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Integrated crop–livestock systems (ICLS) have sustainably intensified modern agricultural practices worldwide. This research assessed how production systems and crop types impact the chemical properties of an Oxisol in the Brazilian Cerrado, the grain yield of corn intercropped with palisade grass (Urochloa) in the off-season in an ICLS, and the grain yield (GY) of soybean in succession. Intercropped and monocropped systems were assessed in a three-year field experiment: corn + Urochloa ruziziensis–soybean; corn + U. brizantha cv. Piatã–soybean; corn + U. brizantha cv. Paiaguás–soybean (ICL–Paiaguás); corn–soybean under a no-tillage system (NTS); corn–soybean under a conventional tillage system (CTS); Piatã grass–continuous grazing (Perennial Piatã); and Paiaguás grass–continuous grazing (Perennial Paiaguás). The residual impact of phosphate fertilization was more pronounced in the ICLS treatments. In the soil layer from 0.0 to 0.2 m depth, ICLS–Paiaguás and Perennial Piatã had the most positive effects on soil chemical quality. In the last year, grain yield was highest in corn monoculture under the NTS and soybean in succession under the ICLS. ICL–Paiaguás improved soil chemical properties for soybean in succession. These results confirm that an intermittent pasture system for legume crops in sequence is an alternative that can maintain or improve soil chemical composition, and that CTS should be avoided in tropical sandy soils. [ABSTRACT FROM AUTHOR]

Urea with micronised sulfur (S) in granules may result in lower nitrogen (N) depletion through ammoniacal N (N[H.sub.3]-N) loss than conventional urea due to the acidification reaction of S near urea granules in soil, and the addition of S to the urea may provide a limiting nutrient in tropical soils. The research objectives were to (1) verify whether urea containing micronised S (urea+S) can mitigate N[H.sub.3]-N volatilisation in comparison to conventional urea, ammonium nitrate, and ammonium sulfate; and (2) evaluate the efficiency of N and S sources for common bean (Phaseolus vulgaris L.) grown on coarse-, medium-, and fine-textured soil. The results showed that ~90% of N[H.sub.3]-N volatilisation occurred during the first 14 days after application. The blend of elemental sulfur and sulfate in urea reduces the loss of N by N[H.sub.3]-N volatilisation compared with regular urea but not enough to achieve the low volatilisation as observed for ammonium nitrate and ammonium sulfate application. Despite the differences in the leaf N and S concentration and bean yield components, no differences were observed among N sources in grain yield in general. Additional keywords: alternative sulfur source, nitrogen sources, no-till, nutrient uptake, soil texture. Received 4 August 2018, accepted 24 March 2019, published online 28 May 2019, Introduction Urea is the synthetic nitrogen (N) fertiliser most used in agriculture, despite its low use efficiency. The low use efficiency of urea is associated to the hydrolysis of urea [...]

The impacts of sugarcane (Saccharum spp.) production include an extensive area of cultivation, high use of technology, and the generation of by‐products that must be utilized. Achieving higher productivity while reducing the expansion of cultivation is challenging. A potential strategy for increasing sugarcane yields and productivity is the foliar application of nutrients and biostimulants at different stages of sugarcane growth. The present study assessed the impact of the foliar application of nutrients (N, B, Cu, and Zn) and a growth regulator as biostimulant (indole butyric acid, gibberellic acid, and kinetin) on sugarcane metabolism, stalk and sugar production, and quality. Field experiments were performed at 17 sites during four growing seasons (2017–2018, 2018–2019, 2019–2020, and 2020–2021) using sugarcane with three harvest times (early, mid‐late, and late harvests). The treatments were as follows: (i) no foliar application of the biostimulant and nutrients (control), (ii) foliar application of the biostimulant and nutrients at the vegetative stage (VS) of sugarcane, (iii) foliar application of the biostimulant and nutrients at the maturation stage (MS) of sugarcane, and (iv) foliar application of the biostimulant and nutrients at both the vegetative and maturation stages (VMS). Foliar application did not increase ribulose 1,5‐bisphosphate carboxylase activity but increased phosphoenolpyruvate carboxylase activity and the activities of the antioxidant enzymes. Peroxidase and catalase activities were higher, >100% and 45%, respectively, in VMS, whereas superoxide dismutase activity increased by 54% in MS compared with control. Consistent with these results, sugarcane had low hydrogen peroxide and malondialdehyde contents in VMS. In addition, the plant biometric parameters were highest in VMS, which sugarcane produced 105, 92, and 86 Mg stalk h−1 in early, mid‐late, and late harvest seasons, respectively. In summary, the foliar application of the biostimulant and nutrients efficiently promoted the growth, productivity, and quality of early, mid‐late, and late harvest seasons. The positive effects of foliar application on the enzymatic and physiological responses of sugarcane can be achieved when applications are performed in both the VMS in all harvest seasons. Core Ideas: Biostimulants are precursors of plant hormone production and its enzymatic metabolism.Foliar application at vegetative and maturation stages effectively increased sugarcane yields in all harvests.Increases in sugarcane antioxidant activity and growth were obtained by foliar application. [ABSTRACT FROM AUTHOR]

Water stress negatively impacts plant morphology and physiology by inducing metabolic oxidative stress, which leads to cellular damage. Applying nutrients and/or organic molecules, such as amino acids, may mitigate the effects of drought stress. In the present study, the effects of a protective foliar complex (PFC) on late‐harvest sugarcane (Saccharum spp L.) (dry season) were evaluated. Four field experiments were carried out in commercial areas of sugarcane production in the central‐south region of Brazil using sugarcane variety CTC4: in the fourth and second ratoons in 2019 and in the fifth and third ratoons in 2020. The treatments consisted of foliar application or no application of the PFC at the beginning of the dry period in June. The PFC was applied at a dose of 10 L ha−1 in a water volume of 100 L ha−1. PFC application increased the activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) in sugarcane leaves. PFC application also reduced leaf levels of malondialdehyde and hydrogen peroxide (H2O2). On average, PFC application increased sucrose accumulation by 2.26 and 1.74 Mg ha−1 in 2019 and 2020, respectively, indicating improved raw material quality. In addition, PFC application mitigated damage caused by drought, with average increases in stalk productivity of 10.7 and 7.6 Mg ha−1 in 2019 and 2020, respectively. The positive effects of PFC application on plant antioxidant enzymes enabled greater biomass accumulation and, in turn, higher energy cogeneration. Core Ideas: Protective foliar complex (PFC) application efficiently mitigates oxidative stress.Foliar PFC application increases sugarcane tolerance to drought.The physiological effects of PFC application increase sugarcane yields and industrial quality.PFC application favors energy cogeneration, even under water stress conditions. [ABSTRACT FROM AUTHOR]