Agriculture

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Browsing Agriculture by Subject "ACE: Dryland Agriculture"

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    Adapting the QUEFTS model to predict attainable yields when training data are characterized by imperfect management
    (Field Crops Research, 2021-03-31) Ravensbergen, Arie Pieter Paulus; Chamberlin, Jordan
    Understanding yield responses to nutrient application is a key input for extension advice and strategic agricultural investments in developing countries. A commonly used model for yield responses to nutrient inputs in tropical smallholder farming systems is QUEFTS (QUantitative Evaluation of the Fertility of Tropical Soils). While QUEFTS has a strong conceptual foundation, a key assumption is that nutrients are the only limiting factors. One implication of this is the required assumption of ‘perfect management’. This may be problematic in the application of QUEFTS in smallholder farming systems with a wide variety of yield limiting factors. In a previous study, QUEFTS was calibrated using farm trials in two major maize production zones in Nigeria. To reduce observed variability in correlations between estimated soil nutrient (N, P, K) supply and soil parameters (e.g. soil organic carbon, soil pH; step 1 of QUEFTS) a Mahalanobis distance method was used to remove data points not adhering to expected correlations. In this study, we assessed an alternative approach: can the QUEFTS model be adapted to fit smallholder farming systems and associated variation in management? Using 676 observations from the same nutrient omission trials in two major maize production zones in Nigeria, we compare a standard linear regression approach with a quantile regression approach to calibrate QUEFTS. We find that under the standard linear regression approach, there is a poor relation between predicted and observed yields. Using quantile regression, however, QUEFTS performed better at predicting attainable yields – defined as the 90th percentile of observed yields – under a wide variety of production conditions. Our results indicate that using quantile regression as a way to predict attainable yields, is a useful alternative implementation of QUEFTS in smallholder farming systems with high variability in management and other characteristics.
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    Growth performance and in vivo nutrients digestibility of growing Yankasa Ram Lambs fed diets containing graded levels of sesame residue
    (J. Anim. Health Prod., 2021-02-17) . Adeola, Emmanuel A.; Garba, Yusuf
    The study was carried out to evaluate the effect of including sesame residue (SR) in the diets of Yankasa ram lambs on feed intake, body weight gain, and nutrients digestibility. Twelve Yankasa ram lambs (initial body weight of 20.08 ± 3.08kg) were allotted to three dietary treatments containing 0, 20 and 30% SR (A, B and C) respectively. A completely randomized design was used for the study which lasted twelve weeks. The results revealed that animals fed 30% inclusion level had higher dry matter, nitrogen free extract and ether extract intakes, which varied among the treatments. Organic matter, neutral detergent fiber and acid detergent fiber digestibilities were higher for the lambs fed 0% SR. Inclusion of sesame residue up to 30% in the diet of growing Yankasa lambs improved nutrients intake without adverse effects on growth performance. It is thus recommended that sesame residue could be incorporated in the diets of growing Yankasa lambs at 30% inclusion level for reduced feed cost in Sudan Savanna agro-ecological zone of Nigeria
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    Increasing temperature elevates the variation and spatial differentiation of pesticide tolerance in a plant pathogen
    (Evolutionary Applications, 2021-01-13) Lurwanu, Yahuza; Wang, Yan-Ping; Wu, E-Jiao
    ,Climate change and pesticide resistance are two of the most imminent challenges human society is facing today. Knowledge of how the evolution of pesticide resistance may be affected by climate change such as increasing air temperature on the planet is important for agricultural production and ecological sustainability in the future but is lack in scientific literatures reported from empirical research. Here, we used the azoxystrobin-Phytophthora infestans interaction in agricultural systems to investigate the contributions of environmental temperature to the evolution of pesticide resistance and infer the impacts of global warming on pesticide efficacy and future agricultural production and ecological sustainability. We achieved this by comparing azoxystrobin sensitivity of 180 P. infestans isolates sampled from nine geographic locations in China under five temperature schemes ranging from 13 to 25°C. We found that local air temperature contributed greatly to the difference of azoxystrobin tolerance among geographic populations of the pathogen. Both amongpopulation and within-population variations in azoxystrobin tolerance increased as experimental temperatures increased. We also found that isolates with higher azoxystrobin tolerance adapted to a broader thermal niche. These results suggest that global warming may enhance the risk of developing pesticide resistance in plant pathogens and highlight the increased challenges of administering pesticides for effective management of plant diseases to support agricultural production and ecological sustainability under future thermal conditions.
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    Investigating the effect of in vitro gastrointestinal digestion on the stability, bioaccessibility, and biological activities of baobab (Adansonia digitata) fruit polyphenolics
    (LWT, 2021) Ismail, Balarabe B.; Guo, Mingming; Pu, Yunfeng
    Baobab (Adansonia digitata) fruit had received growing attention for its myriad nutritional and medicinal benefits, including those from its polyphenol-rich profile and powerful antioxidant activity. The current study evaluated the bioaccessibility of phenolic constituents and antioxidant capacity of baobab fruit pulp (BFP) and its byproduct, the baobab fruit shell (BFS), upon in vitro digestion. In general, the in vitro digestion reduced phenolic contents and antioxidant capacity; however, several flavonoids, particularly quercetin, proanthocyanidin, proanthocyanidins B1 and B2 were highly bioaccessible. Specifically, a significant increase in the bioaccessibility of proanthocyanidins (173%) in BFS was observed following gastric digestion, possibly due to hydrolysis of proanthocyanidin isomers. Moreover, a significantly higher bioaccessibility of proanthocyanidin B2 (170%) and quercetin (304%) in BFP, and proanthocyanidin (363%) in BFS was also observed following intestinal digestion probably due to pancreatin effect on the complex food matrix or the depolymerisation of insoluble proanthocyanidin and quercetin conjugates induced by the increase in pH. A considerable α-amylase and α-glucosidase inhibition in all samples (>50% inhibition) were observed following the in vitro digestion. Hence, both BFP and BFS are good sources of bio accessible polyphenolics that could be utilised as ingredients in functional foods.