Woody species associated with coffee production systems in southern Colombia

In the coffee zone of the town La Unión- Nariño, native or introduced trees are associated with the productive systems of the farms, mainly because they provide shade for coffee crops, where particular aspects such as species biodiversity and silvicultural management are unknown. With the aim of knowing the woody species of common use and the cultural importance, a semi structured survey was applied to 100 coffee growers who were selected at random and aleatorily distributed in three altitudinal ranges: (m.a.s.l.): I (<1500), II (1500-1800) and III (> 1800). Species richness was determined for each chosen range; for diversity between ranges, the Jaccard Index (JI) and the Cultural Importance Index (CI) were used. The latter was determined by adding up the intensity of use (IU), frequency of citation (FC), and use value (UV). In the three altitude ranges evaluated, 59 tree species were found. These were distributed in 32 botanical families and 46 genera. The fabaceae family was the most representative, followed by rutaceae, myrtaceae and bignoniaceae; 45.8% of the species were introduced. Among the altitudinal ranges, a low degree similarity was found; ranks I and II shared 24 species, which is equivalent to 33.8% of their floristic composition. As for ranges I and III, they had an even lower degree of similarity: 24.2%; only 17 species were shared. The species I. densiflora had the highest percentage of CI, with 32.92%, followed by C. sinensis with 31.98%; then the species T. gigantea and P. americana with 30.49% and 26.27% respectively. These species were of great importance to coffee growers due to the positive impact they have on the family economy and their contribution to the environmental well-being of production systems.

Perigonium color and the antioxidant capacity of cañihua (Chenopodium pallidicaule Aellen)

Currently, it is necessary to know the content of bioactive compounds, one of them is the antioxidant capacity of food, which has nutritional importance and functional properties, since these components are natural and play an important role in the prevention and treatment of several diseases, including cancer. Therefore, the objective of the investigation was to determine the nutritional quality and the relationship between the color intensity of the perigonium and the antioxidant capacity of the Chenopodium pallidicaule (Ch. pallidicaule). As material of study, we used four accessions of Ch. pallidicaule with perigonia of defined colors such as light yellow, orange, purple and black. We developed the physical-chemical analyzes and the grain functional components in the Agroindustrial Engineering Laboratories of the National University of Altiplano Puno, and in the Laboratory of Chromatography and Spectrometry of the San Antonio de Abad National University of Cusco. The results were submitted to Pearson's correlation analysis, and they show that the flavonoid indices with the perigonium color intensity values express significant positive correlation. In addition, the antioxidant capacity equivalent to Trolox was significantly different between the perigonium color intensities, where the accession with black perigonium turns out to be the one that reached the highest value (5g eq. Trolox/100g sample). We conclude that the color of the perigonium exhibited antioxidant capacity, which kept a direct correlation with the flavonoid content.

Potentialities and limitations of Planosols with distinct depths of diagnostic horizon

There is a variation in the depth of subsurface horizon of Planosols in semi-arid region, which may influence the agricultural potential and affect food production. The general aim of this study was to identify potentialities and limitations of two Planosols as a function of subsurface horizon depth. The adjacent profiles P1 and P2 were studied in Pentecoste (Ceará, Brazil). Morphological, physical, and chemical analyses were done aiming at soil characterization. Soil bulk density (BD), porosity, and penetration resistance (PR) were analyzed in a completely randomized split-plot design with four replicates to compare P1 and P2 and the horizons Ap and Btf. Btf was found at 62cm depth in P1 and at 18 cm depth in P2. Indicatives of water saturation were more evident in P2. The profile P1 showed lower hardness and higher friability, as well as higher acidity in subsurface (pHH2O from 4.4 to 4.7) and higher aluminum content (1.2cmolc kg-1). Both profiles were eutrophic and showed low contents of organic carbon (1.5 to 8.5g kg-1) and phosphorus (0.9 to 3.9mg kg-1). The sodium percentage in CEC was 9.1% in P1 and 5.5% in P2. Water retention increases in Btf compared with Ap was 7.3% in P2 and 2.7% in P1. Both profiles showed increase in BD in Btf, reaching 1.7g cm-3, while PR was higher in P2 (1.5 MPa). There are potentialities and limitations common to both soil profiles, but P1 has more physical potentialities and more chemical limitations than P2.

