Chilean Journal of Agricultural & Animal Sciences

MICROALGAE IN AGRICULTURE: BOOSTING THE ACHIEVEMENT OF SUSTAINABLE DEVELOPMENT GOALS

Fri, 29 Aug 2025 00:00:00 -0400

Agriculture is currently facing some of the greatest challenges in its history: meeting the growing demand for food while achieving sustainability, in alignment with several Sustainable Development Goals (SDGs) established by the United Nations and closely linked to the agricultural sector. Recent research has increasingly focused on the use of microorganisms as bio-inputs to optimize production systems. Among these, microalgae stand out due to their remarkable potential as innovative tools to address these pressing challenges. The objective of this review was to compile and synthesize scientific knowledge on the agricultural applications of microalgae that contribute positively to the achievement of SDGs 2, 6, and 15. This document examines the documented benefits of microalgae use, as reported in recent studies, emphasizing both current and potential applications across five key areas of agricultural production systems.

SILAGE CHARACTERISTICS OF MAIZE-FORAGE LEGUME MIXTURES ENSILED AT DIFFERENT HARVEST PERIODS

Poloko Mosebi, Casper Madakadze, Moeketsi Ntakatsane, Ratsele Ratsel — Fri, 29 Aug 2025 00:00:00 -0400

This study was conducted to evaluate the effects of different harvest periods on the ensiling characteristics of maize-forage legume mixtures. Sole maize (Zea mays L.), sole common vetch (Vicia sativa L.), sole lablab (Lablab purpureus), maize + common vetch, and maize + lablab intercrops were harvested on different days after planting (DAP). The experiment was conducted using a completely randomized design with a 5 (forage systems) x 3 (harvest periods) factorial treatment arrangement and three replicates. Forage samples were ensiled at early, medium, and late harvest maturity: 50, 75 and 100 DAP. After ensiling in a laboratory mini-silo, samples were collected to determine chemical composition, microbial populations, and fermentation quality. Early harvest demonstrated lower contents of dry matter (DM) and crude protein, with values of 16.99 and 15.84% DM, respectively, in sole forage silages. High water-soluble carbohydrate concentrations and low fibre values (p < 0.05) were recorded when ensiled forage mixtures were harvested at the medium maturity stage. In mixed silages, the medium harvest time resulted in significantly lower populations of enterobacteria, yeasts and moulds, and higher populations of lactic acid bacteria, with values of 3.61, 4.83 and 5.17 log10 cfug-1, respectively. Lower pH values, NH3-N content, and greater lactic acid production (p < 0.05) were observed when the ensiled mixture and sole forages were harvested at the medium maturity stage compared to early and late harvest periods. Mixed silages from the medium harvest produced lower butyric acid and higher acetic and propionic acid concentrations (0.19, 1.07 and 1.25% DM, respectively) in the medium harvest, followed by silages from the late and early harvests. A medium harvest for ensiling mixed forage has the potential to produce high-quality silage for ruminant feeding.

NUTRIENT COMPOSITION, FERMENTATION QUALITY, in vitro DEGRADABILITY, AND METHANE EMISSIONS OF WHOLE-CROP CORN SILAGES TREATED WITH ARBUSCULAR MYCORRHIZAL FUNGI BIOFERTILIZERS DURING PLANTING

Muhammad Ridla , Iwan Prihantoro, Emiralda Prastiwi Gamasari — Fri, 29 Aug 2025 00:00:00 -0400

