Flávio F. Blanco

Estimation of leaf area for greenhouse cucumber by linear measurements under salinity and grafting

A determinacao da area foliar por medidas lineares e uma ferramenta util quando as plantas nao podem ser destruidas para que a medicao direta seja realizada. Os objetivos desse trabalho foram definir equacoes para a estimativa da area foliar do pepino em ambiente protegido e avaliar os efeitos da salinidade e da a enxertia nessa estimativa. Mudas de pepino, cv. Hokushin, nao enxertadas, foram transplantadas em um ambiente protegido e irrigadas com agua de diferentes salinidades (1,0, 3,2 e 5,0 dS m-1). No segundo periodo de cultivo, a mesma cultivar foi enxertada sobre Cucurbita spp., sendo as plantas irrigadas com agua de 1,4, 3,0 e 5,3 dS m-1. Foram coletadas folhas de diferentes tamanhos dos dois cultivos e dos tres tratamentos e a area foliar foi determinada por um medidor de area foliar. O comprimento (C) e a largura (L) da folha tambem foram registrados. Desenvolveram-se equacoes pelas quais a area foliar pode ser estimada a partir de medidas de C e L. A equacao desenvolvida para um dado nivel de salinidade ou condicao de enxertia estimou bem a area das folhas coletadas nos demais tratamentos. A area foliar (AF) do pepino Hokushin pode ser estimada pela funcao AF = 0,88CL - 4,27, para qualquer condicao de enxertia e salinidade.

A new method for estimating the leaf area index of cucumber and tomato plants

Non-destructive methods of leaf area measurement are useful for small plant populations, such as experiments with potted plants, and allow the measurement of the same plant several times during the growing period. A methodology was developed to estimate the leaf area index (LAI) of cucumber and tomato plants through the evaluation of the leaf area distribution pattern (LADP) of the plants and the relative height of the leaves in the plants. Plant and leaf height, as well as the length and width of all leaves were measured and the area of some leaves was determined by a digital area meter. The obtained regression equations were used to estimate the leaf area for all relative heights along the plant. The LADP adjusted to a quadratic model for both crops and LAI were estimated by measuring the length and width of the leaves located at the relative heights representing the mean leaf area of the plants. The LAI estimations presented high precision and accuracy when the proposed methodology was used resulting in time and effort savings and being useful for both crops.

Salt accumulation and distribution in a greenhouse soil as affected by salinity of irrigation water and leaching management

Estudaram-se os efeitos da salinidade da agua de irrigacao, fracao de lixiviacao e sua frequencia de aplicacao na salinizacao de um solo. Durante um ciclo de pepino enxertado em ambiente protegido, foram aplicadas aguas de diferentes salinidades (S1=1,54, S2=3,10 e S3=5,20 dS m-1) e duas lâminas de irrigacao associadas as suas frequencias de aplicacao (W1=1,00 ETc; W2F1=1,25 ETc em todas as irrigacoes e W2F2=1,25 ETc quando a lâmina de irrigacao acumulada em W1 alcancou 100 mm em que ETc e a evapotranspiracao da cultura). O delineamento experimental foi o de blocos casualizados em esquema fatorial 3x3 com 3 repeticoes. A salinidade do solo nas profundidades de 0,1, 0,3 e 0,5 m aumentou linearmente com a salinidade e a fracao de lixiviacao nao teve efeito independente do seu manejo. A concentracao de sais foi maior proximo a superficie do solo e na regiao compreendida entre dois gotejadores.

Evapotranspiration and crop coefficient of cucumber in greenhouse

The evapotranspiration (ETc) and crop coefficient (Kc) of cucumber in a greenhouse were determined during the winter-spring season in Piracicaba, SP, Brazil. Crop was irrigated with water of three different levels of salinity: S1 = 1.5, S2 = 3.1 and S3 = 5.2 dS m-1. Electrical conductivity of S1 was obtained only by addition of fertilizers, as fertigation was used, and the S2 and S3 levels in addition to fertilizers received magnesium sulphate, calcium chloride and sodium chloride. Cucumber seedlings, cv. Hokushin, were grafted on squash, transplanted on beds in double rows and directed vertically with a single stem. Irrigation was performed when soil matric potential reached -30 kPa, which was determined by the mean matric potential at 0.15 and 0.30 m depths, and the depth of irrigation was calculated from a reduced-evaporation pan. A randomized block design was adopted with three replications. The ETc and Kc were found to reduce linearly by the salinity of the irrigation water with reduction in ETc of 4.6% for unit increase of salinity. Due to the reduced evapotranspiration in saline treatments, deep percolation was increased by saline water and corresponded to 4, 7 and 17% of the total applied water in S1, S2 and S3, respectively. Measured Kc values for S1 were very close to the estimated values thus the combined use of tensiometers and evaporation pan was found to be adequate for irrigation management in greenhouse.

