Correlations Between Soil Exchangeable Ca2+, Mg2+, K+ and Foliar Nutrient Concentrations in Mature Biological Olive Groves (Olea europaea L., cv. ‘Chondrolia Chalkidikis’)

Leaf and soil samples were taken and analyzed from two mature biological olive groves (Olea europaea L., cv. ‘Chondrolia Chalkidikis’), in Thessaloniki, Macedonia, Northern Greece, in order to determine the correlations between soil exchangeable cations and foliar calcium (Ca), magnesium (Mg) and potassium (K) concentrations, and the interrelations among leaf nutrients. Τhe nutritional requirements of trees for both biological groves were exclusively based on patent kali supply and nutrient recycling (via pruning material and weed cut recycling). Foliar K, Ca and Mg were positively correlated with soil exchangeable K, Ca and Mg, in the 40–60 cm layer, then in the 20–40 cm layer. Synergistic uptake mechanisms among Ca²⁺, Mg²⁺ and K⁺ probably exist. Leaf N was negatively correlated with foliar K, and positively with leaf Ca, Mg and manganese (Mn). Foliar P was negatively correlated with leaf Ca, Mg and Mn, while foliar Ca was positively correlated with leaf Mg and Mn. Foliar Mg was positively related with leaf Mn. High phosphorus (P) may decrease leaf Ca, Mg and Mn. Enhanced Ca may increase leaf Mg and Mn, while high Mg may also enhance foliar Mn. Finally, based on the determination of foliar nutrient concentrations, the nutritional requirements of olive trees in Ca, Mg, K, P, Fe, Zn were sufficiently (or over-sufficiently) satisfied. However, additional organic fertilization is needed, in order to achieve optimum levels of N, B and Mn (since their foliar concentrations were slightly insufficient). The correlations between leaf and soil exchangeable Ca, Mg and K, as well as among foliar nutrients should be taken into consideration, in order to achieve successful organic fertilization for mature biological olive groves, and to avoid nutritional imbalances and disorders.     

Nutrient Status in Oak Forests in Galicia,Northwest Spain: Foliar and Soil Concentration

The concentration of edaphic and foliar nutrients is an important factor in assessing the nutritional status of an ecosystem. This article presents data on the macronutrients in leaves and topsoil in Quercus robur forests located in northwest Spain. The aim is to evaluate the nutrient level explained by foliar and soil standard values and establish their relationships. We calculated the following nutrients: nitrogen, phosphorus, potassium, calcium, and magnesium. Plots 10 × 10 m were laid out and replicated three times. Soil was collected once per month with three samples from the topsoil, and leaves were collected once every 2 months during the vegetative period. Within the results, we emphasize the absence of nutrient deficiencies. The leaf macronutrient results differed by stand. Soil fertility can be considered low to medium, except for phosphorus and potassium, as compared with soils under pine and eucalyptus. There was no relationship between macronutrients in topsoil and leaves.     

The influence of soil levels of Ca,Mg, P and Zn on the dry matter yield and chemical composition of flax (Linum usitatissimum L.)

Abstract

Flax plants were grown in growth chamber studies using 16 soils in two experiments to examine the effect of soil Ca, Mg, Zn, P, pH and conductance on flax yield and nutrient content and to identify which of these soil characteristics would be most useful in predicting the potential for Zn deficiencies in flax. Dry matter yield increased as Zn content of the soils increased and decreased as Mg content of the soil increased. Availability of P to flax increased with increasing Zn level in the soil and decreased with increasing soil Mg and pH. Availability of Zn to the plant increased as soil levels of Zn, P and the Zn/P ratio increased and decreased as soil Mg, pH and conductance increased. Deficiencies of Zn for flax production appear most likely to occur on soils that have a low Zn and Zn/P ratio and high levels of Mg, pH and conductance.     

