Research work at the Bari Institute on the reuse of low quality water and its impact on soils and plants

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1 Research work at the Bari Institute on the reuse low quality water and its impact on soils and plants Hamdy A. in Bouchet R. (ed.). Reuse low quality water for irrigation Bari : CIHEAM Options Méditerranéennes : Série A. Séminaires Méditerranéens; n pages Article available on line / Article disponible en ligne à l adresse : To cite this article / Pour citer cet article Hamdy A. Research work at the Bari Institute on the reuse low quality water and its impact on soils and plants. In : Bouchet R. (ed.). Reuse low quality water for irrigation. Bari : CIHEAM, p (Options Méditerranéennes : Série A. Séminaires Méditerranéens; n. 1)

2 ~~ ~ ~ ~~ CIHEAM - Options Mediterraneennes Research work at the Bari Institute on the reuse low quality water and its impact on soils and plants Atef Mediterranean Agronomic Institute Bari (IAM-B) - Italy Salt affected soils various types in irrigated soil management, water quality and its areas cover about 20 million hectares (49,42 management and the agronomics various million acres). This is equivalent to all irrigated irrigation methods, as well as the capacity to land in the USA and combined. manage the salinity problems, must be well developed and fully understood beforehand. These figures salt affected soils, with their progressive increase under irrigation practices, The success such plans requires the development will definitely lead to a tremendous reduction in new strategies for using low quality water in food and fiber production unless proper soil irrigation, assessed on scientific, practical and management and soil reclamation programs are economic bases. Such strategies should include immediately undertaken. climatic, soil and crop factors to eliminate as far as possible the drawbacks on crop production and soil The other side the problem is to meet, given lhe Characteristics. limited water resources available, the necessary food demands which are increasing at a very high a research rate. Superficially, it might appear that increasing programme on the use saline water in irrigation the amount cultivated land would fer the best including the following main topics: solution to the problem. However, the scarcity fresh water resources needed for putting the new areas under cultivation makes the problem even -the influence irrigation with saline water more complicated. different salt concentration levels on the growth and yield some main crops in this respect, the utilization water resources area; other than fresh ones is a the meantime, if such water is used for irrigation without proper the management, it could have negative effects on crop production as well as contributing to the deterioration soil productivity due to the side- eflects on the physico-chemical characteristics soils. - the mode saline water application; -salt accumulation and its distribution in the different soil layers under saline water irrigation using different irrigation methods; Thus, if it is planned to use low quality water on a large scale in irrigation, the complex interaction - leaching the accumulated excess salts using fresh water as well as water low quality.

3 86 This paper will summarize the experimental work included in the programme and the results obtained by giving some outlines which could be utilized as far as we are concerned for establishing a new strategy for the use low water quality in irrigation. wide that some good at an EC mmhos/cm, do well up to 20 is which will do equally well in final yields. - Salinity and plant growth a effects on plant development and output quality, depending on as soluble salts, the view this discussion it is a Equally, the identification give than those which show a to know salinity on Salinity effects can i) conditions because effect et al, 1976; 1976; et al, 1976). be ii) by imbalance essential ions, and is no infallible way could be a by ions toxic 1. Seed germination and seedling establishment usual that with both, as well as could is the most is The conditions could be due to the soil solution, which in the seed. be due to the influx enough to make them toxic to the could also the same plant. Some so conducted on a EC values mmhoskm plus a EC value 0.9 leaf the A 1984). 8, 12 and salinity the as a function salinity level Figure 1. could be summed up as follows : lettuce. is in the - to mmhos could be used safely to this level yields. On seed application is needed to maintain a as a some losses seeds. in

4 showed salinity level (16 at the highest at salinity levels above 8 and 12 mmhos, depending on the plant in question. The most sensitive plants at all 8 mmhos. The influence salinity on seedling development was assessed by leaf (Table 1) into the (Table 2). we came to the following conclusion: 1971), validity by is et al., specific conditions salt soil Will such data have the same The fact that classification plants into based on planting seeds in a non-saline and imposing used even at the seedling stage. if seedbed to be an on the plant. The stage the seedlings is at a stand and a We the possible effects it was found that: conditions in the field. i) showed indicating a specific salt to on some beans maintained a salinity. This is evidence salinity which levels; iii) than in vegetation even at modest levels salinity. This indicates a state is effective t,o system influence the and cotton). the modes on The influence EC values 0.9, 4, 8 and 12 mmhoskm applied with its at the data (1984). Tables 3 and 4 is not only affected by the by as et al., 1943), et al., 19781, The development wheat (Table 5 and Figure 2) and beans (Table 6 and Figure 3) was also studied.

