TECHNICAL BULLETIN 186 ISSN 0070-2315

FERTILIZING RAINFED WINE GRAPES (MAVRO, CARIGNANE NOIRAND LEFKAS) WITH NITROGEN, PHOSPHORUS AND POTASSIUM

IN HIGHLY CALCAREOUS SOILS

P.I. Orphanos

AGRICULTURAL RESEARCH INSTITUTE

MINISTRY OF AGRICULTURE, NATURAL RESOURCES

AND THE ENVIRONMENT

NICOSIA CYPRUS

JUNE 1998

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Editor - in Chief

Dr A.P. Mavrogenis, Agricultural Research Institute, Nicosia, Cyprus.

All responsibility for the information in this publication remains with the author(s). The useof trade names does not imply endorsement of or discrimination against any product by theAgricultural Research Institute.

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SUMMARY

In Cyprus, wine grapes are grown mainly in the south-west flanks (elevation 400 to800 m) of the Troodos massif on highly calcareous soils (30 to 80% CaCO3). Limitedareas are also under grapes on higher ground (800 to 1000 m) of the same massif on ig-neous soils. Winter rainfall is normally above 500 mm in most of these areas. In all are-as the soils are low in N (about 0.1% total N) and available (Olsen) P (<4 ppm). Igne-ous soils are also low in available K (exchangeable + soluble K<150 ppm), butcalcareous soils are well supplied with available K (150 to 300 ppm).

A series of longterm fertilizer experiments were carried out with the variety Mavrotesting N rates (up to 150 kg N/ha) in combination with P (35 kg P/ha) and K (up to 150kg/ha). In the last experiment of the series, in addition to Mavro, two other new to Cy-prus varieties, i.e. Carignane noir and Lefkas, were tested.

The results confirmed that the vine is an economical fertilizer user. Indicatively, theamounts of N, P and K removed in a ton of grapes and in the prunings that go with itare 2.0, 0.3 and 3.2 kg, respectively. Therefore, even with a relatively high yield of 15 t/ha the amounts of N, P, and K removed are 30, 4.5 and 48 kg/ha, respectively.

Initially, in all experiments a slight to moderate response to N was obtained, whichthen disappeared, and rates in excess of 75 kg N/ha tended to even reduce yield, particu-larly in the lower yielding experiments. This indicates that vineyards that have been suf-ficiently supplied with N for a few years continue to produce at their potential leveleven when N application is discontinued.

In the last experiment, the fertilizing of which was managed right from planting, 75kg N/ha was sufficient for yields of up to 18 t/ha. This rate could then be used as the ba-sis for extrapolation of N requirement for yield above or below 18 t/ha.

As a result of past P applications, in all experiments available (Olsen) P remainedhigher than 9 ppm. Since freshly applied P did not influence yield, 9 ppm soil P shouldbe considered sufficient. Available soil P increased relatively fast with P application inthese highly calcareous soils and remained available for fairly long. Therefore, analys-ing the soil at relatively wide intervals can safely guide P fertilizing. Like with P, appli-cation of K did not influence yield, but it significantly increased available soil K. Con-centration of K in petioles was in excess of 3% even without K application. Despitethis, K application did not have an adverse effect on yield.

Carignane noir produced the highest yields and Lefkas the lowest, with Mavro in-termediate. The second half of the experimental period was exceptionally dry. This ap-preciably decreased yields of Carignane noir and, particularly, Lefkas but not Mavro,which produced 10 to 12 t/ha throughout the experimental period.

ΠΕΡΙΛΗΨΗ

Στην Κύπρο τα σταφύλια οινοποιίας παράγονται κυρίως στις νοτιοδυτικέςχαµηλές πλαγιές (υψόµετρο 400 ως 800 µ) των βουνών του Τροόδους σε πολύασβεστούχα εδάφη (30 ως 80% CaCO3). Mια µικρή ποσότητα παράγεται και σεψηλότερες περιοχές (υψόµετρο 800 ως 1000 µ) σε πυριγενή εδάφη. Σε όλες αυτέςτις αµπελουργικές περιοχές η χειµερινή βροχόπτωση είναι συνήθως πάνω από 500χλστµ. Τα εδάφη σε όλες τις αµπελουργικές περιοχές είναι φτωχά σε άζωτο (περί-που 0.1% συνολικό Ν) και φωσφόρο (διαθέσιµος (Olsen) φωσφόρος <4 µαε), αλλάτα µή ασβεστούχα εδάφη περιέχουν αρκετό κάλι (150 ως 300 µαε εναλλάξι-µο+διαλυτό Κ) ενώ τα πυριγενή περιέχουν λιγότερο από 150 µαε K.

Σε µια σειρά από πειράµατα µε την ποικιλία Μαύρο δοκιµάστηκαν διάφορεςδόσεις αζωτούχου λίπανσης (µέχρι 150 χλγρ N/εκτάριο) σε συνδυασµό, ή µή, µεφωσφόρο (35 χλγρ P/εκτάριο) και κάλι (µέχρι 150 χλγρ/εκτάριο). Στο τελευταίο

FERTILIZING RAINFED WINE GRAPES (MAVRO, CARIGNANE NOIRAND LEFKAS) WITH NITROGEN, PHOSPHORUS AND POTASSIUM

IN HIGHLY CALCAREOUS SOILS

P.I. Orphanos

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πείραµα, εκτός από το Mαύρο δοκιµάστηκαν καιδυο νέες ερυθρές ποικιλίες, το Carignane noir καιη Λευκάδα.

