Effects of planting density on the survival, development and biomass production of halophyte Sarcocornia ambigua (Michx.) Alonso & Crespo
Sarcocornia ambigua (Michx.) Alonso & Crespo is a perennial halophyte native to mangroves and salt marshes on the Atlantic coast of South America. This species has great potential as a new cultivar irrigated with seawater and / or saline effluents from carcinoculture. In order to evaluate the effects of planting density on mortality, growth and biomass production of S. ambigua irrigated with saline effluent from carcinoculture, seedlings produced from seeds were planted in four different spacing (10, 20, 30 and 40 cm between plants ) in randomized blocks with three repetitions (beds). Seedlings classified as small (≈ 4 cm) and large (≈ 13 cm) were planted alternately in each planting row.The moisture content and electrical conductivity of the sediment in the beds was monitored and the plants collected after 150 days of cultivation. The final mortality of the plants in the beds was 19.3%, being related to the spatial variation of the moisture content of the bed sediment (smaller in a wetter bed) and to the initial size of the seedlings (smaller for large seedlings). The plants had higher mean of total dry biomass when they grew in the two largest spacing of 40 and 30 cm (30.9 ± 5.1 g; 24.4 ± 3.6 g) than in the two smallest spacing of 10 and 20 cm (12.8 ± 1.2 g; 14.7 ± 2.1 g). The same response pattern was observed for the length of the stem branches and for the different vegetative and reproductive components of aerial biomass. The average production per area of S. ambigua was 8.2 ± 1,6 t / ha (fresh biomass) and greater production was achieved in the 10 cm spacing (10.3 ± 5.0 t / ha). Plants originating from large seedlings showed a performance 3 to 4 times higher in all growth parameters compared to small seedlings. It has been shown that S. ambigua plants are subject to infestation by microlepidopteran mining larvae, as well as persistence in sediment saturation inhibits plant growth.