Cover crops biomass yield grown as a 2nd summer crop in relation to sowing periods

Abstract

The aim of this study was to evaluate cover crop precocity and biomass yield growth as a 2nd summer crop after soybean at different sowing periods (January 2nd; February 2nd and March 2nd at 2019 and January 27th and March 3rd at 2020). Experiment was laid out as a randomized block design in a 3x3 factorial for each sowing period, in the 2019 and 2020 off-seasons, being factor A represented by the cover crops (Urochloa brizantha cultivar Xaraés, Crotalaria juncea cultivar IAC-KR-1 and Pennisetum glaucum cultivar ANm 38,) and factor B by the evaluation periods along cover crops development cycle. There was an interaction between cover crops and evaluation period for plant height and dry matter yield for both years. C. juncea and P. glaucum showed faster growth, regardless of the evaluation period and sowing periods, compared to U. brizantha in both years. Cover crop biomass yield reduced as sowing period is delayed from January to March to an extend that P. glaucum yield dropped from 14.6 to 4.2 t DM ha-1 at 2019 and from 14.4 to 6.9 t DM ha-1 at 2020 as a result shorter photoperiod and lower temperature. The same was noticed to U. brizantha and C. juncea which showed yields of 11.676 and 8.800 and 2.220 and 2.555 kg ha-1 at April 29th of 2019 and 12.507 and 7.812 and 3.041 and 2.346 kg DM ha-1 at June 18th 2020 respectively for January and March sowing periods. U. brizantha and C. juncea are more viable 90 days, while P. glaucum showed the fastest dry matter accumulation rate. All species are viable due to the benefits they provide to the productive system, which becomes more diversified and therefore more sustainable