scholarly journals Balanced nutrient requirements for maize in the Northern Nigerian Savanna: Parameterization and validation of QUEFTS model

2019 ◽  
Vol 241 ◽  
pp. 107585 ◽  
Author(s):  
Bello M. Shehu ◽  
Bassam A. Lawan ◽  
Jibrin M. Jibrin ◽  
Alpha Y. Kamara ◽  
Ibrahim B. Mohammed ◽  
...  
Keyword(s):  
Nutrient Requirements ◽  
Nigerian Savanna

scholarly journals Balanced nutrient requirements for maize in the Northern Nigerian Savanna: Parameterization and validation of QUEFTS model

2019 ◽  
Author(s):  
Bello M. Shehu ◽  
Bassam A. Lawan ◽  
Jibrin M. Jibrin ◽  
Alpha Y. Kamara ◽  
Ibrahim B. Mohammed ◽  
...  
Keyword(s):  
Nutrient Uptake ◽  
Yield Potential ◽  
Nutrient Requirements ◽  
Potential Yield ◽  
Site Specific ◽  
Ecological Zones ◽  
Fertilizer Recommendations ◽  
Maize Grain ◽  
Nigerian Savanna ◽  
Agro Ecological Zones

AbstractEstablishing balanced nutrient requirements for maize (Zea mays L.) in the Northern Nigerian Savanna is paramount to develop site-specific fertilizer recommendations to increase maize yield, profits of farmers and avoid negative environmental impacts of fertilizer use. The model QUEFTS (QUantitative Evaluation of Fertility of Tropical Soils) was used to estimate balanced nitrogen (N), phosphorus (P) and potassium (K) requirements for maize production in the Northern Nigerian Savanna. Data from on-farm nutrient omission trials conducted in 2015 and 2016 rainy seasons in two agro-ecological zones in the Northern Nigerian Savanna (i.e. Northern Guinea Savanna “NGS” and Sudan Savanna “SS”) were used to parameterize and validate the QUEFTS model. The relations between indigenous soil N, P, and K supply and soil properties were not well described with the QUEFTS default equations and consequently new and better fitting equations were derived. The average fertilizer recovery fractions of N, P and K in the NGS were generally comparable with the QUEFTS default values, but lower recovery fractions of these nutrients were observed in the SS. The parameters of maximum accumulation (a) and dilution (d) in kg grain per kg nutrient for the QUEFTS model obtained were respectively 35 and 79 for N, 200 and 527 for P and 25 and 117 for K in the NGS zone and 32 and 79 for N, 164 and 528 for P and 24 and 136 for K in the SS zone. The model predicted a linear relationship between grain yield and above-ground nutrient uptake until yield reached about 50 to 60% of the yield potential. When the yield target reached 60% of the potential yield (i.e. 6.0 tonnes per hectare), the model showed above-ground nutrient uptake of 19.4, 3.3 and 23.0 kg N, P, and K, respectively, per one tonne of maize grain in the NGS, and 17.3, 5.3 and 26.2 kg N, P and K, respectively, per one tonne of maize grain in the SS. These results suggest an average NPK ratio in the plant dry matter of about 5.9:1:7.0 for maize in the NGS and 3.3:1:4.9 for maize in the SS. There was a close agreement between observed and parameterized QUEFTS predicted yields across the two agro-ecological zones (R2 = 0.70 for the NGS and 0.86 for the SS). We concluded that the QUEFTS model can be used for balanced nutrient requirement estimations and development of site-specific fertilizer recommendations for maize intensification in the Northern Nigerian Savanna.

Prey groups in the pellets of the barn owl Tyto alba (Scopoli) in the Nigerian savanna

2001 ◽  
Vol 39 (1) ◽  
pp. 38-44 ◽  
Author(s):  
L. M. Lekunze ◽  
A. U. Ezealor ◽  
T. Aken'ova
Keyword(s):  
Barn Owl ◽  
Tyto Alba ◽  
Nigerian Savanna

EURRECA’s Approach for Estimating Micronutrient Requirements

2011 ◽  
Vol 81 (4) ◽  
pp. 256-263 ◽  
Author(s):  
Christophe Matthys ◽  
Pieter van ‘t Veer ◽  
Lisette de Groot ◽  
Lee Hooper ◽  
Adriënne E.J.M. Cavelaars ◽  
...  
Keyword(s):  
Reference Values ◽  
Policy Decision ◽  
Individual Variability ◽  
The Body ◽  
Decision Makers ◽  
Nutrient Requirements ◽  
Factorial Approach ◽  
Dietary Reference Values ◽  
Health Policy Decision ◽  
Quantitative Integration

