Production of lettuce seedlings in substrates with tung compost, carbonized rice husk and earthworm humus

Abstract

Different properties of substrates based on tung compost (TC), carbonized rice husk (CRH) and earthworm humus (H) were analyzed, besides the effect of the formulations on the production of lettuce seedlings, cv. Veneranda. The experiment was carried out in Pelotas, Rio Grande do Sul State, Brazil, from December 2012 to February 2013, in a greenhouse, using completely randomized design with seven treatments and three replications. The used substrates were formulated on a volume basis: T1= commercial substrate S10 ® (control); T2= 90% carbonized rice husk (CRH) + 10% humus (H); T3= 75% CRH + 15% tung compost (TC) + 10% H; T4= 55% CRH + 35% TC + 10% H; T5= 35% CRH + 55% TC + 10% H; T6= 15% CRH + 75% TC + 10% H; T7= 90% TC + 10% H. Seedlings were produced in polystyrene trays with 200 cells, being evaluated 35 days after sowing. The substrate with larger proportion of CRH (T2 with 90% CRH) showed suitable dry density (DD) and total porosity (TP), high pH and aeration space (AS), low easily available water (EAW), electric conductivity (EC), and nutrient content, constituting an inert substrate, not being indicated as substrate due to the lower development of the seedlings. Using 15% TC, an increase was noticed in DD, AEW, EC and nutrients and, a decrease in TP, AS and pH due to, mainly, the size of tung compost particles, which accommodated themselves and altered physical and chemical properties of the substrates. Substrates with 90% and 75% TC (T7 and T6) provided the greatest shoot length, fresh and dry shoot mass and leaf area for lettuce seedlings due to higher nutrient content, also considering physical and chemical properties of these substrates. Pure CRH is not indicated to be used as substrate, but mixed with tung compost (T6), it provides high quality seedlings. Tung compost was effective in producing lettuce seedlings, since the composting is able to eliminate phytotoxic substances from this material which can hinder the seedling growth.Keywords: Lactuca sativa, Aleurites fordii, chemical and physical properties. RESUMOProdução de mudas de alface em substratos com composto de tungue, casca de arroz carbonizada e húmus de minhoca Analisou-se diferentes características em substratos a base de composto de tungue (TC), casca de arroz carbonizada (CRH) e húmus de minhoca (H), assim como, o efeito das formulações na produção de mudas de alface, cv. Veneranda. O experimento foi realizado no município de Pelotas-RS, de dezembro de 2012 a fevereiro de 2013, em casa de vegetação, utilizando delineamento experimental inteiramente casualizado com sete tratamentos e três repetições. Os substratos utilizados foram formulados em base de volume: T1= substrato comercial S10 ® (controle); T2= 90% CRH + 10% H; T3= 75% CRH + 15% TC + 10% H; T4= 55% CRH + 35% TC + 10% H; T5= 35% CRH +55% TC+10% H; T6= 15% CRH + 75% TC + 10% H; T7= 90% TC + 10% H. As mudas foram produzidas em bandejas de poliestireno expandido de 200 células e, aos 35 dias após a semeadura, foram avaliadas. O substrato com maior proporção de CRH (T2 with...

REUTILIZATION OF RESIDUES AS COMPONENTS OF SUBSTRATE FOR THE PRODUCTION OF Eucalyptus grandis SEEDLINGS

“…This condition infl uenced the physical characteristics of the substrates, as it was possible to observe for the CPK, in which, the increase in the mixtures was directly related to the DD (dry density), and inversely related to the TP (total porosity), condition opposite to the CRH and HRH (Figure 1). The CRH is a component recognized for increasing the AE, in relation to the materials available in the market (Vieira;Pauletto, 2009;Faria et al, 2013;Watthier et al, 2017), and when added up to 30%, showed the same behavior as CPK ( Figure 2B), which highlights the peach kernel residue as potential to increase the aeration space, conditioning the drainage. On the other hand, when DD is observed, the use of the highest proportions of CPK are not suitable for containers conventionally used for Eucalyptus seedlings ( seedlings ( 12 cm height), but for containers with a height between 20 and 30 cm (Kämpf, 2005).…”

“…However, the rice husk can also be used as a conditioner (secondary component), which is used to a lesser extent to improve the characteristics of the main component of the substrate. This component has been tested in the production of several plants, especially flowers, vegetables and seedlings of tree species (Rota;Pauletti, 2008;Wendling, 2016;Zavistanovicz et al, 2017;Watthier et al, 2017).…”

Hydrogel Changes the Air-Water Ratio of Plant Substrates

“…For available water, the carbonized rice husk presented extremely low value (6%), which is related to a high percentage of macropores and consequently provide low water holding capacity and high drainage in this material. Therefore, Watthier et al (2017) do not recommend the use of pure carbonized rice husk as a substrate for use in the production of seedlings, due to the low amount of available water.…”

Hydro-Physical Characteristics of Substrates for Lettuce Production in Floating Growth System

“…Rice husk, in its carbonized form, has been used as a structural element in formulations of substrates, conferring high macroporosity, being necessary to combine it with higher microporosity materials to balance the solid-pore ratios of the substrate (KRATZ; WENDLING, 2016). Several studies have indicated the use of rice husk as a component of substrates for plants growth (COSTA et al, 2017;WATTHIER et al, 2017;MENEZES JÚNIOR;VIEIRA NETO;RESENDE, 2018;TERRA et al, 2018), making up most of the commercial substrates available in the market of southern Brazil.…”