Erosional impacts on soil properties and corn yield on Alfisols in central Ohio

Accelerated soil erosion can impact upon agronomic productivity by reducing topsoil depth (TSD), decreasing plant available water capacity and creating nutrient imbalance in soil and within plant. Research information on soil‐specific cause – effect relationship is needed to develop management strategies for restoring productivity of eroded soils. Therefore, two field experiments were established on Alfisols in central Ohio to quantify erosion‐induced changes in soil properties and assess their effects on corn growth and yield. Experiment 1 involved studying the effects of past erosion on soil properties and corn yield on field runoff plots where soil was severely eroded and comparing it with that on adjacent slightly eroded soil. In addition, soil properties and corn grain yield in runoff plots were compared on side‐slopes with that on toe‐slopes or depositional sites. Experiment 2 involved relating corn growth and yield to topsoil depth on a sloping land. With recommended rates of fertilizer application, corn grain yield did not differ among erosional phases. Fertilizer application masked the adverse effects of erosion on corn yield. Corn grain yield on depositional sites was about 50 per cent more than that on side‐slope position. Corn plants on the side‐slope positions exhibited symptoms of nutrient deficiency, and the ear leaves contained significantly lower concentrations of P and Mg and higher concentrations of Mn and K than those grown on depositional sites. Corn grain yield in experiment 2 was positively correlated with the TSD. Soil in the depositional site contained significantly more sand and silt and less clay than that on the side‐slope position. There were also differences in soil properties among erosional phases. The soil organic carbon (SOC) content was 19\7 g kg⁻¹ in slightly eroded compared with 15\1 g kg⁻¹ in severely eroded sites. Aggregate stability and the mean weight diameter (MWD) were also significantly more in slightly eroded than severely eroded soils. Adverse effects of severe erosion on soil quality were related to reduction in soil water retention, and decrease in soil concentration of N and P, and increase in those of K, Ca and Mg. Severe erosion increased leaf nutrient contents of K, Mn and Fe and decreased those of Ca and Mg. Corn grain yield was positively correlated with aggregation, silt and soil N contents. It was also negatively correlated with leaf content of Fe. Copyright © 2000 John Wiley & Sons, Ltd.     

Salinity induced effects on the nutrient status of soil,corn leaves and kernels

Abstract

The effect of salinity in inducing soil macro and micronutrient deficiencies that can decrease crop growth was evaluated in a corn (Zea mays L.) field located in east central Wyoming. In this study water soluble Na was found to be a better predictor of salinity than pH and other cations. Soil saturated paste extracts had electrical conductivities that were negatively correlated with soil total K, Cu, Fe, and Mn. Total N, NO₃‐N, PO₄‐P, Zn, pH, and water soluble Na, Ca, and Mg of the soil were positively correlated with EC. Significant positive relationships existed between soil EC and N, P, Mo, and Zn, and negative relationships with K, Cu, Fe, and Mn of corn leaves and kernels. Concentrations of nutrients in the kernels were positively correlated with corresponding nutrient concentrations in the leaves and with AB‐DTPA extractable soil nutrients. The analysis of variance of EC data indicated that soil samples possessing high salinity were higher in pH and contained significantly higher soluble Na, Ca and Mg, total N, N0₃‐N, PO₄‐P, and Zn and significantly lower Mn compared to samples having low salinity. The kernel weight per cob and plant height were significantly reduced as salinity increased.     

Ranges of nutrient concentrations in Quercus ilex leaves at natural and urban sites

The leaf nutrient concentrations and the N‐to‐nutrient ratios were analyzed to evaluate the nutritional status of holm oaks (Quercus ilex L.) experiencing various anthropogenic pressures. Leaves (1 year old) of Q. ilex and surface soil (0–5 cm) surrounding the trees were collected at seven natural and seven urban sites in Campania Region (Southern Italy) and analyzed for the concentrations of macro (C, N, P, S) and micronutrients (Mn, K, Na, Cu, Mg, Ca, Fe, Zn). The available soil fraction of micronutrients was also evaluated. The nutrients showed different concentration ranges for the natural and the urban sites in the soil (total and available) and in the leaves, that we reported separately. Organic‐matter content and macronutrient concentrations were higher in the natural soils, while the highest leaf N, S, and P concentrations were found at some urban sites. Concentrations of Cu, Na and Zn both in leaves and soil, and Mg and Fe in leaves from the urban sites appeared to be affected by air depositions. Manganese was the only micronutrient to show higher concentrations at the natural than at the urban sites, both in soil and leaves. For this nutrient, in addition, a relationship between leaf and available soil concentrations was found at the natural sites. The ratios between the concentrations of N and each studied nutrient in the leaves highlighted a different nutritional status between the plants from the natural and urban sites.     

