Early sowing increases nitrogen uptake and yields of winter wheat grown with cattle slurry or mineral fertilizers

Abstract

The current study evaluated the effect of sowing date (early, mid-August or timely, mid-September) on two winter wheat (Triticum aestivum L.) cultivars (Hereford, Mariboss) with different rates of nitrogen (N) (0–225 kg total N/ha) applied as animal manure (AM; cattle slurry) or mineral fertilizers (N: phosphorus: potassium; NPK). Overwinter plant N uptake and soil mineral N content were determined during 2014/15, while harvest yields (grain, straw, N content) were determined during 2014/15 and 2015/16. Overwinter uptake of N was 14 kg N/ha higher in early than in timely-sown wheat. Despite very different yield levels in 2015 and 2016 harvests, the advantage of early sowing on grain yields was similar (1.1 and 0.9 t/ha); straw yield benefits were greater in 2015 (1.7 t/ha more) than in 2016 (0.4 t/ha more). In 2015 and 2016, N offtake was 35 and 17 kg N/ha higher in early than in timely-sown wheat, respectively. The mineral N fertilizer value of cattle slurry averaged 50%. Early sowing increased the apparent N recovery (ANR) for wheat regardless of nutrient source. However, ANR was substantially higher for NPK (82% in 2015; 52% in 2016) than for AM (39% in 2015; 27% in 2016). Performance of the two cultivars did not differ consistently with respect to the effect of early sowing on crop yield, N concentration and offtake, or ANR. Within the north-west European climatic region, moving the sowing time of winter wheat from mid-September to mid-August provides a significant yield and N offtake benefit.

Temporal and Organ-specific Responses in NUE Traits to N Fertilization, Fungicide Intensity and Early Sowing in Winter Wheat Cultivars

“…Notably, no significant interaction of sowing date and N level was found for any one of the carbon and nitrogen traits, which is in line with [10]. The relative beneficial effect of earlier sowing was similar to the one found under Danish conditions (+0.9-1.1 t ha −1 ), where it was related to higher pre-winter Nup [29]. If early sowing leads to excessive pre-winter development, it may increase disease susceptibility [23].…”

“…The overall significant decrease in NTEff of all vegetative organs by 1% to 3% with higher fertilization is in line with [29]. In contrast, in a similar experiment conducted at the same site, a negative N effect was found on NTEff of culms but not of leaves [52].…”

The Askov long‐term field experiment (1894–2021) represents a unique research platform#

“…(2017) and Suarez‐Tapia, Rasmussen, et al. (2018) examined the effect of sowing date on harvest yields and crop N uptake in winter wheat subject to increasing rates of nutrients in AM or NPK. Dividing each treatment plot into four sub‐plots allowed a study of the interaction between two wheat cultivars and two sowing dates, an experimental set‐up made possible by the large treatment plots.…”

“…When evaluating the contribution from mineralized soil N by growing a test crop in the absence of N fertilization, a suboptimal plant development may prevent a reliable estimate of the residual N effect, especially in cropping systems with high production potentials. Therefore, studies embedded in the Askov‐LTE examined the residual effect of previous N applications by withholding the usual nutrient treatment and subdividing the plot into six subplots subject to increasing rates of mineral N fertilizer in the test year (Petersen et al., 2010, 2012; Suarez‐Tapia, Thomsen, et al., 2018). The test crops were spring barley and winter wheat.…”