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Long-term applications of organic amendments, such as pig slurry (PS), may represent environmental risk of soil and water pollution by trace metals (TM). Our objective was to examine different soil and manure management scenarios that enhance the long-term agricultural use of soils under repetitive PS applications while avoiding environmental risk. Firstly, we developed a new module for simulating the impacts of soil tillage frequencies in Hydrus-1D. Secondly, we used a previously validated modeling approach to predict the surface accumulation and movement of the TM during the next 100-year in the soil under different PS doses (80 and 40m3ha−1cultivation−1) and tillage frequencies (no-tillage and 20, 10, and 5-year tillage). No-tillage simulations revealed consistent TM surface accumulations, reaching the soil threshold value for Cu in the 0–20cm layer after 86 years of PS amendments at high doses, but in layers 0–5, 0–10, and 5–10cm, this concentration was already reached after 17, 38, and 75 years, respectively. While soil tillage reduced TM concentrations over the top 20cm of the soil profile, it increased their transfer to deeper layers. Periodical soil tillage each 5, 10, and 20 years was found to allow PS applications without reaching the Cu threshold value in soil during 100 years. However, soil solution concentrations of Zn reached the threshold values for groundwater. Therefore, the best manure management practice for the long-term PS disposal with respect to Zn and Cu concentrations in soil is the application of moderate PS rates.

The timing of nitrogen fertilizer application in vineyards can determine the amount of nitrogen (N) absorbed, distributed, and accumulated in grapevine organs. The study aimed to evaluate the annual contribution of N from urea, applied at different times in Cabernet Sauvignon, grown in sandy and clayey soil in a subtropical climate. The sandy soil received 21.42 kg N ha−1 and the clayey soil 30 kg N ha−1, both enriched with 3% excess 15N atoms, applied at different times. The N derived from the fertilizer in grapevines, at all times of N application, and in sandy and clayey soil did not exceed 8%, with the highest values being observed in annual organs, especially in the leaves. The application of N marked at the phenological stages of IBB (50% at beginning of budbreak + 50% at full budbreak) enabled greater absorption of N derived from the fertilizer by the vines grown in both sandy and loamy soil. The N present in the annual organs (leaves, berries, stalks, and shoots) and in the perennial organs (stems and canes) of Cabernet Sauvignon grown in sandy and clayey soil was derived in greater percentages from the soil. [ABSTRACT FROM AUTHOR]

Assessing the phosphorus (P) balance in agricultural soils is crucial for optimizing its use and reducing contamination risks. The objective of this study was to evaluate the impact of different animal wastes on the distribution of P in soil profiles subjected to 12 years of successive applications of animal wastes and mineral phosphate fertilizer, within a crop rotation system under no-till system. The study was conducted from 2004 to 2016 in the southern region of Brazil. The treatments were the applications of pig slurry (PS), cattle slurry (CS), pig deep-litter (PD), mineral fertilizer (MF), and a control treatment without application. The highest accumulation of P and its movement was observed in the 0–40 cm layer, in the soil submitted to applications of all P sources. The inputs of P via MF, CS, PS, and PD promoted the accumulation of 18, 42, 48, and 100 kg P ha−1 year−1. The P mass balance showed that between 77 and 98% of the P added by animal manure and MF was accounted for in grain exports (17–34%), soil storage (41–72%), and post-harvest residues (<1%), with the remaining 2–33%, unaccounted for, which was attributed, especially, to P transfer at the soil surface. [ABSTRACT FROM AUTHOR]

