Advanced Journal of Agricultural Research (AJAR) ISSN: 2367-9816, Vol. 8 (3), pp. 226-236, July, 2021.  © Advanced Scholars Journals

Full length Research paper

Crop Diversification to Enhance No-Till System in the Brazilian Savannah

*1Spehar CR, Trecenti R2

*1University of Brasília (UnB), Faculty of Agronomy and Veterinary Medicine (FAV), C. Postal 4508, CEP 70910-970, Brasília-DF, Brazil

2Campo Consultancy/Agribusiness SEPN 516 Conj A 49, Sala 424, CEP 70770-521, Brasília-DF, Brazil

*Corresponding Author email: spehar@unb.br

Accepted 7 September, 2019.

Abstract 

Agricultural systems in the Brazilian Savannah have been dominated by monoculture of soybeans [Glycine max (L.) Merrill]. Diversification would provide positive attributes including high carbon sequestration, soil quality, disease control, water use efficiency, and producer income. The objective of this work, conducted in savannah farm for two years on Ferralsol, was to evaluate grain and forage species, relay cropped on no-till soybeans at reproduction and drill planted after soybean harvest. Seeds of the C4 plant species and cultivars, grain amaranth (Amaranthus cruentus) cv. “BRS Alegria”, finger millet (Eleusinecoracana), pearl millet (Pennisetum glaucum) cv. “BN 2”, Sorghum bicolor cv. “BR 501” (grain), S. bicolor cv. “AG 2501” (forage) and the perennial grasses Urochloa brizantha cv. “Marandu”, U. brizantha cv. “Xaraés” and U. ruziziensis, were spread over soybean at the R5, R6 and R7 reproductive sub-periods, in three densities. Rainfall data were collected and used to relate with crop performance. Plant number and height, dry matter yield and soil shading rate defined crop response to canopy shade at early growth. Pearl millet, forage sorghum, finger millet, grain sorghum, the pasture species and grain amaranth ranked for dry matter yield, between 6.5 and 2.7 Mg ha-1, proportional to soil shading. Biomass obtained from sowing at R6 and R7, 30-50 days before harvest, utilized residual moisture for carbon sequestration and soil protection, causing no interference in soybean yield. Poor performance on drilling after soybean harvest was related to drought stress. It is concludedthat continuous soil cover in no-till system is achievable by crop species seed broadcasted over soybeans at the reproductive phase. Performance of monocots was ascribed to their tillering and exponential growth under direct sunlight. In dicotyledonous grain amaranth stand is attainable by adjusting sowing density. The effective use of residual moisture stimulate studies on shade tolerance  at early growth and water use, including innovative, small-seeded, crops such as quinoa, buckwheat, sesame, tef and kenaf. On-farm relay cropping experiments shall lead to pursuit of technology, associating commercial production and soil quality on sustainable basis.

Key-Words: soybean, relay cropping, over sowing, yield, soil cover, canopy shade