Desenvolvimento vegetativo do pepino enxertado irrigado com água salina

Greenhouse soil salinization by excessive fertilization and lack of leaching has been a common cause of cucumber yield reduction in Brazil. The aim of this work was to evaluate the effects of irrigation with saline water on the vegetative development of grafted cucumber plants in a greenhouse. Three water salinities (S1=1.58; S2=3.08 e S3=5.13 dS m-1), two irrigation water depths (L0=1.00 x ETc e L1=1.25 x ETc) and two application frequencies of L1 (F1=in all irrigations and F2=when the irrigation water depth of L0 reached 100 mm) were used. Irrigation water depths and frequencies of L1 were grouped and, therefore, the experimental design was in a factorial scheme 3x3, with randomized blocks. Results showed that plant height, unit leaf area and leaf area index were linearly affected by water salinity. No differences were observed for the various irrigation water depths and frequencies of L1 application.

Sampling equipament for soil bulk density determination tested in a Kandiudalfic Eutrudox and a Typic Hapludox

3 Pos-Graduando em Irrigacao e Drenagem - USP/ESALQ. 4 ABSTRACT: In spatial variability studies of soil physical properties the influence of different samplers on the results is seldomly taken into account. The objective of this work was to evaluate the performance of five different types of sampling equipment for soil bulk density determination, in two different soils a Kandiudalfic Eutrudox and a Typic Hapludox, both of Piracicaba, SP, Brazil. Equipment used for soil undisturbed sampling were: (i) Uhland soil sampler; (ii) Kopeckys Ring; (iii) soil core sampler, model Soil Moisture; (iv) soil core sampler Bravifer AI-50 and (v) soil core sampler Bravifer AI-100. The sampling was made in 4 grids of 1m2 , each with 25 sampling points, with five replications, resulting 100 samples for each soil. It was concluded that the sampling techniques can influence soil bulk density distributions, mainly in the case of clayey soils (Kandiudalfic Eutrudox). The Kopeckys Ring presented larger soil density values, overestimating this property for the two soils studied. The soil core sampler Bravifer AI-50 presented results closest to the overall average of the Typic Hapludox.

Calibration of cardy-ion meters to measure nutrient concentrations in soil solution an in plant sap

ABSTRACT: Fertigation management requires rapid and accurate methods to determine nutrient concentrationsin soil solution and in plant sap. This study was developed to evaluate the performance of cardy-ion meters(CIM) for the determinations of NO 3- , K + and Na + concentrations in soil solution and tomato plant sap, forfertigation management purposes. Tomato was cultivated in a greenhouse with different levels of N, K andNa in the irrigation water. Soil solution was collected by suction at the 15 cm depth with porous ceramic cupsand the concentrations of NO 3- , K + and Na + were determined by CIM and also in the laboratory by standardmethods. At the end of the cropping season, 50 leaf samples were also collected and concentrations of thenutrients in the petiole sap were analyzed by CIM and compared to the amounts of total-N, K and Na in thedry matter of the leaves. Concentrations in soil solution and plant sap determined by CIM presented goodcorrelations with measurements in soil solution and in leaf dry matter, respectively, analysed by standardmethods. The use of CIM is advantageous due to the quickness of the analyses and the low cost.Key words: ion electrodes, fertigation, mineral nutrition, soil solution extractor, tomato

Reclamation of a salinized soil after cultivation in greenhouse

Overapplication of fertilizers and inadequate irrigation management in greenhouse crops have caused soil salinization, resulting in reduction of crop yields. The aim of this work was to evaluate different depths of leaching and methods of application for reclamation of a salinized soil under greenhouse conditions. Three relative water depths (2/3, 1, 3/2), based on calculated leaching water depth, were applied by drip irrigation and flooding, in a 2 x 3 factorial scheme, with 3 replications. From the obtained results, it may be concluded that the application by drip was more efficient than flooding in leaching the accumulated salts in the soil and the relative water depth and coefficient k of 0.9 and 0.1 for drip and 1.3 and 0.2 for flooding, respectively, should be used.

Greenhouse irrigation water depths in relation to rose stem and bud qualities

The cultivation of roses occupies a special place in the flower production of Brazil, the concern with the quality of the buds being intimately related with the appropriate supply of water and nutrients to the plant. With the objective of evaluating stem and bud quality the rose variety Osiana was cultivated in a greenhouse using different irrigation water depths based on fractions of pan evaporation (0.25, 0.50, 0.75, 1.00 and 1.25). The experimental design consisted of total randomized blocks with five replications and five treatments. There is a linear tendency of increasing the length and diameter of the stems and the length and diameter of the buds with increasing irrigation water depths.

Viabilidade econômica da irrigação da manga para o Estado de São Paulo

The State of Sao Paulo is the largest producer of mango in Brazil, but most of the orchards do not have an irrigation system yet and this technique presents a great potential to raise the mean productivity of mango in this State. A methodology was used in the present study for evaluation of the economic viability of installation of an irrigation system in mango orchards, which was applied for different localities of the State of Sao Paulo. Results showed that the acquisition price of the irrigation system, associated with its durability, is the most important factor to be considered in the viability analysis. The water charging for the use did not turn unfeasible the implantation of irrigation system and had little influence on the yield increment necessary to cover additional costs.