Developing Strategies for Spatially Variable Nitrogen Application in Cereals, Part II: Wheat |
| |
| Authors: | J P Welsh G A Wood R J Godwin J C Taylor R Earl S Blackmore S M Knight |
| |
| Institution: | 1 Cranfield University at Silsoe, National Soil Resources Institute, Silsoe, Bedfordshire MK45 4DT, UK; e-mail of corresponding author: g.a.wood@cranfield.ac.uk;2 Arable Research Centres, Shuttleworth Centre, Old Warden Park, Biggleswade, Bedfordshire SG18 9EA, UK |
| |
| Abstract: | For precision agriculture to provide both economic and environmental benefits over conventional farm practice, management strategies must be developed to accommodate the spatial variability in crop performance that occurs within fields. Experiments were established in crops of wheat (Triticum aestivum) over three seasons in two fields. The aim was to evaluate a set of variable rate nitrogen strategies and examining the spatial variation in crop response to applied N. The optimum N application rate in the field with three different soil series (predominantly calcareous silty clay loam over oolitic limestone) was uniform across the field. In contrast the other field with uniform soil type (slightly calcareous brown clay loam), provided a more variable response. Estimates of yield potential, produced from either historic yield data or shoot density maps derived from airborne digital photographic images, were used to divide experimental strips into management zones. These zones were then managed according to two N application strategies. The results from the historic yield approach, which is currently the most practical commercial system, based on 3 yr of yield data, were variable with no overall yield or economic advantages. It was concluded that that this approach may not provide a suitable basis for varying N rates. The shoot density approach, however, offered considerably greater potential as it takes account of variation in the current crop. Using this approach, it was found that there was insufficient variation in the shoot density in the field with diverse soil types. However, in the field with the uniform soil type, applying additional N to areas with a low shoot population and maintaining the standard N rate to areas with an average shoot population resulted in an average strategy benefit of up to 0·46 t ha−1 compared with standard farm practice. It is necessary to combine the ‘real-time’ data on relative crop structure, obtained by remote sensing with ground truth assessments and absolute benchmark values to successfully adjust N input levels to maximise yield. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