5 following conclusions: we came to the yield, glpot, given in Tables 7, 8 and 9 is influenced not only by the salt by the mode 60%140% both beans and to if is a at seedling is a the salinity damage. by which is to blend (Allison, 1964; 1984; and which is low and good is: in low salt both indicated that wheat is 8 4 mmhoskm. -if we it is we wish to but also how to manage effectively such obtained by as if the saline is as high as 60%, good be maintained. is once at the seedling stage to allow the young plants to develop a stages development and to gain access is at the than conducted on wheat as it is crops in the it is as a a application. one good two possibilities. The at a allowable cycle second is to use both by We two available: the to this, to we have is to blend the two the final A. good quality it is not to its quality by mixing. Such could be used at the time it should most be instance, at and seedling stages which the salinity level to establish a well developed seedling will The continuous EC values between modes application only. 1 and 12 mmhodcm. Two bottom the accumulation in soils to To the soil to level, the excess salts must be leached out and this good quality. This is tedious. big

6 89 C. salinity level could only be good mixing could be completely eliminated and a possibility conditions. The cyclic use because dilution. will by long low and high salinity too saline while the substitution a needs. A suitable the total salt load, but volume caused by the timing and amount possible substitution will, the quality the two soil to evaluate the two when with EC values exceeding 8 the soil low to be used, be a choice, but at the end the season the soil must be flushed with enough to wash down This could be the case when we zone and it is will be complicated if such conditions it should always be as well as the soil physical the effective zone the sub-.. - Salinity and salt accumulation and distribution in soils A knowledge the effect on soil maintain good was devoted to the analysis the soil This was designed to ones. as well as the shoots developed was soil depths as a function the mode methods. soil given in Figure 4 and 5. in so as to allow by by to the salt development. is kept level, hence the losses to Soil analysis indicated that the mode application found to be only gives to a accumulation salts, but also to a salts salt concentation about 1.6 to 2.8 times to that excessive saline build up in soil. options

7 Salt accumulation, like its was with the in the salt content was always less than 15 indicating the onset salinity alkalinity. it should be safe, months good to 1. Salinity and irrigation methods only once again that is is is good. evidence and foliage, though the yield is only evident in clay soils. 6 development is as leaf good, and is some the salinity sandy clay loam, is unaffected which in the management could be outlined as: methods, and management up to 6 mmhoskm. Above this level salinity, at 9 good, but it develop good do not the attention the best possible conditions total soil a given quality also has the advantage which is the The same qualities low is is to seek out soil applied with At as salinity, A detailed study was take place in the maize L.) and its yield is may even be a if soil is sandy clay. two besides following the build up soil done by sucking All both when two low salinity. At levels, such as 9 substantially yield yield at The influence its yield Figures 6, 7, 8, 9 and 10 for development we salinity and the method plant height, yield. plant the way affect plant indicates that to accumulation salt soil followed by by Table 10). salts in the maize, found to lead is an effect the

8 91 wetting-d cyc1.e a salts when the soil is a salts showed a (1 the two found is a notable salt accumulation they avoid the salt that accumulates at the good by we faced with salt accumulation which must be moved zone. The last devoted to salt leaching. 2. Salinity and leaching practices well as the one at the botton had an 50% how the salts (Figure 11) 13). which soils. is by successive saline (Figures 12 and accumulated salts. Nowadays, as widely it is intended to examine the validity.excess accumulated salts in saline soils beside elucidating its 5.8 and 25 subjected to successive the classic view following conclusions: we came to the efficiency the two methods. - accumulation in soils is not only dependent on the system also on the soil as well as the salt content is a the complex between at 15 cm depth, the EC noted at some depths, indicating that most salts the salts than at 17 with the two soil depths 15 cm and 30 salts its we at the zone. This maintains a low. salt leaching the zone below the to leached zone so the simplicity as follows: application system was found to be leaching the total salt content the columns up to a salinity level 25 mmhoskm, beyond which (Figure 14). show that the two leachings the the the salts the soil salinity level. This indicates that a wise soil management policy can maintain soil salinity within acceptable levels valuable non- - leached soils, even those (25 at EC values well below the 4 the technique used, with a a bottom with (Figure 16). it options

