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The main aim of this study is to develop a mechanistic model of fertilization for recommending the application of zinc (Zn) fertiliser for maize based on the mass balance of Zn. The model would consider the critical Zn level for maize (ZnCL), Zn availability in the soil (ZnA) and Zn buffering capacity (Znb). Soil samples were collected from 78 maize fields for chemical and physical characterization including measuring ZnA and Znb. Additionally, a crop management survey was carried out in each field. The classification and regression trees method (CART) was used and relationships between Znb and some soil properties were established, clay content being the most relevant to the model, besides soil reaction (pH) and silt content. The application of Zn fertilizer can be adequately calculated by a mechanistic model that considers ZnA, Znb and ZnCL above that which maize crop yields do not increase. This work highlights the importance of Znb evaluation by the incubation procedure and the extraction of available Zn by DTPA solution. As hypothesised and then demonstrated in this work, Znb is closely related to soil pH and texture (clay and silt). Our results suggest that, in between 51 and 97% of fields examined, it would be necessary to apply Zn fertilisers to produce the maximum maize yield.

Analyses of potential sources and products that aim to balance nutrients in soil and plants; improve physical, mineral, and biological attributes of soil; and reduce environmental impacts require greater attention. Therefore, the aim of this study was to evaluate the agronomic efficiency of organomineral fertilizers (OMF) in Atlantic potato cultivar. The experimental design was a randomized complete block design (RCBD), with four treatments and six replicates. The treatments consisted of NPK mineral fertilizers (recommended according to soil analysis and nutritional crop requirements), as control, and NPK plus OMF according to composition and form of application (planting, ridging, and leaf), referred to as managements A and B, which indicate the amount of nutrients that the plants received. Therefore, treatments with OMF were designated as: P-OMF(A): organomineral fertilizer management (A) applied via planting furrow; PR-OMF(B): organomineral fertilizer management (B) applied via planting and ridging, and PR-OMF(B) + L-OMF(B): organomineral fertilizer management (B) applied via planting, ridging, and leaf application. The applications of P-OMF(A) and PR-OMF(B) + L-OMF(B) resulted in positive effects on Special Class production and total productivity of Atlantic potato tubers, which increase were between 12% and 16% and 11% to 15.5%, respectively. The application of PR-OMF(B) + L-OMF(B) improved their soluble solid content by 2.7% compared to the control (absence of OMF application). Therefore, organomineral fertilizers have the potential for improving the quantitative and qualitative attributes of potatoes.

The nitrogen nutrition in blueberry has been studied by some authors; however, the effect of N-nitrate or N-ammoniacal fertilizers with nitrification inhibitors on plant growth and physiology has not been known. The aim of this investigation was to study the effectiveness and physiological implications of ammoniacal fertilizers, with or without nitrification inhibitors in blueberry. An experiment was conducted on 1-year “Emerald” blueberries grown in 20-L plastic pots. Our data indicate that ammonium-containing fertilizers promote vegetative growth and increase the leaf nitrogen concentration and gas exchange in plants, possibly due to higher nitrogen root absorption compared with nitrate. On the other hand, fertilization with ammonium with a nitrification inhibitor increases the leaf chlorophyll concentration compared with the addition of ammonium without a nitrification inhibitor and nitrate. However, the ammonium supply decreases the concentration of calcium and potassium in leaves. Our data suggest, for the first time, that fertilization with ammonium accompanied by a nitrification inhibitor is an effective strategy to improve the nitrogen status and promote plant development in “Emerald” blueberry.

Recently, the use of alternative vessels to oak barrels during winemaking has become increasingly popular, but little is known about their impact on the chemical composition of the resulting wines. To address this issue, a Sauvignon Blanc wine was elaborated from the same grape juice by using cylindrical stainless-steel tanks, oval-shaped concrete vessels, oval-shaped polyethylene vessels, and clay jars in triplicate. Each vessel was used for alcoholic fermentation and the aging of wines over its own lees. Wines elaborated in concrete vessels showed the highest pH and the lowest titratable acidity, most likely related to the observed release of inorganic compounds from the concrete walls. Little effect of the vessels was seen on the wine color and phenolic composition. Wines elaborated in clay jars showed the highest turbidity and the highest content of soluble polysaccharides, while those made using cylindrical stainless-steel tanks showed the highest content of volatile compounds. Despite the observed differences, all of the vessels tested seem suitable for white wine production since every wine showed chemical features that corresponded with the quality standards of Sauvignon Blanc wines. España Universidad de Sevilla, VI Plan Propio de Investigación y Transferencia (Contract number USE-18644-Z)