In Europe, micronutrient dietary reference values have been established by (inter)national committees of experts and are used by public health policy decision-makers to monitor and assess the adequacy of diets within population groups. The approaches used to derive dietary reference values (including average requirements) vary considerably across countries, and so far no evidence-based reason has been identified for this variation. Nutrient requirements are traditionally based on the minimum amount of a nutrient needed by an individual to avoid deficiency, and is defined by the body’s physiological needs. Alternatively the requirement can be defined as the intake at which health is optimal, including the prevention of chronic diet-related diseases. Both approaches are confronted with many challenges (e. g., bioavailability, inter and intra-individual variability). EURRECA has derived a transparent approach for the quantitative integration of evidence on Intake-Status-Health associations and/or Factorial approach (including bioavailability) estimates. To facilitate the derivation of dietary reference values, EURopean micronutrient RECommendations Aligned (EURRECA) is developing a process flow chart to guide nutrient requirement-setting bodies through the process of setting dietary reference values, which aims to facilitate the scientific alignment of deriving these values.

The nutritional consequences of foraging in primates: the relationship of nutrient intakes to nutrient requirements

1991 ◽  
Vol 334 (1270) ◽  
pp. 161-170 ◽  
Keyword(s):  
Food Selection ◽  
Nutrient Requirements ◽  
Nutrient Intakes ◽  
Protein Levels ◽  
Nutrient Density ◽  
High Nutrient ◽  
Relationship Of ◽  
The Relationship ◽  
High Dietary Protein ◽  
Growth And Reproduction

Many studies have examined the proportion of time that primates devote to feeding on various types of food, but relatively little is known about the intake rates associated with each food. However, the nutritional consequences of foraging can only be interpreted by comparing nutrient intakes with estimated nutrient requirements. The energy available to primates from ingested foods will depend both on the composition of the food and the extent to which various constituents, including fibre fractions, are digested. Both human and non-human primates have relatively low requirements for protein as a consequence of slow growth rates, small milk yields and relatively dilute milk. Because the nutrient demands of growth and reproduction are spread out over time, it appears that primates do not need to seek out foods of particularly high nutrient density, except perhaps during weaning. Although food selection in some species of primates appears to be correlated with the protein concentration of foods, it is unlikely that high dietary protein levels are required, at least when foods of balanced amino acid composition (such as leaves) are included in the diet.

scholarly journals Drivers of Macrophyte and Diatom Diversity in a Shallow Hypertrophic Lake

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1569
Author(s):  
Kateřina Šumberová ◽  
Ondřej Vild ◽  
Michal Ducháček ◽  
Martina Fabšičová ◽  
Jan Potužák ◽  
...  
Keyword(s):  
Fish Farming ◽  
Spatial Diversity ◽  
Spatiotemporal Variability ◽  
Water Level Fluctuations ◽  
Nutrient Requirements ◽  
Diatom Assemblages ◽  
Climatic Extremes ◽  
Growing Seasons ◽  
High Species Richness ◽  
Different Parts

We studied macrophyte and diatom assemblages and a range of environmental factors in the large hypertrophic Dehtář fishpond (Southern Bohemia, Czech Republic) over the course of several growing seasons. The spatial diversity of the environment was considered when collecting diatoms and water samples in three distinct parts of the fishpond, where automatic sensor stations continually measuring basic factors were established. Macrophytes were mapped in 30 segments of the fishpond littoral altogether. High species richness and spatiotemporal variability were found in assemblages of these groups of autotrophs. Water level fluctuations, caused by the interaction of fish farming management and climatic extremes, were identified as one of the most important factors shaping the structure and species composition of diatom and macrophyte assemblages. The distance of the sampling sites from large inflows reflected well the spatial variability within the fishpond, with important differences in duration of bottom drainage and exposure to disturbances in different parts of the fishpond. Disturbances caused by intensive wave action are most probably a crucial factor allowing the coexistence of species with different nutrient requirements under the hypertrophic conditions of the Dehtář fishpond. Due to a range of variables tested and climatic extremes encountered, our study may be considered as a basis for predictive model constructions in similar hypertrophic water bodies under a progressing climate change.