Silage fermentation quality and nutrient composition are significantly influenced by the raw material used before ensiling, including agronomic practices such as fertilizer application. This study evaluated the effects of different levels of Arbuscular Mycorrhizal Fungi (AMF) biofertilizer applied during corn cultivation on nutrient composition, silage fermentation characteristics, in vitro rumen fermentation dynamics, and methane emissions. Corn plants were harvested 82 days post-planting, cut 10 cm above ground level, and manually chopped into pieces of 3–5 cm in length. The chopped forage was packed into 10-liter silos, compacted to expel air, and sealed to ensure anaerobic conditions. All samples were ensiled for 30 days. A completely randomized design was employed with three AMF biofertilizer levels (0, 10, and 20 g per planting hole) and six replications. Data were analyzed using ANOVA followed by Tukey’s test for multiple comparisons. The results indicated that AMF application had a limited effect on nutrient composition but significantly increased (P < 0.05) water-soluble carbohydrate (WSC) content, which is crucial for efficient fermentation. All silages were well preserved, as evidenced by a pH below 4. Enhanced in vitro rumen fermentation, indicated by increased total short-chain fatty acid (TSCFA) production, higher gas output, and a slight improvement in degradability, was associated with higher WSC content. Elevated WSC levels also contributed to reduced methane emissions by promoting more efficient microbial fermentation.

DEMOGRAPHIC AND GENEALOGICAL STRUCTURE OF THE COSTEÑO CON CUERNOS COLOMBIAN CREOLE CATTLE

Fri, 29 Aug 2025 00:00:00 -0400

The aim of this study was to assess the demographic structure and genetic diversity of the Costeño con Cuernos (CCC) Colombian creole cattle population using pedigree data. A total of 8,164 genealogical records of the CCC breed, spanning 1958 to 2023, were analyzed to estimate population censuses, effective population size, generational intervals, pedigree completeness, inbreeding coefficient, and effective number of founders. A progressive increase in population size was observed, reaching a population of 1,524 animals by 2022, with an average generational interval of 5.6 and 6.5 years for paternal and maternal lines, respectively. Pedigree completeness has significantly improved since the 1990s, reaching current values close to 100% over six generations. Inbreeding coefficients increased over time and estimates of effective population size were 253 and 89 based on census and inbreeding, respectively. Among the animals analyzed, 852 were found to have both parents unknown. The effective number of founders and ancestors was 69.6 and 42, respectively. The breed conservation strategy has maintained its genetic variability, but there is a need to incorporate new individuals into the Germplasm Bank.

USE OF A MULTIVARIATE SEXUAL DIMORPHISM INDEX: AN EXAMPLE IN Bos taurus L.

Fri, 29 Aug 2025 00:00:00 -0400

Sexual dimorphism refers to morphological differences between males and females of the same species, traditionally evaluated using univariate methods (e.g., size) and, less frequently, multivariate approaches that integrate quantitative and qualitative traits. This study proposes the use of the Gower index to assess multivariate sexual dimorphism in Bos taurus L. The robustness of this approach is based on the mean values of the ethnological descriptors from 25 existing taurine cattle breeds (Iberian, European, and Creole). For each breed, nine traits were recorded: two ordinal qualitative traits and seven quantitative continuous traits. The qualitative data considered neck length and dewlap size. The quantitative data considered live weight, height at the withers, longitudinal diameter, dorso-sternal diameter, thoracic perimeter, anterior shank perimeter, and bicostal diameter. It can be concluded that, by integrating variables of different types, the Gower index is a good indicator of sexual dimorphism in Bos taurus L.

DEVELOPING A BREEDING OBJECTIVE FOR DUAL-PURPOSE MERINO PRECOZ BREED IN CENTRAL CHILE: DERIVATION OF ECONOMIC WEIGHTS

Felipe Lembeye , Giorgio Castellaro — Fri, 29 Aug 2025 00:00:00 -0400

Defining economically important traits is crucial in the design of a genetic program. These are referred to as the breeding objective, and determining their economic values ( ) is essential. Currently, no breeding objective has been established for Merino Precoz sheep in central Chile. This study proposes a breeding objective and calculates for five traits: greasy fleece weight (GFW), fiber diameter (FD) with three pricing scenarios: 3.5%, 7% and 14% of GFW price, number of lambs weaned (NLW), weaning weight (WW), and adult weight (AW). Economic values were: USD5.42 for GFW; USD-0.59, USD-1.18, USD-2.35 for FD scenarios (3.5, 7, 14%, respectively); USD151.1 for NLW; USD4.93 for WW, and USD-0.09 for AW. The greatest emphasis was placed on NLW and WW, which collectively represent over 80% of the breeding emphasis. A negative value for AW indicates that smaller ewes are preferable in production systems operating in drylands like central Chile. Furthermore, the inclusion of NLW in the breeding objective must be supported by reliable data-recording protocols and effective management practices to ensure accurate selection.

