The complex ramifications of global climate change, which is caused by heightened concentrations of greenhouse gases in the Earth’s atmosphere, are deeply concerning. Addressing this crisis necessitates the immediate implementation of adaptive mitigation strategies, especially within the agricultural sector. In this context, this study aimed to assess how the supply of nitrogen (N) (0, 70, 140, and 210 kg N ha⁻¹) in the forms of ammonium nitrate and urea affects the agronomic performance, food quality, greenhouse gas emissions (GHG), and carbon footprint of potato plants. The examined hypothesis was that by precisely calibrating N doses alongside appropriate sourcing, over-fertilization in potato cultivation can be mitigated. A decline in stomatal conductance and net photosynthetic rate disturbs physiological mechanisms, reflecting in biomass production. Application of 136 kg N ha⁻¹ as urea showed a remarkable yield increase compared to other doses and sources. The highest nitrate content in potato tubers was achieved at 210 kg N ha⁻¹ for both sources, not exceeding the limit (200 mg kg⁻¹ of fresh mass) recommended for human consumption. The lowest carbon footprint was obtained when 70 kg N ha⁻¹ was applied, around 41% and 26% lower than when 210 kg N ha⁻¹ and 140 kg N ha⁻¹ were applied, respectively. The results demonstrated that over-fertilization not only worsened the yield and tuber quality of potato plants, but also increased greenhouse gas emissions. This information is valuable for establishing an effective fertilization program for the potato crop and reducing carbon footprint.

Watermelon (Citrullus lanatus) belongs to the plant family Cucurbitaceae. It is cultivated in many regions of Brazil, particularly in rainfed areas; thus, it is subject to the problems arising from irregular rainfall. Hydrogel is a soil conditioner used to retain and provide water to plants for long periods of time. Therefore, incorporating hydrogel into the soil should increase water availability for watermelon cultivation, and may be an alternative method to reduce the risk of water deficit. This study evaluated the effect of different concentrations of hydrogel on the initial growth of watermelon cv. 'Crimson Sweet' under different shading conditions. The experiment was carried out in a greenhouse with completely randomized design with a 4×3 factorial scheme. The treatments consisted of four hydrogel doses (0.0; 1.5; 3.0; and 6.0 g L-1 substrate), three shading conditions (under full sun; black shade net, and red shade net, both with 50% shading), and five replicates per treatment. The variables evaluated were plant height; stem diameter; shoot, root, and total dry matter; and leaf area. The best hydrogel dose for watermelon cultivation was 1.5 g L-1, but the higher doses impaired plant growth, regardless of shading conditions. The black net improved biomass accumulation in 'Crimson Sweet' watermelon, whereas the red net induced plant etiolation.

The successful intercropping with vegetables depends on the type of crops grown and on the proper handling of tested treatments, such as the time of transplanting a crop in relation to transplanting another crop, among others. Thus, the objective of this work was to evaluate the bio-agronomic performance of eggplant and tomato for industry, in intercropping, in relation to their single crops, as a function of the transplanting time of the eggplant in relation to the tomato and of the cultivation season (summer or winter). The experimental design used was a randomized complete block with ten treatments and four replications, implanted in two growing seasons (from February to September and from August to February), where the treatments consisted of ten eggplant transplanting times (-30, -25, -20, -15, -10, -5, 0, +5, +10 and +15 days in relation to tomato transplantation). In each block, plots of eggplant monocultures were planted in each transplanting time, as well as a plot in tomato monoculture in order to obtain the bio-agronomic indices. The competition and bio-agronomic efficiency indices of the crops and of the intercropped systems were evaluated. The variation in the transplanting time of eggplant in relation to tomato significantly interferes in the bio-agronomic performance of both species. Eggplant transplanting performed between -20 and -15 days compared to tomato transplantation reduces the dominance of one crop over the other and the interspecific competition for environmental resources. The intercropped system has greater land equivalent ratio when the eggplant is transplanted at +15 days after transplanting the tomato.

Fertiliser recommendation tables for beet culture have been prepared based on the response to potassium (K) doses in soils with a low nutrient content. However, there is little research that evaluates potassium fertilisation for beet crops in soil with high K content, a condition commonly found, which allows a better understanding of the crop’s response to the nutrient. The objective was to evaluate the response of beet to doses of K in Oxisol with a high K content. The experiment was carried out in the field, with an experimental design in randomised blocks, in a 4 x 2 factor scheme with four replications. The doses of K were 0, 60, 120 and 180 kg ha-1 of K2O, and the cultivars were ‘Early Wonder’ and ‘Kestrel’. At 50 days after transplantation, the levels of nitrogen (N), phosphorus (P), K and boron (B) in the diagnostic leaf were evaluated. Beet yield and accumulation of these four nutrients were analysed at harvest. The doses of K positively influenced the leaf content of K; however, without an effect on beet yield. Therefore, in Oxisol with a high K content available, potassium fertilisation is not recommended. To maintain soil fertility at a high potassium content, fertilisation with 162 and 126 kg ha-1 of K2O is recommended for ‘Early Wonder’ and ‘Kestrel’, respectively; doses equivalent to the quantities exported by the beet root.

The incorporation of organic substrate into the soil can reduce aluminum toxicity in pigeon pea (Cajanus cajan (L.) Millsp.) plants, making it a viable alternative for use by small farmers in acidic soil regions such as the northeast semi-arid regions of Brazil that contain toxic aluminum in the soil. The aim of this study was to evaluate the effect of increasing aluminum doses and different commercial substrate concentrations on the initial growth of the pigeon pea. The experiment was undertaken in a greenhouse using a completely randomized design with a 5 × 3 factorial scheme. The first factor consisted of five doses of aluminum (0, 13.5, 27, 54, and 108 mg L-1) and the second factor consisted of three percentages of commercial substrate Vivato Slim Pro® (0%, 10%, and 20%), with five replicates per treatment, totaling 60 experimental units. The variables evaluated were plant height; total chlorophyll; shoot, root, and total dry matter; and root volume. The use of the commercial substrate attenuated the aluminum toxicity and favored the initial growth of pigeon pea plants, regardless of the concentration used. Thus, the aluminum was detrimental to the initial plant growth at all tested concentrations and showed more pronounced signs of toxicity on the root volume.