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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
The Cemitério Palaeolake deposit in Catalao, Goiás State, Brazil, comprises a single, complete lacustrine sequence, dated from less than 27,500 ± 4000 yr B.P. to more than 51,780 ± 400 14C yr B.P. The unprecedented presence of spongillite and diatomite layers in this deposit was investigated using spicules of continental sponges as proxy data for environmental and climate reconstruction, which was relatively extensive for the ages examined. From the analysis of the sedimentary features and the associations of spicules preserved in the deposit, it was possible to reconstruct the evolution of the limnic system. Five developmental stages were thus identified, corresponding to the installation (lotic and erosion phase), establishment and development of the lake and its colmatation, the latter correlating to the Last Glacial Maximum (LGM). Moreover, based on the ecological requirements of the sponge species identified in the deposit, it was possible to infer the likely weather patterns related to respective phases of the lake. The presence of the sponge species Corvoheteromeyenia australis, presently recorded only from southern South America, indicated that polar incursions originating from the Antarctic were frequent during the last glacial period and might have played a notable role in what is now central Brazil. However, for a short time, drier and hotter weather conditions might have predominated, as suggested by the presence of the species Corvomeyenia thumi.