Copper (Cu) and zinc (Zn) fraction accumulation and adsorption capacity were evaluated in sandy-soil after 16 pig slurry (PS) and deep-litter (DL) applications under subtropical climate. Sixteen PS and DL applications to a Typic Hapludalf increased soil Cu and Zn soluble, exchangeable, mineral, organic, and total fractions. Cu mostly accumulated in organic and residual fractions (1.03, 4.39, 9.81, and 9.68, 12.9, 13.98 mg Cu kg−1 in the control, PS, and DL, respectively), whereas Zn presented a greater increase in mineral and exchangeable fractions (0.42, 6.39, 15.46 and 1.67, 8.96, 14.83 mg Zn kg−1 in the control, PS, and DL, respectively). Manure applications changed Cu and Zn adsorption behavior, with the greatest (895.8 mg Cu kg−1 and 945.9 mg Zn kg−1) adsorption occurring in DL, which is related to the 1.5- and 1.6-times organic matter increase compared to PS and control. Cu showed a preference for soil exchangeable sites under the competitive adsorption system, reducing Zn absorption about 11 and 6 times in the PS and DL, respectively. Application of pig manure rates based solely on crop N demand is unwise as it potentiates Cu and Zn accumulation, Zn bioavailability, increasing the risk of Zn toxicity and transference to aquatic environments. [ABSTRACT FROM AUTHOR]

A suinocultura tem grande importância social e econômica no Brasil. Contudo, os dejetos cada vez mais representam potenciais contaminantes do ambiente, mais do que uma opção à nutrição de plantas. A aplicação de dejetos líquidos de suínos pode resultar em perdas de elementos, principalmente nitrogênio e fósforo, resultando em menor eficiência de utilização pelas plantas e aumentando os riscos de contaminação da água. Esse trabalho teve por objetivo avaliar a percolação de nitrogênio e fósforo em área submetida a aplicações sistemáticas de dejeto líquido de suínos. O trabalho foi desenvolvido na Universidade Federal de Santa Maria, RS no período de maio de 2000 a maio de 2002, em Argissolo Vermelho distrófico arênico, com a rotação aveia preta (Avena strigosa), milho (Zea mays) e nabo forrageiro (Raphanus sativus) e com a utilização das doses de 0, 20, 40 e 80 m³ ha-1 de dejeto líquido de suínos, distribuídas a lanço e em superfície antes da semeadura de cada espécie. Com o aumento da dose de dejeto ocorre incremento nas concentrações de nitrato na água percolada, principalmente logo após a aplicação, que coincide com estádios iniciais de desenvolvimento das culturas. Por outro lado, não se percebe efeito expressivo da dose de dejeto sobre as concentrações de fósforo disponível na água percolada. As perdas de nitrogênio e fósforo, em kg ha-1, são pouco expressivas em relação às quantidades adicionadas, mas as concentrações de N-NO3- na água percolada nos maiores picos de perda estiveram acima do limite tolerável à qualidade da água.

A volatilização de amônia é umas das principais formas de perdas de nitrogênio, especialmente com a aplicação de dejetos, devido a sua distribuição a lanço, em superfície. Este trabalho teve por objetivo determinar as perdas de N por volatilização de amônia em função de doses e horários de aplicação de dejeto líquido de suínos. O trabalho foi conduzido a campo em fevereiro, maio, outubro e dezembro de 2001, sendo que, em fevereiro e dezembro, aplicou-se o dejeto em dois horários (10 e 18h). As doses testadas foram 0, 20, 40 e 80m³ ha-1 e as determinações das perdas de amônia foram feitas às 3, 6, 12, 24, 30, 36, 42, 48, 60, 72, 96, 120, e 144 horas após a aplicação do dejeto, totalizando um período de avaliação de seis dias. O uso de menores doses de dejeto líquido de suínos minimizou as perdas de N por volatilização de amônia. Os picos de perda ocorreram nas primeiras horas após a aplicação indicando que, quando possível, a sua incorporação seria uma alternativa à diminuição nas perdas de N por volatilização de amônia. O horário de aplicação do dejeto não afetou de maneira consistente as perdas de N por volatilização de amônia.

