Effects of different manuring systems with and without biogas digestion on soil mineral nitrogen content and on gaseous nitrogen losses (ammonia, nitrous oxides)

2009 ◽  
Vol 30 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Kurt Möller ◽  
Walter Stinner
1985 ◽  
Vol 25 (3) ◽  
pp. 603 ◽  
Author(s):  
A Petch ◽  
RW Smith

Wheat was grown in a series of 1:1 rotation cycles with sweet lupins over 8 years on three sites in Western Australia. Grain yield of wheat was the main test used to compare five lupin management treatments with a control treatment, 'no-lupins'. The lupins were cut as for silage, cut as for hay, or harvested as mature grain, the stubble being burnt or removed in summer, or turned into the soil the next autumn. Nitrogen taken up in the lupins and in the wheat was measured, as well as soil mineral nitrogen in the top 10 cm in the final year. Lupin yield and nitrogen content within any year were similar over all treatments. As much nitrogen was removed in hay and silage as in mature lupins, but wheat yielded most grain after the 'silage' and 'hay' treatments, and least after 'no-lupins' or after the 'remove' and 'turn-in' stubble treatments. Nitrogen uptakes in young wheat plants point to treatment effects due to differences in nitrogen availability, but the treatments also caused different weed populations which at least partially affected wheat yields. Herbicide control of encroaching weeds in the lupins raised soil nitrate levels the following summer and increased subsequent wheat yields.


2009 ◽  
Vol 31 (2) ◽  
pp. 103-109 ◽  
Author(s):  
Branko Kramberger ◽  
Anastazija Gselman ◽  
Marjan Janzekovic ◽  
Mitja Kaligaric ◽  
Brigita Bracko

1965 ◽  
Vol 5 (18) ◽  
pp. 310 ◽  
Author(s):  
RR Storrier

Water, in addition to the natural rainfall, was applied at five different stages of crop development to Heron wheat growing on a highly fertile soil. Dry matter yield, grain yield, the grain yield parameters (ear number, grain number per ear, weight per grain), and nitrogen content were measured. Changes in soil mineral nitrogen content as a consequence of water application and subsequent plant uptake were also studied. A single application of water at jointing, and treatments involving watering at all pre-anthesis stages during a period of moisture stress, increased straw and grain yields and floret development, as reflected in grain number per ear. Water applied after anthesis controlled to some degree the loss of dry matter and plant nitrogen exhibited by a maturing wheat crop. The number of tillers produced, the number surviving, or the number of ears were not increased by adding water at any stage of development. The increased grain yield that followed late additions of water was due to increases in the weight per grain. The addition of water during the jointing to milk stage increased the uptake of mineral nitrogen by the crop, to a depth of 30 inches. No increase in the mineralization of organic nitrogen was detected by soil analysis, but an approximate balance sheet indicated that mineralization, which was occurring during the growing season, was further stimulated by watering.


Geoderma ◽  
2018 ◽  
Vol 326 ◽  
pp. 9-21 ◽  
Author(s):  
Masuda Akter ◽  
Heleen Deroo ◽  
Eddy De Grave ◽  
Toon Van Alboom ◽  
Mohammed Abdul Kader ◽  
...  

1999 ◽  
Vol 50 (2) ◽  
pp. 115-125 ◽  
Author(s):  
Maria Stenberg ◽  
Helena Aronsson ◽  
Börje Lindén ◽  
Tomas Rydberg ◽  
Arne Gustafson

2009 ◽  
Vol 21 ◽  
pp. 13-24 ◽  
Author(s):  
Y. Conrad ◽  
N. Fohrer

Abstract. This study provides results for the optimization strategy of highly parameterized models, especially with a high number of unknown input parameters and joint problems in terms of sufficient parameter space. Consequently, the uncertainty in model parameterization and measurements must be considered when highly variable nitrogen losses, e.g. N leaching, are to be predicted. The Bayesian calibration methodology was used to investigate the parameter uncertainty of the process-based CoupModel. Bayesian methods link prior probability distributions of input parameters to likelihood estimates of the simulation results by comparison with measured values. The uncertainty in the updated posterior parameters can be used to conduct an uncertainty analysis of the model output. A number of 24 model variables were optimized during 20 000 simulations to find the "optimum" value for each parameter. The likelihood was computed by comparing simulation results with observed values of 23 output variables including soil water contents, soil temperatures, groundwater level, soil mineral nitrogen, nitrate concentrations below the root zone, denitrification and harvested carbon from grassland plots in Northern Germany for the period 1997–2002. The posterior parameter space was sampled with the Markov Chain Monte Carlo approach to obtain plot-specific posterior parameter distributions for each system. Posterior distributions of the parameters narrowed down in the accepted runs, thus uncertainty decreased. Results from the single-plot optimization showed a plausible reproduction of soil temperatures, soil water contents and water tensions in different soil depths for both systems. The model performed better for these abiotic system properties compared to the results for harvested carbon and soil mineral nitrogen dynamics. The high variability in modeled nitrogen leaching showed that the soil nitrogen conditions are highly uncertain associated with low modeling efficiencies. Simulated nitrate leaching was compared to more general, site-specific estimations, indicating a higher leaching during the seepage periods for both simulated grassland systems.


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