Over the past 20 years, the use of center-pivot irrigation has increased tomato (Solanum lycopersicum L.) yields in Brazil from 42 Mg ha−1 to more than 80 Mg ha−1. In the absence of field trials to support fertilizer recommendations, substantial amounts of phosphorus (P) have been applied to crops. Additional P dosing has been based on an equilibrated nutrient P budget adjusted for low-P fertilizer-use efficiency in high-P fixing tropical soils. To document nutrient requirements and prevent over-fertilization, tissue samples and crop yield data can be acquired through crop surveys and fertilizer trials. Nevertheless, most tissue diagnostic methods pose numerical difficulties that can be avoided by using the nutrient balance concept. The objectives of this study were to model the response of irrigated tomato crops to P fertilization in low- and high-P soils and to provide tissue diagnostic models for high crop yield. Three P trials, arranged in a randomized block design with six P treatments (0–437 kg P ha−1) and three or four replications, were established on a low-P soil in 2013 and high-P soils in 2013 and 2014, totaling 66 plots in all. Together with crop yield data, 65 tissue samples were collected from tomato farms. We found no significant yield response to P fertilization, despite large differences in soil-test P (coefficient of variation, 24%). High- and low-yield classes (cutoff: 91 Mg fruits ha−1) were classified by balance models with 78–81% accuracy using logit and Cate–Nelson partitioning models. The critical Mahalanobis distance for the partition was 5.31. Tomato yields were apparently not limited by P but were limited by calcium. There was no evidence that P fertilization should differ between center-pivot-irrigated and rain-fed crops. Use of the P budget method to arrive at the P requirement for tomato crops proved to be fallacious, as several nutrients should be rebalanced in Brazilian tomato cropping systems.

RESUMO:Com o objetivo de avaliar o efeito da omissão de macronutrientes no crescimento e no estado nutricional da couve-flor, bem como descrever sintomas visuais de deficiência nutricional, foi conduzido um experimento em casa de vegetação, em solução nutritiva. O delineamento experimental foi inteiramente casualizado, com sete tratamentos, que corresponderam à solução completa e à omissão individual de N, P, K, Ca, Mg e S, com três repetições. Foram avaliados a altura das plantas, o número de folhas, a área foliar, a massa seca da parte aérea, das raízes e planta inteira, os teores dos macronutrientes da parte aérea e raízes e descritas as desordens nutricionais. As omissões individuais de N, P, K, Ca e Mg foram as mais limitantes para o crescimento vegetativo da couve-flor, reduzindo consideravelmente a altura, o número de folhas, área foliar, assim como massa seca da parte aérea, raízes e planta inteira. Foram observados sintomas de deficiência nutricional de cada elemento. Os teores dos macronutrientes na parte aérea do tratamento completo e com omissão dos nutrientes foram respectivamente: N = 36,3 -11,0; P = 5,0 -1,0; K = 37,0 -4,7; Ca = 26,0 -5,7; Mg = 5,3 -1,0; S = 15 -3,0 g kg -1 .Palavras-chave: Brassica oleracea. Deficiência nutricional. Nutrição mineral. Hidroponia. ASSESSMENT OF NUTRITIONAL STATUS OF PLANTS OF CAULIFLOWER GROWN IN NUTRIENT SOLUTION SUPRIMIDAS OF MACRONUTRIENTS SUMMARY:An experiment was conducted under greenhouse conditions, to evaluate the effects of macronutrient omission on cauliflower nutritional status and development, as well as describe nutritional deficiency symptoms. The experiment was arranged in completely randomized design with three replications and seven treatments, corresponding to complete nutritive solution and individual N, P, K, Ca, Mg and S omission. Plant height, number of leaves, leaf area, shoot, root and whole plant dry mass and macronutrient levels were determined and nutritional deficiency symptoms were described. Individual omissions of N, P, K or Ca were the most limiting for cauliflower growth, considerably reducing plant height, number of leaves, and shoot, root and whole plant dry mass. Nutritional deficiency symptoms were observed for each element. Shoot macronutrient levels in control and nutrient omission treatments were, respectively: N = 36.3 -11.0; P = 5.0 -1.0; K = 37.0 -4.7; Ca = 26.0 -5.7; Mg = 5.3 -1.0; S = 15.0 -3.0 g kg -1 .