Apesar de o esterco líquido de suínos ser um fertilizante, seu uso inadequado pode comprometer a qualidade do solo e água. O objetivo deste trabalho foi avaliar alterações em algumas características químicas de um solo sob pastagem natural com o uso de esterco líquido de suínos e suas implicações agronômicas e ambientais. O experimento foi conduzido de novembro de 1995 a novembro de 1999 em Paraíso do Sul, RS, em condomínio de suinocultores. Os tratamentos constituíram-se de 0, 20 e 40 m³ ha-1 de esterco líquido de suínos, aplicado em intervalos de 45 a 60 dias. Em cada época de aplicação de esterco, a pastagem natural era roçada, a forragem retirada e o esterco reaplicado. Os resultados mostraram que o uso sistemático de esterco líquido de suínos representa a adição de grandes quantidades de nutrientes ao solo, elevando principalmente os teores de P, Ca e Mg em áreas sob pastagem natural. O ambiente para o crescimento das plantas também pode ser melhorado com o uso de esterco líquido de suínos pela diminuição na saturação de Al, mas deve-se monitorar o teor de K no solo, porque, sob pastoreio, os teores podem decrescer. O fato de adicionar altas quantidades de N por meio do esterco líquido de suínos sem alterar seus teores no solo evidencia que ocorrem grandes perdas de N, principalmente na forma de nitrato. Além disso, a elevada concentração de P na camada mais superficial do solo mostra que estes elementos podem comprometer a qualidade do ambiente, especialmente como contaminantes da água.

The studies of fertilization splitting are necessary specially for the grass succession black oat-corn where N immobilization is very common. Four experiments were carried out in commercial farms under no-tillage, in four counties - Itaara, Santo Ângelo, Júlio de Castilhos and Tupanciretã, all of Rio Grande do Sul, Brazil, with the objective of evaluating the splitting of N application in a corn/black oat crop rotation, during the 97/98 and 98/99 cropping seasons. The N was applied at three times -- pre-planted, starter and sidedressed. The pre-planted applied N for corn, corresponding to total or partial rates that would be sidedressed presented similar results in relation to the sidedress application, however, years of above average rainfall presented N deficiency for corn, reducing yield, which indicates that N application as starter or sidedress is recommended.

Vineyard soils normally do not provide the amount of nitrogen (N) necessary for red wine production. Traditionally, the N concentration in leaves guides the N fertilization of vineyards to reach high grape yields and chemical composition under the ceteris paribus assumption. Moreover, the carryover effects of nutrients and carbohydrates stored by perennials such as grapevines are neglected. Where a well-documented database is assembled, machine learning (ML) methods can account for key site-specific features and carryover effects, impacting the performance of grapevines. The aim of this study was to predict, using ML tools, N management from local features to reach high berry yield and quality in 'Alicante Bouschet' vineyards. The 5-year (2015–2019) fertilizer trial comprised six N doses (0–20–40–60–80–100 kg N ha−1) and three regimes of irrigation. Model features included N dosage, climatic indices, foliar N application, and stem diameter of the preceding season, all of which were indices of the carryover effects. Accuracy of ML models was the highest with a yield cutoff of 14 t ha−1 and a total anthocyanin content (TAC) of 3900 mg L−1. Regression models were more accurate for total soluble solids (TSS), total titratable acidity (TTA), pH, TAC, and total phenolic content (TPC) in the marketable grape yield. The tissue N ranges differed between high marketable yield and TAC, indicating a trade-off about 24 g N kg−1 in the diagnostic leaf. The N dosage predicted varied from 0 to 40 kg N ha−1 depending on target variable, this was calculated from local features and carryover effects but excluded climatic indices. The dataset can increase in size and diversity with the collaboration of growers, which can help to cross over the numerous combinations of features found in vineyards. This research contributes to the rational use of N fertilizers, but with the guarantee that obtaining high productivity must be with adequate composition. [ABSTRACT FROM AUTHOR]