Living costs and welfare ratios in Western Europe: new estimates using a linear programming model

2021 ◽  
Author(s):  
Luis Felipe Zegarra
Keyword(s):  
Linear Programming ◽  
Western Europe ◽  
Programming Model ◽  
Living Standards ◽  
Linear Programming Model ◽  
Nutrient Requirements ◽  
European Cities

Abstract This study provides new estimates on welfare ratios for London, Amsterdam, Paris, Strasbourg, Munich, and Leipzig for 1600–1850. I use a linear programming model to compute the basket that minimizes the food cost subject to nutrient requirements. For a balanced nutrition, I take into consideration that people should ingest not only calories and proteins, but also fat, iron, and some basic vitamins. The results suggest that living standards in Western Europe were lower than previously thought. However, like previous studies, this article suggests that welfare ratios in London were higher than in other European cities.

scholarly journals Predicting Daily Dry Matter Intake Using Feed Intake of First Two Hours after Feeding in Mid and Late Lactation Dairy Cows with Fed Ration Three Times Per Day

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 104
Author(s):  
Shulin Liang ◽  
Chaoqun Wu ◽  
Wenchao Peng ◽  
Jian-Xin Liu ◽  
Hui-Zeng Sun
Keyword(s):  
Dairy Cows ◽  
Milk Yield ◽  
Dry Matter ◽  
Prediction Equation ◽  
Dry Matter Intake ◽  
Validation Dataset ◽  
Nutrient Requirements ◽  
Independent Dataset ◽  
Lactating Dairy Cows ◽  
Proposed Model

The objective of this study was to evaluate the feasibility of using the dry matter intake of first 2 h after feeding (DMI-2h), body weight (BW), and milk yield to estimate daily DMI in mid and late lactating dairy cows with fed ration three times per day. Our dataset included 2840 individual observations from 76 cows enrolled in two studies, of which 2259 observations served as development dataset (DDS) from 54 cows and 581 observations acted as the validation dataset (VDS) from 22 cows. The descriptive statistics of these variables were 26.0 ± 2.77 kg/day (mean ± standard deviation) of DMI, 14.9 ± 3.68 kg/day of DMI-2h, 35.0 ± 5.48 kg/day of milk yield, and 636 ± 82.6 kg/day of BW in DDS and 23.2 ± 4.72 kg/day of DMI, 12.6 ± 4.08 kg/day of DMI-2h, 30.4 ± 5.85 kg/day of milk yield, and 597 ± 63.7 kg/day of BW in VDS, respectively. A multiple regression analysis was conducted using the REG procedure of SAS to develop the forecasting models for DMI. The proposed prediction equation was: DMI (kg/day) = 8.499 + 0.2725 × DMI-2h (kg/day) + 0.2132 × Milk yield (kg/day) + 0.0095 × BW (kg/day) (R2 = 0.46, mean bias = 0 kg/day, RMSPE = 1.26 kg/day). Moreover, when compared with the prediction equation for DMI in Nutrient Requirements of Dairy Cattle (2001) using the independent dataset (VDS), our proposed model shows higher R2 (0.22 vs. 0.07) and smaller mean bias (−0.10 vs. 1.52 kg/day) and RMSPE (1.77 vs. 2.34 kg/day). Overall, we constructed a feasible forecasting model with better precision and accuracy in predicting daily DMI of dairy cows in mid and late lactation when fed ration three times per day.

scholarly journals Use of Pelleted Diets in Commercially Farmed Decapods during Juvenile Stages: A Review

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1761
Author(s):  
Mohd Amran Aaqillah-Amr ◽  
Ariffin Hidir ◽  
Mohamad N. Azra ◽  
Abdul Rahim Ahmad-Ideris ◽  
Muyassar H. Abualreesh ◽  
...  
Keyword(s):  
Feeding Behavior ◽  
Optimal Growth ◽  
Careful Consideration ◽  
Physical Characteristics ◽  
Market Demand ◽  
Nutrient Requirements ◽  
Natural Diet ◽  
Feed Formulation ◽  
Juvenile Stages ◽  
Formulated Feed

The increasing market demand for decapods has led to a considerable interest in cultivating decapod species at a larger scale. Following the development of hatchery technologies, most research has focused on the development of formulated feeds for commercially farmed decapods once they enter the juvenile stages. The use of formulated feed for decapods at a commercial scale is still in the early stages. This is probably because of the unique feeding behavior that decapods possess: being robust, slow feeders and bottom dwellers, their feeding preferences change during the transition from pelagic larvae to benthic juveniles as their digestive systems develop and become more complex. The current practice of decapod aquaculture involves the provision of juveniles with food such as natural diet, live feed, and formulated feed. Knowledge of nutrient requirements enables diets to be better formulated. By manipulating the levels of proteins and lipids, a formulated feed can be expected to lead to optimal growth in decapods. At the same time, the pellet’s physical characteristics are important factors to be considered upon formulating commercially farmed decapod feeds, considering the unique feeding behavior of the decapod. However, most published studies on decapod nutrition lack data on the physical characteristics of the feed types. Thus, it is difficult to establish a standard feed formulation that focuses on the physical pellet properties. Moreover, careful consideration must be given to the feeding behavior of species, as decapods are known as bottom feeders and are robust in terms of handling feed. Information on the pellet forms, diet composition, and unique feeding behaviors in commercially farmed decapods is gathered to suggest potential better formulated diets that can optimize growth and reproduction. Thus, the purpose of this review is to summarize the information that has been published to date and to come up with suggestions on ways to improve the feed formulation in decapods that comply with their feeding behavior and nutrient requirements. Further research is needed to explore the potential of the pelleted feed at the adult stage so the decapod can take full advantage of the nutrients present in the pellets.