An Investigation on Nutritional Problems of Hazelnut Grown on Acid Soils

Abstract

The purpose of the study was to determine the nutritional problems of hazelnut (Corylus avellana L.) grown on acid soils. For this purpose, soil and leaf samples were taken from 30 different hazelnut growing areas from Trabzon Region in Turkey. Some physical and chemical properties and some nutrient element contents of soil and leaf samples were determined. These determined values were compared with critical values, and the degree of sufficiency was evaluated. In general, organic matter, total nitrogen (N), available phosphorus (P), exchangeable potassium (K), and magnesium (Mg) contents of soil samples were sufficient. Calcium (Ca) deficiency was obtained in 93.4% of the soil, because of acid property of the soils. Available iron (Fe), copper (Cu), and manganese (Mn) contents of the soils were found to be sufficient. In 70% of the soils, Zn deficiency was found. Nitrogen, P, K, Ca, Mg, and Zn deficiencies of leaf samples were 20.0, 26.7, 6.7, 73.4, 50.0, and 66.7%, respectively. Iron, Cu, and Mn contents of leaf samples were found to be sufficient.     

Sugarcane yield and plant nutrient response to sulfur-amended Everglades histosols

High soil pH causes leaf nutrient deficiencies and reduces sugarcane yield. Soil pH in Florida histosols has been increasing as these soils subside and depth to limestone is decreased. A factorial experiment of four sulfur (S) rates and three added calcium carbonate (CaCO₃) levels in soil was designed to determine S-amendment effectiveness in reducing pH and increasing nutrient availability in sugarcane as calcium (Ca) carbonate levels were increased. Sulfur-amendment and increased CaCO₃ level had limited effects on yield and leaf nutrient concentrations during the growing season. Most leaf nutrients were within optimum range except nitrogen (N), phosphorus (P), iron (Fe), and manganese (Mn). Unexpected increases in Mn concentrations with added CaCO₃ were associated with reducing conditions due to increased soil bulk density. High soil pH caused Mn deficiencies in the plants. Soil pH, P and Mn concentrations were important factors in predicting sugarcane yield.     

Short-Term Effect of Drought and Salinity on Growth and Mineral Elements in Wheat Seedlings

Both drought and salinity cause nutrient disturbance, albeit for different reasons: a decrease in the diffusion rate of nutrients in the soil and the restricted transpiration rates in plants for drought and extreme soil sodium (Na)/calcium (Ca), Na/potassium (K), and chloride (Cl)/nitrate (NO₃) ratios for salinity. The objective of this study was to examine short-term effects of drought and salinity on nutrient disturbance in wheat seedlings. Wheat was grown in a greenhouse in soil under drought and saline conditions for 26 days after sowing. At harvest, shoot biomass and length, and fresh weight and dry weight of the blade and sheath in expanded leaves 3 and 4 and expanding leaf 5 were determined. Mineral elements (K, Ca, magnesium (Mg), phosphorus (P), nitrogen (N), Na, sulphur (S), iron (Fe), zinc (Zn), and manganese (Mn)) in leaf blades and sheaths were also analyzed. At harvest, the reduction in plant height, shoot biomass, and accumulative evapotranspiration under drought was similar to that under salinity as compared with control plants. However, drought decreased the accumulation of all ions in the blade of the youngest leaf 5 compared with the control, whereas there was either an increase or no difference in all ion concentrations under saline conditions. The change in concentration for most ions in the blade and sheath of expanded leaves 3 and 4 varied among control, drought, and salinity plants, which indicated a different competition for nutrients between the sheath and blade of expanded leaves under drought and saline conditions. It can be concluded from this study that ion deficiency might occur in expanding leaves under drought but not saline conditions.     

Dryland corn response to tillage and nitrogen fertilization. II. P,K, CA,MG

Abstract

Nitrogen fertilization and tillage practices may influence the availability and uptake of essential plant nutrients other than N. This study was conducted to assess the interactive effects of N rate and timing and tillage practices on uptake and concentration of P, K, Ca and Mg in corn grown under dryland conditions. Potassium accumulations in no till (NT) soils were greater than in conventional till (CT) near the surface and lower than CT in the subsoil. Phosphorus and Ca levels decreased with soil depth, while Mg tended to accumulate in the subsoil. Phosphorus uptake and concentration of 5‐leaf stage corn was increased as tillage intensity decreased. Nitrogen rate at planting increased 5‐leaf P uptake but reduced P concentration; however, by silking no effect of tillage or N fertilization practice on ear leaf P concentration was obtained. Increases in 5‐leaf corn K uptake and concentration as tillage intensity decreased may have reduced Mg and Ca concentrations via cation antagonism. Ear leaf Mg and Ca concentrations were increased by N rate, probably as a result of solubilization of Ca and Mg and improved crop growth. Distribution of essential elements in the soil due to tillage in combination with varying N fertilization practices can influence temporal nutrient uptake, thereby altering plant nutrient diagnosis.     

