Influence of reduced tillage and fertilization regime on crop performance and nitrogen utilization of organic potato

DRAKOPULOS, D.; SCHOLBERG, J.M.S.; LANTINGA, E.A.,; TITTONELL, P.

Organic Agriculture

Springer

Año: 2016 vol. 6 p. 75 - 87

The majority of Dutch farmers perceive thatmouldboard ploughing prior to potato planting is necessary,despite its negative impacts on inherent soil fertilityand soil structure. An innovative agronomic practicein Dutch organic agriculture is the use of cut-and-carryfertilizers with which above-ground biomass of cropswith high nitrogen content (e.g. grass/clover) is harvestedand transferred to other fields as plant-based fertilizers.The objective of this study was to investigate theinteractive effects of two tillage systems (reduced tillage(RT), standard tillage (ST)) and three organic fertilizeramendments (solid cattle manure (SCM), lucerne pellets(LP), grass/clover silage (GCS)) on crop performanceand nitrogen utilization of organic potato. Use of RTdecreased tuber yield by 13.4 % compared to ST due tolower average tuber size which was related to higher soilbulk density and increased vulnerability to droughtstress during tuber bulking. On the other hand, use ofRT positively affected nitrogen utilization and tuberquality in terms of specific gravity, dry matter andstarch contents. However, the price premium associatedwith enhanced tuber quality may not offset the observedyield gap between RT and ST. Plant-based fertilizersenhanced nitrogen utilization in terms of apparent nitrogenrecovery compared to animal-based. Although useof LP resulted in the highest yield for both tillagesystems, its high price may be cost-inhibitive. Anintegrated approach taking into account N release patterns,environmental conditions, final yields, and productioncosts is needed in order to optimize resource useefficiency and overall profitability for farmers.