IMPACT OF TWO POULTRY LITTER FERMENTATION METHODS ON THE PRODUCTIVE AND ECONOMIC PERFORMANCE OF BROILER CHICKENS

Fri, 29 Aug 2025 00:00:00 -0400

Poultry litter fermentation is a sanitary practice that contributes to the elimination of residual pathogens and improves the hygienic conditions of the rearing environment, thereby helping to reduce production costs and environmental impact. The aim of this study was to evaluate the effect of two poultry litter fermentation methods on the productive and economic performance of broiler chickens. Two treatments were compared: aerobic fermentation (34,272 birds) and anaerobic fermentation (36,288 birds). The evaluated parameters included final live weight, feed intake, feed conversion ratio, and mortality, along with economic indicators such as the European Efficiency Factor (EEF) and production cost. The results indicate that aerobic fermentation had a better performance than anaerobic fermentation, with higher final body weight (2.49 kg vs. 2.46 kg; p<0.05), similar feed intake (3.57 kg vs. 3.53 kg; p>0.05), higher feed conversion efficiency (1.43 vs. 1.45; p<0.05), lower mortality (3.32% vs. 3.78%; p<0.05), lower FEE (482 vs. 466; p<0.05), and lower production cost per kg (S/ 0.011 vs S/ 0.014; p<0.05). In conclusion, aerobic fermentation of poultry litter proved to be technically and economically more efficient than anaerobic fermentation, by enhancing productive performance and profitability in broiler chicken farming.

IMPORTANCE OF THE MILPA SYSTEM IN ANIMAL FEED IN MIXTEC COMMUNITIES: USE OF PRODUCTS AND BY-PRODUCTS

Fri, 29 Aug 2025 00:00:00 -0400

The milpa system is the foundation of traditional agriculture in Mesoamerica. It is characterized by the polyculture of maize (Zea mays L.), beans (Phaseolus spp.), and squash (Cucurbita spp.), and is associated with a wide diversity of crops and wild species. In Oaxaca, this crop-growing system is closely linked to backyard livestock farming, as its products and by-products serve as an essential source of animal feed. The objective of this study was to evaluate the diversity and quantity of milpa-derived products and by-products used for domestic animal feed in the municipalities of Santo Domingo Yanhuitlán and San Martin Huamelúlpam, Mixtec region, Oaxaca, Mexico. The study used a qualitative approach, supported by site visits, interviews, field trips, and semi-structured surveys conducted with 194 household heads in the two municipalities. The results showed that, among products derived from the milpa system for animal feed, 68.5% of the surveyed households used maize seed and 4.2% used squash. Among by-products, 46.9% used maize stover, while 34.02% combined maize stover with grasses and weeds. Most milpa-derived feed lasted four to six months, after which animals were supplemented with forage species, primarily alfalfa (17%), along with grazing and/or purchased feed. The main animal species reared in the surveyed households included sheep, goats, poultry, pigs, rabbits, and large livestock. This study highlights the central role of the milpa system in supporting both household livestock production and family subsistence in the Mixtec region, Mexico.

