Abstract The effectiveness soil cover in no-till is relating to quantity and quality of the phytomass produced by crops in rotation and, its persistence over the soil depends on residues decomposition. The objective of this study was to evaluate the phytomass production, decomposition rate and the half-life of crops in rotation at the Subtropical region, Brazil. The study was carried out at the Agronomic Institute of the Paraná (IAPAR), in Ponta Grossa, Parana State, Brazil. The experimental design was randomized blocks, with six treatments and four replicates. Winter cash crops and cover crops, single and in consortium, were evaluated in the year 2014 (wheat, black oats + hairy vetch + rye, black oats + ryegrass and black oats + blue lupine), in 2015 (canola, black oats, and black oats + hairy vetch + forage turnip) and in 2016 (barley, triticale, and triticale + black oats + rye). The phytomass was evaluating by collect three subsamples of 0.25 m2 per plot. For decomposition rate and the half-life of the crop residues, litter bags (LBs) methodology was used. A mathematical model (Q=Q0exp-kt) was used to represent the crop residues decomposition and the half-life of crop residues were obtained by the equation t1/2 = (ln2)/k. Poaceae consortia, single Poaceae and canola presented higher phytomass production when compared to Poaceae-Fabaceae consortia. The half-life for Poaceae-Fabaceae corsortia was shorter than single Poaceae.

Gerbera (Gerbera jamesonii) is one of the most popular ornamental plants in the world, used as cut or vase flower. The experiment aimed to evaluate the effect of milk in natura to control powdery mildew (Erysiphe cichoracearum) on gerbera. The treatments tested were: two concentrations of cow's milk in natura (8 and 16%), with and without adjuvant (vegetal oil), three fungicides (fenarimol -6 g a.i.100 L-1 H2O, chlorothalonil -150 g a.i.100 L-1 H2O and azoxystrobin + mineral oil - 10 g a.i.100 L-1 H2O) and control treatment. The area under the disease progress curve (AUDPC) was calculated for each plot based on disease severity. Milk in natura applied with adjuvant controlled the disease and did not allow the infection and development of pathogen. The addition of adjuvant improves the efficiency of milk in natura, but it requires subsequent washing of plants with H2O + detergent. The fungicide fenarimol promoted the best control and also the best gerbera visual aspect. The fungicide azoxystrobin + mineral oil and the chlorothalonil were phytotoxic to gerbera plants, affecting the aspect of leaves and flowers.

A gérbera (Gerbera jamesonii) é uma das mais populares plantas ornamentais do mundo, tanto como flor de corte como de vaso. O objetivo deste trabalho foi avaliar o leite in natura no controle do oídio (Erysiphe cichoracearum) na cultura da gérbera. Foram utilizadas duas concentrações de leite de vaca in natura (8 e 16%), com e sem adição de adjuvante (óleo vegetal), três fungicidas (fenarimol -6 g i.a.100 L-1 H2O, chlorothalonil -150 g i.a.100 L-1 H2O e azoxystrobin + óleo mineral -10 g i.a.100 L-1 H2O) e testemunha. Com os dados de severidade foi calculada a área abaixo da curva de progresso da doença (AACPD). O leite in natura aplicado com o adjuvante controlou o oídio, não permitindo a instalação e o desenvolvimento do patógeno. O uso do adjuvante melhorou a eficiência do leite in natura, no entanto requer a lavagem posterior das plantas com H2O + detergente. O fungicida fenarimol promoveu melhor controle de oídio e aspecto visual das plantas de gérbera. O fungicida azoxystrobin + óleo mineral e o chlorothalonil foram fitotóxicos à planta de gérbera, o que prejudicou a aparência das folhas e flores.