SUMMARYAmong the toxic elements, Cd has received considerable attention in view of its association with a number of human health problems. The objectives of this study were to evaluate the Cd availability and accumulation in soil, transfer rate and toxicity in lettuce and rice plants grown in a Cd-contaminated Typic Hapludox. Two simultaneous greenhouse experiments with lettuce and rice test plants were conducted in a randomized complete block design with four replications. The treatments consisted of four Cd rates (CdCl 2 ), 0.0; 1.3; 3.0 and 6.0 mg kg -1 , based on the guidelines recommended by the Environmental Agency of the State of São Paulo, Brazil (Cetesb). Higher Cd rates increased extractable Cd (using Mehlich-3, Mehlich-1 and DTPA chemical extractants) and decreased lettuce and rice dry matter yields. However, no visual toxicity symptoms were observed in plants. Mehlich-1, Mehlich-3 and DTPA extractants were effective in predicting soil Cd availability as well as the Cd concentration and accumulation in plant parts. Cadmium concentration in rice remained below the threshold for human consumption established by Brazilian legislation. On the other hand, lettuce Cd concentration in edible parts exceeded the acceptable limit.Index terms: Lactuca sativa L., Oryza sativa L., soil pollution, chemical extractants, heavy metals, human health.(1) Received for publication in January 2010 approved in december 2010.

Guava response to fertilization can be monitored through plant tissue analysis. Correct interpretation of these results, based on standard levels, is of great importance for correct nutrient management of the crop. However, standard levels are constantly criticized for not considering interactions among elements. To improve the nutritional diagnosis of 'Paluma' guava (Psidium guajava L., Myrtaceae), an experiment was conducted using nitrogen fertilization (0, 0.5, 1.0, and 2.0 kg per plant per cycle of N, with urea as a source with 45 % N), and potassium fertilization (0, 0.55, 1.1, and 2.2 kg per plant per cycle of K 2 O, with potassium chloride as a source with 60 % K 2 O) in an irrigated commercial area for five consecutive cycles, 2009 through 2012, observing the influence of fertilizers and climate and assessing yield and leaf element content, using the concept of isometric log ratios (ilr) to interpret leaf analysis results (N, P, Ca, Mg, K, and S). This paper showed that nutrient balances and nutrient concentration values can be interpreted coherently using compositional data analysis. Ranges of nutrient balances also were established for "Paluma" guava and validated through ranges grounded in nutrient contents currently used in Brazil. Nitrogen fertilization increased "Paluma" guava yield. The 0.5 kg N application rate per plant and the other studied treatments practically showed the same results, and their values were affected by pruning time as well as the nutrient balances.

Soil analysis is used to estimate nutrient availability, but nutrient concentrations are not always related to yield in most fruit plants, including grapevines. Thus, additional multivariate mathematical models, such as the compositional nutrient diagnosis (CND), which takes into account leaves nutrient concentration, and yield, can contribute to estimating critical levels or sufficiency bands of elements, as well as to detect deficiency and/or excess of nutrients. The aim of the present study was to establish CND standards, and the critical level and sufficiency band of nutrients, in the grapevine Vitis vinifera L., grown in a subtropical climate region. Leaves were collected in 81 vineyards in the Campanha Gaúcha do Rio Grande do Sul region, Southern Brazil, and analyzed for macro- and micro-nutrient concentration. The yield of each vineyard was assessed. Grapevine nutritional status was calculated through the CND method. CND-r2 indices were effective in establishing the nutritional status of grapevines for macro- and micro-nutrients as sub-optimal, excessive, or balanced. The CND methodology established the critical level and sufficiency bands of nutrients more accurately than the current recommendations for grapevines. Multi-nutrient associations were more effective than the single nutrient determination in defining the threshold of a given nutrient that can reduce grapevine yield.

ResumoA determinação da quantidade de unidades amostrais que irão compor a amostra exprimirá a otimização da mão-de-obra, além de diminuir erros inerentes ao laudo de recomendação e avaliação da fertilidade do solo. Com este trabalho se objetivou determinar em três sistemas de uso e manejo do solo, o dimensionamento do número de unidades amostrais, necessárias a formar a amostra composta, para avaliação da fertilidade do solo. Concluiu-se que o número de unidades amostrais necessário a compor a amostra composta para determinação dos atributos de matéria orgânica, pH, P, K, Ca, Mg, H+Al e saturação por bases do solo variam conforme o uso e manejo do solo e o erro aceitável para a estimativa da média. Para uma mesma profundidade de coleta, o aumento do número de unidades amostrais, reduziu o erro porcentual na estimativa da média, permitindo a recomendação de 14, 14 e 11 unidades amostrais no manejo com mata nativa, pastagem e milho, respectivamente, para um erro de 20% na estimativa da média. Palavras-chave: Amostragem de solo, unidades amostrais, milho, Panicum, mata, variabilidade horizontal AbstractThe determination of the amount of sample units that will compose the sample express the optimization of the workforce, and reduce errors inherent in the report of recommendation and evaluation of soil fertility. This study aimed to determine in three systems use and soil management, the numbers of units samples design, needed to form the composed sample, for evaluation of soil fertility. It was concluded that the number of sample units needed to compose the composed sample to determination the attributes of organic matter, pH, P, K, Ca, Mg, Al and H+Al and base saturation of soil vary by use and soil management and error acceptable to the mean estimate. For the same depth of collected, increasing the number of sample units, reduced the percentage error in estimating the average, allowing the recommendation of 14, 14 and 11 sample in management with native vegetation, pasture cultivation and corn, respectively, for a error 20% on the mean estimate.

