Effects of plant density and the number of emitters on plant growth and nitrate concentration in spinach cultivated in substrate

The effects of plant density and the number of emitters per Styrofoam box on plant growth and nitrate (NO3-) concentration were evaluated in spinach (Spinacia oleracea L. cv. Tapir). Spinach seedlings were transplanted at 45 days after emergence into Styrofoam boxes filled with the substrate and were grown during winter in an unheated greenhouse with no supplemental lighting. The experiment was carried out with four treatments, including two plant densities (160 and 280 plants/m2) and two number of emitters per Styrofoam box (4 and 8 emitters). Each planting box was irrigated daily and fertigated with a complete nutrient solution. Shoot dry weight was not affected by plant density. However, yield increased with plant density and emitter number. Leaf-blade NO3- concentration was not affected by the interaction between plant density and number of emitters, but petioles NO3- concentration was greater in treatment with 160 plants/m2 and 8 emitters. Although leaf-blade NO3- concentration was not affected by plant density, it decreased with the number of emitters. On the other hand, petiole NO3- concentration was not affected by plant density or number of emitters. Leaf-blade NO3- concentration ranged from 3.2 to 4.1 mg/g fresh weight, occurring the highest value in the treatment with 280 plants/m2 and 4 emitters. Petiole NO3- concentration ranged from 3.5 to 5.3 mg/g fresh weight, values that were higher than allowed by EU regulation.

Evaluation of water use, yield and water productivity of a high-density orchard (cv. Cobrançosa) subjected to different irrigation regimes – An account of four years

The impact of different irrigation scheduling regimes on the water use, yield and water productivity from a high-density olive grove cv. Cobrançosa in southern Portugal was assessed during the irrigation seasons of 2011, 2012, 2013 and 2014. The experiments were conducted in a commercial olive orchard at the Herdade Álamo de Cima, near Évora (38o 29' 49.44'' N, 7o 45' 8.83'' W; alt. 75 m) in southern Alentejo, Portugal. The orchard was established with 10-year old Cobrançosa trees in grids of 8.0 x 4.2 m (300 trees ha-1) in the E-W direction, and experiments conducted on a shallow sandy loam Regosoil Haplic soil. From mid-May to the end of September the orchard was irrigated and three plots were subjected to one of two irrigation treatments: a control treatment A, irrigated to replace 100% ETc, a moderate deficit irrigation treatment B irrigated to 70% of ETc, and a more severe deficit irrigation treatment C that provided for approximately 50% of ETc. Daily tree transpiration rates were obtained by continuously monitoring of sap flow in representative trees per treatment. Among the irrigated treatments, water use efficiency (WUE, ratio of water used to irrigation- water applied) of treatment C was the highest, with a value of 0.89, being treatment B slightly lower, with a WUE of 0.76. Olive harvest for 2012 was an exceptional “on year”. Bearing yields showed contrasting differences within years where an “on year” was followed by an “off year”. In 2011 and 2012 treatment B yields were 41 and 50% higher than treatment C, respectively. In 2013 treatment B yield was 45% higher than yield of the fully irrigated treatment A, and treatment C showed practically the same yield than treatment A. In the “on year” of 2014 treatment B averaged 48% higher yield than treatment C. Treatment B farm irrigation water productivity (WPI-Farm, ratio of yield to water applied) was the highest among all treatments. Treatment A showed the lowest conversion efficiency of all treatments, indicating treatment B as the adequate deficit irrigation treatment for our Cobrançosa orchard

The flora and communities Carnaubal Palm Forest in the northern region of Ceará - Brazil

The “dicótilo-palmácea” mixed forest is found in the fluvial plains (floodplains) of watercourses on the Ceará semiarid region (Brazil), distinguishing from the surrounding vegetation (caatinga) by the prevalence of larger tree species. In the river’s margins, presenting high variability in the extension of the riverbanks, arise floodplains in pedologic complexes mainly composed by neossols and argissols, resulting from the deposition of sediments. In these areas of high fertility soils and subjected to flooding during part of the year, it develops a particular type of riparian vegetation dominated by carnauba palm tree (Copernicia prunifera (Mill.) H.E. Moore) forming a particular type of riparian forest, designated by carnaubal palm forest. We aimed to carry out floristic and phytosociological surveys of carnauba palm forests located in the northern region of Ceará. The classical sigmatist method of Braun-Blanquet was applied and classification analysis (Twinspan) was perfomed. The field work occurred in March 2014 and 2016 in eight areas: Fazenda Pedra Branca (03º 37’ 10’’ S e 40º 18’ 30’’ W, 104 m asl), Vale do Rio Bom Jesus (04º 04’ 42’’ S e 39º 57’ 08’’ W, 200 m asl), Lagoa do Peixe (03º 56’ 28’’ S e 40º 23’ 23’’ W, 97 m asl), Fazenda Peixes (04º 06’ 03’’ S e 40º 32’ 43’’ W, 114 m asl), Fazenda Natividade (04º 02’ 50’’ S e 40º 29’ 03’’ W, 109 m asl), Fazenda Morro Alto (02º 53’ 42’’ S e 39º 54’ 51’’ W, 16 m asl), Fazenda Araticum (03º 04’ 58’’ S e 40º 09’ 36’’ W, 19 m asl) and Fazenda Experimental da UVA (03º 37' 04'' S 40º 18' 18'' W, 200 m asl).The floristic list consists of 170 species, distributed between 127 genera and 50 families. Twenty-seven Brazilian endemic species were identified, from which 8 are exclusive of the Caatinga biome. The Fabaceae was the most representative family, with the highest number of species (28), followed by Poaceae (17), Malvaceaea (14), Euphorbiaceae (12), Asteraceaea (9), Convolvulaceae and Rubiaceae (9). The dominant life forms were therophytes (34%), phanerophytes (30%) and chamaephytes (18%). Two communities were identified as a result of the classification analysis using the Twinspan.