Relationship between citrus productivity and indicators of uniformity in trickle irrigation system

In trickle irrigation systems, the design is based on the pre-established emission uniformity (EU) which is the combined result of the equipment characteristics and its hydraulic configuration. However, this desired value of the EU may not be confirmed by the final project (in field conditions) and neither by the yield uniformity. The hypotheses of this research were: a) the EU of a trickle irrigation system at field conditions is equal to the emission uniformity pre-established in the its design; b) EU has always the lowest value when compared with other indicators of uniformity; c) the discharge variation coefficient (VC) is not equal to production variation coefficient in the operational unit; d) the difference between the discharge variation coefficient and the productivity variation coefficient depends on the water depth applied. This study aimed to evaluate the relationship between EU used in the irrigation system design and the final yield uniformity. The uniformity indicators evaluated were: EU, distribution uniformity (UD) and the index proposed by Barragan & Wu (2005). They were compared estimating the performance of a trickle irrigation system applied in a citrus orchard with dimensions of 400m x 600m. The design of the irrigation system was optimized by a Linear Programming model. The tree rows were leveled in the larger direction and the spacing adopted in the orchard was 7m x 4m. The manifold line was always operating on a slope condition. The sensitivity analysis involved different slopes, 0, 3, 6, 9 and 12%, and different values of emission uniformity, 60, 70, 75, 80, 85, 90 and 94%. The citrus yield uniformity was evaluated by the variation coefficient. The emission uniformity (EU) after design differed from the EU pre-established, more sharply in the initial values lower than 90%. Comparing the uniformity indexes, the EU always generated lower values when compared with the UD and with the index proposed by Barragan. The emitter variation coefficient was always lower than the productivity variation coefficient. To obtain uniformity of production, it is necessary to consider the irrigation system uniformity and mainly the water depth to be applied.

Productivity and water suppression in different beans (Phaseolus vulgaris L.) phenological stages

Common Bean (Phaseolus vulgaris L.) is widespread in the social and economic scene in Brazil, as well it is Brazilian population main dish, and it also helps small and medium farmers' income. The objective of this study was to compare the productivity performance of common bean Carioca - IAC Alvorada with irrigation suppression in each of the five phenological phases. The experiment was conducted in plots in a greenhouse at College of Agronomical Sciences, São Paulo State University (UNESP), Botucatu - SP. The hypothesis is that if the water supply is suppressed in one of the five development stages of irrigated common beans, the yield reduction would be at least 20%. The treatments consisted of suppression irrigation in one of the five development stages (stage V1 to V3, stage V4 to early flowering, flowering stage, pod formation stage and pod filling stage) compared with the irrigation at all stages and suppression of irrigation at all stages, with seven treatments and four replications. The treatments most affected by water suppression were those which suffered suppression of irrigation during the vegetative phase and flowering stage. Treatments with water suppression in all stages, and suppression during the phases (stage V1 to V3, stage V4 to early flowering, flowering stage, pod formation stage and pod filling stage) showed yield reduction of approximately 95%, 55.1%, 49.5%, 63,1%, 30.2% and 35.6%, respectively, when compared to treatment with irrigation all stages. All treatments considered confirmed the hypothesis.

Productivity: agriculture compared with the economy at large

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Women: productivity and labour in the United States

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Productivity, growth and industrial exports in Brazil

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Structural changes and productivity in Latin American industry, 1970-1996

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Sectoral regimes, productivity and international competitiveness

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Mexico: total productivity changes at the principal container ports

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Productivity differences in Brazilian manufacturing firms, by industrial sector: school bullying and academic achievement

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Innovation, R and D investment and productivity in Chile

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Colombia: public capital and manufacturing productivity

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Structural change and productivity growth 20 years later: old problems, new opportunities. Summary

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