Inoculation with phosphate-solubilizing bacteria (PSB) and the application of phosphorus (P) sources can improve soil P availability, enhancing the sustainability and efficiency of agricultural systems. The implementation of this technology in perennial grasses, such as Kikuyu grass, for cattle feed in soils with high P retention, such as Andisols, has been little explored. The objective of this study was to evaluate the productive response of Kikuyu grass and soil P dynamics to BSF inoculation with different P sources. The experiment was conducted on a Kikuyu pasture, which was evaluated for 18 months (September 2020 to March 2022). Three P fertilizers with different solubility levels were applied: diammonium phosphate (DAP) (high-solubility), rock phosphate (RP), and compost (OM) (low-solubility). Moreover, the inoculation of a PSB consortium (Azospirillum brasilense D7, Rhizobium leguminosarum T88 and Herbaspirillum sp. AP21) was tested. Inoculation with PSB and fertilization with rock phosphate (RP) increased soil labile P and acid phosphomonoesterase activity. Increased grass yield and quality were related with higher soil inorganic P (Pi) availability. This study validated, under field conditions, the benefits of PSB inoculation for soil P availability and Kikuyu grass productivity.

Introduction. The evaluation and selection of new fodder species with appropriate production and quality attributes is a safe and effective strategy to improve the efficiency of milk production systems in Colombia. Objective. To describe the development process and the main characteristics of Altoandina, a new variety of fodder oats. Materials and methods. During the second half of 2016, an agronomic assessment test (PEA) was carried out in four locations in the Altiplano Cundiboyacense subregion and in four locations in the Altiplano of Nariño subregion, in a randomized complete block design, with two genotypes of fodder oats AV25-S and AV25-T and three varieties (Avenar, Cajica, Cayuse). Results. AV25-S and AV25-T showed: tolerance to overturn unlike the three controls that showed a overturn of more than 30%, resistance to leaf and stem rust, and green forage performance of 64.6 and 65.3 t ha-1, respectively, higher than that obtained in Avenar (55.5), Cajica (43.7) and Cayuse (59.1). Conclusion. AV25-T for its tolerance to overturning, resistance to leaf and stem rust and green fodder yield superior to commercial varieties, was registered in the national cultivar system as a new fodder variety called Altoandina, with recommendation for the Cundiboyacense Altiplano and Nariño Altiplano.

Single nucleotide polymorphism (SNP) markers have multiple applications in plant breeding of small grains. They are used for the selection of divergent parents, the identification of genetic variants and marker-assisted selection. However, the use of SNPs in varietal purity assessment is under-reported, especially for multi-line varieties from the public sector. In the case of variety evaluation, these genetic markers are tools for maintaining varietal distinctness, uniformity and stability needed for cultivar release of multi-line or pure-line varieties of inbred crops. The objective of this research was to evaluate the purity and relationships of one original (AV-25) and two multi-line sub-populations (AV25-T and AV25-S) of the inbreeding species, oats (Avena sativa L.). Both sub-populations could be useful as forages in the central highland region of Colombia (>2000 masl), such as in the departments of Boyacá and Cundinamarca, even though they were derived from an original composite mixture widely used in the mountainsides of the southern department of Nariño named Avena 25. Representative single plant selections (SPS) from the two sub-populations were grown together with SPS harvests from off-type plants (early and late) and plants from the original AV25 composite mixture, to determine their genetic similarity. Plants were genotyped by DNA extraction of a plateful of 96 individual plant samples and SNPs were detected for an Illumina Infinium 6K Chip assay. The data were used for the analysis of genetic structure and population relationships. The grouping observed based on the genetic data indicated that AV25-T and AV25-S were homogeneous populations and somewhat divergent in their genetic profile compared to the original AV25-C mix. In addition, to the two commercial, certified oat varieties (Cajicá and Cayuse) were different from these. The early and late selections were probable contaminants and could be discarded. We concluded that the use of SNP markers is an appropriate tool for ensuring genetic purity of oat varieties.

