Luiz Guilherme Medeiros Pessoa

Freshwater scarcity and soil salinization are major constraints to agricultural production in semiarid regions, requiring irrigation strategies that enable the use of saline water while maintaining crop performance. This study evaluated the interactive effects of irrigation scheduling and organic manure application on soil salinity, physiological responses, biomass accumulation, and quinoa (Chenopodium quinoa Willd.) production under saline irrigation in the Brazilian semiarid region. A field experiment was conducted using three irrigation shifts-(IS) (48, 72, and 120 h) and four organic matter–cattle manure (OM) rates (0, 15, 30, and 60 t ha⁻¹), arranged in a 3 × 4 factorial scheme with four replications. Plant growth, leaf area index (LAI), stomatal conductance (gs), transpiration (E), fresh and dry biomass, harvest index (HI), and soil electrical conductivity (EC) were evaluated. Quinoa responses to organic manure depended on irrigation scheduling. The 120 h interval promoted greater phytomass accumulation, while intermediate manure rates (15–30 t ha⁻¹) improved plant growth and leaf area index (LAI) under longer irrigation intervals. The treatments did not result in soil salinization at the end of the crop cycle. These findings indicate that combining irrigation scheduling with organic manure management can support quinoa production under saline irrigation in semiarid environments.

Drought is a striking feature of the semiarid region and is part of the region’s natural climate variability. According to climate change projections, it will continue to occur and will probably in...

Onions are a vegetable of great importance worldwide, and the production has been growing in several regions of the Country, especially in the Northeast Region. Vale do São Francisco Region in Pernambuco is considered to have great agricultural potential, attracting significant investments in agriculture. Post-harvest conservation is important for the commercialization of onions, which exhibit large price variations. This study aims to evaluate the characteristics and post-harvest losses of open-pollinated cultivars and commercial hybrids. The experiment was carried out on HORTIVALE-Sementes do Vale farm in the city of Petrolina-PE. The experimental design used was randomized blocks with eight open-pollinated cultivars and commercial hybrids with three replications. After harvesting, the bulbs were stored under uncontrolled ambient conditions for 75 days. We observed that the bulbs stored at ambient temperature showed significant mass losses in relation to storage time, mainly after 45 days. The authors verified that most cultivars showed good characteristics, in relation to shelf life and bulb quality concerning commercial interests, after 40 days of storage at uncontrolled ambient temperature.

Salinity poses a significant challenge in modern agriculture, often inhibiting growth and yield, especially in sensitive crops like onions (Allium cepa L.). This study evaluated the effectiveness of a freshwater-algae-based biostimulant on two onion cultivars, Franciscana IPA-10 and Vale Ouro IPA-11, to mitigate saline irrigation’s adverse effects. Five biostimulant concentrations (0, 1, 2, 3, and 4 mL L⁻¹, applied to the soil) were tested, along with two foliar treatments at 2 mL L⁻¹ as controls. Our findings showed that applying 4 mL L⁻¹ to the soil boosted growth rates to 1.0 cm per day (1), increased the potassium-to-sodium ratio in bulbs, and improved both average bulb weight by 25.11% and overall productivity by 24.28%, relative to untreated conditions. These results suggest that the biostimulant at 4 mL L⁻¹ is an effective method to enhance resilience to saline stress and increase productivity in the IPA-10 and IPA-11 cultivars. However, while the biostimulant improved plant performance, it did not counteract the accumulation of salts in the soil. Therefore, additional management practices such as leaching and drainage are recommended to ensure sustainable onion production under saline water irrigation.

Water quality affects soils by promoting their degradation by the accumulation of salts that will lead to salinization and sodification. However, the magnitude of these processes varies with soil attributes. Saturated hydraulic conductivity (K_sat) is the rate at which water passes through saturated soil, which is fundamental to determining water movement through the soil profile. The K_sat may differ from soil to soil according to the sodium adsorption ratio (SAR), water electrical conductivity (EC_w), soil texture, and clay mineralogical assemblage. In this study, an experiment with vertical columns and constant-load permeameters was conducted to evaluate changes in soil K_sat with waters comprising five EC_w values (128, 718, 1709, 2865, and 4671 µS cm⁻¹) and five SAR values [0, 5, 12, 20, and 30 (mmol_c L⁻¹)^0.5] in combination. Horizons from nine northeastern Brazilian soils (ranging from tropical to semiarid) were selected according to their texture and clay mineralogical composition. The data obtained were fit with multiple regression equations for K_sat as a function of EC_w and SAR. This study also determined the null SAR at each EC_w level, using K_sat = 0 on each equation, to predict the SAR needed to achieve zero drainage on each soil for each EC_w level and the threshold electrolyte concentration (C_TH) that would lead to a 20% reduction of maximum K_sat. Neither the EC_w nor SAR of the applied waters affected the K_sat of soils with a mineralogical assemblage of oxides and kaolinite such as Ferralsol, Nitisol, and Lixisol, with an average K_sat of 2.75, 6.06, and 3.33 cm h⁻¹, respectively. In smectite- and illite-rich soils, the K_sat increased with higher EC_w levels and decreased with higher SAR levels, especially comparing the soil’s estimated K_sat for water with low EC_w and high SAR in combination (EC_w of 128 µS cm⁻¹ and SAR 30) and water with high EC_w and low SAR in combination (EC_w of 4671 µS cm⁻¹ and SAR 0) such as Regosol (4.95 to 10.94 cm h⁻¹); Vertisol (0.28 to 2.04 cm h⁻¹); Planosol (0 to 0.29 cm h⁻¹); Luvisol (0.46 to 2.12 cm h⁻¹); Cambisol (0 to 0.23 cm h⁻¹); and Fluvisol (1.87 to 3.34 cm h⁻¹). The C_TH was easily reached in soils with high concentrations of highly active clays such as smectites. In sandy soils, the target C_TH was only reached under extremely high SAR values, indicating a greater resistance of these soils to salinization/sodification. Due to their mineralogical assemblage, soils from tropical sub-humid/hot and semiarid climates were more affected by treatments than soils from tropical humid/hot climates, indicating serious risks of physical and chemical degradation. The results showed the importance of monitoring water quality for irrigation, mainly in less weathered, more clayey soils, with high clay activity to minimize the rate of salt accumulation in soils of the Brazilian semiarid region. Our study also proved that clay mineralogy had more influence on the K_sat than clay concentration, mainly in soils irrigated with saline and sodic waters, and that soils with highly active smectite are more prone to degradation than soils with high concentrations of kaolinite.