Mineral acquisition by arbuscular mycorrhizal plants

Arbuscular mycorrhizal fungi (AMF) benefit plants by allowing them to grow and produce in relatively harsh mineral stress environments. This has been attributed extensively to ability of AMF to expand the volume of soil for which mineral nutrients are made available to plants compared to what roots themselves would contact. This article reviews the effects of AMF on enhancing/reducing acquisition of phosphorus (P), nitrogen (N), sulfur (S), boron (B), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), zinc (Zn), copper (Cu), manganese (Mn), iron (Fe), aluminum (Al), silicon (Si), and some trace elements in plants. The nutrients enhanced most in host plants grown in many soils (e.g., high and low soil pH) are P, N, Zn, and Cu, but K, Ca, and Mg are enhanced when plants are grown in acidic soils. Many AMF have also the ability to ameliorate Al and Mn toxicities for plants are grown in acidic soil.     

Genetic variation for Mg tissue concentration in pearl millet lines grown under Mg stress conditions

Efficient nutrient utilization by plants is extremely important in developing countries and is becoming more important in the developed countries as the costs of fertilizers are increasing. Pearl millet is a world food and forage crop usually grown on droughty soils low in nutrients. Eighty‐five genetically diverse pearl millet, Pennisetum glaucum (L.) R. Br. lines were grown in low Mg and K sand for three weeks to screen for efficient Mg uptake. Magnesium free Hoagland's solution at one‐fourth strength was used to water the plants as needed. Forage produced was clipped, dried, ground, ashed, and analyzed for Mg and K content. A 2‐fold difference for Mg concentration in the forage existed among the lines. The data indicated that a low [K]/[Mg] ratio in the plant was indicative of a Mg efficient genotype. The data also suggest that caution should be used in making general nutrient recommendations based on tissue or soil tests without knowing the nutrient requirement of the cultivar.     

Soil Aluminum Effects on Growth and Nutrition of Cacao

In acid soils, Al toxicity and nutrient deficiencies are main constraints for low yield of cacao (Theobroma cacao L.). A controlled growth chamber experiment was conducted to evaluate the effect of three Al saturations (0.2, 19, and 26%) adjusted by addition of dolomitic lime on growth and nutrient uptake parameters of cacao. Overall, increasing soil Al saturation decreased shoot and root dry weight, stem height, root length, relative growth rate, and net assimilation rate. However, increasing soil Al saturation increased leaf area, specific leaf area (total leaf area/total leaf dry wt), and leaf area ratio (total leaf area/shoot+root wt). Increasing soil Al saturation decreased uptake of elements. Nutrient influx (IN) and transport (TR) decreased significantly for K, Ca and Mg, and showed an increasing trend for S and P as soil Al saturation increased. However, increasing soil Al saturation significantly increased nutrient use efficiency ratio (ER, mg of shoot weight produced per mg of element in shoot) of Ca, Mg and K and decreased ER for other elements. Reduction of soil acidity constraints with addition of lime and fertilizers appear to be key factors in improving cacao yields in infertile, acidic, tropical soils.     

Soil P and cation availability and crop uptake in a forage rotation under conventional and reduced tillage

Long‐term conservation tillage can modify vertical distribution of nutrients in soil profiles and alter nutrient availability and yields of crops. This study aimed to evaluate the effect of 14 yr of conventional (CT) and reduced tillage (RT) on soil macronutrient availability (0–5, 5–15, 15–30 cm) and uptake by Italian ryegrass and maize in a forage rotation under a temperate–humid climate (NW Spain). Soil contents of total C, plant available Ca, Mg, Na, K and P and their uptake by plants were evaluated over 2 yr. The three‐way ANOVA showed that tillage and its interactions with soil depth and sampling date have little influence on soil C and macronutrients contents (<13% of variance explained). In the topsoil layer, all studied variables (except K) increased in RT compared with CT, but they remained unchanged (C, Ca and Na) or decreased (Mg, K and P) in deeper layers. Crop yields were greater with RT than CT during the year with soil‐water‐deficit periods, while limited tillage effect was found in the other year. Whereas no differences were obtained for maize, nutrient concentration (Mg, Na, K and P) in ryegrass increased under RT. Conservation tillage improved surface soil fertility, maize yield and ryegrass nutrient content.     