CHARACTERIZATION AND COMPARISON OF THE BIOCHEMICAL PROFILE AND ANTIOXIDANT CAPACITY OF TWO LETTUCE VARIETIES (COSTINA AND ESCAROLE)

Javier Leiva-Vega, Lucía De La Fuente-Jiménez, Luis Ríos-Soto — Fri, 29 Aug 2025 00:00:00 -0400

Leaves are a potential source of biologically active lipids; however, effective extraction requires cell disruption. The objective of this study was to characterize and compare the lipid content, total phenolic compounds, vitamin C, nitrogen, and total chlorophyll levels in two lettuce varieties (costina and escarole), in order to evaluate their biochemical profiles and antioxidant capacities. Nitrogen and total chlorophyll levels in leaves were measured. Lipid extraction was carried out using vortex-agitation with hexane and distilled water as solvents. Phenolic content was determined using the Folin-Ciocalteau method, and vitamin C was measured using spectrophotometry in the extracted lipid fractions. Escarole lettuce exhibited lower nitrogen (3.15 ± 1.74 mg kg^-1) and total chlorophyll levels (10 ± 5.38 SPAD). Conversely, it showed a higher concentration of polar lipids (5.28 ± 1.28 g g^-1 dry weight), while non-polar lipids were not detected in either variety. The phenolic content was higher in costina lettuce (60.34 ± 17.08 mg tannic acid g^-1 dry polar lipid) compared to escarole lettuce (21.24 ± 12.76 mg tannic acid g^-1 dry polar lipid). Similarly, vitamin C content was greater in costina with respect to escarole lettuce, with values of 0.2167 ± 0.0347 and 0.1038 ± 0.0166 mg ascorbic acid g^-1 dry polar lipid, respectively. The results suggest that lettuce leaves are a valuable source of lipids, phenolic compounds, and vitamin C. The concentration of these bioactive compounds appeared to be influenced by nitrogen and total chlorophyll levels in the leaves, as well as by lettuce variety.

AGRONOMIC RESPONSE TO CHITOSAN NANOPARTICLES AND QUALITY INDICATORS IN CUCUMBER FRUITS (Cucumis sativus L.)

Fri, 29 Aug 2025 00:00:00 -0400

The cultivation of cucumber (Cucumis sativus L.) has acquired importance in agriculture globally, both for its economic contribution and nutritional value, which generates a sustainable source of income and encourages the diversity of agricultural systems. The use of chitosan in agriculture represents an innovative and sustainable strategy, promoting plant growth, improving soil health and reducing dependence on agrochemicals, thus contributing to safer and more environmentally responsible food production. The objective of this research was to determine the responses of cucumber plants to the application of chitosan nanoparticles. The applied concentrations were 1,000 mg L^-1 (T-1), 1,500 mg L^-1 (T-2), 2,500 mg L^-1 (T-3), and a control (T-4), which were distributed in a random block design with four treatments and three replications. Different plant growth variables were evaluated: stem height and diameter, root length, number of leaves and tendrils, and number of flowers, as well as the production of fresh and dry matter from different plant organs. At the end of the growing cycle, the yield and nutraceutical quality of the fruits were assessed by determining the contents of polyphenols, flavonoids, antioxidant capacity, and total soluble solids in the pulp. Applications of chitosan at different concentrations promoted overall plant growth, although not all variables responded equally. The concentration of 2,500 mg L^-1 increased both yield and nutraceutical quality of the fruits.

DIVERSITY OF ARBUSCULAR MYCORRHIZAL FUNGI ACROSS TWO PRODUCTION SYSTEMS OF SOURSOP (Annona muricata L., 1753) IN MEXICO

Fri, 29 Aug 2025 00:00:00 -0400

Soursop (Annona muricata L., 1753) is a valuable tree native to Mexico and other regions of Central and South America, known for its edible fruit and medicinal properties. Few studies have examined the interactions between Annona muricata and arbuscular mycorrhizal fungi (AMF). However, understanding the biology, ecology, diversity, and limiting factors of AMF is essential for their agricultural application. This study aimed to compare the diversity parameters of AMF associated with Annona muricata under conventional and agroecological production systems in Nayarit, Mexico. The high-input (HT) field received periodic fertilization and irrigation, whereas the low-input (HNT) field did not receive either. AMF spores were extracted for morphological identification and the abundance and diversity index were estimated. Soil characterization included measurements of pH, potassium, phosphorus, magnesium, calcium, and nitrogen. The diversity index and percentage of root colonization by AMF were higher in the HNT field compared to the HT field. These findings suggest that AMF communities associated with Annona muricata under organic or agroecological management (low-input) exhibit greater diversity of species than those in conventional cultivation systems (high-input).