9 in a way identical to up. be conditions (Figure 1). is available on the consumptive use many EC 3,6 and 9 mmhoskm. The leaching is is shown the two application methods in Figures and 4. indicated in the soil was to those all soil will to that two low be EC value leaching soil type, but at a level than that the to aim at is a soil salinity equivalent to that excessive leaching. - Conclusions and outlook for the future condition in the huge bulk would Egypt. studies the potential using low the demand Egypt as an example, if a notable expansion in would satisfy a food paid to this could be applied what adjustment needs to be made? and it in osmotic yield due to salinity is the cause consumption or versa. potential is is a function the soil it is not, the salinity and by an adequate and timely is to keep the soil solution at a so as to effect on if' it is possible and to apply in soils, excess accumulated salts we should leach accumulation in soils becomes excessive, leaching should be done at The last point, which has a to be used conditions. or if is needed between scientists soil science, physiology, and socio-economics to assess, in scientific.and technology and potential using low on a economic basis. The use a the vast is thus now now available on how to successfully to minimize the Allison, E.L., Salinity in relation to irrigation advances. Vol. 16,pp

10 l ~ H.S. and Wescot, C.A., The effect soluble salts on Ag. Exp. Stat. 874, Vol. 33,No. 5,pp alfalfa yield with Soilsci., Vol., 122, pp A.L salinity. G.J. and J.A. Jabes, as influenced by humidity. J., Vol..70, No. 5, pp Jul., pp for New Today and at Flagstafi ASCE. the water ASCEmeno, Nevada, Speciality O.C., Wadleigh and Cauth, Effect salt salt and climate on plant sand physiol. 18: pp E.V., 1984.Agron. J. S.A. and Use Vol., 20, Nos Wan J. and use pa at the 1979 meeting. ASCE, New USA... options méditerranéennes

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12 ~ ~ ~~ CIHEAM - Options Mediterraneennes ~ ~~ ~ Table Leaf area (cmzlplant) under different salt concentration levels so Salinity level in mmhos/cm C) S3 Barley Sugarbeet Wheat Corn Tomato Lettuce Broad bean Pea Onion Carrot -_ - - _- -- -_ - - Table Dry weight vegetative and radical part the seedlings under different irrigation treatments Salt concentration levels Crop SO ~~ S1 S4 Veget. Root Veget. Root Veget. Root Barley Sugarbeet Wheat Tomato _- -- Corn Broad bean Lettuce Pea _ _ Onion _ -- _- -- Carrot _ options

13 ~ CIHEAM - Options Mediterraneennes ~ ~ ~ Table Influence different salinity levels in irrigation water, and their modes application on relative leaf area wheat and bean plant Modes ipplication Relative leaf area (cm2/50 leaves) LEVELS - S, S1 S2 S X 3F SALINITY Leaf area (cmz/plant) s3 - X Table Influence different salinity levels in irrigation water, and their modes application on dry matter production wheat and bean plants Modes application so Dry weight (g/pot) LEVELS - X s3 I SALINITY Dry weight (g/pot) - so S2 X B E X -1

14 97 Table 5: salinity level 'the irrigation water and their modes application the dry weight the root system wheat application S, weight, Salinity level gr. B. Figure 2: roots under different irrigation treatments for wheat v-v c -0 E 1 1 s3 Salinity E options

15 Table 6 salinity level the irrigation water and their modes application on the dry weight the root system beans weight, gr. Salinity level application So S1 S3 B c E Figure 3: roots under different irrigation treatments for beans \ $-' L m *li l s O s I 1 1 S E

16 ~ CIHEAM - Options Mediterraneennes 99 Table Straw dry weight (g/pot)underdifferentirrigationtreatments with different salinity levels and modes application Water salinity level Mode water application Constant mixtures Alternative FW FW FW SW SW Fresh Saline vater (FW) SW SW SW water (SW A C D E + + FW at FW FW seedling G H -- Surface irrigatio _ Subirrigation h B e I, Mean

17 Table 8:Rootdryweight (g/pot)underdifferentirrigationtreatments with different salinity levels and modes application i Mode water application Water salinity Constant mixtures Alternative level 70% FW 50%FW 30%FW 70% SW SW Fresh Saline + + FW at mmhos/cm) tater (FW) SW 50% SW 70% SW water (SW) 30% FW 76Y0 FW seedling A B C E F G H I Surface irrigatio Mean A B C Subirrigation _ Mean options