The presence of bicarbonate in soils is an important inducer of nutritional deficiencies in some grapevine genotypes. The aim of this experiment was to assess the effects of different nitrogen sources on physiological variables in the grapevine rootstock 110 Richter grown in a sub-alkaline media. Plants of the grapevine rootstock 110 Richter were treated with different nitrogen sources (NO3−, NH4+, or NH4NO3) in a nutrient solution enriched with bicarbonate. Root enzyme (PEPC, MDH, CS, NADP+-IDH) activities, organic acid concentrations in roots, plant growth and leaf greenness, leaf gas exchange, and mineral concentrations in leaves were determined. The presence of NH4+ promoted an enhancement in leaf greenness, and the treated plants did not trigger physiological response mechanisms to nutritional deficiencies in the roots. However, NH4+ decreased the leaf K concentration. On the other hand, the presence of NO3− in the nutrient solution decreased the leaf greenness, and increased the organic acid concentration in the roots, indicating that these plants were affected by nutritional deficiencies. Instead, intermediate results were obtained in plants treated with NH4NO3. Under the experimental conditions used in this experiment, treatments did not significantly influence the plant biomass, the activity of some enzymes related to organic acids biosynthesis, and the leaf gas exchange. These results suggest that the presence of NH4+ can be an effective strategy to alleviate the negative effects on plant nutrition induced by bicarbonate in plants, an alternative to the soil acidification through inorganic acid applications to the soil.

The aim of this investigation was to study the effectiveness and physiological implications of sustainable strategies to correct Fe chlorosis in blueberries, based on Fe-heme applications or intercropping with graminaceous species. The experiment was conducted in a blueberry orchard established on a sub-alkaline soil. The Fe-heme applications increased shoot length without increasing the leaf chlorophyll concentration, gaseous exchange, and fruit yield components in comparison with control plants. On the other hand, intercropping with graminaceous species increased the leaf chlorophyll concentration, photosynthetic activity, and fruit yield, with similar effectiveness to the Fe-EDDHA treatment. However, this management technique reduced the shoot length and leaf N, P, and K concentrations in the plants. The results obtained highlight the potential of intercropping with graminaceous species as a sustainable management technique to correct Fe chlorosis in blueberry. Further studies will need to select new graminaceous species characterized by low nutrient requirements in order to optimize the effectiveness of this management technique.

The chemical characteristics of mine tailings, organic amendments (doses), and plants are the critical factors that must be evaluated and monitored to ensure the sustainability of phytostabilization. The aim of this study was to evaluate the mobility of copper (Cu) in mine tailings (MT) of the Zone Central of Chile to which commercial humic substances were added, examining their effect on the uptake of Atriplex halimus. Two commercial humic substances (HS1 and HS2) extracted from leonardite (highly oxidized lignite), of different pH and total organic carbon, were evaluated by adsorption curve for Cu. In columns, soluble Cu, pH, and electrical conductivity in leachates were evaluated for MT, MT + HS1, and MT + HS2, and HS1 and HS2 in doses of 120 mg kg-1. In pot assay, seeds were germinated directly in MT and cultivated for 140 days with the addition of HS2 in 120 and 240 mg kg-1. Mine tailing presents high concentration of Cu (2016 ± 223 mg kg-1, pH 6.3 ± 0.1). The results of sequential extraction indicate that Cu is associated with the sulfide fraction of low risk of mobility. The amount of Cu sorbed by HS1 was higher than that sorbed by HS2, and both humic substances showing better fit to the Freundlich than Langmuir model. Lixiviation of Cu was significantly lower in MT + HS1 (0.166 ± 0.043 mg kg-1) and MT + HS2 (0.157 ± 0.018 mg kg-1) than in MT (0.251 ± 0.052 mg kg-1). Copper concentration in plants reached 185.8 ± 37.8 mg kg-1 in the roots and 32.6 ± 7.4 mg kg-1 in the aerial parts cultivated in MT without effect of the humic substance addition in Cu uptake nor growth. Copper concentrations in the aerial parts were adjusted to sufficient or normal levels in plant. A good management of mine tailings through phytostabilization could consider an adequate mixture of humic substances (to avoid leaching of metals) and an organic amendment that provides essential nutrients and increases biomass generation.