PRODUCTIVITY AND QUALITY OF PEPPERS (Capsicum annumm L.) IN RESPONSE TO SILICON CONCENTRATIONS

Fri, 29 Aug 2025 00:00:00 -0400

The effect of silicon fertilization on plant growth is well documented in monocotyledonous species; however, this effect has not been extensively studied in dicotyledonous plants. The objective of this study was to determine the effect of different doses of silicon on the morphophysiological, productive, and quality traits of pepper (Capsicum annuum L.) cv. Quetzal. Four doses of silicon (0, 20, 25 and 30 g plant^-1) were applied using a randomized block design with four replicates per treatment. At 60 days post-transplant, three morphophysiological variables (plant height, stem diameter, and number of leaves), nine productive variables (length, diameter, number, and weight of fruits; fruit biomass, fruit biomass without the placenta; mesocarp thickness; fruit biomass including the placenta with seeds; and yield), and three fruit quality variables (total flavonoids, phenolic content, and antioxidant capacity) were evaluated. The response for all variables was determined using analysis of variance, while the response trend to silicon doses was assessed through regression analysis. Significant differences were observed among silicon concentrations for all variables (P<0.05), with a positive linear trend. Therefore, it can be concluded that the application of 30 g of potassium silicate plant^-1 improves the morphophysiological, productive and quality traits of peppers.

PRODUCTION OF OFFSHOOTS AND MORPHOLOGICAL CHARACTERISTICS IN Agave americana var. Oaxacensis IN RESPONSE TO STIMULANTS AND NUTRIENT SOLUTION

Fri, 29 Aug 2025 00:00:00 -0400

Agave americana var. Oaxacensis is a wild species used in the production of mezcal. It has low asexual reproduction and seed production until 15-20 years of age. The objective of this study was to evaluate the effect of stimulants and nutrient solution on the production of offshoots. The experiment was carried out in San Agustín Amatengo, Ejutla de Crespo, Oaxaca, Mexico, with a randomized complete block design, with 3x2 factorial arrangement. The stimulant factor included the following treatments: no stimulant, 2.5 L ^ha-1 of SeaMel Booster, and 2.0 L ^ha-1 Algaroot™; the nutritional factor consisted of: 0 and 100% Steiner solution. Each treatment included four replications, and the experimental unit consisted of six plants. In the mother plants, the following variables were measured: rosette base diameter, rosette diameter, plant height and number of offshoots. In the offshoots, the same variables were evaluated, with the addition of the number of leaves. Soil samples were collected to determine physical and chemical properties. The variables rosette base diameter, rosette diameter and plant height did not show significant effects due to the use of stimulant or nutrition. However, the stimulant Algaroot^MR produced the largest number of offshoots in mother plants, while the morphological variables were enhanced in the offshoots. The soil was moderately alkaline, with negligible salinity. Organic matter and nitrogen levels were estimated as medium, while P levels ranged from medium. The bulk density of the sampled area corresponded to loam and sandy soils, with textures identified as silty loam, sandy loam and loamy sand.

