Forages of the genus Brachiaria stand out among those used in integrated systems. Little is known about the potential value of new species and cultivars when intercropped with sorghum and planted in the second crop season. The objective of this study was to evaluate the performance (agronomic characteristics) of grain sorghum and the production and nutritional characteristics of forage plants of the genus Brachiaria in an integrated agricultural production system in the second season. The experiment had a randomized block design with four replicates. The treatments consisted of the intercropping of sorghum with forage plants of the genus Brachiaria (Ruziziensis grass, Marandu, Xaraes, Piata, Paiaguas palisadegrass and Ipypora grass), in addition to an extra treatment with sorghum in monoculture. The results showed that sorghum intercropping with Ruziziensis grass, Paiaguas palisadegrass, Piata, and Ipypora grass did not cause a reduction in grain yield. The Xaraes, Piata, and Paiaguas palisadegrass showed higher forage production. However, the Paiaguas, Piata palisadegrass, and Ipypora grass showed better nutritional value. The sorghum intercropping with forage plants of the genus Brachiaria were promising alternatives for grain and forage production in the off-season. The right forage grass combined with sorghum in an integrated system can intensify agricultural production, optimizing the use of the area and increasing sustainability.

Ensiling sorghum with tropical forages has been shown to be a promising alternative for ruminant feed production, as this approach improves the quality of the sorghum silage. In this context, the goal of this study was to evaluate the fermentation characteristics and nutritive value of sweet sorghum silage made with different levels of Paiaguas palisadegrass and Ipypora grass. The experiment was conducted in a completely randomized 2 x 6 factorial design with four replications. Two forages (Paiaguas palisadegrass and Ipypora grass) were added to sorghum at six levels (0, 20, 40, 60, 80 and 100%), for a total of 48 experimental silos. After 50 days of fermentation, the silos were opened, and the fermentation profile and chemical composition of the silage were analysed. The results showed that the addition of Paiaguas palisadegrass and Ipypora grass to the sorghum silage increased the pH, buffering capacity and NH3-NT of the silage and reduced its dry matter content but did not affect its fermentation characteristics, which remained within an appropriate range. The addition of increasing levels of Paiaguas palisadegrass and Ipypora grass to the sorghum silage increased the crude protein and in vitro dry matter digestibility (IVDMD) of the silage and decreased the fibre fraction (neutral detergent fibre, acid detergent fibre and lignin) and ether extract contents. Adding tropical forages to sorghum silage material at levels above 40% is recommended. Among forage crops, addition of Paiaguas palisadegrass to sorghum silage resulted in higher content of crude protein and IVDMD. Mixed silages can be an effective alternative to improve the quality of forage sorghum silage.

Análise de regressão para avaliar deriva de herbicidas e injúria em algodoeiro Roundup Ready em túnel de vento

Potassium (K) is the nutrient most required by sugarcane crops and is predominantly supplied through potassium chloride (KCl). However, as KCl production is highly concentrated in a few countries, Brazil—the world’s largest sugarcane producer—relies heavily on imported K fertilizers. In this context, identifying alternative sources, even if also imported, is strategic to diversify supply and reduce the risks associated with dependence on a single product. This study evaluated the performance of polyhalite, a natural multinutrient mineral, compared with KCl, as an alternative fertilizer for ratoon cane (CTC 4 variety) grown in a clay-textured Oxisol in Jataí, Brazil. A two-year field experiment was conducted evaluating four treatments: control (without K fertilization), KCl, polyhalite, and a 25/75 polyhalite + KCl blend. Potassium fertilization increased culm yield by about 38–61% compared with the unfertilized control. In addition, the association of polyhalite + KCl promoted greater plant height compared to the treatment without K fertilization and, when comparing the K sources applied alone, polyhalite promoted a larger culm diameter and a higher leaf S content than KCl. These results demonstrate the agronomic advantages of polyhalite and its blends for sugarcane fertilization, which reiterates their potential as efficient and sustainable alternatives to KCl and as part of a broader strategy for fertilizer-source diversification.

Polyhalite is a potential alternative source of potassium (K) for sugarcane cultivation. Its lower solubility, compared to potassium chloride (KCl), suggests it may act as a slow-release fertilizer, providing residual benefits to subsequent crops. This study aimed to assess the residual effects of polyhalite on the soil following two cycles of potassium fertilization in ratoon cane, in comparison with KCl. The treatments included a control (no K fertilization) and K sources applied individually (polyhalite or KCl) or in combination (polyhalite + KCl). The polyhalite performed similarly to KCl and led to the highest K levels in the 0-20 cm soil layer after two sugarcane harvests. For the sulfur (S) content, the polyhalite significantly outperformed all other treatments, with the highest concentrations in the 0-20 and 20-40 cm layers. On the other hand, the supply of calcium and magnesium from polyhalite did not result in higher soil levels of these nutrients, with no significant differences among the evaluated sources. These findings highlight the residual benefits of polyhalite application, particularly for S, which may be beneficial for sugarcane or any subsequent crops.

A resistência de plantas daninhas a herbicidas demanda novas estratégias de manejo químico da comunidade intraespecífica, visto sua capacidade de interferência em sistemas de cultivo. Objetivou-se avaliar a eficácia de inibidores da ACCase aplicados em mistura ou sequencial com o herbicida 2,4-D, como alternativas de controle de capim-amargoso. O delineamento experimental foi em blocos casualizados, com onze tratamentos e quatro repetições, entre 2015 e 2016. Os manejos foram compostos pelos herbicidas cletodim, haloxifope-p-metílico, fenoxaprope-p-etílico, quizalofope-p-etílico e fluazifope-p-butílico em mistura ou sequencial com 2,4-D, além de aplicações de paraquate e dos graminicidas associados ao glyphosate em todos os tratamentos. Foram realizadas avaliações visuais de controle aos 5 dias antes da semeadura (DAS), e com 0; 10; 20; 40; 50 e 65 dias depois da semeadura (DDS) para determinar o controle de capim-amargoso. A aplicação dos herbicidas cletodim e haloxifope-p-metílico em mistura ou sequencial com 2,4-D não diferem no controle das plantas de capim-amargoso. A aplicação dos herbicidas fenoxaprope-p-etílico, quizalofope-p-etílico e fluazifope-p-butílico em sequencial com o herbicida 2,4-D apresentaram maior controle quando comparada com a aplicação dos mesmos em mistura com 2,4-D. O herbicida fluazifope-p-butílico em mistura com 2,4-D não é indicado para o controle de capim-amargoso.