Vine performance following preveraison shoot trimming is well documented, but the consequences of this treatment later in the season are poorly understood. Here, a four-year study was conducted in a mature vineyard of Sangiovese (clone 12T) grafted onto Kober 5BB rootstock at a spacing of 1 m × 2.8 m (intra- and interrow) to analyze the influence of postveraison shoot trimming on vine growth characteristics, cluster architecture (cluster compactness), and yield from a physiological viewpoint. The treatments consisted of shoot trimming during postveraison in a randomized block design with eight replications (six vines each). Three treatments were imposed when soluble solids reached 15 Brix in August (40 to 45 days before expected harvest): light trimming (14 nodes), severe trimming (10 nodes), and an untrimmed control. Following the treatments, vine growth characteristics, cluster morphology, and fruit quality attributes were measured. Postveraison shoot trimming (especially severe trimming) reduced cluster weight, cluster compactness, productivity, and total yield. Effects on fruit quality included lowering of Brix and pH, with minor effects on titratable acidity, yeast assimilable nitrogen, the anthocyanin profile, and total anthocyanins. These results demonstrated that postveraison shoot trimming can be a valuable production practice by reducing cluster compactness without compromising overall fruit quality in Sangiovese.

Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) FONDECYT-11160510 FONDEQUIP EQM-140007 FONDEQUIP EQM-130129

The aim of this investigation was to study the effect of sustainable strategies to correct iron deficiency in blueberries, based on Fe-heme applications or intercropping with graminaceous species, on yield, and berry quality variables. The experiment was conducted in a blueberry orchard established in a sub-alkaline soil. The association with grasses increased the crop load and yield (only Festuca rubra), and decreased the skin/flesh ratio. In addition, these treatments increased anthocyanins as well as some hydroxybenzoic acids, hydroxycinnamic acids, flavanols, and flavonol concentrations in skins with a similar effectiveness as Fe-EDDHA, whereas the Fe-heme applications did not influence such parameters. Moreover, data revealed that the association with both grasses decreased the firmness of the berries, whereas none of the treatments assessed changed the soluble solids, pH, acidity, and the soluble solids/acidity rate compared to the control. These results suggest that Fe nutrition is crucial for yield and berry quality in blueberry, and that intercropping with grasses may be an effective and sustainable alternative to counteract Fe deficiency in blueberry, with a similar effect on berries to that achieved with Fe-EDDHA.

The control of iron chlorosis by synthetic Fe chelates is costly, and their application can have adverse environmental impacts. We investigated the effectiveness of alternative strategies to prevent Fe chlorosis in avocado based on different acidifying nitrogen fertilizers. The experiment was conducted on a commercial orchard of avocado cv. Hass cultivated in a calcareous soil. The application of (NH4)2SO4 was highly effective at reducing the soil pH and, when applied with a nitrification inhibitor, at increasing the leaf chlorophyll concentration in trees. Fertilization with urea was also effective at increasing leaf chlorophyll, but only when applied without a nitrification inhibitor. However, the acidifying effect of urea on the soil was significantly lower than (NH4)2SO4. The different N sources also modified the concentration of N-NO3 -, N-NH4 + and total N within the leaves, but did not influence the length of the shoots or the leaf gaseous exchange. These results suggest that the fertilization strategy based on (NH4)2SO4 + DMPP or urea can be an effective and sustainable alternative to counteract Fe chlorosis symptoms in avocado trees. Our results provide evidence of the effectiveness of agronomic strategies, alternative to synthetic Fe chelates, for preventing Fe deficiency in avocado.

