Grape Rootstocks and Nutrient Uptake Efficiency
Rootstock trials established in Oregon’s three main viticultural regions were evaluated for the effect of rootstock on petiole nutrient content at four vineyard sites during the 1996 growing season. Pinot noir grafted to the following seven rootstocks was replicated five times in blocks of five vines at each of the four locations: ungrafted Pinot noir, 3309 Couderc, 101-14 Millardet et De Grasset, 44-53 Malègue, 420 A Millardet et De Grasset, 5 C Teleki, and Harmony. Soil samples (0 – 30 cm depth) and petioles of leaves opposite flower clusters were collected at bloom and analyzed for macro and micronutrients.
All of the vineyards had acidic soil pH values, but differed their amounts of total acidity. Levels of boron were sub-optimal, except at one location. The amount of exchangeable Al is well correlated to the pH of the soil. Levels of extractable Al are high at one of the vineyards. It is not clear at this point weather Al limits the growth and productivity at this site. One of the sites was low on P and Mg and another had high levels of potassium.
Ungrafted vines showed lower efficiency than grafted vines in assimilating potassium and Boron. They ranked among the most efficient in phosphorous uptake. Rootstock 44-53 tended to have the highest efficiency in K and B uptake but had a very poor performance in Mg uptake. Compared to other rootstocks, 101-14 showed an intermediate performance in the uptake of K, Mg, P, and B. 3309 C was efficient in B uptake but intermediate in the uptake of other nutrients. 420 A assimilated K and B poorly compared to other rootstocks. 5C ranked among the least efficient stocks in Mg and P uptake. Harmony was highly efficient in the uptake of Mg and P but performed poorly in B uptake. Rootstock ranking in B uptake were consistent in all four vineyards studied.
The advent of phylloxera in Oregon led to an urgent need of evaluating viticultural characteristics of rootstocks with potential adaptation to different sites in Oregon, a cool climate grape production zone. Soil factors including native fertility, past fertility management, and available soil moisture would be expected to play a significant role in rootstock selection, vine spacing, and cultural practices in replanted vineyards. Little published data is available from which to judge the response of rootstocks over the range of soil and climatic conditions found in Oregon.
The efficiency in nutrient uptake of American Vitis species differs considerable from that of vinifera (Fregoni and Bavaresco, 1984; Pouget, 1984; Schaller and Löhnertz, 1990; Delas, 1992; Fardossi et al. 1992, Candolfi-Vasconcelos et al., 1996). This subject is receiving some attention in the past few years due to its importance for overall plant growth and performance. Winegrape production techniques should have a low impact on the environment and promote sustainable production while maintaining profitability. Selection of rootstocks with high nutrient uptake efficiency, well adapted to the soil and climate, will decrease production costs and contribute to the sustainability and competitiveness of the Oregon winegrape production. This study aims at comparing rootstock uptake efficiency of cations and anions that are most commonly deficient to fully evaluate their potential adaptation to the Oregon vineyards.
MATERIALS AND METHODS
The following rootstock trials, planted in 1992, were followed in this study: Winters Hill Vineyard (Lafayette), Whistling Ridge Vineyard (Newberg), Henry Estate Vineyard (Umpqua), and Ousterhout Vineyard (Eagle Point). The trials include five replicated blocks of five Pinot noir vines ownrooted and grafted onto the following six stocks: 3309 Couderc, 101-14 Millardet et De Grasset, 44-53 Malègue, 420 A Millardet et De Grasset, 5 C Teleki, and Harmony. All of these rootstocks except Harmony are characterized by a high resistance to phylloxera. Harmony has V. vinifera in the parentage (which is usually associated with insufficient phylloxera resistance) and showed low resistance to phylloxera in Australia (Cirami et al., 1984) and South Africa (Southey, 1992).
Table 1 summarizes geographical, climatic and pedological information as well as choice of trellis systems and spacing of each site included in this study.
