William Natale

The plant ionome revisited by the nutrient balance concept

Tissue analysis is commonly used in ecology and agronomy to portray plant nutrient signatures. Nutrient concentration data, or ionomes, belong to the compositional data class, i.e., multivariate data that are proportions of some whole, hence carrying important numerical properties. Statistics computed across raw or ordinary log-transformed nutrient data are intrinsically biased, hence possibly leading to wrong inferences. Our objective was to present a sound and robust approach based on a novel nutrient balance concept to classify plant ionomes. We analyzed leaf N, P, K, Ca, and Mg of two wild and six domesticated fruit species from Canada, Brazil, and New Zealand sampled during reproductive stages. Nutrient concentrations were (1) analyzed without transformation, (2) ordinary log-transformed as commonly but incorrectly applied in practice, (3) additive log-ratio (alr) transformed as surrogate to stoichiometric rules, and (4) converted to isometric log-ratios (ilr) arranged as sound nutrient balance variables. Raw concentration and ordinary log transformation both led to biased multivariate analysis due to redundancy between interacting nutrients. The alr- and ilr-transformed data provided unbiased discriminant analyses of plant ionomes, where wild and domesticated species formed distinct groups and the ionomes of species and cultivars were differentiated without numerical bias. The ilr nutrient balance concept is preferable to alr, because the ilr technique projects the most important interactions between nutrients into a convenient Euclidean space. This novel numerical approach allows rectifying historical biases and supervising phenotypic plasticity in plant nutrition studies.

Calagem na nutrição de cálcio e no desenvolvimento do sistema radicular da goiabeira

The application of lime in acid soils improves the plant root system and, consequently, enhances water and nutrients absorption by the plants. The objective of this work was to evaluate the effects of lime application on the development of root system and calcium nutrition of guava plants cultivated in an acid distrofic Red Latosol (Typic Hapludox). Soil samples were collected in four equidistant points, at 75 cm of the trunk and at 0-20 cm and 20-40 cm of depth, in the plots that had received zero (control), 3.7 and 7.4 t ha -1 of lime. Soil samples were chemically analysed. Lime material was applied at planting, incorporated with grating and moldboard plow. On the second and third years after guava plantation, effects of liming in chemical properties were determined. Forty two months after lime incorporation in the soil (third year of guava plants cultivation), samples of roots were collected with a cylindrical auger, for dry mass and calcium content evaluation. Samples of leaves were also collected. Liming corrected soil acidity increased base saturation and improved calcium availability to plants and, consequently, improved guava root system. Calcium concentrations of 30 mmol c dm -3 in the soil and of 7.5 g kg -1 in the roots were associated with the highest guava root growth.

Calcário e escória de siderurgia avaliados por análise foliar, acúmulo, e exportação de macronutrientes em cana-de-açúcar

Slag can be used as an alternative for lime as soil amendment, having influence on nutrient uptake by the plant and, as a result, on leaf analysis and nutrient accumulation. To study the effect of the application of increasing rates of slag and lime stone on the uptake of macronutrients by sugar cane (variety SP 80-1842) an experiment was installed under field conditions, in January 1998, at Ituverava-SP, Brazil. Slag and limestone were applied to the sugarcane crop at planting, in four rates: 0; 1.23; 2.52 and 3.80 t ha-1 of CaCO3, using a Typic Haplorthox. In addition to the cane stalk production a verification was performed for the first and second ratoons (120 days and 345 after the emergence of the shoots, respectively). Macronutrient concentrations on the leaf +3 and in the aerial part of sugar cane for were analysed for the second cutting. Through leaf analysis data it was found that the corrective agents and rates did not modify the degree of absorption of macronutrients by the sugar cane. Slag had some effect on sugarcane evaluation, acting in a similar way in comparison to limestone, in relation to the nutrition of the plant.