Background and aims In many important viticultural areas of the Mediterranean basin, plants often face prolonged periods of scarce iron (Fe) availability in the soil.The objective of the present work was to perform a comparative analysis of physiological and biochemical responses of Vitis genotypes tosevere Fe deficiency. Methods Three grapevine rootstocks differing in susceptibility to Fe chlorosis were grown with and without Fe in the nutrient solution. Results Rootstock 101-14, susceptible to Fe chlorosis, responded to severe Fe deficiency by reducing the root activity of phosphoenolpyruvate carboxylase (PEPC) and malate dehydrogenase(MDH),however,itaccumulated high levels of citric acid. By contrast, rootstock 110 Richter, tolerant to Fe chlorosis, maintained an activemetabolismoforganicacids,butcitricacidaccumulationwaslowerthanin101-14.Similarlyto101-14, rootstock SO4 showed a strong decrease in PEPC and MDH activities. Nevertheless it maintained moderate citric acid levels in the roots, mimicking the response by 110 Richter. Conclusions Root PEPC and MDH activities can be used as tools for screening Fe chlorosis tolerance. Conversely, organic acids accumulation in roots may not be a reliable indicator of Fe chlorosis tolerance, particularly under conditions of severe Fe deficiency, because of their probable exudation by roots.Our results show that drawing sound conclusions from screening programs involving Fe deficiency tolerance requires short as well as long-term assessment of responses to Fe deprivation.

Background and Aims The control of iron (Fe) chlorosis by synthetic Fe chelates is costly and their application can have adverse environmental impacts. We investigated the effectiveness of alternative vineyard strategies to prevent Fe chlorosis in grapevines. Methods and Results An experiment was conducted over two consecutive seasons on Vitis vinifera L. cv. Cabernet Sauvignon grafted on the Fe-chlorosis susceptible Vitis riparia grown in pots filled with calcareous soil. Intercropping with Festuca rubra enhanced leaf chlorophyll index and reduced the root activity of phosphoenolpyruvate carboxylase enzyme, a physiological marker of Fe deficiency. This response was similar to that of supplying Fe-ethylenediamine-N,N'-bis(2-hydroxyphenyl)acetic acid to soil. Application of ammonium with 3,4-dimethylpyrazole phosphate (a nitrification inhibitor) increased leaf chlorophyll index and stomatal length, and induced root biochemical responses similar to those with Fe-ethylenediamine-N,N'-bis(2-hydroxyphenylaceticacid) application. Leaf-applied Fe-ethylenediaminetetraacetic acid induced a high root citric acid concentration, suggesting a limited translocation of Fe from leaves to roots. Intercropping with Festuca rubra decreased the leaf fluorescence-derived parameters in the first year and increased the leaf stomata conductance in the second year of the experiment. Conclusions The results demonstrate the potential for preventing grapevine Fe chlorosis more sustainably through managing ammonium nutrition and adopting intercropping with Fe-efficient grasses. Significance of the Study The data provide evidence of the effectiveness and physiological responses of agronomic strategies, alternative to synthetic Fe chelates, for preventing Fe deficiency in the grapevine.

Iron (Fe) is essential for chlorophyll formation and plant growth. Iron-deficiency chlorosis is a major nutritional disorder in several fruit trees cultivated in calcareous and alkaline soils, reducing fruit yield and quality and causing heavy economic losses. Since chelated Fe, the most widespread fertilizers used for preventing or curing Fe deficiency, pose risks of environmental pollution, the development of sustainable agronomic alternatives represents a priority for the fruit industry. In this work, we investigated the effectiveness of a bovine blood-derived product (BB; 0,125% Fe) for preventing Fe-deficiency in grapevine plants. During the vegetative season 2011 potted plants of five graft combinations: Sangiovese/SO4, Cabernet Sauvignon/SO4 and Cabernet Sauvignon/140 Ruggeri, 140 Ruggeri/Cabernet Sauvignon, Vitis riparia/Cabernet Sauvignon were grown on calcareous soil. Soil treatments included: 1) Control; 2) Fe-EDDHA (Fe 6%); 3) Bovine-Blood (5 g/l); 4) Bovine-Blood (20 g/l). With the exception of Cabernet Sauvignon/SO4 plants, Fe-EDDHA increased SPAD units (leaf chlorophyll content). Bovine-blood at low concentrations had similar or higher SPAD units than Fe-EDDHA. Increasing concentration resulted in further increases in SPAD units only in some graft combinations. Data highlight the efficiency of Fe blood-compound in the prevention of grapevine Fe-deficiency over one growing season.