Table 1. Geographical and pedological characterization and cultural choices of the vineyards under study.
|SITE CHARACTERISTICS||LOCATION AND COUNTY|
|Newberg (Yamhill)||Lafayette (Yamhill)||Umpqua (Douglas)||Eagle-Point (Jackson)|
|Soil Series & Type||Willakenzie silty clay loam||Jory clay loam||Alluvial silty clay loam||Agate gravelly loam|
|Training System||Double Guyot||Double Guyot||Scott Henry||Lyre|
Western Oregon soils are typically deep, well drained, and acidic. Available water and soil acidity are two of the more important factors effecting vine response. The total available soil moisture in western Oregon soils is a function of the effective rooting depth of the vine. Values for plant available soil moisture will vary depending on soil depth, texture, presence of competing grass sod stripes between the vine rows, site characteristics, modification of rooting volume by soil acidity or other nutrient related factors, and the effective rooting depth. The effective rooting depth has not been established for grapevines in western Oregon.
Estimates for the soil properties in this study were obtained from local county soil surveys. Willakenzie soils are typically moderately deep (32″), well drained silty clay loams, medium acidic in the surface to acidic in the subsoil. They have a parent material substratum of siltstone at 20-40″. Plant available water in these soils is from 5 to 7.5″. Estimates of plant available water capacity are based on the texture, soil depth, and assumed rooting depth for the soil are deep soils (60+”), well drained silty clay loam, medium to strongly acid with depth. The substratum of the Jory consists of a basaltic bed-rock at a depth of 60″ or more. The effective rooting depth of the Jory soil can be greater than 60″, with a 9-11″ of plant available water. The vineyard located at Umpqua was planted on the valley floor and the soil is very deep (60″) and fertile. Plant available water is likely to be more than 11″. Agate soils are typical of arid regions and are moderately deep (32-40″), well drained gravelly loams. This site is irrigated during periods of plant water stress. Consumptive use of water by grape vines in the Willamette Valley is in the range of 12-14″. Values for vine consumptive use would be expected to be a function of vineyard site factors, such as temperature, average relative humidity, and wind speed. The vines can use water in the spring prior to the last rainfall which replenishes the reservoir of soil moisture.
Soil and tissue analysis
Soil samples (0 – 30 cm depth) and leaf petioles were collected at bloom. The plant material was oven dried at 60°C for 48 hours and ground to pass through a 40 mesh screen. The soil samples were dried at 40°C, ground on a mortar and sieved. Soil and petiole samples were analyzed for macro and micronutrients by the Central Analytical Laboratory of the Crop Science Department at Oregon State University.
The vineyards were harvested at commercial ripening. The vineyard at Eagle Point was harvested on September 18, at Umpqua on October 1, at Lafayette on October 3, and at Newberg on October 12, 1996. A sample of 25 clusters per replicate was crushed and filtered for determination of potassium concentration via atomic absorption spectroscopy.
RESULTS AND DISCUSSION
A large portion of the plant available nutrients is associated with the organic matter found in the surface horizons of a soil. This is generally in the first 16″ of a typical western Oregon soil and includes most of the soil nitrogen, sulfur, potassium, phosphorus, zinc, and boron. The concentration/availability of these nutrients would be expected to decrease with depth in the soil. A typical soil used for vineyard production in western Oregon usually becomes more acid with depth, that is soil pH decreases. Nutrient availability is generally negatively correlated to acidity. This is either the result of toxicities induced by the acid conditions, or the fact that acid soils are generally highly weathered and lack high concentrations of plant nutrients in their deeper horizons.
Soil pH and titratable acidity values for the four vineyards studied is shown in Table 2. As expected for a southern Oregon vineyard site Eagle Point has the highest pH of the four vineyards, but still in the acid range. The relationship between soil pH and soil titratable acidity is analogous to grape juice pH and total acidity values. Soil titratable acidity is a measure of the total capacity of reserve acidity. As with juice chemistry, the amount of titratable acidity is not necessarily correlated to the soil pH. The total acidity of a soil depends on the texture and the humus content.
Values for exchangeable soil Al correlated with soil pH. A value of greater than 30 is considered to be the threshold for Al toxicity induced plant stress. Al toxicity manifests itself in stunting and suberization of fine roots, leading to a decrease in vigor. The Newberg vineyard has values above 30 ppm, suggesting that Al toxicity my limit vine productivity at this site. Plant induced Al stress could potentially control excess vigor, a continuing problem in some Oregon vineyards. The occurrence of Al toxicity in Oregon vineyards with its potential effects on vigor and productivity is largely unexplored.