Τα αποτελέσµατα επιβεβαίωσαν τις µικρέςαπαιτήσεις της αµπέλου σε λίπανση. Ενδεικτικόείναι το ότι οι ποσότητες Ν, P και Κ που περιέ-χονται σε ένα τόνο σταφυλιών και στα αναλο-γούντα αποκλάδια είναι 2.0, 0.3 και 3.2 χλγρ,αντίστοιχα. Εποµένως και µε παραγωγή 15 τ/εκτάριο, που είναι αρκετά ψηλή, οι ποσότητες Ν,Ρ και Κ που αφαιρούνται είναι 30, 4.5 και 48χλγρ, αντίστοιχα.

Αρχικά, σε όλα τα πειράµατα το άζωτο αύξη-σε ελαφρά την παραγωγή, αλλά δεν είχει επίδρα-ση στη συνέχεια, και δόσεις µεγαλύτερες από 75χλγρ/εκτάριο τη µείωσαν λίγο, ιδίως στους αµπε-λώνες χαµηλής παραγωγής. Αυτό δείχνει πωςµια και λιπανθεί ικανοποιητικά ένας αµπελώναςγια µερικά χρόνια συνεχίζει να αποδίδει στο µέ-γιστο του, ακόµα και αν διακοπεί η λίπανση γιαµερικά χρόνια. Στο τελευταίο πείραµα, που η λί-πανση του αµπελώνα ήταν ελεγχόµενη από τηφύτευση του, ετήσια εφαρµογή 75 χλγρ Ν/εκτάριοήταν αρκετή για απόδοση µέχρι 18 τ/εκτάριο.Αυτή η δόση θα µπορούσε, εποµένως, να χρησι-µοποιηθεί ως βάση για τη λίπανση του αµπελιούµε ανάλογη αυξοµείωση της για παραγωγή µεγα-λύτερη ή µικρότερη από 18 τ/εκτάριο.

Ως αποτέλεσµα προηγούµενης εφαρµογήςφωσφόρου, σε όλα τα πειράµατα ο διαθέσιµοςεδαφικός φωσφόρος (Olsen) διατηρήθηκε πάνωαπό τα 9 µαε. Εποµένως το γεγονός ότι επιπρό-σθετη εφαρµογή φωσφόρου δεν αύξησε την παρα-γωγή σηµαίνει ότι 9 µαε εδαφικού φωσφόρουεπαρκούν πλήρως. O διαθέσιµος φωσφόρος αυ-ξήθηκε γρήγορα µε τη φωσφορική λίπανση καιπαρέµεινε διαθέσιµος για σχετικά µακρύ διάστη-µα. Εποµένως, τέτοια ασβεστούχα εδάφη µπο-ρούν να αναλύονται για Ρ κατά αραιά διαστήµα-τα.

Οπως και µε το φωσφόρο, η εφαρµογή Κ δεναύξησε την παραγωγή, αλλά αύξησε σηµαντικάτο διαθέσιµο εδαφικό κάλι. Η συγκέντρωση τουΚ στους µίσχους ξεπέρασε το 3% χωρίς να προ-καλέσει µείωση της παραγωγής.

Η ποικιλία Carignane noir έδωσε τη ψηλότε-ρη παραγωγή και η Λευκάδα τη χαµηλότερη. ΤοΜαύρο έδωσε ενδιάµεση παραγωγή (10 ως 12 τ/εκτάριο), αλλά σταθερή, ιδιαίτερα κατά το δεύτε-ρο ήµισυ της πειραµατικής περιόδου που επικρά-τησε ασυνήθης και µακρά ξηρασία.

INTRODUCTION

In Cyprus, wine grapes are grown rainfedon 21 000 ha of undulating or hilly land onhigher ground, and rank areawise as the sec-ond largest rainfed crop after barley. Tablegrapes are grown under irrigation on 2 000ha in coastal areas (Roumbas, 1993). Thesoils are calcareous (30 to 80 % CaCO3), but

limited areas of igneous soils (carbonate-free) are under wine grapes in the Troodosmassif. Wine grapes are dependent on storedwater, as the growing season (April-October) is rainless from May onwards.Winter rainfall is usually relatively high(>500 mm), therefore the depth of the soilprofile determines the amount of water stor-age, and thereby the vigour of the vines andyield. Grape production fluctuates from yearto year in response to rainfall but extreme bi-ennial bearing is not observed probably be-cause rarely does serious water stress occurin May-June when floral initiation takesplace (Mathews and Anderson, 1989).

Two varieties have long, and almost ex-clusively, been grown for wine-grape pro-duction, i.e. the red variety Mavro (CyprusBlack) and the white variety Xynisteri (Cy-prus White). Neither is a true wine-grape va-riety, as their berries are medium to large.Mavro is particularly plastic. Under condi-tions of sufficient water, the large size of itsberries and their poor color result in lowquality wine. Both varieties have long beenused mainly for wine making; however, theirgrapes were also converted into raisins, andtheir condensed juice was processed to dif-ferent specialty confectionery products.