scholarly journals Dynamic modeling of nutrient use and individual requirements of lactating sows1

2019 ◽  
Vol 97 (7) ◽  
pp. 2822-2836 ◽  
Author(s):  
Raphaël Gauthier ◽  
Christine Largouët ◽  
Charlotte Gaillard ◽  
Laetitia Cloutier ◽  
Frédéric Guay ◽  
...  
Keyword(s):  
Feed Intake ◽  
Average Daily Gain ◽  
Individual Performance ◽  
Maintenance Cost ◽  
Nutrient Requirements ◽  
Modeling Approach ◽  
Ex Post ◽  
Nutrient Use ◽  
The Mean ◽  
On Farm

AbstractNutrient requirements of sows during lactation are related mainly to their milk yield and feed intake, and vary greatly among individuals. In practice, nutrient requirements are generally determined at the population level based on average performance. The objective of the present modeling approach was to explore the variability in nutrient requirements among sows by combining current knowledge about nutrient use with on-farm data available on sows at farrowing [parity, BW, backfat thickness (BT)] and their individual performance (litter size, litter average daily gain, daily sow feed intake) to estimate nutrient requirements. The approach was tested on a database of 1,450 lactations from 2 farms. The effects of farm (A, B), week of lactation (W1: week 1, W2: week 2, W3+: week 3 and beyond), and parity (P1: 1, P2: 2, P3+: 3 and beyond) on sow performance and their nutrient requirements were evaluated. The mean daily ME requirement was strongly correlated with litter growth (R2 = 0.95; P < 0.001) and varied slightly according to sow BW, which influenced the maintenance cost. The mean daily standardized ileal digestible (SID) lysine requirement was influenced by farm, week of lactation, and parity. Variability in SID lysine requirement per kg feed was related mainly to feed intake (R2 = 0.51; P < 0.001) and, to a smaller extent, litter growth (R2 = 0.27; P < 0.001). It was lowest in W1 (7.0 g/kg), greatest in W2 (7.9 g/kg), and intermediate in W3+ (7.5 g/kg; P < 0.001) because milk production increased faster than feed intake capacity did. It was lower for P3+ (6.7 g/kg) and P2 sows (7.3 g/kg) than P1 sows (8.3 g/kg) due to the greater feed intake of multiparous sows. The SID lysine requirement per kg of feed was met for 80% of sows when supplies were 112 and 120% of the mean population requirement on farm A and B, respectively, indicating higher variability in requirements on farm B. Other amino acid and mineral requirements were influenced in the same way as SID lysine. The present modeling approach allows to capture individual variability in the performance of sows and litters according to farm, stage of lactation, and parity. It is an initial step in the development of new types of models able to process historical farm data (e.g., for ex post assessment of nutrient requirements) and real-time data (e.g., to control precision feeding).

Small change: individual farm work and collective life in a western Nigerian savanna town, 1969–88

Africa ◽  
1992 ◽  
Vol 62 (4) ◽  
pp. 465-489 ◽  
Author(s):  
Jane I. Guyer
Keyword(s):  
Farming System ◽  
Farm Size ◽  
Small Scale ◽  
Cropping Patterns ◽  
Farm Work ◽  
Small Change ◽  
Returns To Labour ◽  
Individual Farm ◽  
Ceremonial Life ◽  
Nigerian Savanna

AbstractA comparison of data collected in western Nigeria (the Yoruba area) in 1968-69 and 1988 suggests that small-scale male farmers' patterns of work remained quite similar in the total amount of work they did and in the amount by task. This finding seemed surprising, since the study area lies in the food supply hinterland of the rapidly growing cities of Ibadan, Lagos and Abeokuta. The farming system has changed in several ways in response to increased urban demand and improved transport, including an increase in farm size on the part of male farmers. Changed cropping patterns, the increased use of hired labour and somewhat increased returns to labour seem only partly to account for the persistence. Analysis of the work data in terms of its timing, rather than in terms of time, suggests that farmers are tending to work at the same task in longer stretches ofconsecutive days, and this, in turn, is related to the marked rescheduling of traditional ceremonial life and the intensified politico-associational life moved to the weekend.

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