The nitrogen (N) critical level in leaves and maximum technical efficiency (MTE) doses contribute to the grape yield, must quality, and fertilizers rationalization. This study aimed to define sufficient ranges and critical levels in leaves and maximum technical efficiency doses to obtain high yields and quality must in grapevines grown in sandy soil in a subtropical climate. 'Chardonnay' and 'Pinot Noir' grapevines were subjected to the annual application of 0, 10, 20, 40, 60, and 80 kg N ha−1 in a vineyard. The nitrogen concentration in leaves at flowering and veraison, grape yield and grape must chemical parameters (total soluble solids—TSS, total titratable acidity—TTA and total anthocyanins—TA) were evaluated. The N critical level in leaves at flowering was different between grapevines cultivars, but this was not observed in leaves at veraison. It was possible to estimate MTE for 'Chardonnay' grapevines, in the evaluated growing seasons. In the range of higher probability of the N critical level in leaves, the TSS and TTA variables showed opposite responses, for both cultivars. This study proposes different N critical levels for red and white grapevines, in a subtropical climate. [ABSTRACT FROM AUTHOR]

Grass species native to South American can have mechanisms to tolerate copper (Cu) excess, which improves their use to phytoremediate Cu-contaminated soils. The aims of the present study are to assess the tolerance of grass species native to South American grasslands to copper-contaminated soils, as well as their adaptive responses under high Cu-stressed condition and to identify native grass species presenting the highest potential to be used for phytoremediation purposes. Soil samples were air-dried and their acidity, phosphorus and potassium levels were corrected, and the samples were incubated. Three Cu levels were used in the experiment: natural (Dose 0), with added of 40 mg kg−1 of Cu and with added of 80 mg kg−1 of Cu. Three Axonopus affinis, Paspalum notatum and Paspalum plicatulum seedlings were transferred to 5-L pots filled with soil in August and grown for 121 days. Soil solution was collected during cultivation with the aid of Rhizon lysimeters. Main concentrations of cations and anions, dissolved organic carbon and pH in the soil solution were analyzed and the ionic speciation was carried out. Cu toxicity impaired the growth of grass species native to South America, since Cu excess led to both changes in root morphology and nutritional unbalance. Among all assessed native species, Paspalum plicatulum was the one presenting the greatest potential to phytostabilize in Cu-contaminated soils, since it mainly accumulates Cu absorbed in the roots; therefore, its intercropping with grapevines is can be beneficial in Cu-contaminated soils. [ABSTRACT FROM AUTHOR]

Fruit and vegetable waste can be used for the production of organic compost, which when mineralized can increase the availability of nitrogen. The objectives of this study were: (a) to produce compost from different ratios of fruit and vegetable waste, rice husk and poultry manure that meets the legislation on organic fertilizers and (b) to assess the mineralization of N in substrates prepared with different ratios of compost. In experiment 1, the following treatments were prepared using (fruit and vegetable residue: rice husk: poultry waste) (v:v): Treatment 1 (2:1:0), T2 (1:1:1), T3 (1.5:1:0) and T4 (1.2:1:0). All the treatments were subjected to composting for 95 days, were subjected to analysis of nutrients, organic carbon, C/N, CEC/C, pH and moisture content. The composts were compared in regards to the parameters required by legislation. In experiment 2, the treatments consisted of eight blends of agricultural peat, carbonized rice husk and organic compost pre-selected from experiment 1. The NO3 --N and NH+ 4-N contents were analyzed in the substrate at time zero and at 7, 14, 28, 56, 112 days after incubation. Compost (C2) met the parameters required by legislation and the use of 40% in the substrate composition promoted the mineralization of N. [ABSTRACT FROM AUTHOR]