Faixas normais de nutrientes pelos métodos ChM, DRIS e CND e nível crítico pelo método de distribuição normal reduzida para laranjeira-pera

The use of nutritional diagnoses methods to define ideal and critical nutrient concentrations in plant tissues has proved promising, provided the limits are known. This study determined the normal nutrient ranges for an orange pear population, using the methods mathematical chance (MCh), Integrated Diagnosis and Recommendation (DRIS) and Compositional Nutrient Diagnosis (CND), in addition to the critical level by the reduced normal distribution method. The study was conducted in Bebedouro, Sao Paulo state, at the Experimental Station of Bebedouro. The total nutrient contents of 50 leaf samples and orange pear yield from an experiment to test applied limestone rates were used as database. For N, the highest value was obtained by MCh class 2 (23.6-24.7 g kg-1), with values similar to those obtained by DRIS (22.1-24.0 g kg-1) and CND (22.1-23.9 g kg-1). Values below these normal ranges agree with the critical level reached (22.7 g kg-1), which is very close to the threshold proposed in the literature. For P, K, Mg, Zn, and B, normal nutrient ranges and critical levels were distant from those reported in the literature. The Ca, Fe, Mn, and Cu values of the normal range and critical level approached the recommended limits, possibly due to a greater variation in the levels. The proposed methods for a population were more appropriate when variation in nutrient content was greater. The amplitude of normal range was narrower than the range of sufficiency levels found in the literature.

Uso fertilizante de resíduo da indústria processadora de goiabas

The guava processing industry waste (GPIW) has been used in some areas, however is not known its effect on soil fertility. A greenhouse experiment was carried out to evaluate the effect of GPIW on soil fertility, using corn as testing plant. The experiment was in randomized blocks design combining five GPIW rates (0; 20; 40; 60 and 80 t ha-1) in the absence and the presence of mineral fertilization. The GPIW increased P and K concentration and behaved as a slow release source of N and P for corn.

Resposta de mudas de goiabeira à aplicação de escória de siderurgia como corretivo de acidez do solo

A escoria de siderurgia pode constituir-se em uma fonte alternativa de Ca e Mg, bem como corretivo de acidez do solo, melhorando o estado nutricional de mudas de goiabeira, podendo contribuir para o sucesso da implantacao de um pomar. O presente trabalho objetivou avaliar os efeitos da escoria de siderurgia nas alteracoes dos atributos quimicos do solo, na nutricao das plantas e no crescimento de mudas de goiabeira. Para tanto, instalou-se um experimento em Taquaritinga-SP, em condicoes de vasos, com doses crescentes de escoria de siderurgia: zero; metade; uma vez; uma vez e meia; duas vezes e duas vezes e meia a dose para elevar a saturacao por bases para 70%. Apos 90 dias da incubacao da escoria no solo, procedeu-se o plantio das mudas de goiabeira (cv. Paluma), propagadas vegetativamente por estaquia, em substrato de um Argissolo Vermelho-Amarelo acido (vaso com 2,8 dm3), cultivando-as por 105 dias. A aplicacao de escoria de siderurgia elevou os valores de pH, SB, V%, e as concentracoes de Ca, Mg e P, diminuindo H+Al do solo. Nas mudas de goiabeira, houve aumento significativo na altura, no numero de folhas, na area foliar, nas concentracoes de Ca, Mg e P da parte aerea e das raizes das plantas e, consequentemente, na materia seca da parte aerea e das raizes. Portanto, a escoria de siderurgia mostrou-se viavel na producao de mudas de goiabeira como corretivo de acidez do solo e fonte de nutrientes (Ca e Mg ).

Resposta de mudas de goiabeira à aplicação de zinco

The subsoil normally used for guava cuttings production presents low concentration of Zn. Considering the inexistence of informa- tion on the subject, it was studied to evaluate the effect of zinc application in the substratum of production of the guava cuttings and, to follow the effect in the development, the production of dry matter and the nutrition status of plants. The experimental design used was randomized blocks with 5 treatments and 5 replications. The doses of zinc were: 0; 2; 4; 6 and 8 mg dm -3 of Zn. All plants received constant doses of N, P, K and B of 300; 100; 150 and 0.5 mg dm -3 of Zn respectively. The experiment was lead in vases with 2.8 dm 3 of substratum of a Yellow Red Argissolo (Ultisol). After 135 days of planting, it was evaluated: height, foliar area, dry matter, nutritional status of plants and soil nutrients. The guava had answered positively to zinc application. The biggest development of the plants was associated with 2 mg dm -3 of Zn dose. The equal or upper doses 4 mg dm -3 of Zn had presented significant reduction in the growth and the accumulation of macronutrients in the guava cuttings. Index terms: Zn, guava, Psidium guajava. INTRODUCAO

