Pedro R. F. Medeiros

Tolerance of cucumber crop to salinity in greenhouse

The objective of this work was to evaluate the cucumber crop in saline conditions resulting from fertilizer salt, under six levels of soil salinity (1.5, 2.5, 3.5, 4.5, 5.5 and 6.5 dS m-1). The study was carried out in the experimental area of the Department of Rural Engineering of the ESALQ/USP, Piracicaba/SP, Brazil. The planting was carried out in recipients using sandy soil during the period of 28/08/07 to 20/10/07. As the main results, it was verified that the maximum productivity was 2.45 kg m-2 for the salinity level of 3.5 dS m-1, that with the values of relative production the threshold salinity (SL) observed was of 4.08 dS m-1, and that there was a decline of 19.33% in production for unit increase of soil salinity above the threshold point.

Sleep desaturation and its relationship to lung function, exercise and quality of life in LAM.

BACKGROUND Lymphangioleiomyomatosis (LAM) is characterised by progressive airway obstruction and hypoxaemia in young women. Although sleep may trigger hypoxaemia in patients with airway obstruction, it has not been previously investigated in patients with LAM. METHODS Consecutive women with lung biopsy proven LAM and absence of hypoxaemia while awake were evaluated with pulmonary function test, echocardiography, 6-min walk test, overnight full polysomnography, and Short Form 36 health-related quality-of-life questionnaire. RESULTS Twenty-five patients with (mean±SD) age 45±10 years, SpO(2) awake 95%±2, forced expiratory volume in the first second (median-interquartile) FEV(1)(% predicted) 77 (47-90) and carbonic monoxide diffusion capacity, DL(CO) (%) 55 (34-74) were evaluated. Six-minute walk test distance and minimum SpO(2) (median-interquartile) were, respectively, 447m (411-503) and 90% (82-94). Median-interquartile apnoea-hypopnoea index was in the normal range 2 (1-5). Fourteen patients (56%) had nocturnal hypoxaemia (10% total sleep time with SpO(2) <90%), and the median sleep time spent with SpO(2) <90% was 136 (13-201)min. Sleep time spent with SpO(2) <90% correlated with the residual volume/total lung capacity ratio (r(s)=0.5, p: 0.02), DL(CO) (r(s)=-0.7, p: 0.001), FEV(1) (r(s)=-0.6, p: 0.002). Multivariate linear regression model showed that RV/TLC ratio was the most important functional variable related to sleep hypoxaemia. CONCLUSION Significant hypoxaemia during sleep is common in LAM patients with normal SpO(2) while awake, especially among those with some degree of hyperinflation in lung function tests.

Dynamic blockage of drippers as a function of the application of super simple phosphate and nítric acid in localized irrigation

The super simple phosphate (SS) is an alternative to the phosphorous fertilizers which are used through fertigation, as the phosphoric acid, which triggers acidification of the wetted volume in the soil, and the monophosfato of purified ammonium, that has a higher price. However, the effect of such fertilizer in the emitters function, mainly in the drippers, is not known neither if it is possible to control the blockage for SS through acid applications. Thus, this study was developed in order to evaluate the possibility of the use of super simple phosphate trough drip irrigation, as an alternative to the use of other phosphorous fertilizers, and the attempt of controlling the blockage with nitric acid. The work was carried out in bench of drippers rehearsals, located at the Hydraulic laboratory in ESALQ-USP. Doses of 50; 75 and 100% of the super simple phosphate (SS) were applied in 26 emitter tubes with different commercial marks, and after 360 hours the nitric acid with a pH of 2 was applied, in the attempt of clearing the most sensitive drippers to the blockage. With the results it was possible to infer that: the use of super simple phosphate can be done by fertigation without causing damages to the system and the nitric acid, applied according to this methodology, did not provide the clearance of the emitters.

Tolerância da cultura do tomate à salinidade do solo em ambiente protegido

ABSTRACT In order to contribute to data available in the literature on tolerance of crops to soil salinity derived fromfertilizer salts, the present study aims to determine the tolerance of tomato crop to the soil salinity, basedon two managements of fertirrigation and six initial levels of salinity (1.0; 2.0; 3.0; 4.0; 5.0 and 6.0 dS m -1 )from the variables production and components of production, in a protected environment with sandy-clay soil. The experiment was conducted at the Department of Biosystems Engineering of ESALQ/USP,Piracicaba/SP. The experimental design was in randomized blocks, with 4 repetitions. Concluding thatthe production and the components of production of tomato crop were significantly affected both by thetype of management of fertirrigation and by the levels of soil salinity, with a reduction in the tolerance oftomato crop, being classified as sensitive to soil salinity. Key words : Irrigation, fertilizers, relative production Revista Brasileira deEngenharia Agricola e Ambiental