AMARANTHUS (Amaranthus hybridus L.) RESPONSE TO COCOA POD HUSK POWDER AND NITROGEN FERTILISER APPLICATIONS

Tajudeen B. Akinrinola, Adedayo O. Salami, Samuel A. Adegoke — Fri, 29 Aug 2025 00:00:00 -0400

Amaranthus is a fast-growing vegetable affected by inadequate soil nutrient supply due to intensive cultivation. Inorganic fertiliser application reduces vegetable quality, thus, farm waste such as Cocoa pod husk (CPH) was encouraged as organic fertiliser. However, limited information is available on CPH powder or its combination with urea on amaranthus performance. Therefore, the response of amaranthus to CPH and urea fertiliser was investigated. In a replicated 3 × 3 factorial experiment, CPH powder at 0, 30, and 60 kg N ha^-1 and urea fertiliser at 0, 30, and 60 kg N ha^-1 were evaluated in a randomised complete block design with five replicates using 4 kg soil. Data collected were subjected to ANOVA and significantly different means were separated at p<0.05. The results indicated that the control (0 kg CPH) had better growth than the CPH-treated plants at both plantings. Applying 60 kg N ha^-1 urea significantly increased the number of leaves and shoot biomass compared to the other treatments in both plantings. The CPH × urea interactions resulted in significant variations in amaranthus height, number of leaves and shoot biomass among the treatments. The growth parameters observed at 0 kg CPH × 60 kg N ha^-1 urea were significantly higher than other treatments but not different from CPH at 60 kg N ha^-1 × 60 kg N ha^-1 urea and CPH at 30 kg N ha^-1 × 30 kg N ha^-1 urea applications in both plantings. Consequently, CPH powder at 30 kg N ha^-1 with urea at 30 kg N ha^-1 was considered appropriate for sustainable amaranthus production.

MORPHOLOGICAL AND BIOCHEMICAL RESPONSES OF Amaranthus viridis TO CHEMICAL FERTILIZER AND BLACK SOLDIER FLY FRASS

Shao-Zhen Teo, Raihana Ridzuan, Fazilah Abd Manan — Fri, 29 Aug 2025 00:00:00 -0400

The prolonged use of chemical fertilizer is associated with adverse environmental effects. To date, insect-derived fertilizer from Black Soldier Fly (BSF), has emerged as a promising organic alternative. However, the impact of BSF frass on the morphology and biochemical compositions of leafy vegetables necessitates further investigation. Therefore, the objective of this study was to evaluate the effects of chemical NPK fertilizer and BSF frass fertilizer, applied individually or in combination, on the morphology and biochemical composition of Amaranthus viridis (A. viridis). The experiment consisted of four treatments; untreated control (T1), BSF frass (T2), NPK fertilizer (T3), and BSF frass + NPK fertilizer (T4). The results indicated that A. viridis plants in T4 exhibited the highest stem length, root length, leaf area, as well as weight of the stems, leaves, and roots. However, no significant differences were observed in terms of plant morphology and total chlorophyll content among the fertilizer treatments. Additionally, T4 significantly increased the total phenolic content in A.viridis (0.481 ± 0.012 mg GAE/g DW) compared to plants treated solely with NPK fertilizer. These results indicate that the combined application of BSF frass and NPK fertilizer significantly enhances plant growth of leafy vegetables, particularly by influencing specific biochemical compositions.

HYDROLATES AND ESSENTIAL OILS AFFECT Varroa destructor MITES IN in vitro ASSAYS

Fri, 29 Aug 2025 00:00:00 -0400

The beekeeping industry is affected by infestation of hives by Varroa destructor mites, reducing both honey yield and quality. The objective of this study was to evaluate the effects of hydrolates or essential oils on the survival of V. destructor mites using in vitro assays. Six hydrolates obtained from Lavandula angustifolia, Tithonia diversifolia, Ruta graveolens, Dalbergia palo-escrito, Populus alba, and Retama sphaerocarpa, as well as two essential oils from Lavandula angustifolia and Origanum vulgare were used. Behavioral changes and survival rates were evaluated to determine the effects of hydrolates or plant-based essential oils on V. destructor mites. Results indicate that essential oils of L. angustifolia and O. vulgare at low concentration (1.25 µL), as well as the hydrolate obtained from the flowers of Retama sphaerocarpa are effective against V. destructor without compromising bee survival. In conclusion, essential oils and hydrolates may serve as alternative treatments to reduce V. destructor mite infestations, particularly R. sphaerocarpa flower and T. diversifolia hydrolates, and 4 µL of O. vulgare essential oil.

