Agricultural Sciences

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    Soil CO2 emissions in cropland with fodder maize (Zea mays L.) with and without riparian bufer strips of differing vegetation
    (Springer Nature, 2022) Dlamini, J. C.; Cardenas, L. M.; Tesfamariam, E. H.; Dunn, R. M.; Evans, J.; Hawkins, J. M. B.; Blackwell, M. S. A.; Collins, A. L.
    Vegetated land areas play a significant role in determining the fate of carbon (C) in the global C cycle. Riparian buffer vegetation is primarily implemented for water quality purposes as they attenuate pollutants from immediately adjacent croplands before reaching freashwater systems. However, their prevailing conditions may sometimes promote the production and subsequent emissions of soil carbon dioxide (CO2). Despite this, the understanding of soil CO2 emissions from riparian buffer vegetation and a direct comparison with adjacent croplands they serve remain elusive. In order to quantify the extent of CO2 emissions in such an agro system, we measured CO2 emissions simultaneously with soil and environmental variables for six months in a replicated plot-scale facility comprising of maize cropping served by three vegetated riparian buffers, namely: (i) a novel grass riparian buffer; (ii) a willow riparian buffer, and; (iii) a woodland riparian buffer. These buffered treatments were compared with a no-buffer control. The woodland (322.9 ± 3.1 kg ha− 1) and grass (285 ± 2.7 kg ha− 1) riparian buffer treatments (not significant to each other) generated significantly (p = < 0.0001) the largest CO2 compared to the remainder of the treatments. Our results suggest that during maize production in general, the woodland and grass riparian buffers serving a maize crop pose a CO2 threat. The results of the current study point to the need to consider the benefits for gaseous emissions of mitigation measures conventionally implemented for improving the sustainability of water resources.
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    Modelling greenhouse gas emissions of cacao production in the Republic of Côte d’Ivoire
    (Springer Nature, 2022) Vervuurt, W.; Slingerland, M. A.; Pronk, A. A.; Van Bussel, L. G. J.
    The current expansion of cacao cultivation in the Republic of Côte d’Ivoire is associated with deforestation, forest degradation, biodiversity loss and high greenhouse gas (GHG) emissions. Global concerns about emissions that are associated with tropical commodity production are increasing. Consequently, there is a need to change the present cacao-growing practice into a more climate-friendly cultivation system. A more climate-friendly system causes lower GHG emissions, stores a high amount of carbon in its standing biomass and produces high cacao yields. GHG emissions and carbon stocks associated with the present cacao production, as assessed in 509 farmers’ fields, were estimated by using the Perennial GHG model and the Cool Farm Tool. On average, the production of 1 kg cacao beans is associated with an emission of 1.47 kg CO2e. Deforestation contributed largely to GHG emissions, while tree biomass and residue management contributed mainly to carbon storage. The collected data combined with the model simulations revealed that it is feasible to produce relatively high yields while at the same time storing a high amount of carbon in the standing biomass and causing low GHG emissions. The climate-friendliness of cacao production is strongly related to farm management, especially the number of shade trees and management of residues. Calculated emissions related to good agricultural practices were 2.29 kg CO2e per kg cacao beans. The higher emissions due to the use of more agro-inputs and other residue management practices such as recommended burning of residues for sanitary reasons were not compensated for by higher yields. This indicates a need to revisit recommended practices with respect to climate change mitigation objectives.
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    Allelopathic effects of leachates of Juglans regia L., Populus tremula L. and juglone on germination of temperate zone cultivated medicinal and aromatic plants
    (Springer Nature, 2021-02) Zubay, Péter; Kunzelmann, Jakob; Ittzés, András; Zámborine, Éva Németh; Szabó, Krisztina
    The environmental benefits of agroforestry systems are well known. However, current knowledge of potential allelopathic interactions is inadequate. The decrease in soil fertility, the increasingly rhapsodic distribution of precipitation, and the special metabolism and cultivation of medicinal and aromatic plants are all harbingers of medicinal-agroforestry systems. The authors aimed to discover the allelopathic effects of Juglans regia L. and Populus tremula L. on germination of medicinal and aromatic plants cultivated in a temperate zone. Accordingly, an in vitro germination trial was conducted with leachates of these trees and two juglone concentrations. These allelopathic effects were evaluated for germination vigour, germination rate, and total fresh weight of seedlings of twelve different species. A pronounced species specificity was observed in tolerance of seeds and seedlings to the allelopathic effect of Populus and Juglans. In four of the species studied, the allelopathic effect may inhibit germination, but only initially. Poppy and angelica proved to be the most sensitive to the treatments. The following species had relative tolerance to the allelochemicals, so further research under natural conditions is suggested for: Althea officinalis L. (9.34 ± 5.04–68.66 ± 13.62 GR%), Anethum graveolens L. (12.00 ± 2.00–100.00 ± 6.12 GR%), Cannabis sativa L. (72.66 ± 9.02–91.34 ± 1.16 GR%), Dracocephalum moldavica L. (38.00 ± 2.00–80.00 ± 17.44 GR%), Linum usitatissimum L. (44.66 ± 2.00–58.00 ± 3.46 GR%), and Satureja hortensis L. (52.00 ± 28.22–82.00 ± 8.00 GR%). The aim would be to introduce them into agroforestry systems.
