Efeito residual do lodo de esgoto na produtividade do milho safrinha Residual effect of sewage sludge on off-season corn yield

Das opções de disposição final do lodo de esgoto, a reciclagem agrícola tem sido uma das mais utilizadas em diversos países desenvolvidos, sendo considerada a forma mais adequada em termos técnicos, econômicos e ambientais. Este trabalho teve por objetivo avaliar o efeito residual do lodo de esgoto na produtividade do milho safrinha, após dois anos de aplicação consecutiva desse resíduo em um Latossolo Vermelho eutroférrico. O experimento foi realizado em campo, em delineamento em blocos ao acaso com três repetições, e os tratamentos foram os seguintes: testemunha e adubações com lodo de esgoto nas doses de 6, 12, 24 e 36 t ha-1 (peso de matéria seca). Houve efeito residual do uso do lodo de esgoto caleado na produtividade de milho safrinha; a dose de 36 t ha-1 foi estatisticamente superior às doses de 6 e 12 t ha-1.<br>Among the possibilities of final disposal of sewage sludge, agricultural recycling has become one of the most widely used in several developed countries, and is considered the most appropriate in technical, economical and environmental terms. This study aimed at evaluating the sewage sludge residual effect on off-season corn yield on an Eutroferric Red Latossol (Oxisol). The field experiment was in a randomized block design with three replications, with treatments consisting of increasing doses of sewage sludge (0, 6, 12, 24 and 36 t ha-1, on a dry weight basis), applied in the two previous cropping seasons.. The residual effect of the application of lime-stabilized sewage sludge increased the yield of off-season corn; the grain yield under a rate of 36 t ha-1 was statistically higher than those under 6 and 12 t ha-1

The need to breed crop varieties suitable for organic farming, using wheat, tomato and broccoli as examples: A review

It is estimated that more than 95% of organic production is based on crop varieties that were bred for the conventional high-input sector. Recent studies have shown that such varieties lack important traits required under organic and low-input production conditions. This is primarily due to selection in conventional breeding programmes being carried out in the background of high inorganic fertilizer and crop protection inputs. Also, some of the traits (e.g., semi-dwarf genes) that were introduced to address problems like lodging in cereals in high-input systems were shown to have negative side-effects (reduced resistance to diseases such as Septoria, lower protein content and poorer nutrient-use efficiency) on the performance of varieties under organic and low-input agronomic conditions. This review paper, using wheat, tomato and broccoli as examples, describes (1) the main traits required under low-input conditions, (2) current breeding programmes for organic, low-input agriculture, (3) currently available breeding and/or selection approaches, and (4) the benefits and potential negative side-effects of different breeding methodologies and their relative acceptability under organic farming principles. © 2010 Royal Netherlands Society for Agricultural Sciences. Published by Elsevier B.V. All rights reserved