18 101 Table 9: Wheatgrainyield (g/pot)underdifferentirrigationtreatments with different salinity levels and modes application Water salinity level mmhos/cm) Mode water application Constant mixtures Alternative 70%FW 50%FW 30%FW 70% SW 30% SW Fresh Saline + + FW at water (FW) 30% SW.50% SW 70% SW water (SW) A B c D E 30% FW 70% FW seedling G H I Mean Surface irrigatio _ Subirrigation - A B C D _ l _ ' Mean

19 ~ ~~~ ~ 102 Figure 4: EC values under different application modes saline water and through different soil depths 10 O I I l m 1'- I M I IMI IHI.. 10 O

20 103 Figure 5: values under different application modes saline water and through different soil depths n B 10 U 10 t n 10 A 9 c E 5 15 n.e o 10 i U 25 l s3 options

21 1 O4 Figure 6: modes irrigation, soil type and water salinity I 3 Soil type 6 h Soil type U Surface irrigation Flowering il Con 6 9 Con Water salinity -. - Average options méditerranéennes

22 105 Figure 7: lnfluence modes irrigation, soil type and water salinity cm a (mmhos/cm)

23 106 Figure 8: modes irrigation, soil type and water salinity on Plant (g/pot) j c Sc Soil type c Flowering 7:T 60 Con Con 6 Water salinity (mmhos/cm) O0 90 i c SC SC{ c type Surface irngation m irrigation Con Con Water salinity (mmhos/cm) options méditerranéennes

24 107 Figure 9: modes irrigation, soil type and water salinity (g/pot) type options

25 108 Figure 10: modes irrigation, soil type and water salinity on Production (g/pot)- SGL ' Soil ' (mhos/cm) -,

26 1 o9 Table Influence modes irrigation, soil type and water salinity on EC value in mmhos/cm Modes irrigation Surface Water salinity Soil type Drip Clay Sand Mean clay Sand clay loam Clay Sand clay Sand clay loam Mean Control.l, - 10 Mean Control 10 - ' Mean Control - Mean I.

27 110 Figure 11: EC value in mmhodcm under surface irrigation for the three soil types ''4 I. 1 I, 5 1:.k I 1 ' options

28 111 Figure 12: the EC value in mmhos/cm under surface irrigation at 5 cm from the dripper i' -- - m - m --\o - m -3 --M -ru

29 112 Figure 13: EC value in mmhos/cm under drip irrigation at 17 cm from the dripper -l Lo I k U I CI 4 Lo. I l H Lo > U- I n Z 4 Lo Lo > 4 u

30 113 Figure 14: Salts removed under successive leachings using submersion and drip techniques leaching % 95. A * r* B. * ' A /.?i. Nos. * m A *, * - 2 %. - A *. ' mmhos/cm B A 1. 1, Nos. 12 A B -... I A

31 114 Figure 15: Variation the EC value in the columns after 12 leachings with distilled water (mmhoskm) o ! n E V v U ti 6 \4 c???? O r r r

32 Q 40 CIHEAM - Options Mediterraneennes 115 Diagram 1: design plan the leaching on columns 5 25,C 25 QI CL I, 13.8 L 15.7 L o I The symbols A, B, C, refer to soil clay sand clay and sand clay loam respectively. - The numbers refer to salt concentration level in leaching water. - The values on the columns refer to EC values, in mmhos/cm for each soil depth. options

33 116 Diagram 2: EC values (in mmhos/cm) before and after the leaching columns and their respective variation as a percentage for each soil layer, with surface technique I 40 B3 B6 B c The symbols A, B, C, refer to soil clay, sand clay and sand clay loam respectively. - The numbers refer to salt concentration level in leaching water. - The values on the columns refer to EC values, in mmhos/cm, for each soil layer. options medi

34 117 + Diagram 3: EC values (in mmhoshm) before and after the leaching on columns and their respective variation as a percentage for each soil layer, with drip technique A, I I 25 bef. aft. I l g 251 n bef. aft. Ê 10 W 5 25 p. g 40 - The symbols A, B, C, refer to soil clay, sand clay and sand clay loam respectively - The numbers refer to salt concentration level in leaching water. - The values on the columns refer to EC values, in mmhos/cm, for each soil layer, options