Aplicação de potássio no estado nutricional e na produção de matéria seca de mudas de maracujazeiro-amarelo

O subsolo, normalmente utilizado para a producao de mudas de especies frutiferas, apresenta baixa concentracao de potassio e, assim, existe grande probabilidade de resposta a aplicacao deste nutriente. Desse modo, objetivou-se avaliar a aplicacao de potassio ao substrato de producao de mudas de maracujazeiro-amarelo (Passiflora edulis) e os seus efeitos no desenvolvimento, na producao de materia seca e no estado nutricional das plantas. O delineamento experimental foi o de blocos ao acaso, com cinco tratamentos e quatro repeticoes. As doses de potassio (cloreto de potassio) foram: 0; 75; 150; 225 e 300 mg de K dm-3. As mudas receberam doses de N, P, B e Zn de 300; 450; 0,5 e 5 mg dm-3, respectivamente. O experimento foi conduzido em casa de vegetacao, em vasos com 2 dm3 de solo (Latossolo Vermelho distrofico), durante 60 dias. A aplicacao de potassio afetou de forma quadratica o desenvolvimento e a nutricao de mudas do maracujazeiro. A maior producao de massa seca das plantas ocorreu na faixa entre 200-220 mg de K dm-3, e concentracao de 3 mmolc de K dm-3 no solo.

Efeitos da aplicação de calcário no desenvolvimento, no estado nutricional e na produção de matéria seca de mudas de maracujazeiro

Este trabalho objetivou avaliar os efeitos da aplicacao de calcario ao substrato de producao das mudas de maracujazeiro, acompanhando os beneficios no desenvolvimento, na producao de materia seca e no estado nutricional das plantas. O delineamento experimental foi em blocos ao acaso, com cinco tratamentos e quatro repeticoes. As doses de calcario calcinado foram aplicadas objetivando elevar em meia; uma vez; uma vez e meia, e duas vezes a dose para elevar o V = 80%, correspondendo a 0,44; 0,88; 1,32; 1,76 g por vaso, respectivamente, alem da testemunha sem aplicacao. As mudas receberam doses de N, P, K, Zn e B de 300; 450; 150; 5,0 e 0,5 mg dm-3, respectivamente, sendo o N e o K parcelados em tres vezes (30; 45 e 60 dias apos a semeadura). O experimento foi conduzido em casa de vegetacao da FCAV/Unesp, em Jaboticabal-SP, no periodo dezembro/2002 ate abril/2003. A unidade experimental foi constituida por vasos com 2 dm3 de substrato de um Latossolo Vermelho distrofico. Apos 80 dias da semeadura, avaliaram-se: o diâmetro do caule, a altura, o numero de folhas, a area foliar e a materia seca da parte aerea e das raizes, bem como os teores de macro e micronutrientes. As mudas de maracujazeiro responderam a aplicacao de calcario. O maior desenvolvimento das plantas esteve associado a saturacao por bases do solo de 56% e a concentracoes de Ca e Mg no solo de 20 e 8 mmolc dm-3, e a teores de Ca e Mg na parte aerea de 12,8 e 4,0 g kg-1, respectivamente.

Alterações anatômicas induzidas pelo cálcio na parede celular de frutos de goiabeira

The objective of this work was to evaluate modifications in cell walls of guava fruits produced either under liming or not. The study made use of fruits of the Paluma cultivar harvested from nonlimed and limed areas. Fruits harvested from the calcium treated plants had cell walls and the middle lamella well defined and soundly structured. Fruits from the nontreated plants showed poorly structured cell walls and middle lamella. The application of calcium has an important effect on the subcellular structural organization of guava fruit and on the increase of fruits shelf life.