Physiological and productive performance of papaya plants irrigated in a semiarid environment

Papaya tree has great economic importance and potential of cultivation in semiarid environment. However, water scarcity in this region may inhibits photosynthetic activity and limit the production of this crop, being necessary to use strategies of irrigation management that rationalize water and allow the production of the plants without affecting photosynthetic activity. In this sense, this study aimed to evaluate the physiological and productive performance of papaya “Calimosa” under different water replacement rates in semiarid environment. Papaya plants were irrigated with four water replacement rates (50, 75, 100 and 125% ETo) from 30 days after transplant of seedlings to the experimental area.  At 10 months after transplant were realized evaluations of gas exchange and chlorophyll fluorescence, and at 12 months after transplant, it was started harvesting fruits to determine the yield. Water replacement rates significantly influenced the parameters of gas exchange of papaya with better results on rates of 125% ETo. However, application of water replacement rates of 100% ETo provide conditions adequate for the activity of gas exchange and better quantum efficiency of photosystem II, that contribute to fruit production in papaya. With rates less than 75% ETo occur drastic reductions in gas exchange, quantum efficiency of photosystem II, and fruit production of papaya, which impairs its cultivation in semiarid environments

Lettuce production according to different sources of organic matter and soil cover

Lettuce (Lactuca sativa L.) is one of the leading vegetables produced by farmers in the Itabaiana region, and thus it is important to study means of sustainable management for the crop. The objective of this work was to evaluate the behavior of lettuce with different sources of organic matter and soil cover. Therefore, it was chosen to cultivate Veronica. The experiment was carried out in the experimental field plot of Project Small Farmer—Great Entrepreneur in the municipality of Itabaiana-SE, in 2010. The design was a randomized block design with four replications, with treatments consisting of five sources of organic matter (organic compost, chicken manure, cattle manure, sheep manure, and castor bean) and a control (no fertilizer), all with and without mulch, totaling 12 treatments. We evaluated the characteristics of plant diameter, plant height, fresh and dry root and shoot matter. We also evaluated the influence on the temperature and soil water tension. All productivity characteristics valuated showed the significant interaction between the type of fertilizer and the mulch, except for root dry weight, where only organic manure was a significant factor. When soil mulch was used, the best source of organic matter for growing lettuce was chicken manure, and in the impossibility of using this cover, we recommend the use of organic compost as a source of organic matter, as it showed the best result in the absence of coverage. The cover age also showed good results in relation to a temperature that promoted lower soil water tensions

Physiology and yield of piel de sapo melon (Cucumis melo L.) under water deficit in semi-arid region, Brazil

Melon (Cucumis melo L.) is a crop of great socioeconomic importance in regions with semiarid climate, as found in Northeast Brazil. In this region water deficit is a usual condition as well as the main reduction factor of plant productivity. Due to this phenomenon, irrigation techniques are used to make available the amount of water needed for plant production. Therefore, this research evaluated the physiology and fruit production changes of ‘Juazeiro’ Piel de sapo melon plants under different water replacement rates. ‘Juazeiro’ melon was grown under four reference evapotranspiration replacement rates (40, 60, 80 and 100% of ETo) distributed randomly in blocks with 5 replicates. The plants were cultivated in the field, in an experimental area located in the Brazilian Northeast region, under hot and dry semiarid climatic conditions, and during the growing cycle the ‘Juazeiro’ hybrid melon plants were evaluated for leaf area, biomass accumulation, gas exchange, photochemical efficiency of photosystem PSII and production of fruits per plant. Application of water replacement rates of 100% ETo leads to highest growth, net photosynthesis, and fruit yield of 'Juazeiro' melon. Water replacement at 80% ETo can be used for ‘Juazeiro” melon under semiarid climatic conditions, but with small losses in fruit yield. Water replacement below 80% ETo leads to drastic reductions in growth, gas exchanges, quantum efficiency of photosystem II and fruit yield, which impairs melon production in semi-arid climate environments

Vegetative development, fruits yield and optimization of pineapple cv. Pérola with different levels of irrigation

Apesar de ser uma planta com necessidades hídricas relativamente baixas, o abacaxizeiro tem demanda permanente de água, variável ao longo do ciclo e dependente do seu estádio de desenvolvimento. Assim, objetivou-se analisar volumes de irrigação no desenvolvimento vegetativo, no rendimento da fruta e na otimização do abacaxizeiro cv. Pérola. O experimento foi realizado na Universidade Federal de Sergipe, município de São Cristóvão (11°01'S, 37°12'W), no delineamento em blocos ao acaso, com quatro tratamentos (lâminas de água) (100% da evaporação do tanque Classe A (523,7mm ano-1); 75% da evaporação do tanque Classe A (392,8mm ano-1), 50% da evaporação do tanque Classe A (261,8mm ano-1) e 0% da evaporação do tanque Classe A, seis repetições e 12 plantas úteis por parcela. O sistema de irrigação foi por aspersão convencional disposto em linha, com pressão de 20mca e vazão de 1,33m3 h-1. A área foliar (cm2) mínima atingida de 4552,6cm2 foi observada no volume de água de 122,9mm ano-1, enquanto a massa seca das folhas (147,6g) foi constatada com 17mm ano-1. O máximo comprimento da folha D (88,9cm) foi estimado com 532,7 mm ano-1. Já o máximo comprimento do fruto (23cm) foi observado na lâmina de 296,9mm ano-1. A massa do fruto máxima estimado de 1.736g foi constatado na lâmina de 356,4mm ano-1. No contexto, a irrigação contribui de forma positiva no desenvolvimento vegetativo e rendimento da fruta do abacaxizeiro. Ressalta-se remuneração mensal líquida de R 1.161,17ha-1, quando se adota lâmina de irrigação de 356,4mm ano-1. _________________________________________________________________________________________ ABSTRACT: Regardless a relatively low water needs, pineapple fruit has a variable behavior related to water need throughout its biological cycle depending on the development stage. The objective of this work was to analyze irrigation on the vegetative development and fruits yield in pineapple cv. Pérola. The experiment was conducted at the Universidade Federal de Sergipe Experimental Station, at São Cristóvão - SE (11°01'S, 37°12'W), in a randomized block design, with four water level treatments as follow: 100% of Class-A (523.7mm ano-1) evaporation pan; 75% of Class-A (392.8mm ano-1) evaporation pan, 50% of Class-A (261.8mm ano-1) evaporation pan and 0% of Class-A evaporation pan, in six replications and twelve plants per plot. The splinkler watering system of irrigation was installed in a line, with an operating pression of 20 mca and a sprinkler dischrage of 1.33m3h-1. A minimum leaf area of 4552.6cm2 was observed, considering a water level of 122.9mm year-1, while a leaf dry matter was 147.6 g in 17mmyear-1. The maximum leaf length (D) of 88.9cm was estimated considering 532.7mmyear-1. The maximum fruit length of 23cm was observed, considering a water level of 296.9mmyear-1. The maximum estimated fruit weight was 1.736g in a water level of 356.4mm year-1. The irrigation seems to contribute in a positive way to the vegetative development in the pineapple fruit yield. It is important to mention that it could be observed a net profit of R 1,161.17 ha-1, when a water level of 356.4mm ano-1 of irrigation was adopted