Marlene Estevão Marchetti

Determinação de faixas normais de nutrientes no algodoeiro pelos métodos ChM, CND e Dris

SUMMARY : DETERMINATION OF NORMAL NUTRIENT RANGES FORCOTTON BY THE CHM, CND AND DRIS METHODS The use of diagnosis methods for the determination of normal nutrient ranges is efficientsince it is region-specific, thus not always applicable to other regions. This study aimed todetermine the optimum nutrient ranges for cotton based on the Best likelihood (ChM), Diagnosisand Recommendation Integrated System (DRIS) and Compositional Nutrient Diagnosis(CND). The study was conducted in commercial cotton fields for the 2004/2005 growingseason, in Sao Desiderio, state of Bahia, Brazil. The total nutrient content of 65 whole leafsamples and seed cotton yield of plots with an average size of 120 ha were used as database. Toadjust the method the population was divided into two classes, one with yield above and theother with yield below 4,250 kg ha -1 . The values of ChM for N were higher in Classes 3 and 5(32.0 to 35.5 g kg -1 ). These values agree with DRIS (32.7 to 35.4 g kg -1 ) and CND (32.8 toabove 35.4 g kg

Produção do milho safrinha em função de doses e épocas de aplicação de nitrogênio

A adubacao nitrogenada e importante para potencializar a produtividade do milho safrinha, que se tornou a principal cultura de outono-inverno, semeada apos a soja, nos seguintes Estados: Parana, Sao Paulo, Mato Grosso do Sul, Mato Grosso e Goias. Com o objetivo de avaliar a produtividade de graos e outras caracteristicas agronomicas do milho safrinha em funcao de doses e epocas de aplicacao de N, foi realizado um experimento em Latossolo Vermelho Eutroferrico argiloso, em Dourados (MS), no periodo de marco a agosto de 1998. Utilizaram-se cinco doses de N (30, 60, 90, 120 e 150 kg.ha-1), na forma de ureia em quatro epocas de aplicacao: E1 (todo N na semeadura), E2, E3 e E4 (1/3 na semeadura e os restantes 2/3, quando a cultura apresentou quatro, oito e dez folhas completamente expandidas, respectivamente) e um tratamento sem adicao desse nutriente. Os tratamentos foram arranjados como fatorial 5 x 4 + 1, no delineamento de blocos casualizados, com quatro repeticoes. Avaliaram-se a altura de insercao de espiga, altura de planta, teor de N foliar e produtividade de graos. A adubacao nitrogenada influenciou todas as caracteristicas estudadas, sendo a dose de 120 kg.ha-1 de N a que proporcionou os melhores resultados. Verificou-se que, para doses ate de 60 kg.ha-1 de N nao ha necessidade de se parcelar a adubacao nitrogenada. O melhor parcelamento foi 1/3 do N na semeadura e 2/3 em cobertura, quando as plantas apresentavam quatro a oito folhas totalmente expandidas, para as doses de 90 e 120 kg.ha-1 de N.

Desenvolvimento de normas DRIS e CND e avaliação do estado nutricional da cultura do algodoeiro

Among the different methods of assessing the nutritional status of plants, DRIS and CND have the main purpose of ranking the limiting nutrients. This study aimed to develop DRIS and CND norms and compare the diagnoses of these methods in evaluations of cotton cash crops in the region of Sao Desiderio, state of Bahia, Brazil. The database consisted of the total nutrient content of 65 whole leaf samples and seed cotton yield of plots with an average size of 120 ha. To adjust the method the population was divided into two production classes, one with yield above and the other below 4,250 kg ha-1. The best response in terms of yield was observed for potassium, calcium and manganese by DRIS as well as CND. In the assessment of the frequency of concordant diagnoses for the potential of positive response to fertilization, it was found that N (70.8 %) was the nutrient with best agreement between the two methods (DRIS and CND) whereas DRIS diagnosed greater relative deficiency for N than CND. For the other nutrients, the frequency of concordant diagnoses based on the potential response to fertilization was from around 73.8 % for Zn to 87.7 % for P. With the adjustment of the methods DRIS and CND, the diagnoses of the nutritional status of cotton in western Bahia were similar.

