Growth, nutrient uptake capacities and tissue constituents of the macroalgae Cladophora vagabunda and Gracilaria tikvahiae related to site-specific nitrogen loading rates

1994 ◽  
Vol 121 (1) ◽  
pp. 175-185 ◽  
Author(s):  
P. Peckol ◽  
B. DeMeo-Anderson ◽  
J. Rivers ◽  
I. Valiela ◽  
M. Maldonado ◽  
...  
Keyword(s):  
Nutrient Uptake ◽  
Nitrogen Loading ◽  
Site Specific ◽  
Loading Rates ◽  
Gracilaria Tikvahiae

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.

Metagenomics reveals microbial community differences lead to differential nitrate production in anammox reactors with differing nitrogen loading rates

2020 ◽  
Vol 169 ◽  
pp. 115279 ◽  
Author(s):  
Wei Li ◽  
Jin-long Zhuang ◽  
Yuan-yuan Zhou ◽  
Fan-gang Meng ◽  
Da Kang ◽  
...  
Keyword(s):  
Microbial Community ◽  
Nitrogen Loading ◽  
Loading Rates ◽  
Nitrate Production

Comparison of quasisteady-state performance of the DEAMOX process under intermittent and continuous feeding and different nitrogen loading rates

2007 ◽  
Vol 2 (7) ◽  
pp. 894-900 ◽  
Author(s):  
Sergey Kalyuzhnyi ◽  
Marina Gladchenko ◽  
Arnold Mulder ◽  
Bram Versprille
Keyword(s):  
Nitrogen Loading ◽  
Loading Rates ◽  
Continuous Feeding

Abundance, Biomass, and Species Richness of Fish Communities in Relation to Nitrogen-Loading Rates of Waquoit Bay Estuaries

1996 ◽  
Vol 191 (2) ◽  
pp. 321-322 ◽  
Author(s):  
J. Tober ◽  
C. Fritz ◽  
E. LaBrecque ◽  
P. J. Behr ◽  
I. Valiela
Keyword(s):  
Species Richness ◽  
Fish Communities ◽  
Nitrogen Loading ◽  
Loading Rates ◽  
Waquoit Bay

Process performance and anammox community diversity in a deammonification reactor under progressive nitrogen loading rates for swine wastewater treatment

2020 ◽  
Vol 311 ◽  
pp. 123521 ◽  
Author(s):  
Angélica Chini ◽  
Camila Ester Hollas ◽  
Alice Chiapetti Bolsan ◽  
Bruno Venturin ◽  
Gabriela Bonassa ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Loading ◽  
Community Diversity ◽  
Swine Wastewater ◽  
Process Performance ◽  
Loading Rates
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