In the last 40 years a number of re-nowned wine-grape varieties have been in-troduced and are being established accordingto a vine replanting scheme, for partly re-placing Mavro or Xynisteri. Presently about10% of the wine grapes produced belong tosuch new to Cyprus varieties.

All soils in Cyprus are deficient in N (lessthan 0.1 % total N) and P (less than 4 ppm bi-carbonate-extractable P). Calcareous soils arewell supplied with K (about 150 to 300 ppmavailable K) but igneous soils are low in K(<150 ppm). Fertilizers have long been avail-able and used. Loizides (1958) reportedmarked response to N by wine grapes, smallresponse to P but no response to K.

The grapevine is an economic fertilizeruser in the sense that it exploits the soil nu-trient reserves better than other crops, andthe amounts of N, P and K removed with thegrapes and prunings are small (Winkler etal., 1974).

The present work aimed to assess the fer-tilizer requirements of the traditional varietyMavro and that of two introduced wine grapevarieties, i.e. Carignane noir and Lefkas.

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MATERIALS AND METHODS

The work started in 1969 with two exper-iments on Mavro grapes, one at Omodos andone at Arsos, continued with an experimentat Vasa, again with Mavro, initiated in 1973,and was concluded with an experiment atPachna with Mavro, Carignane noir and Lef-kas, initiated in 1985.

Omodos and Arsos experimentsThe layout of these experiments, which

tested four levels of N (0, 50, 100, and 150kg N/ha, as ammonium sulphate) in combi-nation with two levels of P (0 and 35 kg P/haas triple superphosphate) and two levels of K(0 and 96 kg K/ha), has been described in aprogress report (Orphanos, 1973). AvailableP (Olsen) and available K (exchangeable +soluble) were 12 ppm and 140 ppm at Omo-dos and 14 ppm and 160 ppm at Arsos, re-spectively.

Vasa ExperimentThe vineyard occupied a slope at Vasa

village (altitude 750 m). The vines werespaced at 1.6x1.6 m, were fully grown (12-years old) when the experiment was startedin 1973, and were head formed. They hadbeen fertilized with N and P but their exactfertilizing history was not known. The soilwas medium textured and contained 65 to70% calcium carbonate. As a result of ap-plied P the soil contained 15 ppm bicarbo-nate-extractable P. In common with all othercalcareous soils, it was inherently high inavailable K (280 ppm).

As the Omodos and Arsos experiments,and also an experiment with Sultanina at Ak-helia (Orphanos, 1992), showed initiallysome response to N, applied as ammoniumsulphate, it was considered possible that sucheffect of ammonium sulphate could be an in-direct one. Alternatively, gaseous losses of Nfrom ammonium sulphate could be reducingthe N rates applied. Therefore, in the Vasaexperiment two N carriers were tested, i.e.ammonium sulphate and ammonium nitrate,at 0, 50, 100 or 150 kg N/ha in combinationwith two P rates, i.e. 0 or 35 kg P/ha, astriple superphosphate. The fertilizers wereapplied broadcast in late winter and rotovat-ed into the soil.

Because of the rugged terrain, variability

within the vineyards is very high. To reducesuch variability in the Vasa experiment, six-vine row lengths (plots) were marked, eachcomprising vines of as uniform vigour aspossible. The weight of prunings was used togroup the plots according to vigour so thateach of the four replicates consisted of plotsof similar vigour. The recorded six-vine rowof each plot was guarded on all sides by atleast a half-row buffer.

The nutritional status of the vines wasmonitored by analysing leaves sampled atend of bloom from opposite the first cluster.Prunings were also analysed.

Pachna ExperimentThe experimental vineyard was estab-

lished on sloping land at Pachna (altitude700 m) by replanting an old vineyard of thevariety Mavro. The vines were removed andthe land was reterraced. Barley was grownfor one year with only N fertilizing. As thetop soil had been moved from the inner partof all terraces, and from varying areas of theremainder of the terraces, barley was stuntedand exhibited severe P deficiency symptomsin these areas. It was ploughed in at headingand the terraces were smoothed to receivethe vines. As Cyprus is still free of phylloxe-ra, own-rooted and unrooted cuttings of thetest varieties were planted in 1975. Supple-mentary planting was done in 1976 and1977.

Three vine rows were planted along thelength of the terrace, but in the steeper partof the vineyard the terraces were more nar-row, and accomodated only two rows. Spac-ing was 2.4 m between rows and 1.35 m onthe row. The test varieties were Carignanenoir, Lefkas (an introduction from Greece)and the local variety Mavro as a control.

Lefkas was privately introduced in Cy-prus in the mid 1950's from the Greek islandLefkas, hence the name, and was grown atAchera until 1974, when the cuttings used inthis experiment were taken. In Greece, Lef-kas was described as Bartzami or Verzami(Logothetis and Vlachos, 1966), and prob-ably belongs to the Italian group of Marze-mino grapes (Moretti and Liessi, 1996), aview rejected by Galet (1993) on the basisthat Lefkas leaves have round teeth, whereasMarzemino leaves have pointed teeth. In anycase, Lefkas is now considered indigenous to

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Cyprus (Galet, 1990). Incidentally, a recent-ly-bred table-grape variety has also beennamed Lefkas (Vlachos, personal communi-cation).