This study aimed to identify genotypes that present better agronomic performance by evaluating the genotype x sowing time interaction in a no-tillage system in the semiarid region of Pernambuco. The experimental design was a randomized block design, in a 7x4 factorial scheme, with four replications, the first factor being the seven hybrids (1-BM 815 PRO3; 2- BM 930 PRO 3; 3-SHS 7939 PRO3; 4-SHS 8525PRO3; 5-B2856 VYHR; 6- B2612 PWU and 7- B2433 PWU) and the second the four sowing dates (1- 04/03/2024; 2-11/03/2024; 3-18/03/2024 and 4-25/03/2024). The agronomic and yield parameters of the corn hybrids were evaluated. It was concluded that the principal component analysis showed that the sowing dates influenced the agronomic characteristics of the corn hybrids mainly due to temperature, rainfall and relative humidity; the hybrids that presented greater productive stability due to the different sowing dates were B2612PWU and SHS7938PRO3; the dendrogram showed that there was a phenotypic distinction between the hybrids and separated them into three distinct groups according to their agronomic characteristics; the sowing date influences the agronomic characteristics of corn hybrids.

The conversion of caatinga vegetation areas into pastures in the Brazilian semiarid region has depleted soil fertility due to degradation. The natural regeneration of the caatinga has been the alternative adopted to restore soil fertility. However, the real effectiveness of this practice in recovering organic carbon (SOC) and nutrient stocks is unknown. This work evaluated the effect of natural regeneration of the caatinga vegetation on the restoration of levels and stocks of SOC, N, and P as a strategy to maintain the sustainability of the environment. We collected soil samples every 5 cm, up to 20 cm deep, in areas of degraded pasture, caatinga in regeneration (10 years), and regenerated caatinga (35 years) to evaluate the levels and stocks of SOC, N, and P. The depth significantly affects the levels and stocks of SOC, N, and P. Stocks and levels of SOC, N, and P were higher in regenerated caatinga > regenerating caatinga > degraded pasture. The regenerated caatinga increased SOC, N, and P stocks by 115%, 110%, and 117%, respectively, compared to the degraded pasture. Although 35 years of regeneration of the caatinga has improved soil fertility, the levels and stocks of SOC, N, and P remain low.

The conversion of caatinga vegetation areas into pastures in the Brazilian semiarid region has depleted soil fertility due to degradation. The natural regeneration of the caatinga has been the alternative adopted to restore soil fertility. However, the real effectiveness of this practice in re-covering organic carbon (SOC) and nutrient stocks is unknown. This work evaluated the effect of natural regeneration of the caatinga vegetation on the restoration of levels and stocks of SOC, N, and P as a strategy to maintain the sustainability of the environment. We collected soil samples every 5 cm, up to 20 cm deep, in areas of degraded pasture, caatinga in regeneration (10 years), and regenerated caatinga (35 years) to evaluate the levels and stocks of SOC, N, and P. The depth sig-nificantly affects the levels and stocks of SOC, N, and P. Stocks and levels of SOC, N, and P were higher in regenerated caatinga > regenerating caatinga > degraded pasture. The regenerated caatinga increased SOC, N, and P stocks by 115%, 110%, and 117%, respectively, compared to the degraded pasture. Although 35 years of regeneration of the caatinga has improved soil fertility, the levels and stocks of SOC, N, and P remain low.

Silicon is known to be an effective salt stress attenuator for crops, and evaluating its application effectiveness in combination with other salt stress attenuators is essential for crops and soils. This work aimed to assess whether applying organic matter (OM) and Trichoderma (T) potentiates silicon (Si) in mitigating soil salinization and promoting quinoa growth under salt stress. Quinoa plants were grown in pots under saline irrigation (3.12 dS m⁻¹) and subjected to the following treatments: quinoa only; quinoa + Si; quinoa + Si + OM; quinoa + Si + T; and quinoa + Si + OM + T, at two levels of soil moisture—30 and 80% of the available water content (AWC). Sixty days after transplanting, soil and quinoa plants were collected from the pots. At 80% AWC, Si + OM and Si + OM + T promoted the highest fresh mass for quinoa—301.54 and 247.26 g, respectively. Si + OM + T significantly mitigated saline parameters (EC = 9.82 dS m⁻¹; ESP = 32.27%). Si combined with OM and T was the most effective way to attenuate salt stress in quinoa and soil salinization and promote a more sustainable way to manage saline irrigation in semiarid regions.