The present work aimed to compare the physiological responses to Fe deficiency in Vitis vinifera L. cv. Cabernet Sauvignon grafted on two Vitis rootstocks with different Fe chlorosis susceptibility: 110 Richter (moderately tolerant) and 3309-C (susceptible). Plants were grown in hydroponic solutions with 50 μM of Fe-EDTA or without Fe. Our data showed that, in a first step (18 days after treatment, DAT), Fe deficiency reduced net photosynthesis in leaves from both variety/rootstock combinations, without modifying leaf chlorophyll concentration. Moreover, Fe deficiency increased the activity of PEPC and NADP + -IDH enzymes and the concentration of malic and total organic acids in roots of both rootstocks. During such period, no differences related to Fe level were recorded in the main shoot length and biomass. After a longer exposure to Fe deficiency (32 DAT), the activity of PEPC and organic acid-linked enzymes in roots of both genotypes remained unaltered. However, at 32 DAT, plants grafted on 110 Richter reacted to Fe deficiency by reducing the main shoot length and biomass, whereas such reduction was not observed in plants grafted on 3309-C. In addition, at 32 DAT Fe deficiency reduced the net photosynthesis as well as the chlorophyll concentration in plants grafted on 3309-C, without modifying these parameters in 110 Richter plants. In conclusion, our results revealed significant differences between the two variety/rootstock combinations in severity of Fe deficiency symptoms and physiological responses.

A study to evaluate the effect of a three-year rotation with cover crops for the management of plant-parasitic nematodes (PPNs) was performed in two vineyards producing table grapes ( Vitis vinifera L.) in a semiarid region in the north of Chile. In the first vineyard, located in Copiapo valley (trial I), the crops used in the rotations or monoculture were fava bean ( Vicia faba ) cv. Aguadulce, rape ( Brassica napus var. napus ) cv L-456, forage turnip ( B. rapa var. rapa ) cv. Barkant, barley ( Hordeum vulgare ) cv. Aurora, oat ( Avena sativa ) cv. Urano-INIA, and mustard greens ( Brassica juncea ). At the second vineyard employed in the study, located in Huasco valley (trial II), the same crops and varieties were used in a rotation system with the incorporation of crop/goat manure mixtures or manure only at a rate of 10 Mg ha -1 . In both studies, two control treatments were included: a nontreated control and a chemical control in which ethoprop was applied at a rate of 7 kg ha -1 . The results from trial I indicated no significant differences between the cover crop rotation treatments and controls for Xiphinema index and for the other PPNs populations. In trial II, treatments 4 (manure) and 5 (manure and crop rotation) showed significantly lower values compared to treatment 2 (chemical control), with the highest X. index levels, but no differences from the control. No differences were detected for the other PPNs. Se realizo un estudio destinado a evaluar el efecto de cultivos de cobertura en rotacion durante tres anos, sobre el control de nematodos fitoparasitos en dos plantaciones de uva de mesa en una region semiarida del norte de Chile. La primera plantacion correspondio a un parronal en Copiapo (ensayo I), donde los cultivos utilizados en rotacion o en monocultivo fueron haba ( Vicia faba ) cv. Aguadulce; raps ( Brassica napus var. napus ) cv L-456; rabano forrajero ( B. rapa var. rapa ) cv. Barkant; cebada ( Hordeum vulgare ) cv. Aurora; avena ( Avena sativa ) cv. Urano-INIA y mostacilla ( Brassica juncea ). El segundo parronal utilizado para el estudio esta ubicado en la localidad de Huasco (ensayo II), donde se utilizaron los mismos cultivos y variedades, en un sistema de rotacion, incorporandose ademas una mezcla de cultivos sembrados sobre guano de cabra y guano de cabra solo, en dosis de 10 Mg ha -1 . En ambos estudios se incluyo un control absoluto y un control quimico, ethoprop, en una dosis de 7 kg ha -1 . Bajo las condiciones de este estudio, los resultados indican que en el ensayo I, no hubo diferencias significativas en los tratamientos basados en los cultivos de cobertura en rotacion y el control de poblaciones de Xiphinema index asi como en el resto de los fitoparasitos. En el ensayo II, solo se observan diferencias entre los tratamientos en base solo a guano y guano y rotaciones con el tratamiento quimico, siendo este ultimo el menos efectivo de todos los tratamientos. En el resto de los fitoparasitos, no hay diferencias despues de tres anos de evaluaciones.