A fourth variety, Souzao, was also initial-ly included in the experiment. However, itsyield, although reportedly high (Winkler etal., 1974), proved to be negligible. It was,therefore, uprooted in 1982, and AlicanteBouschet was planted in its place. AlicanteBouschet started well but it, too, later beganto decline, so it was not included in the ex-periment. No obvious reason can be givenfor this decline. However, as the varietieswere randomly assigned to the plots, any soileffect must be ruled out. A biotic factor in-troduced by Souzao should be causing thisdecline. In any case, Alicante Bouschet, too,was destroyed when the experiment was ter-minated.

The vines were trained as goblets and re-ceived spur pruning. However, Mavro hasthe tendency to form a head, and indeed re-verted to this shape over the years.

The experiment was laid out on a split-plot design with the varieties in the mainplots and the fertilizer treatments in the sub-plots. There were four replications, of whichthree in 3-rowed terraces and one in 2-rowedterraces. A subplot consisted of three 5-vinerow lengths in the 3-rowed terraces and two7-vine row lengths in the 2-rowed terraces.In this way each plot comprised vines grow-ing in the inner, the middle and the bank-endof each terrace. In both cases the central 12vines were recorded, the remaining two orthree vines, respectively, serving as half-rowguards.

Until 1985, when the experiment was ini-tiated, all vines received at approximatelyequal annual doses mostly the compound fer-tilizer 14-22-9, and were thus supplied with atotal of 620 kg N, 400 kg P and 370 kg K/ha.

The parent-material of the soil was alter-nating layers of marl and chalk. As the landwas drastically disturbed in the process ofterracing, soil variability was accentuated.However, the soil is classified as a CalcaricRegosol of loamy texture (clay 30%, silt50%, sand 20%). Calcium carbonate contentwas 65 to 70% (active lime 20%) increasingslightly with depth. Probably, part of the clayfraction was clay-size calcium carbonate, ashas been shown for another highly calcare-

ous soil (Orphanos and Kokkinos, 1983).Available (bicarbonate-extractable) P was 6ppm in the surface soil and 3 ppm in the sub-soil, and available K was 220 and 200 ppm,respectively. These soil characteristics arerepresentative of the main grape-growingarea of Cyprus (Koudounas and Makin,1981; Luken, 1987; Koudounas, 1990).

Rainfall is the most variable weather pa-rameter, and was recorded on the site using astorage gauge. Average monthly maximumand minimum temperature in the area is: 20and 13 oC in October, 17 and 10 oC in No-vember, 12 and 7 oC in December, 11 and 6oC in January, 13 and 7 oC in February, 14and 8 oC in March, 18 and 11 oC in April, 23and 14 oC in May, 27 and 18 oC in June, 30and 21 oC in July, 29 and 20 oC in August,and 26 and 17 oC in September.

Weed control is critically important ineconomizing on stored water. Initially thevineyard was rotovated but in 1982 chemicalweed control using simazine and caragardwas initiated. This, however, led to infesta-tion by perennial bush species, mainly Inulaviscosa, Genista sphacelata and Foeniculumvulgare, and by the annual Crepis aspera.Because of this, rotovation was resumed in1986.

Incidentally, as rotovation needs to bedone by walking rotovators, or 2-wheel roto-vators, the vines should be so spaced as tofacilitate to the greatest extent this laboriousand costly operation. There should be suffi-cient free space in both the inner and thebank end of the terrace.

Powdery mildew is the major disease ofwine grapes in Cyprus and berry moth is themajor pest. Two dustings with sulphur weresufficient (Carignane required four dustings)to prevent attack by powdery mildew, and 3to 4 dustings with parathion, later pyrifos,were required for preventing attack by theberry moth.

The experiment was initiated in Spring1985 to test three rates of N (0, 75 and 150kg N/ha), two rates of P (0 and 30 kg P/ha),and two rates of K (0 and 150 kg K/ha) infactorial combination. Nitrogen was appliedas ammonium nitrate, phosphorus as triplesuperphosphate, and potassium as potassiumsulphate. The fertilizers were applied broad-cast in late winter and rotovated into the soil.Because of severe drought all fertilizing was

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discontinued in Spring 1991 and 1992, andonly N fertilizing was resumed from Spring1993 onwards.

Initially only Carignane noir and Mavrowere entered into the experiment. Lefkas hadadmixtures of alien vines and, therefore, re-quired culling and additional replanting. Itwas entered in the experiment in 1988.

The grapes were harvested when theirBaumé value was around 12.5o.

The N, P and K concentration in laminaeand petioles was monitored on leaves sam-pled at the end of bloom from opposite thefirst cluster, and soil fertility was appraisedby analysing for bicarbonate-extractable Pand available K (exchangeable + soluble K).

RESULTS

Omodos and Arsos ExperimentsNitrogen increased yield slightly and er-

ratically at first, but it then tended to reduceit, particularly at Arsos (Fig. 1).