Forest species Angico-Vermelho (Parapiptadenia rigida (Bentham) Brenan) is an alternative for the revegetation of areas contaminated with high levels of heavy metals such as copper (Cu). However, excess Cu may cause toxicity to plants, which is why the use of soil amendments can facilitate cultivation by reducing the availability of Cu in the soil. The aim of this study was to assess how the use of amendment can contribute to growth and nutritional status as well as reduce oxidative stress in Angico-Vermelho grown in Cu-contaminated soil. Samples of a Typic Hapludalf soil containing high Cu content were used for the application of four amendments (limestone, organic compost, Ca silicate and zeolite), in addition to a control treatment. The treatments were arranged in a completely randomized design, with four replicates. The use of amendments decreased Cu content available in soil and contributed to improve both plant nutritional status and its antioxidant response expressed by enzymatic activity. The application of the amendments, especially zeolite and Ca silicate, increased dry matter yield of Angico-Vermelho. Thus, the results presented here suggest that the use of amendments contributes to improving Cu-contaminated soils and favors revegetation with Angico-Vermelho. [ABSTRACT FROM AUTHOR]

Heavy metals and bromine (Br) derived from organic and industrialized fertilizers can be absorbed, transported and accumulated into parts of plants ingested by humans. This study aimed to evaluate in an experiment conducted under no-tillage for 10 years, totaling 14 applications of pig slurry manure (PS), pig deep-litter (PL), dairy slurry (DS) and mineral fertilizer (MF), the heavy metal and Br contents in soil and in whether the grains produced by corn ( Zea mays L.) and wheat ( Triticum aestivum L.) under these conditions could result in risk to human health. The total contents of As, Cd, Pb, Cr, Ni, Cu, Zn and Br were analyzed in samples of fertilizers, waste, soil, shoots and grains of corn and wheat. Afterwards, enrichment factor (EF), accumulation factor (AF), health risk index (HRI), target hazard quotient (THQ) and target cancer risk (TCR) were determined. Mineral fertilizer exhibited the highest As and Cr content, while the highest levels of Cu and Zn were found in animal waste. The contents of As, Cd, Cr, Cu, Ni, Pb and Zn in soil were below the limits established by environmental regulatory agencies. However, a significant enrichment factor was found for Cu in soil with a history of PL application. Furthermore, high Zn contents were found in shoots and grains of corn and wheat, especially when the plants were grown in soil with organic waste application. Applications of organic waste and mineral fertilizer provided high HRI and THQ for Br and Zn, posing risks to human health. The intake of corn and wheat fertilized with pig slurry manure, swine deep bed, liquid cattle manure and industrialized mineral fertilizer did not present TCR. [ABSTRACT FROM AUTHOR]

The use of copper (Cu)-based fungicides to control diseases in vineyards can cause excessive Cu accumulation in soils. Greater Cu availability is expected in acid sandy soils with low organic matter (OM), where the risk of toxicity to plants and environment contamination is high. This study aimed to study the evolution of Cu in acid, sandy soils planted with grapevines for a period of time between 2 and 32 years. Two studies were carried out in South Brazil: in the first study, soil samples, from 19 vineyards were collected and analyzed in the first 0.2 m depth-layer for the total and available Cu. In the second study, 3 soils were selected among the previous 19 according to the age of vineyard (5, 11, and 30 year-old), and their 0.60 m-depth profile was analyzed for 5 fractions of Cu (soluble, exchangeable, mineral, organic, and residual). All the soils were classified as Ultisols. The vineyards with more than 25 years under cultivation had a mean total Cu concentration of 90 mg kg−1in the 0–0.10 m layer. Approximately 80% of it was potentially available to plants. The greatest total and available Cu were found in the soil surface layers (0.2 m depth), where up to 75% of the total Cu is adsorbed in clay minerals and only 20% is complexed in the OM. [ABSTRACT FROM PUBLISHER]

