Impact of Early Sowing on Winter Wheat Receiving Manure or Mineral Fertilizers

Core Ideas Grain yield benefits of early sown wheat was 0.5 and 1.0 Mg ha−1 for mineral fertilizers and animal manure. Over‐winter N uptake was 11 kg N ha−1 higher in early than in timely sown wheat. At harvest, 19 kg N ha−1 more N was removed in early than in timely sown wheat. The beneficial effect of early sowing compares to that of N catch crops. Surface‐applied cattle slurry provides a poor N use efficiency and grain protein. To reduce over‐winter nitrate leaching from temperate soil, nitrate catch crops can be grown between main crops. We hypothesize that earlier sowing can replace catch crops sown before winter wheat (Triticum aestivum L.) and improve wheat yields and N uptake. Early sown (late August) and timely sown (late September) wheat were tested over two cropping seasons (2011–2012 and 2013–2014) using two contemporary cultivars (Hereford and Mariboss) and increasing rates of N (0–300 kg total N ha−1) with animal manure (AM; cattle slurry) or mineral fertilizers (NPK), surface applied in late March. We measured over‐winter N uptake in wheat, harvest yields, and N concentrations in grain and straw. Over‐winter N uptake was 11 kg ha−1 higher for early than for timely sown wheat; at harvest this benefit increased to 19 kg N ha−1. Mariboss yielded more straw than Hereford whereas grain yields did not differ. Early sowing increased grain yields by 0.5 and 1.0 Mg ha−1 for NPK and AM, respectively, regardless of N rate. Grain and straw N concentrations were higher with NPK than with AM, and NPK showed higher N use efficiency (0.48–0.53) than AM (0.15–0.22). Moving sowing of winter wheat from late September to late August provided higher grain and straw yields; the increased over‐winter N uptake suggests that the beneficial effect of earlier sowing may surpass that of a catch crop. Cattle slurry surface applied in late March gave poor N use efficiency and low grain protein content.