There was virtually no response to P orK, therefore the results presented are averag-

es over the P and K treatments. At the con-clusion of the Arsos experiment, i.e. aftereight annual applications of 35 kg P/ha or 96kg K/ha, respectively, available soil P andsoil K increased significantly (Table 1).

Concentration of K in leaves (wholeleaves), sampled from opposite the first clus-ter at end of bloom, significantly increasedfrom the third year onwards. To monitor thepersistence of this increase, leaves continuedto be sampled at Arsos every-other year foreight years after the experiment had beenotherwise terminated. Leaf K continued tobe persistently higher in plots that had re-ceived K (Fig. 2).

Vasa ExperimentYield varied from 6 to 12 t/ha but its rela-

tion to rainfall was not always clear (Fig. 3).However, the low yield in 1973 was due tovery low rainfall. Indeed, 1972/73 was thedriest year on record for the whole of the is-land. Then a serious hailstorm in mid April1977 set another low yield point. From 1980onwards yields were relatively low, eventhough rainfall was not always low.

N increased yield at first but then tendedto reduce it. The only statistically significanteffect was a small yield reduction with Nfertilizing in 1981 and 1983. Yields weresimilar with either N carrier, and with orwithout phosphorus (data not presented).

The N fertilizer rates were reflected inhigher NO3-N concentrations in petioles(Table 2) and higher soil NO3-N values (Ta-ble 3) confirming the higher N status with Nfertilizing. Differences between the two Ncarriers were insignificant. The marked dif-ferences in NO3-N levels among years were

Table 1. Available P (Olsen P) and available K (ex-changeable + soluble K) in the surface soillayer following eight annual applications of35 kg of P and 96 kg K, respectively, ArsosExperiment

Total P or K Available P or K (ppm)appied(kg/ha) Initial After 8 years

Phosphorus0 14 9280 14 38

Potassium0 160 160768 160 418

Table 2. Concentration of NO3-N, P and K in petioles of Mavro leaves sampled from opposite the first cluster atend of bloom, as influenced by four levels of N fertilizing, Vasa Experiment

NO3-N (ppm) P(%) K (%)N rate(kg/ha) 0 50 100 150 0 50 100 150 0 50 100 150

1977 93 258 554 477 0.26 0.18 0.18 0.17 1.83 1.36 1.38 1.311978 120 271 415 453 0.13 0.10 0.10 0.10 1.62 0.96 1.04 0.961979 119 166 272 2661981 6 23 32 74 0.11 0.10 0.10 0.08 0.66 0.48 0.47 0.481982 47 123 291 290 0.12 0.13 0.15 0.14 1.05 0.81 0.89 1.131983 12 28 101 140 0.14 0.15 0.15 0.12 1.09 0.93 0.90 1.131984 39 135 193 220 0.24 0.27 0.26 0.24 1.16 0.95 0.87 1.001985 368 426 596 536 0.15 0.20 0.21 0.15 1.17 0.93 0.78 0.93

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Figure 1. Yields of Mavro grapes as influenced by four levels of N, Omodos (upper) and Arsos (lower) Ex-periments. In 1972 the crop was destroyed by hail at Omodos.

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Figure 2. Rainfall (), and concentration of K in leaves (whole leaves), sampled at end of bloom from op-posite the first cluster, as influenced by K application (: no K, :96 kg K/ha). Arsos experi-ment. Note: hail damage in 1972; sampling every other year after 1976.

Table 3. Concentration of NO3-N (ppm), available (Olsen) P (ppm) and available K (ppm) (exchangeable + sol-uble) in the top 30 cm layer following six annual applications of 75 or 150 kg N/ha, 30 kg P/ha, and150 kg K/ha, respectively. Pachna experiment

N rate (kg/ha) P rate (kg/ha) K rate (kg/ha)

Depth (cm) 0 75 150 0 30 0 150

0-15 3.0(5.9) 4.6 (9.0) 7.7(15.0) 14.6 31.1 291 55515-22 4.0(3.9) 15.8 (15.4) 31.0 (30.2) 4.2 6.4 227 34923-30 5.4(5.3) 20.6 (20.1) 43.6 (42.5) 2.6 4.1 199 253

* Values in parenthesis denote kg N/ha for the respective layer.

partly due to even small variations in thetiming of leaf sampling, as NO3-N decreasessharply with time at bloom time (Cook andKishaba, 1956; Christensen, 1969). N ferti-lizing tended to decrease concentration of Pand K in petioles, a fact observed also withirrigated Sultanina grapes (Orphanos, 1992),but this was not consistent.

The weight of fresh prunings was about 2t/ha (1 t/ha dry matter) but was not affectedby N or P fertilizing. The prunings containedabout 0.65% N, 0.07% P and 0.45 % K ondry matter basis. There was no relationshipbetween the weight of prunings and yieldover the experimental period (Fig. 4).

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Figure 3. Rainfall, and yields of Mavro grapes as influenced by four levels of N fertilizing.Vasa ex-periment.