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    Acrocomia aculeata fruits from three regions in Costa Rica: an assessment of biometric parameters, oil content and oil fatty acid composition to evaluate industrial potential
    (2020) Alfaro-Solís, Jose David; Montoya-Arroyo, Alexander; Jiménez, Víctor M.; Arnáez-Serrano, Elizabeth; Pérez, Jason; Vetter, Walter; Frank, Jan; Lewanowski, Iris
    Due to increased global demand for vegetable oils, diversification of the supply chain with sustainable sources is necessary. Acrocomia aculeata has recently gained attention as a multi-purpose, sustainable crop for oil production. However, the information necessary for effective selection of promising varieties for agricultural production is lacking. The aim of this study was to assess variability in fruit morphology and oil composition of individual Acrocomia aculeata plants growing wild in different climatic regions of Costa Rica. Fruits at the same ripening stage were collected at three locations, and biometric features, oil content, fatty acid composition of oils from kernels and pulp, as well as fiber composition of husks were determined. Biometric parameters showed high variability among the regions assessed. Moreover, oil content and relative proportions of unsaturated fatty acids were higher at the most tropical location, whereas lauric acid content was lowest under these conditions, indicating a potential environmental effect on oil composition. Pulp oil content correlated positively with annual precipitation and relative humidity, but no clear relation to temperature was observed. The oil chemical composition was similar to that reported for Elaeis guineensis, suggesting that Acrocomia aculeata from Costa Rica may be a suitable alternative for industrial applications currently based on African palm oil. Analysis of husks as a coproduct revealed the possibility of obtaining materials with high lignin and low water and ash contents that could be used as a solid bioenergy source. In conclusion, Acrocomia aculeata oil is a promising alternative for industrial applications currently based on African palm oil and byproducts of its oil production could find additional use as a renewable energy source.
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    Understanding forest land conversion for agriculture in a developing country context: An application of the theory of planned behaviour among a cohort of Nigerian farmers
    (Sciendo (De Gruyter), 2022-09-22) Ibrahim, Fausat Motunrayo; Osikabor, Benson; Olatunji, Bolanle Tawakalitu; Ogunwale, Grace Oluwatobi
    Natural and forest-rich ecosystems are determinants of environmental sustainability, which are threatened by forest land conversion for agricultural purposes, especially in less-developed contexts. Moreover, human behaviour is central to achieving the much desired ecologically balanced environment. Hence, a partly novel model informed by the theory of planned behaviour was used in the examination of forest land conversion for agricultural purposes. The study design was a cross-sectional survey targeted at a group of farmers of southwestern Nigeria. Data were collected using a structured questionnaire among 320 randomly selected crop farmers. Independent samples t test and one-way analysis of variance (ANOVA) were used to test the significance of difference in respondents’ forest conversion behaviour across subgroups of gender and age/education, respectively. Stepwise multiple linear regres sion was used to identify the determinants of forest conversion behaviour. Results showed that 87.8% of respondents had ever engaged in forest conversion. Gender and education had no significant effect on forest conversion behaviour (p > 0.05), but age did (p < 0.05). Attitude was the best determinant (β = 0.289, r = 0.510, R2 = 0.260, p < 0.001), subjective norm was better (β = 0.257, r = 0.496, R2 = 0.055, p < 0.001), while perceived behavioural control was good (β = 0.131, r = 0.398, p < 0.001, R2 = 0.012, p < 0.005). The three vari ables correlated with intention by a degree of 57.2% (multiple R = 0.572), while they explained 32.7% of the variance in intention (R2 =0.327). Intention was also found to be a significant determinant of behaviour (β = 0.222, r = 0.222, R2 = 0.049, p < 0.001). Middle age predisposes to, whereas younger and older age protects against greater extent of forest conversion. The partly novel model derived from the theory of planned behaviour proves the likely viability of the pursuit of socio-psychologically predicated interventions to enthrone forest conservation.