Cover crops (CCs) have demonstrated their significance in enhancing the agronomic and economic performance of corn in succession. In this paper, we assess the agronomic responses and short-term economic returns of adopting cover crops (CCs) for corn cultivation in the sandy soils of the semiarid region of northeast Brazil, with the aim of addressing the additional challenges of CCs adoption in semiarid regions. The field study was conducted in Arapiraca, Alagoas, under no-tillage conditions for two cropping seasons. A randomized complete block design was employed, comprising six CCs (sunn hemp, spectabilis, jack bean, pigeon pea, lab lab, and millet) treatments and one fallow, with 18 replications. The CCs were cultivated for 60 days before corn planting. Drip irrigation was applied during the grain-filling stage of corn growth. Over the two cropping seasons, the biomass and nutrient cycling of the CCs, corn yield, and economic returns were determined, as well as the total organic carbon (TOC) and Mehlich-1 extractable P levels in the soil after corn harvest. The grain yields with sunn hemp, spectabilis, and jack bean were superior (~10%) to that of the fallow (7.7 vs. 7.1 Mg ha⁻¹), irrespective of the cropping season. Sunn hemp exhibited a higher biomass accumulation and ensured greater nutrient cycling, except for K, while lab lab and millet displayed a similar potential, although substantial variations were observed between seasons. Under sunn hemp and jack bean, the TOC increased by ~9%, particularly in the second season. Regarding the available P, spectabilis and jack bean exhibited the highest levels, with an increase of ~74% compared to the fallow (~31.1 vs. 17.9 mg dm⁻³). Spectabilis and lab lab demonstrated more promising results, both agronomically and economically. However, millet and sunn hemp have the potential to reduce costs over multiple cropping seasons. Therefore, the adoption of cover crops is a sustainable and economically viable agricultural practice. However, it is essential to acknowledge that our results do not represent rainfed conditions and require further investigation.

Water availability is a limiting factor for plant production, especially in Brazilian semi-arid regions. The main aim of the study was to investigate the physiological effects of drought during the fruiting stage of watermelon cultivation. A completely randomized block design with four replications and six treatments varied by the number of lateral drip tapes (1 or 2) and the duration of drought stress (0, 4, and 8 days) was used. The following parameters were evaluated: relative chlorophyll content, relative leaf water content, electrolyte leakage, CO₂ assimilation (A), stomatal conductance (g_s), internal CO₂ concentration, leaf temperature, transpiration (E), water use efficiency (WUE), carboxylation efficiency (CE), yield, thickness, diameter, length, and fruit °brix, at 4 and 8 days of drought. Drought negatively affected photosynthesis, particularly in treatments with a single dripper and 4 days of drought, resulting in reductions of up to 60% in A, 68% in g_s, 44% in E, 58% in WUE, and 59% in CE, but did not have a significant effect on watermelon yield after 4 or 8 days of irrigation. It was concluded that drought influences the physiological responses of watermelon plants, mainly in reducing photosynthesis, but does not drastically affect fruit productivity in short periods of stress.

Abiotic stresses, such as water limitation, are significant limiting factors in basil production. One alternative to mitigate the harmful effects of this stress on plants is using plant growth regulators. This study’s objective is to evaluate different doses of plant regulators in basil under water deficiency conditions. A randomized block experimental design in a factorial scheme with two factors was used: the first factor referred to the water regimes of 50% and 100% stomatal conductance, the second to different doses of the plant regulator mixture: 0 mL L⁻¹ (control), 3 mL L⁻¹, 6 mL L⁻¹, 9 mL L⁻¹, and 12 mL L⁻¹. Each treatment consisted of 12 pots per repetition. Biometric parameters, chlorophyll a fluorescence, and gas exchange were analyzed. The plant regulator positively influenced basil plants under water deficiency, with the most pronounced effects observed at the 12 mL L⁻¹ dose: a 17% increase in the number of leaves, a fourfold increase in CO₂ assimilation and carboxylation efficiency, and a sevenfold increase in water use efficiency. Therefore, the application of plant regulators on basil is recommended to mitigate the negative effects of water stress, with the most significant results observed at a dose of 12 mL L⁻¹.

The aim of this study was to evaluate the influence of different planting times and meteorological variables on the productive performance of industrial cassava in the Agreste region of Alagoas state, Brazil. The treatments were five planting dates, 25 days apart: D₁ - April 10, D₂ - May 5, D₃ - May 30, D₄ - June 24 and D₅ - July 19. The experiment was conducted from April 2021 to September 2023 (two cultivation cycles), using randomized blocks, with four replicates. The variables analyzed were agrometeorological data, crop growth and yield. In the Agreste region of Alagoas, the average daily ET₀ varies from 2.9 to 4.7 mm between the rainy and dry seasons, respectively. The average temperature of 24.3 °C meets the thermal demands of cassava cultivation. Although annual rainfall is sufficient to guarantee cassava production, it is seasonal, with a dry period from spring to summer, which compromises subsequent plantings. In the Agreste region of Alagoas, the best time to plant cassava is from April 10 to May 5, which is the beginning of the rainy season and ensures better vegetative canopy height (3.2 m), stem diameter (2.8 cm), leaf area index (3.0), maximum root length (43.1 cm), number (6.6) and yield (72.8 t ha^-1), total biomass (145 t ha^-1) and starch content (34.3%).

Cover crops have gained attention due to their potential benefits for the soil and physiological performance of subsequent crops. This study aimed to evaluate the physiological and productive aspects of maize grown in succession to cover crops in northeastern Brazil. A randomized complete block design with four repetitions was employed, in which the treatments consisted of the following cover crops: sunn hemp, spectabilis, pigeon pea, Brachiaria sp., jack bean, millet, and fallow. Physiological aspects and production components of maize were evaluated at the tasseling (VT) and smooth grain (R3) phenological stages. Millet cover increased carotenoid content in maize leaves by up to 78% at R3. Maize grown after pigeon pea, millet, and Brachiaria sp. showed up to 42% greater CO₂ assimilation efficiency compared to jack bean. Carboxylation efficiency increased by up to 34% in maize grown after millet and Brachiaria sp., while water use efficiency improved by up to 76% in maize after sunn hemp and pigeon pea at R3. Sunn hemp, spectabilis, and jack bean reduced soil temperature by 2 °C compared to fallow. The highest maize yield was observed after jack bean, with an 8% increase over fallow. These findings demonstrate the benefits of incorporating cover crops into maize cultivation systems in the semi-arid region of Brazil.

The objective of this research was to evaluate meteorological variables, water balance and agro-industrial quality of sugarcane under isolated and combined application of pH correctives and organic and mineral fertilization in planting furrows, in rainfed conditions. The statistical design used was in randomized blocks, with five replications and 8 treatments: T1 = limestone, T2 ­= agricultural gypsum; T3 = poultry litter; T4 = T1 + T2; T5 = T1 + T3; T6 = T2 + T3; T7 = T1 + T2 + T3 and T8 = conventional mineral fertilizer. The cultivar used was RB92579 and the agro-industrial quality variables studied were: brix of broth, sugarcane broth apparent sucrose, broth purity, reducing sugars, total recoverable sugars and fiber. The air temperature was not a limiting factor for the growth of sugarcane. The crop evapotranspiration, in 16 months of cultivation, was 2,054 mm. In general, the application of agricultural gypsum in the planting furrow generates higher agro-industrial quality of the sugarcane in comparison with the application of poultry litter. The agro-industrial quality of sugarcane fields cultivated with agricultural limestone and conventional fertilization does not differ significantly from the areas where agricultural gypsum is applied or the areas where poultry litter is used.