POPULATION FLUCTUATION OF Bemisia tabaci IN Capsicum chinense THROUGH APPLICATIONS OF Cordyceps fumosorosea UNDER GREENHOUSE AND OPEN-FIELD CONDITIONS

Omar Pinto Gonzalez, Wilberth Chan Cupul, Andrea Mendoza Arceo — Fri, 29 Aug 2025 00:00:00 -0400

Bemisia tabaci is the main insect pest affecting Capsicum chinense production worldwide. Although Cordyceps fumosorosea has demonstrated efficacy against multiple insect pests under in vitro and in vivo conditions, further in situ evaluations are required to determine its effectiveness in real-world environments. The objective of this study was to evaluate the population fluctuation of B. tabaci in C. chinense cultivation under greenhouse and open-field conditions through the application of C. fumosorosea (Cf) as a biological control agent. A factorial experimental design A×B was used, where factor A corresponded to the site (greenhouse or open-field) and factor B to the application of Cf conidiospores (with or without application). Four treatments were established: T1) greenhouse + application of Cf; T2) greenhouse without application of Cf; T3) open-field + application of Cf; and T4) open-field without application of Cf. Response variables were population fluctuation (PF), efficacy, and the area under the population progress curve (AUPPC) in adults and nymphs. A multifactorial analysis of variance (ANOVA) followed by Tukey’s test was used to analyze the response variables. A greater fluctuation of adults and nymphs was found in the open-field; however, from 56 DAT, the greenhouse crop showed greater fluctuation. The efficacy of Cf in adults was greater in the greenhouse (52.4%) than in the open-field (27.2%). The same effectiveness was found in nymphs in both the open-field (64.6%) and greenhouse (62.7%). AUPPC showed that the use of Cf, under both greenhouse and open-field conditions, helped maintain low population levels of B. tabaci nymphs and adults. Overall, the application of Cf effectively suppressed B. tabaci population fluctuations in habanero pepper, highlighting its potential for its integration into sustainable management strategies against B. tabaci.

PRODUCTION OF ASSOCIATIONS OF GRASSES AND FORAGE LEGUMES TREATED WITH BACTERIAL INOCULANTS (Azotobacter spp. and Pseudomonas fluorescens)

Fri, 29 Aug 2025 00:00:00 -0400

Livestock production in Ecuador faces the challenge of sustainably improving pasture productivity to maintain sectoral economic viability in the face of fluctuating prices of meat and inputs such as fertilizers. The objective of this study was to evaluate the biomass production, bromatological concentration, and microbiological population of associations of fescue grass (Festuca arundinacea) and ryegrass (Lolium multiflorum) associated with red clover (Trifolium pratense) and alfalfa (Medicago sativa),and inoculated with plant growth-promoting rhizobacteria. The following bacterial inoculants were evaluated: Azotobacter chroococum, Azotobacter vinelandii, Azotobacter beijerinck, Pseudomonas fluorescens, and a control. The associations of grasses and legumes (2:2 ratio) were distributed in a block design with a subdivided plot arrangement and three replications. Harvest ages of 30 and 60 days after sowing (DDS) were allocated, and the following variables were evaluated: root length, root weight, protein concentration, ash, ether extract, fiber, and dry matter. It was found that the grass L. multiflorum associated with M. sativa and inoculated with + A. beijerinck had the highest dry biomass (2454.75 kg ha^-1) and the legume M. sativa associated with F. arundinacea and inoculated with A. vinelandii showed the highest dry biomass (1464.40 kg ha^-1) at 60 DDS. The highest concentrations of proteins with the inoculant A. beijerinki in the forages of F. arundinacea + T. pratense and L. multiflorum + T. pratense were 28.12% and 26.87%, respectively. It was evidenced that bacterial inoculants represent an environmentally friendly strategy to improve the morpho-productivity and nutritional quality of forage species.

