Chitosan (CS) is a natural polymer used in agriculture as a biostimulant that has been evaluated in different plant models. In this study, we evaluated the effect of the foliar application of chitosan–poly(acrylic acid) complexes (CS–PAA) and two nutrient solutions (A and B) on the parameters of growth and yield of two habanero pepper cultivars (Chichen Itza and Jaguar) in a greenhouse. Over the course of the experiment, eight foliar applications were carried out at 15-day intervals. Our results showed that foliar applications of CS–PAA complexes have a biostimulant effect on the habanero pepper crop by increasing the total dry biomass of the plant and the number of fruits of the two cultivars. Regarding nutrient solutions, the nutrient solution A increased the yield of the Chichen Itza cultivar; this effect was because it had a better balance of potassium and calcium compared to the nutrient solution B. These results provide advances on the use of CS–PAA complexes as a biostimulant and the management of nutrient solutions in the crop of habanero peppers.

Background: Calcium nitrate is a widely used fertilizer in the preparation of nutrient solutions. However, there is still a need to determine the effects of different levels of calcium nitrate on the Persian cucumber crop to optimize fertilization practices and improve crop yield. Objective: To determine the effects of two levels of calcium nitrate in the nutrient solution on the growth, yield, and nutrient content of two Persian cucumber hybrids (Bereket and Cruz). Methodology: The experiment was carried out in a completely randomized design in a factorial arrangement (two hybrids and two nutrient solutions) under greenhouse conditions. Results: The nutrient solution with 11 meq L-1 of calcium nitrate increased the concentration of nitrate and calcium in the petiole sap of the Cruz hybrid in the flowering stage; however, the yield of both hybrids decreased. On the other hand, the nutrient solution with 9 meq L-1 of calcium nitrate increased the number of fruits of both hybrids and the yield per plant of the Cruz hybrid. Implications: The Cruz hybrid showed to be more efficient in calcium uptake than the Bereket hybrid, which is interesting since it could require less calcium application without affecting yield. However, other studies are necessary to expand this information. Conclusion: The nutrient solution containing 9 meq L-1 of calcium nitrate showed a significant increase in the number of fruits per plant for both the Cruz and Bereket hybrids. This highlights the importance of appropriate calcium nitrate supplementation in the nutrient solution, as it enhances the production of hydroponically grown Persian cucumbers.

The use of organic sources presents itself as a viable alternative to mitigate the excessive reliance on chemical fertilizers in agricultural practices. However, in the realm of pineapple cultivation, research exploring the synergy between chemical and organic fertilizers remains scarce. In this context, the objective of this research was to evaluate the impact of the combination of chemical and organic fertilizers on the growth and yield of the MD-2 pineapple cultivar under two shade net conditions (installed 45 and 250 days after planting). The experiment was conducted in a split-plot design, with the main plot being the shade net conditions and the sub-plots the five fertilization treatments, which were applied 18 times via drip irrigation (control, 100% chemical fertilization, 50% reduced chemical fertilization, organic fertilization, and a combination of 50% chemical fertilization with organic fertilization). The results showed that the early installation of shade netting 45 days after planting decreases the growth and yield of pineapple; thus, the use of shade netting at this age is not recommended. Regarding fertilization, the combination of 50% chemical fertilization with organic fertilization showed similar growth and yield values compared to 100% conventional chemical fertilization under both shade net conditions. Furthermore, this combination presented similar nitrate and potassium values in the plant and did not negatively affect malic acid content. Therefore, the use of organic fertilizers in pineapple cultivation is a promising strategy to reduce the excessive use of chemical fertilizers, and it could also improve soil fertility.

In the present study, the kinematic and stress analysis of an aerator roller with blades was performed. The trajectories of the aerator roller blades were obtained, which included the rotational and translational movements on the ground. Longitudinal underground areas and volumes of the cracks were calculated for rectangular blades (Type A), symmetric triangular (Type 1) and asymmetric triangular (Type 2) blades. The results of the kinematic analysis reported that type A blades significantly modified soil with respect to the other two. Normal forces were calculated numerically and per finite element, obtaining for blade type 1 numerically calculated forces of 4.52 MPa in the upper zone of the element and -7.06 MPa in its lower zone. The normal stress calculated per finite element were found in the range from 3.66 to 6.52 MPa for the upper part of the element and -7.8 MPa for its lower part. For type 2 design, a normal stress was obtained numerically of 8.83 MPa. The normal stress calculated per finite element was found in the range from 3.95 to 12.86 MPa.

The cultivation of Soledad pepper (Capsicum annuum L.) is essential in Oaxaca and Veracruz, but it faces issues with pests and diseases, which affect yield and cause economic losses. To mitigate these impacts, farmers have started using biostimulants such as chitosan and plant growth-promoting bacteria instead of agrochemicals due to their environmental and health benefits. This study evaluated the effect of Bacillus subtilis and chitosan, both individually and combined, on the growth, yield, and fruit quality of Soledad pepper under greenhouse conditions. Four treatments were applied at different stages of the crop cycle: Q (Chitosan), BS (Bacillus subtilis), Q+BS (Chitosan + Bacillus subtilis), and T (Control). The results showed that the combination of chitosan and Bacillus subtilis significantly improved plant growth, especially in height and stem diameter. The chitosan treatment produced the highest number of fruits and plant weight, while the combination of chitosan and Bacillus subtilis enhanced fruit quality, increasing characteristics such as size, weight, pericarp thickness, and physicochemical parameters, notably in brix degrees, citric acid percentage, and pH, outperforming the individual treatments and the control.