The concentrations of Ca and Mg are generally correlated the soil pH in the vineyards studied. The values for the Willamette Valley vineyards are somewhat low. This consistent with the genesis of these soils in a humid weathered environment the Ca and Mg carbonates have been completely weathered and leached out of the soil profile.
Table 2. Soil pH, titratable acidity, macro and micronutrient content at 0-30 cm depth in four vineyards (n=35). Samples were collected at full bloom in 1996
|Soil titratable acidity(cmol/kg)||6.11||13.72||7.82||6.57|
Potassium concentrations in the Willamette Valley foothill soils range from 75-150 ppm K for soils which have received no potassium fertilizer. Vineyard soils which have been “over fertilized” may lead to excessive uptake of K and elevated levels of K in the grape juice (see discussion below). All four vineyard sites appear to have adequate levels of soil K. The concentrations of K do not follow the same trends with pH as do Ca and Mg, suggesting that the vineyards have received some K fertilization in their histories. Potassium fertilization of serpentinic soil has been found to increase grape yields.
The boron concentration in typical western Oregon soil is low. A value of less than 1 ppm is usually considered sub-optimal for vine growth. Only the southern Oregon vineyard soil contains optimal levels of boron. Boron is often found to be deficient in intensely weathered soils in high rainfall areas, such as western Oregon. Boron also adsorbs or precipitates with soil mineral in fashion similar to P. This process further serves to limit the supply of plant available B in Oregon soils. Much of the plant available pool of soil boron may be present as organically combined forms. This may in part explain why boron deficiencies are more severe after dry falls or cool springs when the mineralization of soil organic boron would be expected to be low. Boron is thought to be combined with the soil organic fraction. It follows that most of the soil B is probably found in the topsoil layers (0-15″, or less). Soils with shallow or eroded topsoil would be expected to have low values of B.
The soil P levels observed in this study range from 12-44 mg P/kg soil (ppm). A response to soil applied P has not been observed for many western Oregon crops. A value of 20-25ppm is generally considered adequate for grass seed crops. As with many other plants grapevines undoubtedly have a root/fungal mycorrhiza association. In this association the fungus gets energy from the grape plant in the form of sugars. The grape vine benefits in return by getting a larger surrogate root system with an enhanced capacity for water and nutrient (phosphorus) uptake. Zinc and copper are present at levels expected in western Oregon. All of the vineyards have optimal levels of these nutrients in the soils.
Figure 1. Effect of rootstock on petiole and soil macro-nutrient content at four different locations in Oregon. Samples were collected at full bloom. The three graphs on the right combine the four sites. In each case, there was a significant interaction between site and rootstock. Mean soil concentrations for each of the elements is shown just below each set of graphs.
Petiole nutrient levels varied greatly with rootstock but the ranking of rootstocks varied from site to site (Fig. 1). Vines grafted to 44-53 tended to have highest and own-rooted Pinot noir tended to have the lowest petiole K content. 420A was among the least efficient rootstocks in potassium uptake (Fig. 1). Harmony ranked among the top two rootstocks in magnesium uptake and 44-53 had the lowest petiole magnesium content in two of the sites, 5C being the least efficient in magnesium uptake at the other two locations (Fig. 1). This is in agreement with Galet’s report that 420 A uptakes K poorly and 44-53 efficiently and that the latter tends to induce Mg deficiency in the scion (Galet, 1991). In two of the sites, vines grafted to 5C had the lowest petiole phosphorous content and ranked low to intermediate at the other two locations. Harmony and own-rooted vines ranked among the top stocks in phosphorous uptake (Fig. 1).
Petiole micronutrient levels varied more with location than with rootstock. The only exception was Boron that was more efficiently taken up by all the grafted vines as compared to ownrooted Pinot noir (Fig. 2). Among rootstocks, 44-53 Malègue was the most efficient, followed by 3309 Couderc (Fig. 2); Harmony was the least efficient in Boron uptake. These patterns were consistently observed in all the vineyards.
