Vegetables such as those found in the Brassicaceae plant family are grown in a conventional farming method, with intensive tillage and use of high solubility fertilizers and agrochemicals (^{Torres et al., 2017}). These plants present high rates of nutrient extraction from the soil, requiring high amounts of mineral fertilizers in short periods, becoming crops highly dependent on industrialized inputs. However, ^{Altiere & Nicholls (2003)} emphasize that the intensive use of mineral fertilizers in high quantities can cause the nutritional imbalance of plants and influence the quality of production.

So-called specialty corn varieties (popcorn, green, sweet and baby corn) derive from a common ancestor and are gaining ground among Brazilian growers because they attract different markets when compared to common maize. It can also be consumed fresh or industrially processed (^{Souza et al., 2013}).

Biostimulants currently available on the market include those containing seaweed extract. There is sufficient scientific evidence to conclude that applying biostimulants to agricultural crops can positively impact plant growth and yield. However, results differ between plants species and environmental conditions. As such, the present study aimed to assess the effects of doses and application times of a biostimulant based on seaweed (Ecklonia maxima) extract on the morphology and yield of soybean crops. The experiment was conducted in a field in the municipality of Uberaba, Minas Gerais state (MG), Brazil, in dystrophic red latosol. A randomized block design was used, with four repetitions, in a 3 x 5 factorial scheme consisting of three application times (phenological growth stages: V4, R1 and V4+R1) and five doses of foliar -applied biostimulant (0, 250, 500, 750 and 1000 mL ha-1). In general, biostimulant application influenced the number of branches, nodes, flowers, and pods on the soybean plants and, consequently, crop yield. A dose of 607 mL ha-1 promoted a 6.1% greater grain yield (5379 kg ha-1) than that obtained without biostimulant spraying (5070 kg ha-1). Application in stage R1 resulted in plants with more flowers and pods.

No-till vegetable farming is a feasible alternative to reduce erosion-induced losses and to increase soil nutrient availability, because cover crop residue protects the soil and its decomposition promotes nutrient cycling, which can improve the yield of the subsequent crop. The present study assessed the production and decomposition of cover crops and the agronomic performance of broccoli grown on this residue using different nitrogen doses in a no-till system. A randomized block design was used, in a split-split plot arrangement of main plots (cover crops), sub-plots (N doses) and sub-sub plots (decomposition times), with four repetitions. Seven cover crops were studied, as follows: [1) signal grass (SG); 2) sunn hemp (SH); 3) pearl millet (PM): 4) SG+SH; 5) SG+PM; 6) SH+PM and 7) SG+SH+PM]; in addition to four doses of nitrogen topdressing [T1) no N application (control); T2) 60 kg/ha N; T3) 90 kg/ha N and T4) 120 kg/ha N]; and five cover crop residue decomposition times: zero (cutting), 15, 30, 60 and 90 days after transplanting (DAT) the broccoli seedlings. Cover crop dry weight (DW) production, residue decomposition, and the head fresh (HFW) and dry weight (HDW) and yield (YLD) of broccoli were assessed. Among the cover crops, sunn hemp and the intercropped SG+SH treatment exhibited the lowest DW production and, along with signal grass, the shortest half-life (T½) and highest residue decomposition rate. The best-performing broccoli plants were those grown using PM, SH and a combination of both as cover crops. The highest broccoli production was obtained using sunn hemp residue, regardless of nitrogen topdressing, with HFW of 788 g/plant and YLD of 30 t/ha.

Objective: To evaluate the dry mass production of coverings and the productivity of corn and soybeans grown in succession. Method/design/approach: In a randomized block design, with subdivided plots, four covers were evaluated: Sunn hemp, Pearl millet, Signal grass and fallow; at two times of the year: spring and autumn/winter, with 4 repetitions. After cover management, the plots were subdivided, then corn and soybeans were sown on the residues of these plants. The dry mass production of the coverings and the productivity of corn and soybeans in each harvest were evaluated.   Result and conclusion: Pearl millet and Sunn hemp were the covers with the highest dry mass production, with Sunn hemp residues positively influencing the production of corn grown in succession and none of the plants used affected soybean production. Corn and soybean production increased as the system stages evolved until reaching the consolidation stage. Research implications: the study proves that residues from different coverings that are used in rotation with corn can affect its productivity, especially when the covering comes from a Fabacea, as there is more nitrogen available in the soil in these areas, which come from of biological fixation carried out by these plants, while the same does not happen with soybeans. Originality/value: The search for maintaining or increasing crop production using a more conservationist management system in the cerrado is a constant, a condition that is achieved when the appropriate cover plant is chosen.

O presente estudo objetivou avaliar os efeitos de doses de K em atributos morfológicos, produtivos e qualitativos do sorgo sacarino. O experimento foi conduzido em campo em Latossolo Vermelho com teor inicial de 0,6 mmol_c dm^-3 de K. Adotou-se o delineamento em blocos casualizados com cinco tratamentos (0, 50, 100, 150 e 200 kg ha^-1 de K₂O) e quatro repetições. Avaliaram-se: diâmetro de colmos, altura de plantas, teor de K na folha e no caldo, produção de colmos e de caldo e concentração de açúcar total no caldo. Os dados foram submetidos à análise de variância e de regressão polinomial. O fornecimento de K incrementou linearmente o diâmetro do colmo e aumentou a altura de plantas até a dose de 152 kg ha^-1 de K₂O. O maior diâmetro e altura foi, respectivamente, 18,1 mm e 2,73 m. A adubação potássica não afetou o teor de K nas folhas, mas elevou a produção de colmos até 32.454 kg ha^-1 com aplicação de 132 kg ha^-1 de K₂O. Houve incremento linear na produção de caldo, chegando-se a 7.322 L ha^-1. A dose de, aproximadamente, 100 kg ha^-1 de K₂O proporcionou as maiores concentrações de açúcar total (62,7 mg L^-1) e K no caldo (1.144 mg L^-1). Palavras-chave: Sorghum bicolor, biocombustível, adubação potássica. POTASSIUM RATES FOR SWEET SORGHUM CULTIVATED FOR ETHANOL PRODUCTION   ABSTRACT: The objective of this study was to evaluate the effects of K rates on morphological, productive and qualitative attributes of sweet sorghum cultivated for ethanol production. The experiment was conducted in field conditions in a cerrado soil with 0.6 mmol_c dm^-3 of K. The randomized block design with five treatments (0, 50, 100, 150 and 200 kg ha^-1 of K₂O) and four replicate was adopted. The following variables were evaluated: stem diameter, plant height, leaf and juice K content, stem and juice yield, and total sugar concentration in the juice. Data were submitted to analysis of variance and polynomial regression. The K supply linearly increased stem diameter and increased plant height up to the 152 kg ha^-1 of K₂O rate. The largest diameter and height were, respectively, 18.1 mm and 2.73 m. Potassium fertilization did not affect the leaves K content, but increased stem yield up to 32,454 kg ha^-1 with application of 132 kg ha^-1of K₂O. There was a linear increase in juice yield, reaching 7,322 L ha^-1. The rate of approximately 100 kg ha^-1 of K₂O provided the highest total sugar (62.7 mg L^-1) and K concentrations in the juice (1,144 mg L^-1). Keywords: Sorghum bicolor, biofuel, potassium fertilization.