INOCULAÇÃO DO FEIJOEIRO COM RHIZOBIUM TROPICI ASSOCIADA À EXSUDATO DE MIMOSA FLOCCULOSA COM DIFERENTES DOSES DE NITROGÊNIO

The aim of this work was to evaluate the effect of the Rhizobium inoculation, associated with seed exudates of Mimosa flocculosa, under different rates of nitrogen fertilization was evaluated in bean crops following soybean (Glycine max L. Merril) and corn (Zea mays L.). The experimental design was randomized blocks with four replications, with treatments arranged in sub-divided parcels. The parcels were constituted of two summer crops preceding the common bean crop: soybean and corn. In the sub-parcels three treatments involving inoculation of the common bean seeds were considered: control treatment without inoculation; bean seeds inoculated with Rhizobium tropici, strains CIAT 899 and PRF 81, and the association of Rhizobium with the exudates of the Mimosa flocculosa seeds. The sub-subparcels received of four doses of nitrogen fertilization applied on covering: 0, 40, 80 and 120 kg ha-1 N. The inoculation of Rhizobium associated with the addition of exudates of Mimosa flocculosa seeds resulted in higher shoot dry weight. Besides that, the nitrogen fertilization, on the tested doses, reduced, in a linear way, the nodulation of the bean plant. It was also verified that corn as a preceding crop for bean has contributed to the increase of the weight of 100 grains, while the addition of combined N did not contribute to the improvement on the number of beans per plant, neither of the grain yield of bean plants, independent of the dose that was used.

Beaufils ranges to assess the cotton nutrient status in the southern region of Mato Grosso

The relationships between nutrient contents and indices of the Diagnosis and Recommendation Integrated System (DRIS) are a useful basis to determine appropriate ranges for the interpretation of leaf nutrient contents. The purpose of this study was to establish Beaufils ranges from statistical models of the relationship between foliar concentrations and DRIS indices, generated by two systems of DRIS norms - the F value and natural logarithm transformation - and assess the nutritional status of cotton plants, based on these Beaufils ranges. Yield data from plots (average acreage 100 ha) and foliar concentrations of macro and micronutrients of cotton (Gossypium hirsutum r. latifolium) plants, in the growing season 2004/2005, were stored in a database. The criterion to define the reference population consisted of plots with above-average yields + 0.5 standard deviation (over 4,575 kg ha-1 seed cotton yield). The best-fitting statistical model of the relationship between foliar nutrient concentrations and DRIS indices was linear, with R2 > 0.8090, p < 0.01, except for N, with R2 = 0.5987, p < 0.01. The two criteria were effective to diagnose the plant nutritional status. The diagnoses were not random, but based on the effectiveness of the chi-square-tested method. The agreement between the methods to assess the nutritional status was 92.59-100 %, except for S, with 74.07 % agreement.

Frações lábeis e recalcitrantes da matéria orgânica em solos sob integração lavoura‑pecuária

The objective of this work was to evaluate the soil total organic carbon (TOC) and total nitrogen (TN) stocks, C and N in labile and recalcitrant fractions of the soil organic matter (SOM), and the C management index, in soils under integrated crop-livestock (ICL) system after four (ICL4) and eight years (ICL8) of settlement. For comparison purposes, other management systems were used: pasture and crop under no tillage (NT), besides native vegetation. The experiment was carried out in a completely randomized block design, with five replicates. The crop-livestock established in a period of eight years can reach a new steady state equivalent to the no-tillage with 23 years of implementation. There was accumulation in total organic carbon of 101.0 (ICL8) and 104.2 Mg ha -1 (NT), and N total stock of 5.5 (ICL8) and 5.8 Mg ha -1 (NT) in the 0-30 cm layer, as well as increase in the stock of labile and recalcitrant C and N fractions of SOM. For crop-livestock with eight years, the C management index of 88 was higher than other management systems, and not different from native vegetation (0-10 cm), however, it was similar to NT in the analysis of the entire profile (0-30 cm).

Forage accumulation and plant and soil characteristics according to soil base saturation, rates of phosphorus and nitrogen in the establishment of massaigrass.

