Soil phosphorus status of organic farming in Flanders: an overview and comparison with the conventional management

2005 ◽  
Vol 21 (4) ◽  
pp. 415-421 ◽  
Author(s):  
A. Van Den Bossche ◽  
S. De Neve ◽  
G. Hofman

2018 ◽  
Author(s):  
Samiran Banerjee ◽  
Florian Walder ◽  
Lucie Büchi ◽  
Marcel Meyer ◽  
Alain Y. Held ◽  
...  

AbstractRoot-associated microbes play a key role in plant performance and productivity, making them important players in agroecosystems. So far, very few studies have assessed the impact of different farming systems on the root microbiota and it is still unclear whether agricultural intensification influences network complexity of microbial communities. We investigated the impact of conventional, no-till and organic farming on wheat root fungal communities usingPacBio SMRT sequencingon samples collected from 60 farmlands in Switzerland. Organic farming harboured a much more complex fungal network than conventional and no-till farming systems. The abundance of keystone taxa was the highest under organic farming where agricultural intensification was the lowest. The occurrence of keystone taxa was best explained by soil phosphorus levels, bulk density, pH and mycorrhizal colonization. The majority of keystone taxa are known to form arbuscular mycorrhizal associations with plants and belong to the ordersGlomerales,Paraglomerales, andDiversisporales. Supporting this, the abundance of mycorrhizal fungi in roots and soils was also significantly higher under organic farming. To our knowledge, this is the first study to report mycorrhizal keystone taxa for agroecosystems, and we demonstrate that agricultural intensification reduces network complexity and the abundance of keystone taxa in the root microbiota.





2004 ◽  
Vol 35 (11-12) ◽  
pp. 1635-1644 ◽  
Author(s):  
Myungsu Park ◽  
Olayvanh Singvilay ◽  
Wansik Shin ◽  
Eunhee Kim ◽  
Jongbae Chung ◽  
...  


2012 ◽  
Vol 610-613 ◽  
pp. 2968-2973 ◽  
Author(s):  
Ya Jie Zhao ◽  
Xin Chen ◽  
Yi Shi ◽  
Cai Yan Lu ◽  
Bin Huang ◽  
...  

The vegetable utilization rate of phosphorus fertilizer in greenhouse condition was low in the season of fertilizer application, resulting in phosphorus accumulation in the top soil year after year. The risk of phosphorus loss through leaching increased under the circumstance of inappropriate watering management and fertilization. In this study, leaching experiments using columns packed with a greenhouse soil with different soil phosphorus status (low, medium and high levels) were carried out under greenhouse condition to investigate the impact of fertilizer application on phosphorus leaching from greenhouse soil. The fertilization treatments included no fertilizer [CK], organic manure and chemical fertilizer [M+NPK], organic manure [M], chemical fertilizer [NPK]. The vertical migration and leaching loss of soil phosphorus were measured. Results were as follows: (1) total phosphorus (TP) content increased with the extension of leaching time. In the low-level- and medium-level-phosphorus greenhouse soils, TP concentration in the effluent increased with the application of manure; (2) In the high-level-phosphorus greenhouse soil, phosphorus in the effluent from the treatment with the use of fertilizer was the highest TP, with accumulative leaching amount of 2.85 mg in 51 days. The leaching of phosphorus became small after 36 days of leaching experiment. Our study showed that application of manure and chemical fertilizer at proper rates according to soil phosphorus status is beneficial to reduce the leaching loss of phosphorus to the environment.



1978 ◽  
Vol 50 (4) ◽  
pp. 305-316 ◽  
Author(s):  
Erkki Aura

Phosphorus uptake by oats in pot experiments was compared with phosphorus test values obtained for experimental soils. Phosphorus was extracted from the soil using acid ammonium acetate solution, Bray 1 solution, Olsen solution, ammonium fluoride, distilled water and anion exchange resin. Intensity values were determined by equilibrating the soils with 0.01 M CaCl2 solution. Soil samples were collected from 30 mineral soils. The best test for phosphorus status proved to be the anion exchange resin method. Good results were also obtained with simple water extraction. An advantage of the water and resin method is that the microstructure of the soil is not substantially changed when using these methods. An intensity measurement was not in itself sufficient for analysis of the phosphorus status, since the intensity drops rapidly when soil releases phosphorus.



Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1626
Author(s):  
Anne Merot ◽  
Nathalie Smits

Given the need to reduce pesticide use and rising consumer demand for healthy food, organic vineyard areas have increased since 2000. Converting to organic farming requires numerous changes in pest and disease management, fertilization and weeding techniques. These changes can lead to difficulties in sustaining yields. Some studies have highlighted higher yields in conventional farming than in organic agriculture, but knowledge on yield dynamics during conversion is lacking. A set of 26 plots, under conventional management and in conversion to organic farming, were monitored from 2013 to 2016 in southern France throughout the three-year conversion phase to investigate the dynamics of grape yield and yield components. The survey showed that the yield and yield components remained similar levels as in conventional farming from the third year of conversion. However, the first two years of conversion were a transitional and less successful period during which yield and yield components decreased. Based on the in-depth analysis of the yield components, we have put forwards hypotheses on the processes at play and technical advice that could support winegrowers as they convert to organic farming.



Pedosphere ◽  
2019 ◽  
Vol 29 (1) ◽  
pp. 70-81 ◽  
Author(s):  
Claude-Alla JOSEPH ◽  
Lotfi KHIARI ◽  
Jacques GALLICHAND ◽  
Marc HÉBERT ◽  
Ned BEECHER


1983 ◽  
Vol 31 (3) ◽  
pp. 231 ◽  
Author(s):  
B Dell ◽  
JF Loneragan ◽  
D Plaskett

The responses of five Eucalyptus species (E. calophylla, E. globulus, E. maculata, E. marginata and E. resinifera) to four levels of calcium phosphate and three levels of lime (CaCO3) on a granitic pallid zone clay of pH 4.0 from a jarrah forest soil were examined in a glasshouse trial. In the presence of a complete fertilizer, except for lime and phosphate, seedlings made poor growth and had weak root systems with few fine roots. Application of calcium phosphate promoted shoot and root growth in all species. Application of lime had no effect on plant growth except at very high levels (7.1 g per kg soil), where it induced iron deficiency chlorosis in some species. All species achieved maximum yield with an application of calcium phosphate of between 30 and 300 mg per kg soil. Phosphorus concentrations in individual leaves and shoots were low (0.1-0.3%) and responded weakly to phosphate treatments. Phosphorus concentrations in stems responded strongly to increasing phosphate applications over the whole range of phosphate supply. We suggest that stem tissues may be used to indicate the phosphorus status of eucalypts.



1999 ◽  
Vol 39 (2) ◽  
pp. 161 ◽  
Author(s):  
G. D. Batten ◽  
N. A. Fettell ◽  
J. A. Mead ◽  
M. A. Khan

Experiments were sown at Cowra and Condobolin to determine the effect of sowing time (April–June) on the response to and utilisation of phosphorus by the wheat cultivar Osprey which requires vernalisation. Crops sown in April needed only 0–2 kg/ha of applied phosphorus to achieve 90% of the maximum yield for the site. This contrasts with crops sown at the traditional sowing time in May–June which needed from 11.5 kg P/ha, on a site with a moderate soil phosphorus status, to 36 kg P/ha, on a site with a very low soil phosphorus status, to produce 90% of the site maximum yield. Crops sown in April had higher yields and even without applied phosphorus accumulated more phosphorus (kg/ha) than crops sown in June with 40 kg P/ha. Crops sown in April had a lower dry matter harvest index, a lower phosphorus harvest index, produced less grain per kilogram of phosphorus in the shoots at maturity, and had a higher grain phosphorus concentration than crops sown in June. Grain protein was not affected by sowing date or the amount of phosphorus applied at sowing. At 90% of maximum dry matter yield shoots had 0.14–0.20% phosphorus at growth stage 30. The critical concentration of phosphorus in grain at 90% maximum grain yield increased with yield from 0.19 to 0.25% phosphorus. Farmers who sow wheat in April can achieve optimum yields with lower inputs of fertiliser phosphorus. However, this benefit will be offset by a lower phosphorus-use efficiency and more rapid depletion of phosphorus reserves from the soil.



1980 ◽  
Vol 20 (105) ◽  
pp. 477
Author(s):  
GE Rayment ◽  
RC Bruce ◽  
BG Cook

Phosphorus topdressing experiments (rates to 60 kg P ha-1) on 18 commercial Desmodium intortum cv. Greenleaf/grass pastures were conducted over a 4-year period in south-east Queensland. The aim was to determine whether yield responses, which occurred only in the Greenleaf component at six sites, could be predicted using soil or plant chemical tests. Acid-(0.005 M H2SO4) and bicarbonate-(0.5 M NaHCO3) extractable tests of phosphorus status in 0-10 cm soil samples each explained about 60% of the variance in Greenleaf relative yields. The residual variance was not significantly reduced by the inclusion of terms for total soil nitrogen, total soil phosphorus, exchangeable calcium and pH into the independent variable. These empirical soil phosphorus tests had higher predictive value than plant tests based on phosphorus concentrations in tops and diagnostic samples of Greenleaf. With both acid- and bicarbonate-extractable phosphorus, yield responses are likely in the Greenleaf component when phosphorus levels in most soils are below 22 ppm. Above 29 ppm, no response would be expected



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