Sergio Luiz Gonçalves

Zoneamento agroclimático para o pessegueiro e a nectarineira no Estado do Paraná

ABSTRACT - Peach and nectarine crops, despite their high climatic and market potential, are not yet well exploited in the state ofParana. The objective of this research was to indicate zones with lower climatic risk for production of these crops in the state ofParana, Brazil, using climatic risk analysis and agronomic data. Historical data of 32 weather stations of IAPAR were analyzed toestimate and map the risks of late frost and the average totals of chilling hours above 7.2 o C accumulated from May to September. Theregions in which the last frost occurs before flowering and with the total chilling hours suitable to the cultivars needs were consideredapt. Most of the north, west and the coast of Parana do not have enough chilling hours. The areas located in the south with alt itudesabove 800 m are the most suitable. Within the apt areas eight zones were classified according to the chilling requirements of p eachesand nectarine varieties and climatic conditions of each region: zone 1 (75 to 150 hf); zone 2 (150 to 200 hf); zone 3 (200 to 250 hf); zone4 (250 to 300 hf); zone 5 (300 to 350 hf); zone 6 (350 to 400 hf), zone 7 (400 to 450 hf) and zone 8 (> 450 hf). The zones with lower altitudeand higher temperatures accumulate less chilling hours from May to September and are indicated for cultivars with lower chillingrequirement. The zones with higher altitudes and high chilling accumulation are suitable for varieties with high chilling requi rements(> 400 chilling hours). The last frost is likely to occur in the last ten days of August in the colder regions and do not caus e damagesto suitable varieties of peaches and nectarine. The results obtained in this work support the adoption of policies to foment thesecrops in the state of Parana with low risk.

Risco de deficiência hídrica na cultura do milho no estado do Paraná

The goal of this work was to determine soil water deficit risk and the best sowing periods for maize (Zea mays L.) in the State of Parana, Southern Brazil. A climatological soil water balance model adapted for maize was simulated, using historical series of daily values of maximum evapotranspiration and precipitation from 32 weather stations. Soil water holding capacity was calculated using an initial soil depth of 20 cm at plant emergence, which increased exponencially up to 80 cm depth at the beginning of plant flowering, and remained constant until harvest. Ten sowing dates spaced at 10 days interval were simulated between August 20 and November 20, and the frequency of soil water deficit during the flowering period (800 degree-days after emergence) was estimated. Using cluster analysis, Parana State was classified in five homogeneous zones for soil water deficit risk. Results have shown that the North and Northwest regions have very high risk. Appropriate sowing periods with lower risks were identified for all zones.

Cotton zoning based on sowing periods of lower risk in Parana state, Brazil

Cotton is cultivated in the North and West of Parana State, southern Brazil, under conditions of climatic risk variable in space and time. Risks of temperature below 15oC at the establishment period, daily average temperature below 20oC at the stage of cotton boll opening, and soil water deficit for both plant establishment and flowering periods, were estimated to identify homogeneous zones with sowing periods of lower climatic risk. The time interval with adequate temperature, associated with minimum risks of the other factors and yield data from field experiments allowed the identification of seven distinct zones, with best sowing periods ranging from September 20 to November 20. Official credit to the farmers is conditioned by the Central Bank of Brazil upon following these recommendation of best sowing periods for each municipality.

MORPHOPHYSIOLOGICAL AND PRODUCTIVE RESPONSES OF SUNFLOWER VARIETIES TO IRRIGATION

The high luminosity rates and high annual average temperatures of the Brazilian semiarid region, combined with the use of irrigation and adaptability of the sunflower crop to local climate, favor increased achene yield due to acceleration of morphophysiological processes. The objective of this work was to evaluate the morphophysiological and productive characteristics of sunflower varieties grown under drip irrigation in the Sub-Mid São Francisco River Valley. The experiment was conducted in the Experimental Field of the Brazilian Agricultural Research Corporation (Embrapa Semiarid), in Petrolina, State of Pernambuco, Brazil, in a randomized block design, with 21 sunflower varieties and four replications. The variables evaluated were flowering time, plant height, number of live leaves, stem and capitulum diameter, number of lodged and broken plants, stem curvature, relative chlorophyll index, photosynthesis, stomatal conductance, transpiration, average leaf temperature, 1000-achene weight and achene yield of the sunflower varieties. The treatments presented flowering time of 43 to 59 days after sowing, plant height of 1.0 to 1.4 m, capitulum diameter of 0.154 to 0.221 m, chlorophyll content of 30.8 to 33.98 Spad units and 1000-achene weight of 35.61 to 80.30 g. The sunflower varieties V7 and V8 stood out, with achene yields above 2,960 kg ha and low number of lodged and broken plants, indicating a greater adaptability irrigation crops in the Sub-Mid São Francisco River Valley.