Plantas de cobertura em sistema de produção orgânica de milho verde na região oeste do Paraná

Abstract

Soil cover plants play an essential role for the no-tillage system and especially for an organic production system. Alternating soil cover plants with crops of economic interest is indispensable when seeking a sustainable production system.Thus, the objective was to evaluate the performance of radish turnip and black oat cultivated as winter cover plants in single crops and consortia with different sowing densities, soil protection and productivity of subsequent green corn crop in organic production system in western Paraná. The experiment was developed 2019 and 2020 at the Experimental Station of the Federal Technological University of Paraná, Campus Santa Helena, being arranged in a randomized block design, with five treatments and three replications. The treatments consisted of systems using the intercropping between radish turnip and black oat, at different sowing densities for each species, as well as the respective species in exclusive cultivation (single), being: Black Oats (AP 100%); Radish turnip - NF (100%); Black Oats 25% + Radish Turnip 75% (AP 25% + NF 75%); Black Oats 50% + Radish Turnip 50% (AP 50% + NF 50%) and Black Oat 75% + Radish Turnip 25% (AP 75% + NF 25%). Evaluations were made regarding the soil coverage rate, production of green matter (MG) and dry matter (DM), decomposition and C/N ratio of DM of the cover plants. In corn, the characteristics were evaluate dregarding the productivity of green corn ears, total productivity of green corn with straw, average weight of ears with straw, average length of spread ears and diameter of spread ears. For soil cover rate in 2019 at 49 days after emergence (DAE) of cover plants, and in 2020 to 28 DAE, all treatments exceeded 60% of soil cover, presenting a high potential for soil protection. The lowest MG production for both years was the isolated cultivation of black oat, produced 6.8 and 19.0 Mg ha-1 differing from the other treatments. The highest rate of decomposition occurred at 24 days after placement (DAP) of litter bags in the field, remaining on the soil surface on average 84% of DM in 2019 and 77% of DM in 2020. The average productivity of green corn ears in the first year was 5.02 Mg ha-1 and in the second year 7.64 Mg ha-1. And in relation to thelength and diameter of the ears, all treatments tested in both years were considered commercialable. Even though the work being carried out in the first two years of establishment of the no-tillage system with organic production of green corn,and under atypical climatic conditions, presented results that indicated potential for the use of consortia between species for straw intake in the system and production of green corn.