Pachna ExperimentIn deference to other data (Reuther,

1987), Carignane yielded appreciably morethan Mavro in the first half of the experi-mental period, but Lefkas consistently yield-ed less than Mavro. However, by the end ofthe 12-year experimental period, yield of Ca-rignane was reduced to that of Mavro (Fig.5). In the 1991 drought year, Mavro yieldedalmost twice as much as Carignane or Lef-kas. Thereafter, rainfall remained below av-erage with a third, though less severe,drought in 1994. Despite the drought, yieldof Mavro was remarkably stable. The lowyield of all varieties in 1987 was due to thecombination of a heat wave and severe at-tack by the berry moth. Even though Lefkasyields less than Mavro, its grapes sell atthree times the price of Mavro grapes.

Only N influenced the yield of all threevarieties from the second experimental yearonwards, and the 75 kg N/ha rate was suffi-cient (Fig. 6). However, such yield increasewas not statistically significant in any one

Figure 4. Yields of Mavro grapes versus weight ofprunings by year and individual plotover the experimental period (R2= 0.07,n=560). Vasa Experiment.

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Figure 5. Yields of Mavro, Carignane noir and Lefkas grapes, and rainfall over the experimental pe-riod. Pachna Experiment.

year. It only reached significance (P<0.05)when the cumulative yield over the yearswas considered. Apparently the high coeffi-cient of variation (range:22 to 38%) reducedthe precision of the experiment (Fig. 6).

Like in the Vasa Experiment, the increas-ing concentration of NO3-N in petioles (Fig.7) confirmed the higher nutrition afforded byincreasing N application but this was not al-ways clear. The year-to-year variation was

again mostly due to varying sampling tim-ing. Moreover, at the same timing, Carig-nane and Lefkas were at a more advancedstage than Mavro, hence the lower nutrientconcentrations in their petioles. Such ad-vancement in growth resulted in a 7 to 10days earlier harvesting of Carignane andLefkas (~ 22 August) compared with Mavro(~ 2 September). However, vines not receiv-ing N had a noticeably paler green colour in-

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Figure 6. Yields of Mavro (upper) Carignane noir (middle) and Lefkas (lower) grapes as influencedby N fertilizing over the experimental period (N was not applied in 1991 and 1992). Pach-na Experiment.

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Figure 7. Concentration of NO3-N in petioles of Mavro (upper), Carignane (middle) and Lefkas(lower) sampled at end of bloom as influenced by application of zero (N0), 75 (N1) or150 (N2) kg N/ha. Pachna Experiment.

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dicative of a low N status. A more detailedcourse of maturation of Mavro, Carignanenoir and other varieties has been reported byRoumbas (1983). Incidentally, earlier har-vesting reduces losses from berry moth at-tack.

Like in the Arsos Experiment, K applica-tion increased K in petioles but not in lami-nae, particularly in the later years (Fig. 8),but to a lesser extent than at Arsos. Similar-ly, application of P, slightly increased leaf P(Fig. 9).

Application of both P and K significantlyincreased available soil P and K (Table 3) inthis highly calcareous soil. The surface soilinitially (before terracing) contained 6 ppmavailable P and 220 ppm available K. Fol-lowing terracing and the application of a to-tal of 400 kg P and 370 kg K/ha from plant-ing until the experiment was started, surfacesoil P increased to 24 ppm and K to 305ppm. By the end of the first 6-year experi-mental period application of 30 kg P/ha/yearfurther raised available P in the surface soilto 31 ppm compared to a reduction to 15ppm in plots which did not receive further Pover this 6-year period. Similarly, the six-year application of 150 kg K/ha/year in-creased available K in the surface layer to555 ppm. Applied K apparently moved downthe soil to at least 30 cm, while P was onlyaccumulated in the 0 to 15 cm layer (Table3); the slight increase of P in the 15 to 22 cmlayer was probably the result of soil mixingduring rotovation.

In plots that did not receive P during thecourse of the experiment, available P was re-duced from 24 to 15 ppm over the first 6-year period of the experiment. For a 15 t/ha/year yield over this period the amount of Premoved in the grapes and prunings wouldbe: 6 years x 4.5 kg P/year=27 kg P. Thisrepresents 14 ppm P in the 0 to 15 cm layer.Available P should therefore have dropped to10 ppm. Apparently, some other pool of Pcontributed to the balance. Possibly, immobi-lized P became available.

It can also be calculated that at the end ofthe first 6-year experimental period abouthalf the K applied was accounted for as in-crease in available K in the top 30 cm layeralone.

DISCUSSION

The present results confirm that winegrapes are not a fertilizer-demanding crop.As already reported (Orphanos, 1973), theamounts of N,P and K removed with one tonof grapes are: 1.2, 0.2 and 2.5 kg, respective-ly. The corresponding amounts for the prun-ings (120 kg dry matter) are: 0.8, 0.1 and 0.7kg. This means that even with a high grapeyield of 18 t/ha the total amounts of N, P andK removed with the grapes and the appor-tioned prunings are: 36, 5.4 and 58 kg/ha, re-spectively. Clearly, for this yield level, 75 kgN/ha was sufficient (Pachna Experiment).This can perhaps be used as a starting pointfor recommending N rates taking into ac-count the yield level, i.e. proportionately in-creasing the rate for yields above 15 t/ha, orreducing it for yields less than this level.This is very close to the recommendationmade by Niekerk and Pienaar (1967) for thewinter-rainfall areas of South Africa.