In Brazilian vineyards planted in sandy soils, nitrogen (N) should be applied at optimal rates and timing that correspond to greatest demand, thus minimizing N losses. The aim of this study was to evaluate the grapevine N distribution and recovery of urea- 15 N applied at budding and bloom. In 2009, in a vineyard ( Vitis vinifera cv. Cabernet Sauvignon) planted in Santana do Livramento, south Brazil, grapevines were treated with 10 kg N ha −1 at budding +10 kg N ha −1 at full bloom (10B + 10F); 20 kg N ha −1 at budding +20 kg N ha −1 at full bloom (20B + 20F); 20 kg N ha −1 at budding (20B); and 40 kg N ha −1 at full bloom (40F). Budding of grapevines in 2009 and 2010 was at the end of August and full bloom in November. In February 2010 and 2011, grapevine organs (leaves, berries, stem and roots) were collected, and in February 2011 soil samples were also collected in the profile. The wine-producing grapevines grown in the sandy soil took up more N derived from 20B treatment, compared with other N treatments, especially in the first crop season. The N derived from fertilizer applied at different rates and time was preferentially distributed in annual plant organs, but most N contained in the plant organs was derived from other sources than the fertilizer N. In the following season, 15 N applied in the previous year was recovered preferentially in leaves and fruits, again in low amounts. Nitrogen derived from fertilizer applied at different rates and time in a sandy soil apparently contributes little to grapevine nutrition. [ABSTRACT FROM AUTHOR]

Content of exchangeable potassium (K) in t soil may influence on its content in grapevines leaves, grape yield, as well as, in must composition. The study aimed to assess the interference of exchangeable K content in the soil on its leaf content, production and must composition of 'Cabernet Sauvignon' cultivar. In September 2011, in Santana do Livramento (RS) five vineyards with increasing levels of exchangeable K in the soil were selected. In the 2012/13 and 2013/14 harvests, the grape yield, yield components, total K content in the leaves in full bloom and berries veraison were evaluated. Values of total soluble sugar (TSS), pH, total titratable acidity (TTA), total polyphenols and anthocyanins were evaluated in the must. Exchangeable K content increase in soil with sandy surface texture increased its content in leaves collected during full flowering and in berries and must pH; however, it did not affect production of the 'Cabernet Sauvignon'. [ABSTRACT FROM AUTHOR]

Symbioses with arbuscular mycorrhizal fungi (AMF) may increase plant tolerance to heavy metals, in addition to the improvement in phosphorus (P) uptake by plants. This study evaluated the effects of the interaction between an increase in the soil phosphorus level and the colonization by Rhizophagus clarus on several biochemical and physiological parameters of Crotalaria juncea plants cultivated in a soil with a high copper (Cu) level. Plant growth and photosynthetic pigment fluorescence parameters, as well as the superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD) enzyme activities in C. juncea plants, were analyzed. The experiment was conducted in a greenhouse, and a 3 × 2 factorial design was employed, including the natural P level, 40, and 100 mg P kg −1 , with and without R. clarus inoculation, with three replicates in a soil with a high Cu level (65 mg kg −1 ). The results demonstrate that the combination of the addition of P together with AMF inoculation improved the plant nutritional status, with consequent increases in the levels of P, K, Mg, Fe, Zn, and chlorophyll a fluorescence parameters . Furthermore, mycorrhization and phosphorus addition increased the activities of the SOD and CAT enzymes, which are responsible for the removal of reactive oxygen species when plants are exposed to high Cu levels. This synergistic effect between P application and inoculation with R. clarus could be of technological interest for achieving increased growth of C. juncea cultivated in soils with high Cu levels via the promotion of effective mechanisms for reducing Cu phytotoxicity. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the mobility of copper (Cu) and zinc (Zn) in the profile and distribution of sandy soil fractions from vineyards. Soil samples were collected from two vineyards of different ages (14 and 30 years) and a natural field area in the south of Brazil. The chemical characteristics, Cu levels and Zn levels, were analyzed in the soils by extraction with ethylenediamine tetraacetic acid (EDTA) using the 3050B method of USEPA and by chemical fractionation. Cu and Zn were accumulated in the vineyard soils, especially in the uppermost soil layers and in the soil from the oldest vineyard. Approximately, 75% of the total Cu was extracted by EDTA, but only 30% of the total Zn was extracted by EDTA. Most of the Cu, especially in the oldest vineyard, was distributed in the mineral-associated fraction, which is characterized by low geochemical mobility, but another important part of the Cu was distributed in the soil organic matter. Most of the Zn in the soil was distributed in the residual and mineral-associated fractions, which are characterized by low mobility and have potential for causing toxicity to plants. [ABSTRACT FROM AUTHOR]