Pathologic findings on ruminant enteric clostridial diseases reveal specificities and differences among iota and iota-like toxins

The iota toxin (ITX) is a binary enterotoxin produced as a protoxin by Clostridium perfringens (C. perfringens) type E that is activated by proteolytic enzymes in the small intestine of infected animals. By depolymerization of the actin filaments, ITX causes cytoskeleton disorganization of cells promoting the increase of the cell permeability. Here, we conducted this review aiming to advance the understanding of enteric clostridial diseases caused by C. perfringens toxins and the specificity of ITX in the intestinal mucosa lesions. ITX consists of an enzymatic component (Ia) and a binding component (Ib). We screened the recently published histological findings of the ITX effects and its relationship with intestinal enteric diseases. Histologically, hemorrhagic necrosis and multifocal hemorrhage have been observed in the jejunum-ileum mucosa, the small intestine, and the abomasum. Although the diagnosis is still based on the presence of toxins in the intestinal contents and the clinical and/or histological history, it is important to develop novel enterotoxemic indicators capable of establishing precise methods for differentiate the actions of ITX and other toxins involved in the infectious process of C. perfringens type E.

Socio-economic characterization of the traditional cacao agroforestry system (Theobroma cacao L.)

Cacao farmers face many challenges to increase yield while adjusting their farms to future environmental and socio-economic uncertainties. Improving the management practices of cacao (Theobroma cacao L.) cultivation systems requires knowledge of their baseline and the determining factors affecting them. The main goal of this research was to characterize traditional cacao agroforestry systems of smallholder farmers in the Municipality of Tumaco, Nariño, Colombia. Using a semi-structured survey and a sample of 218 farmers, the socioeconomic characteristics of the cacao production system were analyzed. Multiple correspondence analysis (MCA) and principal component analysis (PCA) grouped and discriminated the cacao growers. The PCA formed five components representing 50.86% of the total variability, while the ACM grouped them into five factors explaining 29.82% of the variability. The cacao cultivation is a traditional activity of smallholder farmers with very low yields. The age of the farmers is over 50 years old, with despicable levels of education; there was no evidence of generational change. The study shows that the traditional cacao production system is not an attractive activity for young people or investors given its marginality and low economic projection. Timely strategies and subsequent early actions will be imperative to face the main environmental, socio-economic, and productive challenges, which will allow the cacao activity to be a source of well-being for cacao growers and the environment in the region.

Soil vulnerability index to climatic variability in coffee regions of Colombia

Global climate change is one of the main factors threatening agriculture. In this context, variations in precipitation have the strongest effect on soil fertility, plant nutrient availability, and erosion. This research aimed to assess soil vulnerability to climate variability in the central coffee-growing region of Colombia. This study analyzed soil components involved in the sustainability of the coffee production system as affected by extreme high and low precipitation events. For evaluation, three sensitivity indices were constructed, with a weighted aggregation structure and with weight values defined from expert knowledge. The indices were estimated by randomly selecting 432 coffee farms in the municipalities of Balboa and Santuario in Risaralda department and Salamina in Caldas department. The soil nutrient availability and conservation vulnerability index was moderate in the three municipalities (Balboa=2.87 and coefficient of variation-CV 13%; Santuario=2.88 and CV 10%; Salamina=2.9 and CV 9%). The soil leaching vulnerability index was very low in Balboa (4.33 and CV 3%) and Salamina (4.74 and CV 7%) and low in Santuario (3.57 and CV 19%). The soil loss vulnerability index was low in Balboa (3.32 and CV 10.03%) and Salamina (3.49 and CV 11.43%) and moderate in Santuario (3.13 and CV 9.34%). Lastly, the vulnerability of coffee-growing soil to climate variability was low in Balboa (3.33) and Salamina (3.45) and moderate in Santuario (3.09). Based on these results, in the three municipalities, coffee growers must introduce farming practices towards improving soil resilience and decreasing soil vulnerability to high and low precipitation extremes by adequately managing the sources and doses of fertilizers, soil conditioners, and compost and by implementing integrated management of weeds and litterfall.

