what is the maximum allowed amount of N - fertilizer application per crops (for instance: maize, potato, tomato, cotton) on one hectare, at EU?
For instance, the EU Nitrates Directive limits the manure application in Nitrate Vulnerable Zones to 170 kg N/ha/y (or higher in case of derogation).
Holistically, there is a conventional standard guiding application of nutrients to soil and it ranges from critical - low - medium - high
@ David Oluwadare: can you please share document/s on the conventional standard that guide nutrient application (Kg N per ha) at the global/ EU or countries in EU/ level.
Dr.Chukalla, good and relevant question in the present context. As I remember, there were guidelines for use of manure in European countries. As mentioned by you the N limit is170 kg/ha.For P loading through manure the limit is 22kg/ha.In the following publication I find upper limits for N application for some crops like winter wheat,Maize,potato and grass land.Limits are also there for coarse textured and fine textured soils.For more details the following document can be consulted.
The policy implementation of nutrient management legislation and......
Lectureone7.doc1571991559.doc
Lectureone7. doc-440841815.doc
Dear Annangi Subba Rao you are right because European countries soil is less deficient to P fertilizer as compare to Asian countries.
Doctor Annangi Subba Rao comments are very insightful. The needs of P fertilizer are much greater in developing countries which do not have a long history of P amendments. P status of soil is certainly important in managing P whether in organic or conventional production systems.
The limitation on P amendment should be based on soil P levels and soil types and crop and yield and quality goals. P amendment also should focus on the initial stages of crop development and not the later ones where utilization and efficacy may be compromised.
P problems are many times related to P losses with soil erosion and plans for limiting erosion are of paramount importance in holistic management.
In relation to efficacy and issues the composting of raw manures should be the best management practice. Applications of Phosphates in compost have much less issues associated with them than topical raw manure which is a worst case use. When organic amendments including manures are injected and incorporated into the soil many of the potential issues are greatly reduced.
Some thoughts,
Dear Dr.Hepperly I agree with your views on manure management with focus on P addition through manure, composting of manure and appropriate incorporation. As I understand earlier manure was applied on N basis and currently on P basis both in USA and Europe. Earlier the upper limit for manure loading was in the range 40-60 tonnes per ha.Dr.Hepperly, what is the current permitted level of manure application?Also mention whether it is on wet or dry basis.
Dear Doctor Annangi Subba Rao, The issues with over P amendment is based on applying organic amendment to reach the Nitrogen requirement for a high Nitrogen requiring cereal plant such as maize in North America.
The remedy is to apply to Phosphorus requirement and build the soil Nitrogen level through the incorporation of legume based rotation and cover cropping.
With this strategy neither the Nitrogen nor the Phosphorus will be problematic. Compost and manure applications are most effective at 8 to 12 tonnes per ha and people are going way overboard.
In addition by using the moderated application more benefit is accrued by larger area treated. Manure is a resource and not a waste and of course you realize transportation costs are greatly reduced by compost which alleviates problems issues with pathogens and leads to long term Carbon sequestration rather that sustainability without soil C buildup.
I always enjoy your insights Doctor.
Dear Dr.Hepperly, thank you for your nice words ,elaboration and views.Along with fertilizer ,manure application@10-12 tonnes may be adequate but for organic farming one has to go for double or triple the rates.Even with one of the highest animal populations, India currently can not apply more than half of what you have suggested(5-6tonnes/ha). Now our Govrnment, industry and NGOs are promoting phosphocompost and P solubilizing microbes.Of couse we have been pursuing and promoting vermicomposting , rapid composting,composts enriched with fertilizers,inorganic amendments and beneficial microbes.We realize the importance of mycorrhizae but hurdles especially in preparion of inoculum persistent in prompting it.
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