RESUMOObjetivou-se avaliar o efeito da omissão de macronutrientes no desenvolvimento e no estado nutricional de plantas de capim-elefante (Pennisetum purpureum Shum cv. Mott). O experimento foi desenvolvido na FCAV/UNESP, em Jaboticabal-SP com o uso de solução nutritiva. O delineamento experimental foi inteiramente casualizado, com sete tratamentos (solução completa Hoagland & Arnon (1950) e a omissão individual de N, P, K, Ca, Mg e S nessa solução). Após o brotamento dos colmos, as plantas foram colocadas em vasos (5 dm 3 ), contendo solução nutritiva sob aeração constante, aplicando-se os tratamentos com três repetições cada. Semanalmente, avaliou-se a altura das plantas, o número de folhas, o diâmetro do colmo e número de perfilhos, além do estado nutricional. A omissão de N, P, K, Ca, Mg e S limitaram a produção de massa seca da parte aérea do capim-elefante, em relação ao tratamento completo. A deficiência de um macronutriente, além de promover diminuição do seu teor na parte aérea, resultou em redução da acumulação da maioria dos macronutrientes, com conseqüente alterações morfológicas, traduzidas como sintomas característicos de deficiência.Palavras-chave: Pennisetum purpureum Shum; forrageira; desordem nutricional. ABSTRACTThe objective of this work was to evaluate the effect of omission of macronutrients in the growth and the nutritional state of elephant-grass plants (Pennisetum purpureum Shum cv. Mott). The experiment was developed in the FCAV/UNESP, in Jaboticabal-SP,Brazil, using nutrient solution. The experimental design was completely randomized blocks, with seven treatments (the complete solution proposed by Hoagland & Arnon (1950) and the individual omission of N, P, K, Ca, Mg and S, in these solution), in three repetitions. Pre-germinated plants were placed in pot (5 dm 3 ), containing the nutrient solution, which was aerated constantly during the experimental period and the respective treatments, with three replications each. Weekly, the height of the plants, the leaf number, apex diameter and number of tillers were evaluated as well as plant nutritional state. The omission of N, P, K, Ca, Mg and S limited the production of dry weight of shoot the elephant grass, compared to the full treatment. The deficiency of a macronutrient, in addition to promoting reduction of its content in the shoot, resulted in reducing the accumulation of most macronutrients, with resultant morphological changes, translated as characteristic symptoms of deficiency.

The diagnosis of plant nutritional status that aims to balance essential elements in the plant is of utmost importance for sustainable agriculture. Nutritional diagnosis is a technique that has been implemented to maximize the economic return from fertilization and minimize losses to the environment. A balance can be defined as a relationship between components interacting in plant tissue, where some nutrients may be present in excess, deficiency or sufficiency. Diagnostic methods have been evolving constantly, allowing to interpret nutrient levels in isolation to more complex methods accounting for nutrient interactions.Additional keywords: Plant nutrition, nutrient composition, nutrient interaction, compositional nutrient diagnosis. ResumoA diagnose nutricional, ou seja, o conhecimento sobre o equilíbrio entre os elementos essenciais no tecido vegetal, é uma técnica empregada para elevar ao máximo o retorno econômico nas explorações agrícolas, preservando de forma racional o ambiente. O equilíbrio pode ser comparado a uma balança de pratos, na qual os nutrientes podem estar presentes em excesso, deficientes ou em teores adequados (informação relativa), considerando-se o teor dos demais componentes. A predição do diagnóstico do estado nutricional das plantas é de extrema importância para a agricultura durável, cujos métodos têm evoluído constantemente, permitindo uma interpretação imparcial dos teores dos nutrientes e de suas interações.Palavras-chave adicionais: Nutrição de plantas, composição nutricional, interação de nutrientes, CND.