LIQUID FERTILIZATION AND BIOCHAR TO BOOST THE YIELD AND PROFITABILITY OF Arachis hypogaea L. IN DRYLAND AGROECOSYSTEMS

Fri, 29 Aug 2025 00:00:00 -0400

Temporary water deficits during the rainy season adversely affect surface soil, limiting the solubilization of granular fertilizers applied in surface bands. The objective of this study was to evaluate the effectiveness of liquid and granular fertilization in combination with biochar on the yield and profitability of peanut (Arachis hypogaea L.) in rainfed agroecosystems. The study was carried out during the January-June period of both the 2023 and 2024 seasons. Four treatments were evaluated: liquid fertilization + biochar (LFB); conventional fertilization + biochar (CFB); conventional fertilization (CF); and a control treatment (no fertilization). The main variables recorded were seed yield, the partial factor productivity of NPK (PFP_NPK), and net economic benefit (NEB) of fertilization. The results showed that fertilization treatments significantly influenced (p < 0.05) seed yield and partial factor productivity of NPK (PFP_NPK). LFB produced the highest yield values with 2007 kg ha^-1, exceeding CFB, CF, and the control by 182, 396, and 637 kg, respectively. LFB also achieved the highest increases in PFP_NPK compared with CFB and CF, indicating greater nutrient use efficiency. The highest NEB of fertilization was obtained with LFB, with USD 518 ha^-1, compared with USD 377 and 186 ha^-1 for CFB and CF, respectively. It is concluded that the combined application of liquid fertilizer and biochar is an economically viable and sustainable strategy for rainfed peanut production, particularly under surface soil water deficit.

FIRST REPORT OF IMIDAZOLINONE-RESISTANT Bassia scoparia IN ARGENTINA: EVIDENCE FROM DOSE-RESPONSE BIOASSAYS AND ALS GENE SEQUENCING

Jorgelina C. Montoya, Esteban E. Fabressi, Marcos E. Yanniccari — Fri, 29 Aug 2025 00:00:00 -0400

Kochia (Bassia scoparia (L.) A. J. Scott.) is a problematic weed. In Argentina, farmers have recently experienced poor control over imidazolinone-resistant sunflowers, specifically the sensitivity of putative kochia resistant plants to imidazolinone herbicides. Seeds from putative resistant populations from Pellegrini (P), De Bary (DB), and 30 de Agosto (A) and a known susceptible (S) population from Col. Martín Fierro were sown in pots. A mixture of imazapyr (Clearsol® WG 80%) and imazamox (Trigosol WG 70%) was sprayed when plants reached approximately 6 cm in height and 10-leaf stage using a boom sprayer. A trial was conducted to determine the response of kochia to the recommended doses (1x) of imazapyr 80.00 g ai ha^-1 + imazamox 20.30 g ai ha^-1. Plants were harvested 30 days after treatment to determine fresh shoot weight. A dose–response experiment was performed using imazapyr + imazamox at concentrations of 0x, 1/4x, 1/2x, 1x, 2x, 4x, and 8x. Partial ALS gene amplification was performed using leaves of plants that survived an 8x dose. The 1x fresh weight of the putative populations did not differ from 0x. LD₅₀ of imazapyr+imazamox (g ai ha^-1) for each biotype was: S, 18.86 + 4.79; DB, 82.48 + 20.93; A, 179.36 + 45.51; and P, 550.88 + 139.79. The three resistant populations exhibited a single-point mutation from guanine to thymine, detected in codon 574 of the ALS gene. This mutation confers resistance to ALS inhibitors. This is the first reported case of kochia resistance in Argentina, providing valuable insights that extend beyond sunflower weed management.