It was carried out an experiment to test four levels of soil base saturation (20, 40, 60, and 80%), four rates of phosphorus (0, 80, 160, and 240 kg/ha of P2O5) and four rates of nitrogen (0, 100, 200 and 300 kg/ha) during the phase of establishment of Panicum maximum cv Massai, in an Oxisol of Brazilian Cerrado. The experimental design was a randomized uncompleted block, in fractionated factorial type (1/2)43, with four blocks and two replications. Two cuts along 200 days were performed. The evaluated aspects were green dry matter yield (GDM), soil fertility changes, concentration of macronutrients in diagnostic leaves, crude protein (CP) concentration and in vitro organic matter digestibility (IVOMD). It was verified that GDM yield responded mainly to phosphorus (P) fertilization and, in second place, to soil base saturation (V). The nitrogen (N) did not present significant effect in GDM yield. The P rate for highest physical yield was 237 kg/ha and the economical rate was 185 kg/ha, both in 39% of V in the soil. Soil fertility improved with the V and P increment. The concentration of macronutrients in diagnostic leaves increased with the increment of V, P, and N. It was verified high percentage of leaves in GDM and suitable IVOMD and CP concentration in the GDM of leaves. IVOMD and CP increased significantly with N fertilization and increment of V.

Eficiência de extratores de fósforo em dois latossolos do Mato Grosso do Sul

With the objective of evaluating the efficiency of three phosphorus extractors in two Mato Grosso do Sul State oxisols, in Brazil, one greenhouse experiment was carried out with three P sources (triple superphosphate, Araxa rock phosphate and Gafsa rock phosphate), all in five levels (0, 50, 150, 450, and 600 mg per kg of soil). Common bean was used as test plant. In order to evaluate the phosphorus availability in the soils, the dry matter yield, the above ground phosphorus content, the plants height and the number of trifoliate leaves were correlated with the extracted phosphorus by Mehlich-1, Mehlich-3 and ion exchange resin methods. Mehlich-3 and resin were more sensitive to soil variations. According to their efficiencies, the extractors were classified in the following order: resin > Mehlich-3 > Mehlich-1. The resin method showed the best correlations with the plants characteristics, thus showing to be the most suitable in forecasting the available P in different soils and P sources. The best correlations were yielded by the resin and Mehlich-3 methods.

Desempenho agrônomico de soja em função da sucessão de culturas em sistema de plantio direto

With the objective of evaluating the effect of crop rotation or succession on soybeans agronomic performance in no tillage system, an experiment was carried out in a distrophic Red Latosol, at the Nucleo Experimental de Ciencias Agrarias da Universidade Federal de Mato Grosso do Sul, in the county of Dourados-MS. The experimental procedure was a randomized blocks design with nine treatments and four replications. The plots had 36 meters of length and 11 meters of width (396 m2), where were mechanically sawed 26 lines of soybeans, at intervals of 0,45 meters between lines. The treatments were composed of nine systems of crop succession: system 1: corn/vetch/corn/vetch/soybeans; system 2: cotton/oat/cotton/sorghum/soybeans; System 3: soybean/wheat/soybeans/corn/millet/soybeans; system 4: corn/grazing turnip/corn/sorghum/soybeans; system 5: corn/oat/corn/beans/millet/soybeans; system 6: rice/grazing turnip/rice/oat/soybeans; system 7: rice/sorghum/rice/beans/millet/soybeans; system 8: cotton/wheat/cotton/wheat/soybeans and system 9: cotton/grazing turnip/cotton/oat/soybeans. The dry matter of the aerial part of the soybean plants in full flowering stadium, plants height and first pod insertion, number of pods per plant, the productivity and the 100 grains mass, were evaluated. It was concluded that the crop rotation or crops succession was not influenced by the plant height, pods insertion and number of pods per plant. On the other hand, the rotation systems of rice/sorghum/rice/beans/millet/soybean and soybeans/wheat/soybeans/corn/millet/soybean, provided the soybeans the higher grains yield.

Renovação de pastagem degradada com calagem, adubação e leguminosa consorciada em Neossolo Quartzarênico

The degradation is considered to be the major problem of cultivated pastures in the Cerrado. In Quartzipsament, an experiment was conducted to evaluate several degraded pasture recovering treatments of Brachiaria decumbens , introducing Brachiaria brizantha cv. Marandu. The treatments were: Witness; Liming; Liming + P; Liming + ½(PK); Liming + PK. Liming + PK + Micronutrients; Liming + PK + Micronutrients + Legume. The experimental design was that of randomized blocks with four replications. Three cuts in a 325 days period were done and, in the end, the evaluation of roots production and soil chemical analysis. All renovation systems differed from the witness and some of them differed among themselves in terms of dry mass of aerial portion, with emphasis to the legume treatment. The roots production was significantly greater in three treatments when compared to the witness. Significant increases in the nutrient levels and soil pH were verified, in function of lime and fertilization application