The role of bacteria in N fixing from atmosphere and Phosphate solubilizing bacteria has apparently not been taken into account by the authors.
If soil has adequate quantity of N fixing and Phosphate solubilizing bacteria, then there is no need to add chemical fertilizers like Urea and Superphosphate and very high yields without, or with very low dose of, chemical fertilizers are possible. So the concept of N and P limitation in agriculture is not entirely correct. Overuse of chemical fertilizers is in fact responsible for decline in beneficial bacteria in soils. However most agriculture scientists think dosing more chemical fertilizers is necessary to increase yields, when in fact reduction in chemical fertilizers and increase in the beneficial bacteria will be more beneficial. A few links to papers about bacteria in agriculture - Nitrogen - http://www.yourarticlelibrary.com/bacteria/importance-of-bacteria-to-agriculture-and-industries-1049-words/6789/ Phosphate https://en.wikipedia.org/wiki/Phosphate_solubilizing_bacteria https://hal.archives-ouvertes.fr/hal-00886352/document http://www.currentscience.ac.in/Volumes/108/07/1280.pdf http://www.uaar.edu.pk/jabs/files/jabs_1_1_6.pdf http://www.springerplus.com/content/pdf/2193-1801-2-587.pdf Regards Bhaskar On Friday, 3 July 2015 02:19:08 UTC+5:30, andrewjlockley wrote: > > Poster's note : relevant to BECS, CROPS and other bioremediation of CO2 > pollution > > http://www.nature.com/ngeo/journal/v8/n6/abs/ngeo2413.html > > Future productivity and carbon storage limited by terrestrial nutrient > availability > > William R. Wieder, Cory C. Cleveland, W. Kolby Smith & Katherine Todd-Brown > > Nature Geoscience 8, 441–444 (2015) doi:10.1038/ngeo2413 > 20 April 2015 > > The size of the terrestrial sink remains uncertain. This uncertainty > presents a challenge for projecting future climate–carbon cycle feedbacks1, > 2, 3, 4. Terrestrial carbon storage is dependent on the availability of > nitrogen for plant growth5, 6, 7, 8, and nitrogen limitation is > increasingly included in global models9, 10, 11. Widespread phosphorus > limitation in terrestrial ecosystems12 may also strongly regulate the > global carbon cycle13, 14, 15, but explicit considerations of phosphorus > limitation in global models are uncommon16. Here we use global > state-of-the-art coupled carbon–climate model projections of terrestrial > net primary productivity and carbon storage from 1860–2100; estimates of > annual new nutrient inputs from deposition, nitrogen fixation, and > weathering; and estimates of carbon allocation and stoichiometry to > evaluate how simulated CO2 fertilization effects could be constrained by > nutrient availability. We find that the nutrients required for the > projected increases in net primary productivity greatly exceed estimated > nutrient supply rates, suggesting that projected productivity increases may > be unrealistically high. Accounting for nitrogen and nitrogen–phosphorus > limitation lowers projected end-of-century estimates of net primary > productivity by 19% and 25%, respectively, and turns the land surface into > a net source of CO2 by 2100. We conclude that potential effects of nutrient > limitation must be considered in estimates of the terrestrial carbon sink > strength through the twenty-first century. > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/d/optout.