Adaptive attributes of tropical forage species to acid soils I. Differences in plant growth,nutrient acquisition and nutrient utilization among C4 grasses and C3 legumes

Low supply of nutrients is a major limitation of forage adaptation and production in acid soils of the tropics. A glasshouse study was conducted to find differences in plant growth, nutrient acquisition and use, among species of tropical forage grasses (with C₄ pathway of photosynthesis) and legumes (with C₃), when grown in two acid soils of contrasting texture and fertility. Twelve tropical forage legumes and seven tropical forage grasses were grown in sandy loam and clay loam Oxisols at low and high levels of soil fertility. After 83 days of growth, dry matter distribution among plant leaves, stems, and roots, leaf area production, shoot and root nutrient composition, shoot nutrient uptake, and nutrient use efficiency were measured. Soil type and fertility affected biomass production and dry matter partitioning between roots and shoots. The allocation of dry matter to root production was greater with low soil fertility, particularly in sandy loam. The grasses responded more than the legumes to increased soil fertility in both shoot and root biomass production. Leaf area production and the use of leaf biomass for leaf expansion (specific leaf area) were greater in legumes than in grasses, irrespective of soil type and fertility. But soil type affected shoot biomass production and nutrient uptake of the grasses more than those of the legumes. There were significant interspecific differences in terms of shoot nutrient uptake. The grasses were more efficient than legumes in nutrient use (grams of shoot biomass produced per gram of total nutrient uptake) particularly for nitrogen (N) and calcium (Ca).     

太行山低山丘陵区植被及土壤养分变化规律研究

对太行山低山丘陵区3种植被草丛、灌草丛和刺槐林及土壤养分变化进行了研究.结果表明,3种群落类型Shannon-Wiener指数和丰富度指数均为草丛＞灌草丛＞刺槐林,总覆盖度草丛＞灌草丛＞刺槐林.3种植被类型Zn,Mn,Na,Mg,Fe差异不显著.在灌草丛中,Mn,Na,Mg,Fe含量均为下层多于上层,差异均不显著,Zn则上层含量多.但在草丛植被类型中,Mn,Zn,Na含量下层多于上层;Mg,Fe含量上层多于下层.Zn,Mn,Na,Mg,Fe等因子均与有机质无显著相关关系.Mn与其它元素,Fe与其它元素(Na为显著相关),Mg与Na均达到显著相关.     

A comparison of plant available nutrients on decomposed granite cut slopes and adjacent natural soils

Decomposed granite (DG) slopes are often difficult to revegetate after existing topsoil and vegetative cover have been removed. In this study, naturally vegetated soils and denuded DG cut slopes were evaluated to compare edaphic (soil-related) conditions that may differ between the vegetated and non-vegetated states. Potential plant nutrient deficiencies were evaluated by soil nutrient extraction, plant tissue analysis and by greenhouse bioassay methods. The DG cut slopes have approximately one-quarter to one-half the clay content, soil organic matter, water-holding capacity, and total and available nitrogen (N) of the adjacent natural soils. Soil extraction tests for phosphorus (P) availability gave variable results, but a growth response to P amendment was observed in a greenhouse bioassay. The native topsoils and the DG cut slope materials had non-limiting levels of pH, exchangeable Ca, Mg and K, and total P. Cation exchange capacity and sulfate–sulfur (S) were low but similar between the two soil groups. Principle nutrient limitations are interpreted to be N, P, and possibly S and boron (B), in order of decreasing severity. Based on these results, we conclude that the removal of humified soil organic matter on the cut slopes reduces plant growth directly by lowering several of these essential nutrients, and indirectly by decreasing the soil's water-retention and infiltration capacity. Soil organic matter is viewed as a critical factor and major contrast between barren and revegetated DG materials. © 1998 John Wiley & Sons, Ltd.     