Figure 2. Effect of rootstock on petiole Boron content. Samples were collected at full bloom. There was no interacton between location and rootstock indicating that rootstocks ranked similarly at all locations. Bars are the means of each rootstock across the four vineyards. Vertical lines: +/-SE.
Juice potassium content differences were observed at Lafayette and Umpqua but the tendencies observed were not consistent (Table 3). High levels of potassium uptake have been shown to cause grape juice to have higher than desirable pH, leading to wine instability and to color problems in red wines. At Lafayette, must from ungrafted vines had the lowest K content and 101-14 induced higher juice K content. At Eagle Point, ungrafted vines had again the lowest Juice K but 44-53 had the highest content. It is interesting to note that Harmony did not always stand out in terms of juice potassium, since it has been reported that rootstocks of Vitis Champinii parentage (Harmony, Freedom, Ramsey, Dogridge) tend to increase potassium concentration and pH of juice above the levels of own-rooted vines (Hale, 1977). In agreement with the Australian experience (Hale, 1977), the general tendency across the four vineyards is for Harmony inducing the highest potassium levels in the juice and ungrafted vines the lowest.
Table 3. Effect of rootstock on Juice potassium content at four different locations in Oregon.
|Newberg||Lafayette||Umpqua||Eagle Point||4 Sites|
|Harmony||873 a||2184 ab||742 a||666 bc||1116 a|
|5C||796 a||1783 ab||547 a||799 ab||939 ab|
|420A||709 a||1920 ab||572 a||645 bc||962 ab|
|3309C||879 a||1503 b||595 a||749 ab||931 ab|
|101-14||701 a||2474 a||592 a||660 bc||1107 a|
|44-53||935 a||1599 b||630 a||882 a||1012 ab|
|Ungrafted||789 a||1464 b||552 a||540 c||836 b|
In this study, site differences were more important than those induced by the selected rootstocks. The effect of vineyard soil type and local climate represent a set of experimental variables whose influence on plant response was difficult to control. Soil acidity and its effect on the availability of other soil nutrients was most likely the single largest factor in vineyard variability. Rootstock effect on scion petiole nutrient content varied greatly with site and typically, the responses were not consistent from site to site.
Ungrafted vines showed lower efficiency than grafted vines in assimilating potassium and boron. They ranked among the most efficient in phosphorous uptake. Rootstock 44-53 tended to have the highest efficiency in K and B uptake but had a very poor performance in Mg uptake. Compared to other rootstocks, 101-14 showed an intermediate performance in the uptake of K, Mg, P, and B. 3309 C was efficient in B uptake but intermediate in the uptake of other nutrients. 420 A assimilated K and B poorly compared to other rootstocks. 5C ranked among the least efficient stocks in Mg and P uptake. Harmony was highly efficient in the uptake of Mg and P but performed poorly in B uptake. Rootstock ranking in B uptake were consistent in all four vineyards studied.
We thank the CAAR Program and the Oregon Wine Advisory Board for the funding of this research. Special thanks go to John Ousterhout, Scott Henry and Cari Crane from Henry Estate, Richard Alvord and Patricia Gustafson from Whistling Ridge, and Peter Gladhart from Winters Hill for the active participation in this research.
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Schaller, K., and Löhnertz, O.; 1990: Investigations on the nutrient uptake efficiency of different grape rootstock species and cultivars. In: N. El Bassam et al. (Eds.), Genetic Aspects of Plant Mineral Nutrition 42. Kluwer Academic Publishers. Netherlands. Pp 85-91.
Southey, J. M.; 1992. Grapevine rootstock performance under diverse conditions in South Africa. Pp 27-51 In: Rootstock Seminar: A Worldwide Perspective. Wolpert, J.A., Walker, M.A., Weber, E. (eds.) Reno, Nevada, 24 June 1992.
M. Carmo Candolfi-Vasconcelos and Steve Castagnoli Department of Horticulture. John Baham, Department of Crop and Soil Science, Oregon State University, Corvallis. This paper was presented at the 1997 annual meeting of the Oregon Horticultural Society