A - Papers appearing in refereed journals
Hijbeek, R., Ten Berge, H. F. M., Whitmore, A. P., Barkusky, D., Schröder, J. J. and Van Ittersum, M. K. 2018. Nitrogen fertiliser replacement values for organic amendments appear to increase with N application rates. Nutrient Cycling in Agroecosystems. 110 (1), pp. 105-115.
|Authors||Hijbeek, R., Ten Berge, H. F. M., Whitmore, A. P., Barkusky, D., Schröder, J. J. and Van Ittersum, M. K.|
Nitrogen (N) supply from organic amendments [such as farmyard manure (FYM), slurries or crop residues] to crops is commonly expressed in the amendment’s Nitrogen Fertiliser Replacement Value (NFRV). Values for NFRV can be determined by comparison of crop yield or N uptake in amended plots against mineral fertiliser-only plots. NFRV is then defined as the amount of mineral fertiliser N saved when using organic amendment-N (kg/kg), while attaining the same crop yield. Factors known to affect NFRV are crop type cultivated, soil type, manuring history and method or time of application. We investigated whether long-term NFRV depends on N application rates. Using data from eight long term experiments in Europe, values of NFRV at low total N supply were compared with values of NFRV at high total N supply. Our findings show that FYM has a significant higher NFRV value at high total N supply than at low total N supply (1.12 vs. 0.53, p = 0.04). For the other amendment types investigated, NFRV was also higher at high total N supply than at low total N supply, but sample sizes were too small or variations too large to detect significant differences. Farmers in Europe usually operate at high rates of total N applied. If fertiliser supplements are based on NFRV of the manure estimated at low total N supply, N fertiliser requirements might be overestimated. This might lead to overuse of N, lower N use efficiency and larger losses of N to the environment.
|Year of Publication||2018|
|Journal||Nutrient Cycling in Agroecosystems|
|Journal citation||110 (1), pp. 105-115|
|Digital Object Identifier (DOI)||doi:10.1007/s10705-017-9875-5|
|Open access||Published as ‘gold’ (paid) open access|
|Funder||European Commission - EC|
|Online||22 Aug 2017|
|Publication process dates|
|Accepted||10 Aug 2017|
|Copyright license||CC BY|
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