J. M. Soares

Adubação verde com leguminosas em videira no submédio São Francisco

SUMMARY : GREEN MANURING GRAPEVINE WITH LEGUMES IN THESUBMIDDLE SAO FRANCISCO RIVER VALLEY The soils of the Submiddle Sao Francisco River Valley are generally sandy, with lownutrient retention capacity. Since they are located in a semi-arid area, they are very poor inorganic matter (OM) and as a consequence are deficient in nitrogen, which limits agriculturalproduction. Thus, the use of legumes as green manure may overcome this problem becauseit adds carbon and nitrogen to soil. The study comprised two experiments with legumesintercropped with irrigated grape ( Vitis vinifera ) in a sandy Ultisol in Petrolina, State ofPernambuco (Brazil) from June 1996 to July 2002. The objective was to evaluate the effectsof green manure on soil chemical characteristics and on grape yield and quality. The firstexperiment lasted until the fourth grape harvest. The treatments consisted of two legumes:sunnhemp ( Crotalaria juncea ) and jack bean ( Canavalia ensiformis ), submitted to twomanagements (sub-plot): (a) cut and left on the soil surface and (b) cut and incorporatedinto the soil. There was a control treatment (without green manure). In the second experiment,which began in the fifth grape production cycle, the methodology consisted of three treatments:(1) control; (2) sunnhemp and (3) jackbean combined with two subplot treatments: (a) 100 %of the fertilizer recommended by soil analysis, and (b) 50 % of the recommended fertilizer.Altogether, there were eleven legume cycles and nine harvests of table grape. The biomassproduction of the legumes decreased over time. Green manure improved the soil chemicalcharacteristics, increasing OM and exchangeable Ca content, and the CEC value in the0–10 cm soil layer. There was no consistent effect of the green manure on the yield andquality of table grape.Index terms:

Níveis de nitrogênio por fertirrigação e densidade de plantio na cultura do melão em um Vertissolo

O trabalho constou de um experimento com melao (Cucumis melo L.), conduzido em um Vertissolo, em Juazeiro, BA, em 1995, com o objetivo de avaliar o efeito de niveis de N por fertirrigacao e de densidades de plantio na produtividade e qualidade de fruto. Os niveis de N foram 0, 80, 130 e 180 kg/ha, combinados com os espacamentos 2,00 e 1,80 m entre linhas e 0,20 m entre plantas, com uma ou duas plantas por cova. A fonte de N foi a ureia, aplicada diariamente ate 42 dias apos a germinacao, por meio da irrigacao por gotejamento. Todos os tratamentos receberam uma adubacao uniforme de 120 kg/ha de P2O5 e 120 kg/ha de K2 O. Os espacamentos entre linhas nao causaram diferencas significativas em nenhuma variavel estudada. O nivel de 80 kg/ha de N combinado com uma planta por cova proporcionou uma produtividade de 34,07 t/ha, com 55,7% de frutos proprios para o mercado interno, nao-significativamente (P £ 0,05) inferior a produtividade obtida com os niveis mais elevados de N em qualquer combinacao. Com este mesmo nivel, obtiveram-se frutos com 10,22o Brix significativamente (P£ 0,05) superior ao do tratamento sem N e nao-significativamente inferior ao dos outros niveis. Para se obter uma maior parte de frutos proprios para o mercado externo, foi necessario elevar a densidade para duas plantas por cova e o nivel de N para 130 ou 180 kg/ha. O peso medio dos frutos aumentou de 1,008 para 1,705 kg, a medida que foram aumentados os niveis de N ou se diminuiu a densidade de plantio de duas para uma planta por cova.This study consisted of one experiment with melon (Cucumis melo L.), carried out in a Vertisol in Juazeiro, BA, Brazil, in 1995, with the objective of evaluating the effects of nitrogen levels through fertirrigation and plant density on fruit yield and quality. The N levels were 0, 80, 130 and 180 kg/ha, combined with row spacings of 2.0 and 1.8 m and 0.20 m between plants within the row, with one or two plants/hole. The source of N was urea applied daily up to 42 days after germination, through drip irrigation. All treatments had a uniform fertilization of 120 kg/ha of P2O5 and 120 kg/ha of K2O. No significant difference was caused by spacing between rows in the studied variables. Eighty kg/ha of N combined with one plant per hole gave a yield of 34.07 ton/ha, being 55,7% of fruit allocated to inside market, not significantly lower than those obtained with the highest N levels in any combination. This same N level gave fruits with 10.22o Brix, significantly higher than the treatment without N and not significantly lower than the other levels. In order to get high number of good fruit for out side market it was necessary to elevate the density to two plants per hole and N level to 130 or 180 kg/ha. Mean weight of fruits increased from 1.008 to 1.705 kg with the increase in the levels of N and the decrease in plant density of two plants per hole to one plant per hole.

