Effects of lupin-wheat rotations on soil fertility, crop disease and crop yields

1984 ◽  
Vol 24 (127) ◽  
pp. 595 ◽  
Author(s):  
TG Reeves ◽  
A Ellington ◽  
HD Brooke

Three experiments, begun in successive years, were conducted between 1974 and 1979 in north-eastern Victoria to investigate the effects of rotating wheat (cv. Olympic) and 'sweet' lupins (Lupinus angustifolius cv. Uniharvest) on crop yields, soil fertility and crop diseases. The grain yield of continuous wheat was 2.58 t/ha and of continuous lupins 0.66 t/ha (P<0.05). Wheat, grown after a lupin crop, yielded 750 kg/ha more than wheat after wheat, and a second wheat crop, after lupins, yielded 420 kg/ha more than a third successive wheat crop. Lupins, grown after wheat, yielded 50-165% more than lupins after lupins. Grain nitrogen of wheat was significantly increased after lupins (P<0.01). Differences in soil mineral nitrogen were apparent ten weeks after sowing, with mean nitrogen levels of 37 and 55 kg/ha under wheat and lupins, respectively. Soil mineral nitrogen (0-20 cm) was consistently greater after lupins than after wheat (P<0.01) when measured just before seeding the succeeding crop. Overall, mean accretion of mineral nitrogen under lupins was 4 1 kg/ha.year. Residual nitrogen from lupins, after one succeeding wheat crop had been grown, was also evident (mean 23 kg/ha). Crop rotation influenced the incidence of crop diseases in wheat and lupins. Lupins after lupins suffered severely from brown leaf spot (Pleiochaeta setosa), up to 63% of plants being infected compared with only 18% after wheat. Disease incidence (mainly Gaeumannomyces graminis) in wheat increased from less than 1% in the first year of cropping, to 36% infection in year 3. When wheat was grown after lupins, disease incidence was negligible.

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.


1984 ◽  
Vol 24 (125) ◽  
pp. 244 ◽  
Author(s):  
JA Doughton ◽  
J Mackenzie

A field trial was carried out on a black earth (Waco series) at Cambooya on the Eastern Darling Downs to compare the effect of black gram, green gram, grain sorghum and a summer fallow on soil mineral nitrogen (NO3-N + NH4-N) and the yield of grain sorghum grown in the following summer. The initial sorghum treatment severely depleted soil mineral nitrogen to 120 cm; even after a 173-d fallow, there was still 34 kg/ha less nitrogen present than initially in this treatment. Black and green gram also reduced levels of soil mineral nitrogen during crop growth, but these recovered to exceed pre-trial levels by 29 and 42 kg N/ha, respectively, after a winter fallow. The fallow treatment accumulated 100 kg N/ha of mineral nitrogen between January and October, but mineralization was markedly reduced from August to October. Sorghum grown on all plots in the second summer responded markedly to prior treatments, and grain yields and responses to nitrogen applied at 0, 34 and 68 kg N/ha reflected mineral nitrogen levels at planting. Yields of sorghum grain obtained without fertilizer after black gram, green gram and fallow were 8333, 7477 and 9663 kg/ha, respectively, compared with 4658 kg/ha after sorghum. Prior crops of both grams increased sorghum yield as much as a fertilizer application of 68 kg N/ha.


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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