Highlights: [•] The recovery of N by ‘Niagara Rosada’ grape from the decomposition of rye residues deposited on the soil surface was evaluated. [•] We used in the study rye residues labeled with 15N. [•] The N derived from the litter of rye added into the soil surface was accumulated at similar percentage in the annual and perennial organs of the ‘Niagara Rosada’ grape. [•] The N derived from litter of rye apparently contributed little to the ‘Niagara Rosada’ grape nutrition in the time length studied. [ABSTRACT FROM AUTHOR]

No-till farming and manure application are means of storing carbon in soil and increasing soil quality. However, the organic fertilization of no-till soils may sustain subtropical agroecosystems for only a limited period until the soil quality declines. The C, N, P, and other nutrient cycles are perturbed due to the nutrient imbalance in manures and their application on the soil surface, which poses a risk for nutrient dispersion into the environment. Long-term N-based manure application also impacts the apparent nutrient recovery (ANR) by crops and, hence, the crop quality. Our objective was to monitor changes in soil quality and to measure nutrient recovery from N-based organic fertilization in a Brazilian agroecosystem. A long-term experiment was established in May 2004 on Typic Hapludalf soil in Southern Brazil. The experiment comprised two periods: 2004–2009 and 2009–2020. The treatments were unfertilized (control), pig slurry, pig deep litter (swine manure and rice husk), cattle slurry, and mineral fertilizer (urea, triple superphosphate, and K chloride). Grain and cover crops were grown. The maize grain yield and oat biomass were used as indicators of productivity. The application of cattle slurry, pig deep litter, and pig slurry increased the grain production by 20% on average compared to mineral fertilization. Organic manuring increased the soil pH by up to one unit, while urea acidified the soil. The highest crop yields were obtained with pig deep litter, which increased the levels of P, K, Ca, Mg, and C in the soil test. Pig deep litter showed the highest N-ANR for the aboveground part of the plants. The ANRs for P, K, Ca, and Mg were also highest when pig slurry had been applied. The ANR values for the micronutrients varied widely among the organic sources but indicated large marginal offtake gains compared to mineral fertilization. The N-based fertilization with animal manures increased the rate of nutrient uptake by plants but led to an accumulation of nutrients in the soil, threatening the sustainability of the system. Manure applications must be monitored regularly to avoid the accumulation of nutrients that could impair the soil quality and become an environmental problem in the future. [ABSTRACT FROM AUTHOR]

The purpose of this study was to quantify the phosphorus (P) fractions in phosphate-fertilized sandy soils under grapevines. Soil was sampled from a grassland site and two vineyards (13 and 31 years old) in the State Rio Grande do Sul, Brazil, from the layers 0–5, 5–10, 10–15, 15–20, and 20–40 cm deep. The samples were prepared and P fractions were assessed by chemical fractionation. Phosphate fertilization of the vineyard soils increased P contents to a depth of 40 cm, especially in the more recalcitrant fractions but detectable in the more labile fractions as well, which are plant available and may increase the risk of environmental contamination. Phosphate fertilizers and the period of grapevine cultivation had little effect on the levels of organic P forms, whereas cover crops in vineyards could be an appropriate strategy to increase or maintain the levels of soil organic matter and the levels of organic P over the years. [ABSTRACT FROM AUTHOR]