Requerimento hídrico e coeficiente de cultura da cana-de-açúcar irrigada no semiárido brasileiro

O objetivo deste trabalho foi determinar o requerimento hidrico e o coeficiente de cultura (Kc) da cana-de-acucar irrigada durante o ciclo de soca, variedade RB 92-579, na regiao semiarida do Submedio do Vale do Sao Francisco. O experimento foi conduzido em area de cultivo comercial de cana-de-acucar situada no municipio de Juazeiro, BA. Obteve-se o requerimento hidrico da cultura por meio do metodo do Balanco de Energia Razao de Bowen. Foram monitoradas tambem a biomassa acumulada e a fracao da radiacao fotossinteticamente ativa interceptada pela cultura (fRFA). Com os resultados constatou-se que a evapotranspiracao da cana-de-acucar atingiu uma taxa media diaria de 4,7 mm, em resposta ao acumulo de biomassa e, mas a fRFA apresentou, entretanto, influencia do tombamento da cultura durante a fase de crescimento maximo. O requerimento hidrico total da cana-de-acucar foi de 1710 mm, e o Kc atingiu o valor medio de 1,10 na fase de crescimento maximo. As equacoes de estimativa do Kc mensal, tendo graus dias acumulados e dias apos o corte como variaveis independentes apresentaram otimos ajustes (R2 ~ 0,95 e 0,98) e consideram a reducao nos valores de Kc devida ao tombamento da cultura.

Caracterização fenológica e produtiva da variedade de uva Superior Seedless cultivada no Vale do São Francisco

The Superior seedless grape cultivar presents as one of the most important seedless grape, specially due the excelent bunches characteristics and good flavor. In the last years is the most important seedless grape yield in the Sao Francisco Valley. This work aims the phenologic and productive characterization of the Superior Seedless grape cultivar in the Sao Francisco Valley. The evaluations were obtained in the private farm at 1999 and 2000. The cultivar Superior Seedless presented average cycle of 94 days. The pruning in 16/02/1999 promoted the antecipation of 14 days of the harvest. The average yield was very low, showing good bunch characteristics.

Variação do balanço de radiação e de energia da cana-de-açúcar irrigada no semiárido brasileiro

The objective of this work was to analyze the variations in the magnitudes and partition of the radiation and energy balance components, obtained during the growth period of the irrigated sugarcane (variety RB92579). The experiment was carried out in Juazeiro-BA, located in the Brazilian semiarid region. The sensible (H) and the latent (LE) heat fluxes in the air were estimated by means of the Bowen ratio energy balance (BREB). The crop growth was also monitored. In a preliminary analysis of this method, it was verified that 62.7% of the collected data presented physical consistence to be used for estimating the H and LE components. It was observed that the mean value of the Rn/Rg ratio was equal to 59±5%, with smaller values occurring at the beginning and at the end of sugarcane crop cycle, while the magnitude of long wave radiation balance (BOL) was intensified when the leaf area index (LAI) was reduced. Also, it was noticed that the mean value of the albedo was 23±3% and that 81% of the available energy was destined to the latent heat flux, while the sensible heat in the air (H) and in the soil (G) represented 16 and 3%, respectively.

Demanda hídrica e eficiência do uso de água da cana-de-açúcar irrigada no semiárido brasileiro

The objective of this work was to accomplish an analysis of the water use efficiency in a production system of irrigated sugarcane located in the Lower-Middle Sao Francisco river basin, Brazil. Indicators based on the crop yield and the water application performance in the production system were used. These indicators were calculated through accumulated dry biomass, industrial yield data and through the values of reference evapotranspiration, crop evapotranspiration and the water volume that entered in the system by rain and irrigation (P+I). It was verified that, the highest water use efficiency of crop occured between 7th and 8th month, due to increase in the stalk biomass partition and radiation supply, and due to reduction of ETc in response tumbling of the plants. The used indicators demonstrated that the water demand of crop was adequately in relation to maximum evapotranspiration of crop. The irrigated sugarcane presented a production efficiency of 9.49 kg of stalks, 1.22 kg of sugar and 875.23 mL of alcohol per m3 of ETc and of 5.36 kg of stalks, 0.69 kg of sugar and 494.14 mL of alcohol per m3 of P+I.

Evapotranspiração e produtividade da mangueira sob diferentes tratamentos de irrigação

The objective of this study was to determine the evapotranspiration and yield as well, as the appropriate irrigation scheduling, for mango. The experimental design was in randomized blocks, with four treatments and four repetitions. The irrigation treatments were established based on the reference crop coefficient (Kcr), such as: treatment T1 (Kcr - 20%), treatment T2 (Kcr), treatment T3 (Kcr + 20%) and treatment T4 (control). The evapotranspiration of mango was obtained by the soil water balance method and the production components were also evaluated. Soil water pressure suction was measured based on twelve sets of mercury tensiometers positioned under the canopy of individual trees. Measurements were recorded three times per week at 08:00, 12:00 and 16:00 h. Throughout the mango fruiting cycle the mean daily evapotranspirations were 3.0, 3.2, 3.6 and 4.1 mm day-1 in the treatments T1, T2, T3 and T4, respectively. The maximum and minimum yields were 31.1 and 28.1 t ha-1 in the T3 and T4 treatments, respectively. The T3 treatment is more appropriate for the studied area.