Vine vigour is also an important criterionin recommending N rates. In this respect,Orphanos (1992) noted that, although yieldof irrigated Sultanina increased linearly withN application of up to 225 kg/ha, at 150 kgN/ha the vineyard was too dense to be prop-erly managed. In wine grapes, excessive Nin combination with a high water supply re-duces grape quality, and may also lead to thedisorder known as stem necrosis (Winkler etal., 1974).

It is well established (Huett, 1996) thatthe active spring growth of deciduous fruittrees, including vines, depends on nitrogen,and other nutrients, stored in the roots, trunkand branches (canes). Furthermore, Peacocket al. (1989) showed that in irrigated vinesnitrogen applied in the previous summer ismore efficiently used than spring-applied ni-trogen. In any case, timing of N applicationis not critical yieldwise (Christensen et al.,1994). As in Cyprus wine grapes are grownrainfed, fertilizer can only be applied in win-ter-spring. To avoid leaching, such applica-tion should be so timed as to be followed bynot more than 100 mm of rainfall. Obvious-ly, even skipping fertilizer application for ayear, or even longer, will not decrease yield.

In all experiments available soil P wasrather high due to past P application, hencethe lack of response to fresh P application.

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Figure 8. Concentration of K in petioles and laminae of Mavro (upper), Carignane (middle) and Lef-kas (lower) without K fertilizing (K0) or with 150 kg K/ha (K1). The leaves were sampledat end of bloom over the experimental period. Pachna Experiment.

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Figure 9. Concentration of P in laminae and petioles of Mavro (upper), Carignane (middle) and Lef-kas (lower) without P fertilizing (P0) or with 30 kg P/ha (P1). The leaves were sampled atend of bloom over the experiment period. Pachna Experiment.

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As the lowest value of soil P recorded inthese experiments was 9 ppm (at the conclu-sion of the Arsos Experiment), it can be con-cluded that values above this level denotesufficiency of P.

Similarly, potassium is amply suppliedby these calcareous soils, and no response toK can be expected. Despite the drying of thetop soil from June onwards, apparently Ktaken up in early season in redistributed tothe clusters (Williams and Biscay, 1991).However, in the igneous Troodos massif,where the available soil K is less than 150ppm (Koudounas and Makin, 1981), K defi-ciency may occur.

The leaf analytical data confirm the dif-ferent nutrient regimes, particularly of N, re-sulting from fertilizing. However, the greatyear-to-year variation of N content precludesusing such data for appraising the N status ofa vineyard. In contrast, the relative stabilityof P and K contents, does reflect the P and Kstatus of the vineyard. According to the Cali-fornian standards (Cook and Wheeler, 1976),for the leaf opposite the first cluster sampledat bloomtime, all P and K values were abovethe sufficiency norms of 0.3% and 1.5% inpetiole dry matter, respectively. Accordingto these standards, K values, higher than3.0% indicate excess. Such values prevailedin the Pachna Experiment, even without Kapplication (Fig. 8), yet K application did nothave any adverse effect. The higher increasein leaf K with K fertilizer at Arsos comparedwith Pakhna (Fig. 2 and 8) reflects the differ-ent soil K status at the two sites, i.e. 160 vs300 ppm available K.

Even though soil available K was similarat Vasa and Pachna, concentration of K inpetioles was disproportionately low at Vasa(Table 2, Fig. 8). Incidentally, the very lowvalues at Vasa in 1981 were probably due torather late (16 June) sampling, i.e. when theberries had the size of a small pea. Widevariation of K content in vineyards has alsobeen reported by Koudounas (1990).

In any case, leaf analysis at any one timeis governed by the nutrient in deficiency orexcess, therefore, it cannot be expected togive an overall picture of the nutritional stat-us of a crop (Munson and Nelson, 1990).However, leaf analysis will reveal nutrientdeficiencies, and is indispensable in confirm-ing suspected deficiencies.

In contrast to leaf analysis, soil analysisfor P and K provides solid information onthe size of the soil nutrient pool. It is com-monly assumed that P applied to calcareoussoils is fixed, and applied K is strongly an-tagonised by calcium. The present resultsshow that both P and K build up rather fastand remain available for long years. Unlike Pand K, soil NO3-N data are very difficult toobtain, as deep sampling is required. In anycase, the present NO3-N data (Table 3) arenot sufficient to indicate the usefulness, orotherwise, of such data.

The slow change of available P and K in-dicates that the soil only needs to be ana-lysed at wide intervals.

Irrespective of the drought over the sec-ond half of the life span of the Pachna exper-iment, Lefkas apparently requires a higherwater regime, at best secured by higher waterstorage in deeper soils. On the other hand,Carignane, too, although it started rather vig-orous it gradually weakened, most likely dueto the drought, but possibly also due to age-ing. Mavro vineyards in Cyprus have a lifespan of over 100 years, in the head form.They are rejuvenated to a certain extent byallowing a new head to develop from suckersappearing at the base of the head, and remov-ing the old one. This is not possible with thegoblet form given to the introduced varieties,so more frequent replanting will probably benecessary. As with the introduction of newvarieties Cypriot viticulture is at a turningpoint, such matters will have to be resolved.

