams as small particles and deposited under the same conditions as the sand, silt and clay soil particles. A few of the results taken from thousands of samples are presented in Table 1 and the following remarks can be made.

i) There is a difference in the lime content of the sediments transported by the Tigris and Euphrates rivers; the lime content in the former being higher by 2-5%. This characteristic can be used to differentiate between the sediments of the two rivers.

ii) Coarse textured soil samples contain less lime than those with a fine texture as shown in Table 2. This is due to the effects of turbulence, caused by the velocity of the flowing water on the size of the suspended lime particles and their sedimentation; a decrease in velocity of flow permits the sedimentation of finer particles.

Table 1. Average lime content to a depth of one metre in the soils of the various Governates of Iraq

Governate (Arabic)	No. of samples	Lime content %
		Range	Average
Basra	24	27 - 38	33
Muthanna	8	23-28	26
Thi-qar	4	27 - 30	28
Waset	20	24 - 35	29
Babylon	41	18-32	27
Baghdad	45	21 - 38	28
Anbar	11	18 - 39	28
Diala	10	26 - 35	31
Kirkouk	11	23 - 36	32
Arbiel	1	···	20
Sulaimaniya	5	12 - 18	14
Nineveh	1	···	6

Table 2. Relation between soil texture and lime content in representative samples from two projects

Project	Light textured profile			Heavy textured profile
	depth cm	texture	lime %	depth cm	texture	lime %
Almouthana	0 - 10	clay	29	0 - 14	sandy loam	14
	10 - 40	clay	28	14 - 36	silt clay loam	20
	40 - 70	clay	27	36 - 66	sandy loam	18
	70 - 95	clay	28	66 - 96	sandy loam	20
				96 - 120	loamy sand	17
Greater Mussayeb	0 - 12	clay loam	29	0 - 16	sandy loam	20
	12 - 34	clay	30	16 - 37	loamy sand	19
	34 - 65	clay	32	37 - 47	silt loam	26
	65 - 94	silt clay	30	47 - 74	sand	19
	94 - 129	silt clay	27	74 - 104	loam	24
				104 - 150	loamy sand	19

4.6. Effect of Lime on Reclamation of Iraqi Soils

Although 15 to 35% lime is found in most Iraqi soils, as shown in the Map, its presence does not pose a serious problem to land reclamation and development as is the case with a high salt content. Studies have been carried out in various parts of the country on soil reclamation and the following are cited as examples.

i) Experimental work was started in Dujailah area (Mesopotamian Plain) in 1956. Soils were highly saline with about 6% salts in the top 30 cm, of medium texture, below average permeability (80 cm/day) and with a 20 - 30% lime content. It proved possible to reclaim these soils by leaching and most field crops could be grown thereafter.

ii) Studies, investigations and reclamation work started in Abu Ghraib (Mesopotamian Plain) in 1969. The soils were highly saline, of heavy texture and contained 25 - 30% lime. Due to the presence of lime and the possibility of leaching excess salts, cropping was successfully achieved afterwards.

iii) Reclamation experiments in Twairey took place from 1961 to 1969. This area represents the saline soils in the upper basin of the Euphrates river. Salinity was 74 mmhos/cm, the texture varied from sand to light clay and the lime content was about 25%. Results of experiments indicated that the water table could be lowered, salinity decreased and that economic yields from all crops included in the rotation (as shown in Table 3) could be produced. No side effects were observed from the presence of lime in the soils.

Distribution of lime in soils In different physiographic region of Iraq (to a depth of one metre)

Table 3. Relation between reclamation procedures, wheat year net returns per donum^1/ during three years

Reclamation Procedure	Brains		Average yield of wheat in the last year per donum 1/	Salinity		Net return
	distance	depth		Initial	find	Dinar	Fils
	metres
1. Leaching with 80 en;
barley, green gram,
barley, green gram,
wheat	100	1.8	265	11	0	16	600
2. Leaching with 30 cm;
wheat, fallow, wheat,
fallow, wheat	100	1.8	318	26	0	20	200
3. Leaching with 30 cm;
wheat	100	1.8	385	17	0	21	100
4. No leaching;
barley, rice berseem,
berseem, wheat	100	1.8	421	7	0	13	800
5. No leaching;