Influence of soil bulk density on shoot and root traits of crotalaria

The selection of cover crop species with high potential for root growth in dense layers of soil can help in the management of agricultural systems through biological soil unpacking. This study aimed at evaluating the performance of crotalaria species (Crotalaria juncea, C. spectabilis and C. ochroleuca) as unpacking agents, in a dystrophic Oxisol under different bulk densities (1.0 Mg m-3, 1.2 Mg m-3, 1.4 Mg m-3, 1.6 Mg m-3 and 1.8 Mg m-3). All species showed reduction in the growth of shoots and roots, when cultivated in soil with bulk density higher than 1.4 Mg m-3. Crotalaria juncea showed the best results for shoot and root biomass production with bulk density up to 1.4 Mg m-3. The root growth of plants is higher in layers above and below the compacted layer

Produção de fitomassa em sistemas de produção de soja em sucessão a culturas e plantas de cobertura

The objective of this work was to evaluate the biomass (leaves and stems) production of annual and cover crops sown as second crop, and its effects on soybean yield in succession. The experiment was carried out in the 2014/2015 and 2015/2016 crop seasons. Soybean was sown in the crop season and in the second crop, in a randomized complete block design, in nine production systems (treatments) consisting of annual crops (corn, sunflower, and cowpea) and cover crops (Pennisetum glaucum, Crotalaria breviflora, C. spectabilis, Urochloa ruziziensis, Cajanus cajan, Stylosanthes sp., and U. brizantha), which were grown in monocropping or intercropping systems, besides fallow as a control. Monocropped P. glaucum and U. ruziziensis showed a faster establishment and growth of plants, higher-total biomass and soil cover rate in the 2014 crop season. In 2015, corn intercropped with U. ruziziensis and C. spectabilis, and sunflower with U. ruziziensis stood out for total biomass production during flowering and after harvesting of corn and sunflower grains. Biomass composition in the systems showed greater proportions of stems than of leaves, and C. spectabilis stood out after senescence. Sown as a second crop, C. spectabilis promotes yield increase of soybean grown in succession in the no-tillage system.O objetivo deste trabalho foi avaliar a produção de fitomassa (folhas e caules) de culturas anuais e plantas de cobertura semeadas em safrinha e seus efeitos na produtividade da soja em sucessão. O experimento foi conduzido nas safras de 2014/2015 e 2015/2016. A soja foi semeada nas safras e nas safrinhas, em delineamento de blocos ao acaso, em nove sistemas de produção (tratamentos) constituídos de culturas anuais (milho, girassol e feijão-caupi) e plantas de cobertura (Pennisetum glaucum, Crotalaria breviflora, C. spectabilis, Urochloa ruziziensis, Cajanus cajan, Stylosanthes sp. e U. brizantha), em cultivos solteiros ou consorciados, além de pousio como controle. Os cultivos solteiros de P. glaucum e U. ruziziensis apresentaram estabelecimento e crescimento mais rápido, maior fitomassa total e taxa de cobertura do solo na safra de 2014. Em 2015, o milho consorciado com U. ruziziensis e C. spectabilis, e o girassol com U. ruziziensis se destacaram na produção de fitomassa total, durante o florescimento e após a colheita dos grãos do milho e do girassol. A composição das fitomassas nos sistemas apresentou maiores proporções de caules do que de folhas, com destaque para C. spectabilis após a senescência. Semeada em safrinha, C. spectabilis promove aumento de produtividade de soja em sucessão, no sistema plantio direto

Phytomass and nutrient release in soybean cultivation systems under no-tillage

O objetivo deste trabalho foi avaliar o efeito do acúmulo de fitomassa, da cobertura do solo e da ciclagem de nutrientes promovidos por sistemas de cultivo com culturas anuais e de cobertura sobre o rendimento de grãos de soja semeada em sucessão, no Cerrado de Mato Grosso. O experimento foi conduzido em delineamento de blocos ao acaso, com nove sistemas de cultivo e quatro repetições, em duas safras. Em 2014/2015, foram avaliadas forrageiras gramíneas e leguminosas, além de tratamentos em pousio. Já em 2015/2016, avaliaram-se forrageiras e leguminosas consorciadas ou não com milho ou girassol e pousio; o plantio da soja foi avaliado após as culturas de cobertura. Foram determinados a fitomassa, a cobertura do solo e a ciclagem de nutrientes proporcionados pelos sistemas de cultivo, bem como a massa e o rendimento da soja. Urochloa ruziziensis solteira ou em consórcio, quando comparada aos sistemas em pousio, promove incrementos significativos na produção de fitomassa, na cobertura do solo e na ciclagem de nutrientes, com aumento no rendimento de grãos de soja em sucessão. N e K são os nutrientes mais acumulados na parte aérea das culturas de cobertura e são liberados em maior quantidade no solo, nos dois anos de avaliação. Crotalaria spectabilis promove aumento no rendimento de grãos de soja na safra 2015/2016, em comparação a U. ruziziensis, pelo sincronismo entre liberação e absorção de N sob plantio direto. The objective of this work was to evaluate the effect of phytomass accumulation, soil cover, and nutrient cycling promoted by cultivation systems with annual and cover crops on the grain yield of soybean sown in succession in the Cerrado, in the state of Mato Grosso, Brazil. The experiment was carried out in a randomized complete block design with nine cultivation systems and four replicates, in two crop seasons. In 2014/2015, forage grasses and legumes were evaluated, besides fallow treatments. In 2015/2016, forage and legume intercropped or not with corn or sunflower and fallow were assessed; the soybean crop was evaluated following cover crops. Phytomass, soil cover, and nutrient cycling provided by cultivation systems, as well as soybean mass and yield, were determined. Urochloa ruziziensis alone or intercropped, compared with the fallow systems, promotes significant increases in phytomass production, soil cover and nutrient cycling, with an increase in the grain yield of soybean planted in succession. N and K are the most accumulated nutrients in the aerial part of the cover crops and are released in larger quantities in the soil in the two years of evaluation. Crotalaria spectabilis promotes an increase in soybean yield in the 2015/2016 crop season, compared with U. ruziziensis, due to the synchronism between N release and uptake under no-tillage system

Biomass yield in production systems of soybean sown in succession to annual crops and cover crops

<div><p>Abstract: The objective of this work was to evaluate the biomass (leaves and stems) production of annual and cover crops sown as second crop, and its effects on soybean yield in succession. The experiment was carried out in the 2014/2015 and 2015/2016 crop seasons. Soybean was sown in the crop season and in the second crop, in a randomized complete block design, in nine production systems (treatments) consisting of annual crops (corn, sunflower, and cowpea) and cover crops (Pennisetum glaucum, Crotalaria breviflora, C. spectabilis, Urochloa ruziziensis, Cajanus cajan, Stylosanthes sp., and U. brizantha), which were grown in monocropping or intercropping systems, besides fallow as a control. Monocropped P. glaucum and U. ruziziensis showed a faster establishment and growth of plants, higher-total biomass and soil cover rate in the 2014 crop season. In 2015, corn intercropped with U.ruziziensis and C.spectabilis, and sunflower with U.ruziziensis stood out for total biomass production during flowering and after harvesting of corn and sunflower grains. Biomass composition in the systems showed greater proportions of stems than of leaves, and C.spectabilis stood out after senescence. Sown as a second crop, C. spectabilis promotes yield increase of soybean grown in succession in the no-tillage system.</p></div