Effect of dicyandiamide on growth and nutrient uptake of cotton

Abstract

The nitrification inhibitor dicyandiamide (DCD) offers potential for improving efficiency of N applications to cotton grown on sandy soils of the southeastern Coastal Plain. Research has indicated that cotton is sensitive to DCD. The purpose of this greenhouse experiment was to investigate the effect of DCD on growth and nutrient uptake of DPL 90 cotton grown for 73 days in pots containing a typical Coastal Plain soil (Norfolk sandy loam, Typic Paleudult). Nitrogen (50 mg kg^‐1) as NaNO₃ or urea, and DCD (0, 2.5, 5, 10, 15 and 20 mg kg^‐1) were applied to the soil at first true leaf and plants were harvested 58 days later. Sodium nitrate increased leaf dry weight and total dry weight of plants 9.1 and 6.0%, respectively, over urea fertilized plants. Leaf area, dryweight, and stem dry weight were reduced linearly with DCD. Fertilization with urea increased concentrations of leaf P, K, and Mn and reduced the concentration of Mg in leaf tissue. Dicyandiamide increased leaf N, P, and K concentrations but reduced concentrations of Ca, Mg, and Mn. Uptake rates (μg^‐1 g^‐1 fresh root day^‐1) of Ca and Mg were increased 7.5 and 13.7%, respectively, with NaNO₃ vs. urea, while P uptake rate was 15.5% greater for urea‐fertilized plants vs. NaNO₃‐fertilized plants. Dicyandiamide reduced Ca and Mg uptake rates. Phosphorus uptake rates were increased by DCD when urea was the N source. The effects of DCD on cotton growth and nutrient uptake generally resulted from the compound itself and were not an indirect result of nitrification inhibition. Although significant reductions in plant growth did not occur unless DCD exceeded that normally applied with recommended N rates on this soil, these results suggest a need for caution when applying DCD to cotton grown on sandy soils.     

Nutrient status of apple orchards in Canterbury,New Zealand. 1. Levels in soil,leaves and fruit and the prevalence of storage disorders

Abstract

The nutrient status (N, P, K, Ca, Mg, K, Fe, Mn, Zn and Cu) of 26 Cox's Orange Pippin and 20 Braeburn apple orchard sites in the Canterbury region of New Zealand was evaluated by soil, leaf and fruit analysis. Concentrations of available nutrients in soils ranged widely but those in leaves and fruit were generally confined to a relatively narrow range. Concentrations of leaf N were high in the study area, as were levels of extractable soil P, and it is suggested that reductions in fertilizer additions of these nutrients would generally be appropriate.

Soil, leaf and fruit nutrient contents were generally not well correlated with one another. The only highly significant correlations (P≤0.001) were between leaf and fruit Ca for Cox's and soil and fruit Mg for Braeburn. The poor correlations were attributed to the empirical nature of soil tests, the presence of large nutrient reserves within the tree framework and the effects of cultural and environmental factors on nutrient uptake and translocation by the trees.

The storage disorders bitter pit and senescent breakdown in Cox's and lenticel blotch pit in Braeburn were observed in apples harvested from some of the study sites. Such disorders were generally associated with low concentrations of Ca (≤.2.5 mg/100 g) in samples of cortical plugs taken from fruit at harvest.     

Mycorrhizal,nutritional and virgin olive oil parameters affected by groundcovers

Management of olive groves faces the challenge of reconciling yield, soil degradation and virgin olive oil (VOO) quality. We evaluated the effect of replacing tillage management by vegetal groundcovers (GC) on the relationships between mycorrhizal symbiosis, olive nutritional status, and VOO quality under field rainfed conditions. The experiment was set up in 2014 in an existing Cornicabra olive orchard with a Haplic Gypsisol soil under a Mediterranean semiarid climate. Four treatments were replicated four times and consisted of: (1) annual cover of bitter vetch, (2) permanent Brachypodium distachyon, (3) spontaneous vegetation cover (mainly Brassicaceae species), and (4) tilled soil. The use of bitter vetch GC increased the olive root colonization by 50% compared with the tillage treatment. The effect of tillage on VOO differed from that of GC use. Tillage treatment decreased maturity index and its VOO had lower polyphenol content and less luminosity than that from the GC treatments. Olive root colonization, together with changes in nutrients such as Cu, B and other elements resulting from GC use, seems to play an important role in explaining the variability of VOO quality parameters. Although tillage may lead to higher yield by controlling competition for water and nutrients, the introduction of GC in olive groves led to higher polyphenol contents, enhancing VOO quality and, at the same time, protecting soil from erosion.