Purple maize has gained global significance due to its numerous nutraceutical benefits. However, sustaining its production typically requires high doses of nitrogen fertilizers, which, when applied in excess, can contaminate vital resources such as soil and water. Inoculation with nitrogen-fixing microorganisms, such as those from the Azospirillum genus, has emerged as an alternative to partially or fully replace nitrogen fertilizers. This study aimed to evaluate the inoculation effect with A. brasilense and varying nitrogen fertilization levels on the yield and quality of purple maize. The experiment was carried out using a randomized complete block design (RCBD) with a 2 × 5 factorial arrangement and five replications. Treatments comprised two inoculation levels (control without inoculation and inoculation with A. brasilense) under five nitrogen doses (0, 30, 60, 90, and 120 kg∙ha⁻¹, applied as urea). Inoculation with A. brasilense resulted in a 10.5% increase in plant height, a 16.7% increase in root length, a 21.3% increase in aboveground fresh biomass, a 30.1% increase in root fresh biomass, and a 27.7% increase in leaf nitrogen concentration compared to the non-inoculated control. Regarding yield, the inoculated plants surpassed the control in both purple maize yield (kg∙ha⁻¹) and cob weight by 21.8% and 11.6%, respectively. Across all fertilization levels and parameters assessed, the inoculated treatments outperformed the control. Furthermore, for parameters, namely plant height, leaf nitrogen content, and cob dimensions (length, diameter, and weight), the A. brasilense inoculation treatment with 90 kg N∙ha⁻¹ was statistically equivalent or superior to the non-inoculated control with 120 kg N∙ha⁻¹. These results indicate that inoculation with A. brasilense positively impacted purple maize at all nitrogen levels tested and improved nitrogen use efficiency, enabling a reduction of 30 kg N∙ha⁻¹ without compromising performance in key parameters.

The Peruvian Amazon faces an increasing threat of soil erosion, driven by unsustainable agricultural practices and accelerated deforestation. In Neshuya (Ucayali region), agricultural activity has intensified since 2014, but the effect on soil erosion is unknown. The present study aimed to evaluate the increase in erosion levels, at a sub-basin of the central–eastern Amazon of Peru, in a Geographic Information System (GIS) environment. The revised universal soil loss equation (RUSLE) model was used for assessing the effect of vegetation cover change from 2016 to 2022. In the Neshuya sub-basin (973.4 km²), the average erosion increased from 3.87 to 4.55 t ha⁻¹ year⁻¹, on average. In addition, there is great spatial variability in the values. In addition, 7.65% of the study area (74.52 km²) exceeds the soil loss tolerance limit (15 t ha⁻¹ year⁻¹). The deforestation rate was 17.99 km² year⁻¹ and by 2022 the forested area reached 237.65 km². In conclusion, the transition from forest to farmland was related to the most critical erosion values. Unsustainable soil management practices can be the underlying explanation of changes in soil chemical and physical properties. Also, social dynamic changes and differences in landscape patterns play a role.

Forest plantations represent an alternative to reduce timber extraction pressure in the Amazonian forests. In order to tolerate the hostile field conditions of deforested areas, high-quality seedlings are required. This study aimed to find the optimal dose of a native microbial consortium (NMC), which enhances seedling quality indicators, in three forest species at nursery phase. A completely randomized design (3 × 5) was used. Factor 1: Bolaina blanca (Guazuma crinita Mart.), Capirona (Calycophyllum spruceanum Benth. Hook. f.), and Marupa (Simarouba amara Aubl.). Factor 2: Incremental doses of 0, 160, 320, 480, and 640 mL NMC per plant. The nursery survival (%), robustness index, root height/length ratio, shoot–root index, Dickson Quality Index (DQI), Nitrogen (%), Phosphorus (%), and Potassium (%) content in tissues were analyzed. Statistical analyses consisted of two-way ANOVA per variable and correlation analysis. The results indicated that increasing doses of NMC did not improve nursery survival for any species; did not decrease the robustness index, plant height/root length ratio, or the shoot–root index for any species; and did not increase the DQI, P%, or K% for any species; however, they did increase the N% for all species. In conclusion, the incremental dose of 160 mL was chosen for increasing the N% without affecting nursery survival.

The farmers of Andes in rural areas commonly use fish hydrolysate and vermicompost leachate as cost-effective bio-inputs, either due to limited economic resources or a part of organic farming practices. However, their agronomic effectiveness for primary sources of plant nutrition under rainfed conditions remains insufficiently documented. This study evaluated the phenological response of quinoa (Chenopodium quinoa Willd.) to the applications of fish hydrolysate (1% and 2%) and vermicompost leachate (10%) at the Illpa Agrarian Experimental Station in Puno, Peru. Morphological parameters and yield components of quinoa and soil chemical properties were assessed at the end of the crop cycle. The results revealed a differentiated response by phenological stage: vermicompost leachate significantly enhanced plant height during the grain-filling stage, while 1% fish hydrolysate increased above ground dry weight without translating into significant yield gains compared to the control. Both biofertilizers improved soil parameters, including pH and cation exchange capacity, indicating a positive effect on soil quality. In conclusion, these inputs exert specific biostimulant effects during the vegetative stages, but do not entirely replace the function of comprehensive fertilization to achieve high yields. Nonetheless, their strategic use at key phenological stages of the cycle may support the development of more sustainable production systems in high Andean rainfed environments.

A pot experiment was conducted in the campus of La Molina National Agrarian University in order to evaluate the effect of rice husk ash, ladle furnace slag and potassium silicate on the soil chemical properties and biomass of rice (Oryza sativa L.) cv. ‘Fedearroz 60’, using topsoil from a commercial paddy field at Aucayacu, Huanuco, Peru. Doses were calculated taking into consideration each product available Si (SiA), for reaching concentrations of 100, 200 and 400 ppm (w / w) of SiA in soil before sowing. Control pots without any silicon amendment were considered as well. A completely randomized design with factorial arrangement (3 × 4) was used to assess the Si absorption by plant tissues, final SiA in soils, roots volume, whole plant’s dry weight, tillering capacity, panicles per plant and average spikelets per panicle. Salinity and pH of the growing media were registered weekly. Also were environmental temperature, and light intensity on a daily basis. Results showed that potassium silicate 200 ppm sustainably increased SiA in soils and Si in plant tissue, however the yield components were not positively influenced. Ladle furnace slag increased SiA in soils too, nonetheless for doses of 200 ppm and 400 ppm, symptoms of severe nutritional problems appeared. Rice husk ash did not show statistical significance on SiA in soils, Si in plant tissue, nor yield components. It was concluded that for such soil and weather conditions involved in this experiment, silicon increases in soil and tissues had no influence on rice yield components. In spite of this, ladle furnace slag exhibited an outstanding liming capacity and rice husk ash, a great amount of P, K and micronutrients.