Microbial communities regulate the transformation and stabilization of nutrients during composting; however, current knowledge on their specific functional roles across composting stages remains poorly integrated. This review examines the pivotal role of microbial mediation in nitrogen (N) and phosphorus (P) dynamics during composting and their subsequent impact on soil health. We analyze how biotechnological interventions—specifically the inoculation of functional microbial consortia (phosphate-solubilizing bacteria, phosphate-accumulating bacteria, and nitrifiers) and the application of physicochemical additives such as biochar—reconfigure microbial succession patterns to mitigate gaseous losses and enhance nutrient bioavailability. Several studies have reported substantial reductions in ammonia (NH₃) and nitrous oxide (N₂O) emissions under specific composting conditions, while simultaneously promoting the stabilization of labile P into more recalcitrant forms, including polyphosphates. Furthermore, the application of mature compost to agricultural systems induces a profound ecological reassembly of the soil microbiome, shifting community composition toward copiotrophic dominance (Pseudomonadota and Bacteroidota) and increasing functional redundancy. These microbial and functional shifts enhance soil resilience to environmental stressors—such as drought and temperature fluctuations—by stabilizing extracellular enzyme activity and reinforcing microbial co-occurrence networks. We conclude that managing microbial interactions along the compost–soil continuum is essential for developing organic amendments optimized for specific soil and crop requirements. This integrated approach represents a cornerstone of precision sustainable agriculture and contributes to climate change mitigation through soil health restoration.

Este libro aborda algunos conceptos técnicos sobre estrategias productivas existentes para mejorar la adaptación y mitigación al cambio climático en cultivos de interés y que pueden ser aplicadas en cultivos establecidos en el trópico alto colombiano. Primero, se presentan algunas generalidades de la relación entre agricultura y cambio climático, destacando los desafíos y las oportunidades que enfrenta el sector agrícola en este contexto. Luego, se profundiza en las características y los usos de los invernaderos en Colombia, así como su importancia y aplicaciones en la producción agrícola, y se establecen criterios para la selección y el diseño de invernaderos, que permiten maximizar su eficiencia, adaptabilidad y funcionalidad a las condiciones climáticas del trópico alto. Asimismo, se brinda información esencial sobre sistemas de climatización activa y pasiva, destacando su relevancia y eficiencia en el control y la gestión microclimática en el interior de los invernaderos. Además, se muestran resultados de un modelo de producción de agricultura vertical que se plantea como una alternativa innovadora para optimizar e intensificar la producción hortícola. De otro lado, se mencionan algunos conceptos de interés para el uso de invernaderos en prácticas como el endurecimiento de especies vegetales y la cría de insectos, resaltando su importancia en la producción agrícola sostenible. Por último, se dan a conocer técnicas biotecnológicas para enfrentar las condiciones de sequía, que ofrecen soluciones innovadoras y prometedoras para diferentes tipos de cultivos en áreas que pueden verse afectadas por la escasez de agua debido a los efectos adversos generados por el cambio climático.

Introduction. The use of forage oat silage (Avena sativa L.) in dairy cattle in times of feed deficit, allows mitigating biomass losses due to drought in the Colombian high tropics. Objectives. 1) To determine the dry matter yield (DMY) of five forage oat genotypes and the phenotypic stability and the bromatological quality of their silage, and 2) to evaluate the inclusion of the AV25-T genotype silage in diets for dairy cattle. Materials and methods. In the Colombian high tropics two experiments were performed: 1) agronomic evaluation test (October 2017 and February 2018) in a randomized complete block design with five genotypes, eight locations, and four replicates; dry matter yield (DMY) and protein, neutral detergent fiber (NDF) and total digestible nutrients (TDN) contents in silage were determined, and 2) animal response study (January 2018) with the inclusion of the AV25-T genotype in diets, in a simple crossover design with two factors: animal (5) and diets (3); the diets were: D1: only meadow; D2: 35 % AV25-T silage + grazing, and D3: 65 % AV25-T silage + grazing. Milk yield, protein, fat, total solids, were determined in the milk, and weight change was determined in the animals. Results. AV25-T presented adaptation with the highest DMY. The inclusion of AV25-T silage in the animal diet showed a significant change in animal weight (0.1 and 0.25 kg with D2 and D3), milk yield (27.2 - 29.7 L/cow/day with D3 and D2), and the fat content (3.2 - 3.9 % with D3 and D2), without detriment in protein and total solids. Conclusion. The use of AV25-T forage oats in silage allowed increases in animal weight, milk yield, and fat content in Holstein dairy cows without affecting protein and total solids in milk.