Influência do calor armazenado no sistema solo-planta no balanço de energia em pomar de mangueiras

Neste estudo se objetivou a avaliacao da contribuicao do calor armazenado acima das placas de fluxo de calor no solo e no dossel vegetativo sobre os componentes do balanco de energia, no pomar de mangueiras. Os componentes do balanco de energia foram obtidos pelo metodo do balanco de energia com base na razao de Bowen. O teste t-Student foi usado para avaliar a existencia de diferenca significativa entre as medias dos componentes do balanco de energia, obtidas mediante as seguintes condicoes: (i) considerando-se o calor armazenado acima dos fluximetros e (ii) desconsiderando-se o calor armazenado acima dos fluximetros, cujos resultados indicaram que: 1) o efeito do calor armazenado no dossel vegetativo e irrelevante quando comparado com os outros componentes do balanco de energia em pomar de mangueiras; 2) o calor armazenado acima das placas de calor no solo nao interfere significativamente no calculo dos fluxos de calor sensivel e latente nem na evapotranspiracao da mangueira irrigada; 3) o fluxo de calor no solo, corrigido com o calor armazenado acima dos fluximetros, difere estatisticamente a nivel de 5% de probabilidade, daquele obtido sem a correcao do fluxo.

Produção e qualidade de melão influenciados por matéria orgânica, nitrogênio e micronutrientes

The effects of nitrogen, boron, molybdenum and zinc applied as fertigation, and cattle manure applied to the soil, were evaluated on the yield and quality of melon (Cucumis melo) in two types of soils of the Submedio Sao Francisco River Valley, Brazil. Six experiments were carried out in 1998, 1999 and 2000, three being in a red yellow Latosoil in Petrolina, and three in a Vertisoil, in Juazeiro, in a randomized complete block design with four replications and nine treatments, as follows: 1. N1; 2. N2; 3. N3; 4. N1 + C.M.; 5. N2 + C.M.; 6. N2 + B + Mo + Zn; 7. N2 + B + Mo; 8. N2 + B + Zn, and 9. N2 + Mo + Zn, where N1, N2 and N3 represent, respectively, 0 or 30, 80 and 160 kg/ha of N; C.M. was 20 m3 ha-1 of manure; B = 1.1 kg ha-1; Mo = 0.4 kg ha-1, and Zn = 4 kg ha-1. Nitrogen and the micronutrients were applied through irrigation water. Melon yield showed response to nitrogen in the Latosoil in 1998 and in 2000, and in the Vertisoil in 1999. Higher significant yields were obtained with 80 kg ha-1 of N, varying among experiments from 32.0 to 40.2 t ha-1. Cattle manure caused significant increase only in yield in 1998 and in mean fruit weight in 2000 in the Vertisoil. Soluble solid contents in fruits increased with nitrogen application in the Latosoil in 2000. The micronutrients did not have significant effect on yield. In two years, mean fruit weight was higher in Vertisoil than in Latosoil.

Efeito de fertilizantes nitrogenados na produtividade de melão

A study was carried at Petrolina-PE, Brazil, with the melon crop (Cucumis melo L.), cv. Valenciano Amarelo, in a Red-Yellow Latosol with the objective of evaluating the effect of nitrogen fertilizers sources and their combinations, applied through the conventional way and through water irrigation during the crop cycle. The experimental design was a split block with four replica- tions and nine treatments: 1. control (without N); 2. urea; 3. ammonium sulphate, both applied con- ventionally; 4. urea applied up to 42 days after germination; 5. ammonium sulphate applied up to 42 days after germination; 6. urea applied up to 15 days and potassium nitrate from 16 to 42 days after germination; 7. urea applied up to 15 days and ammonium sulphate from 16 to 42 days; 8. urea applied up to 30 days and potassium nitrate from 31 to 42 days, and 9. urea applied up to 15 days, ammonium sulphate from 16 to 30 days and potassium nitrate from 31 to 42 days, at the level of 80 kg/ha of N. The fertilizers used during the crop cycle (treatments 4 to 9) were applied through irrigation water. It was found that urea applied through fertirrigation up to 42 days provided higher yield (31.14 ton/ha), not differing, however, from the other treatments, with the exception of the control and ammonium sul- phate, which gave the lowest yields (25.06 and 24.65 ton/ha, respectively). It was found a variation in fruit mean weight from 1.63 to 1.84 kg/fruit. There was no significant difference in total soluble solid content ( o Brix ) among the treatments.