In Copiapo Valley, the 3 th Region of Chile, a three-year study (2007-2009) was conducted to evaluate the effect of organic amendments and cover crops on soil physical properties (Typic Haplocambid) in a table grape ( Vitis vinifera ) orchard. Four treatments were established during three seasons: control without organic amendments (T1), broad bean-corn-rape rotation (T2), goat manure addition (15 t ha -1 ) (T3) and corn-broad bean-barley rotation (T4). Soils measurements, bulk density, pore size distribution, aggregate stability, water repellence and air conductivity were conducted on soil samples collected at three soil depths (0-10, 10-30 and 30-50 cm). Saturated hydraulic conductivity and mechanical strength were also evaluated. On grape plant measurements, root development, pruning weight and harvested grape production were evaluated. Soil bulk density was reduced with goat manure addition in comparison with any other treatment, which resulted in lower mechanical strength in the top soils. None of the treatments had negative effects on water repellency. The crop treatments enhanced the coarse porosity throughout the soil profile, improving the continuity of porous system with their root development and inducing high air conductivity. Other hand, the control soil and manure application showed a pore discontinuity in a pre-existing plow pan. Aggregate stability and saturated hydraulic conductivity were greater in goat manure application, but the treatments which included crop rotation did not show significant differences compared with the control. Because of the short duration of the study, it is assumed that the soil improvements were not detected as expected in grape production yet. Keywords: Compaction, cover crops, aggregate stability, soil porosity

Background and aims Iron (Fe) deficiency chlorosis associated with high levels of soil bicarbonate is one of the main nutritional disorders observed in sensitive grapevine genotypes. The aim of the experiment was to assess both the independent and combined effects of Fe and bicarbonate nutrition in grapevine. Methods Plants of the Fe chlorosis tolerant 140 Ruggeri rootstock were grown with and without Fe(III)- EDTA and bicarbonate in the nutrient solution. SPAD index, plant growth, root enzyme (PEPC, MDH, CS, NADP+ −IDH) activities, kinetic properties of root PEPC, organic acid concentrations in roots and xylem sap and xylem sap pH were determined. A factorial statistical design with two factors (Fe and BIC) and two levels of each factor was adopted: +Fe and −Fe, and +BIC and −BIC. Results This rootstock strongly reacted to Fe deficiency by activating several response mechanisms at different physiological levels. The presence of bicarbonate in the nutrient solution changed the activity of PEPC and TCA related enzymes (CS, NADP+-IDH) and the accumulation/translocation of organic acids in roots of Fe-deprived plants. Moreover, this genotype increased root biomass and root malic acid concentration in response to high bicarbonate levels in the substrate. Bicarbonate also enhanced leaf chlorophyll content. Conclusions Along with a clear independent effect on Fe nutrition, our data support a modulating role of bicarbonate on Fe deficiency response mechanisms at root level.

As an alternative to organic soil amendments used in the Copiapo Valley (northern Chile), this study analyzed the magnitude of changes in physical soil properties associated with different crop rotations on the rows on a grape orchard. The study was performed in the locality of Los Loros, Atacama Region, during the 2006-2008 seasons. In a Typic Haplocambid soil (2-5% slope, coarse loam) with a 6-year old grape plantation, a control and three crop rotations were established, each with four replicates. Soil samples were taken at three depths (0-10; 10-40; 40-60 cm), evaluating bulk density, penetration resistance, aggregate stability, pore size distribution and air and water flux. Crop rotation did not produce statistical differences in soil density compared with the control treatment; nevertheless, soil mechanical strength decreased compared to the control without crops. Aggregate stability increased on the surface horizon when Poaceae and Fabaceae were used separately, but not when they were planted together. Below the surface this effect vanished and no significant differences were observed compared with the control. The leguminous crops promoted a more continuous porous system, with an increase of coarse porosity and a higher air and water flux capability. A longer time period of crop rotation is required to improve the productive potential of grapes.