Detection of auxinic compounds in germinating seedlings

Tryptophan (TRP) is a metabolite from which several important metabolic syntheses arise in plants, animals, and humans. In bacteria and fungi, it is a precursor of Indole Acetic acid (IAA) using various metabolic pathways. The objective of this study is the detection of intermediate metabolites in the synthesis of IAA in seeds of several species in the germination process. In the study, seeds of plant species grown in deionized water were placed in order to stimulate germination and samples were taken every 24 hours. High performance liquid chromatography (HPLC) was used for the detection of the compounds. The results show that the pH of the medium is altered and there is no pattern of behavior. Regarding the detected compounds, in addition to TRP, there is indole-3-acetamide (IAM), 3-indoleacetonitrile (IAN), tryptamine (TRM), which are part of the TRP-dependent routes, since they use this amino acid as a precursor. Anthranilic acid (AA) and kynurenine (KYN), which are part of the Independent TRP pathway, were also detected. IAA and TRP were also detected during the germination process of the studied seeds (Sorghum bicolor, T aesativum, Zea mayz, Phaseolus vulgaris, G. hirsutum, Cucurbita maxima). Finally, it was observed that the seeds, due to weight loss, suffer physical wear during the germination process, since there is a difference between the initial dry weight and the weight of the seeds at the end of the study.

Macrofauna evaluation in two coffee agroforestry systems

Knowing the soil macrofauna and its distribution is important to predict the degradation state of a soil as well as its physical properties and biological components. This research was carried out in coffee ecotopes 220A and 221A in southern Colombia. Two systems were evaluated, Coffea arabica var Castillo and native forest coffee, during two different seasons, winter and summer. Sampling was carried out using the tropical soil biology and fertility program (TSBF) methodology. The statistical treatment was carried out by means of a non-parametric analysis of variance Kruskal-Wall test. The density of orders present per square meter was evaluated, demonstrating that the highest density occurred in the winter season in the ecotope 220A and 221A forest system, with averages of 9.33 orders/ m2 and 9.67 orders/ m2, respectively. The highest number of density of individuals was obtained in winter, in the forest system and coffee in the 220A and 221A ecotopes with averages ranging between 1808 individuals/ m2 and 1368 individuals/ m2, statistically exceeding the number of individuals/ m2 that appeared in summer season. For biomass, the highest contribution was obtained in the winter season, with averages of 186.5 grams/ m2 in the 220A ecotope and 205.74 grams/ m2 for the 221A ecotope, exceeding the biomass that was presented in coffee winter season time, both in the 220A and 221A ecotopes.

Carbon capture in three land use systems in the Colombian Amazonia

The main strategies to combat climate change are reducing greenhouse gas (GHG) emissions and increasing carbon sinks in terrestrial ecosystems such as forests, forest plantations, and agroforestry systems. Deforestation and land use changes in the Amazonia bear great responsibility both for the fixation and emission of GHG. The aim of this research was to estimate the carbon stored in above-ground biomass of forests, rubber plantations (Hevea brasiliensis Muell Arg.), and trees in pastures in the Colombian Amazonia piedmont. Data was collected in 40 farms located in the rural area of the municipality of Belén de Los Andaquíes (Colombia). A total of 174 temporal sampling plots of 250 m2 each were established (80 in forests, 40 in rubber plantations and 54 in pastures with trees). In these plots, the diameter at breast height (dbh) was measured in trees with dbh ≥ 10 cm, and the above-ground biomass was estimated with allometric models for the Colombian Amazon. The carbon stored was 154.1 Mg ha-1 in forests, 1.4 Mg ha-1 in pastures with trees and 138.9 Mg ha-1 in rubber plantations. Positive changes for mitigation of climate change could be achieved through the conversion of agricultural areas, mainly pastures, to forests (+560 Mg CO2 ha-1). Likewise, if deforestation stops in the area, the estimated emissions reduction would be 0.16 Tg CO2 year-1.

Coffee crop weeds: refuge and food source for pests’ natural enemies

Weeds in coffee crops have diverse ecosystem services, such as sheltering and feeding natural enemies of pest insects. This study aimed to identify the potential of coffee weeds as food and refuge for natural enemies in shaded and sun coffee crops. Weeds were sampled in a 100 m transect installed in each type of coffee crop. Malaise traps and sweep-nets were both used to capture insects every 15 days for five months. After identifying the dominant weeds, observations and a direct recollection of insects were carried out at three different hours during three days. Faunistic analyses were performed, as well as the Bray and Curtis similarity analysis and the Student's t test. Emilia sonchifolia, Acmella oppositifolia, Bidens pilosa were predominant in the free exposure sun plantation coffee crops and Commelina diffusa, Salvia palifolia, Stachytarpheta cayennensis in under shade coffee crops. High insect activity was found between 11:30 am-12:00 pm. In these weeds, we found about 15 families, the most important were Formicidae, Braconidae, and Coccinellidae. We concluded that the shaded coffee crops exhibited a natural enemy community similar to that of the sun. Through this exploratory study, we verified that weeds harbor a diversity of natural enemies important to the coffee agroecosystems.