REFERENCES

Christensen, P. 1969. Seasonal changes and distri-bution of nutritional elements in Thomp-son Seedless grapevines. American Jour-nal of Enology and Viticulture 20:176-190.

Christensen, L.P., M.L. Bianchi, W.L. Peacock,and D.J. Hirschfelt. 1994. Effect of nitro-gen fertilizer timing and rate on inorganicnitrogen status, fruit composition, andyield of grapevines. American Journal ofEnology and Viticulture 45:377-387.

Cook, J. A., and T. Kishaba. 1956. Petiole nitrateanalysis as a criterion of nitrogen needs inCalifornia vineyards. Proceedings of theAmerican Society for Horticultural Sci-ence 68:131-140.

Cook, J.A., and W. Wheeler. 1976. Use of tissue

18

analysis in viticulture. In Soil and Plant-Tissue Testing in California. (H.M. Reise-nauer, ed), pp. 14-16. Bulletin 1879. Uni-versity of California.

Dundon, C.G., R.E. Smart, and M.G. McCarthy.1984. The effect of potassium fertilizer onmust and potassium levels of Shirazgrapevines. American Journal of Enologyand Viticulture 95:200-205.

Galet, P. 1990. Ampelographie Chypriote. Pro-gres Agricole et Vinicole 107:262-268.

Galet, P. 1993. The vines of Cyprus. In Vines andWines of Cyprus pp. 61-71. Vine ProductsCommission, Limassol.

Huett, D.O. 1996. Prospects for manipulating thevegetative-reproductive balance in horti-cultural crops through nitrogen nutrition:a review. Australian Journal of Agricultu-ral Research 47:47-66.

Koudounas, C. 1990. Nutritional studies on per-manent crops in Limassol district. Depart-ment of Agriculture, Nicosia. 161p.

Koudounas, C, and J. Makin. 1981. A study ofrepresentative soil profiles from Limas-sol-Paphos districts. Department of Agri-culture in cooperation with the SouthernConveyor Project, Nicosia. 61p.

Logothetis, B., and M. Vlachos. 1966. Greek Am-pelography. E'. Akominato, Vartzami,Zoumiatico, Mavrodafni, Mavroudi. Sci-entific Report of the School of Agricultureand Forestry 10:373-382. AristotelianUniversity, Thessaloniki. (in Greek).

Loizides, P.A. 1958. Fertilizer experiments in Cy-prus. III. Fruit trees and vines. The Em-pire Journal of Experimental Agriculture26:229-239.

Luken, H. 1987. Calcareous soils of Cyprus. Pe-dology Vol. I. Federal Institute for Geos-ciences and Natural Resources, Hannover.256p.

Matthews, M.A., and M.M. Anderson. 1989. Re-productive development in grape (Vitis vi-nifera L.): Responses to seasonal waterdeficits. American Journal of Enologyand Viticulture 40:52-60.

Moretti, G., and G. Liessi. 1996. Risposte vitico-lo-enologiche dei Marzemini coltivati neltrevigiano. Supplement to L' InformatoreAgrario 29/96:3-5. (in Italian).

Munson, R.D., and W.L. Nelson. 1990. Principles

and practices in plant analysis. In SoilTesting and Plant Analysis. Soil ScienceSociety of America, Book series 3, pp.359-387.

Niekerk, van P.E., and W.J. Pienaar. 1967. Fertili-zation programme for fruit trees and tablegrape vines in the winter rainfall area. De-ciduous Fruit Grower 17:141-148.

Orphanos, P.I. 1973. Grape fertilization experi-ments 1969-72. Progress Report 18. Agri-cultural Research Institute, Nicosia. 19p.

Orphanos, P.I. 1992. An NPK experiment withSultanina grapes. Technical Bulletin 141.Agricultural Research Institute, Nicosia.10p.

Orphanos, P.I., and Ph. Kokkinos. 1983. The soilof Zyghi Station. Miscellaneous Reports11. Agricultural Research Institute, Nico-sia. 7p.

Peacock, W.L., L.P. Christensen, and F.E. Broad-bent. 1989. Uptake, storage, and utiliza-tion of soil-applied nitrogen by Thomp-son Seedless as affected by time ofapplication. American Journal of Enologyand Viticulture 40:16-20.

Reuther, G. 1987. Viticultural investigations oncalcareous soils. Pedology Vol. II. Feder-al Institute for Geosciences and NaturalResources, Hannover. 161p.

Roumbas, N. 1983. Maturation du raisin et pro-duction de la vigne a Chypre en 1979 eten 1980. Connaissance de la Vigne et duVin 17:151-171.

Roumbas, N. 1993. The viticulture of Cyprus. InVines and Wines of Cyprus, pp. 47-59.Vine Products Commission, Limassol.

Winkler, A.J., J.A. Cook, and L.A. Lider, 1974.General Viticulture. Berkley, Universityof California Press.

Williams, L.E., and P.J. Biscay. 1991. Partition-ing of dry weight, nitrogen, and potas-sium in Cabernet Sauvignon grapevinesfrom anthesis until harvest. AmericanJournal of Enology and Viticulture42:113-117.

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