Excessive nitrogen application decreases grain yield and increases nitrogen loss in a wheat–soil system

Dynamics of soil nematode communities in wheat fields under different nitrogen management in Northern China Plain

“…In China, wheat is the second largest staple crop and provides more than 20% of the total grains (National Bureau of Statistics of China). In order to increase grain yield, excessive nitrogen (N) fertilizer has often been applied [3e5], which have caused a series of problems related to production costs and environment such as eutrophication of groundwater and soil acidification [6,7].…”

The influence of fertilization and crop rotation on the winter wheat production

“…The excessive N application (above 240 kg N/ha) also obviously decreased the grain yield and N uptake efficiency. Dry matter and grain N content were influenced by the type and amount of fertilizer-N, too (Doltra et al 2011, Wang et al 2011, Mocanu et al 2012). NE -number of ears; BW -bulk weight; WTG -weight of one-thousand grains; PG -proportion of grains 2.8 + 2.5 mm; H 1 -mineral fertilization N, P, K + organic fertilization Veget®; H 2 -only mineral fertilization N, P, K In 2011 after peas as a preceding crop the grain yield (Table 6) was significantly higher (7.71 t/ha) than in 2010 (7.21 t/ha) and 2012 (5.78 t/ha).…”

Theory and application for the promotion of wheat production in China: past, present and future

“…In 2007, agricultural pollution contributed to 2.70 Mt of N, 0.28 Mt of phosphorus, and a total equivalent chemical oxygen demand (COD) of 13.24 Mt, accounting for 57.2% of the total N level of 4.73 Mt, 67.3% of the total phosphorus level of 0.42 Mt and 43.7% of the total COD level of 30.29 Mt . Thus inappropriate fertilizer application, particularly its overuse, has played a critical role in increasing environmental pollution . It is widely known that in China–a country with skyrocketing development – fertilizer use in agriculture has increased from 0.37 Mt in the first reported year (1961) to 57.04 Mt in 2011, and has become the predominant factor enhancing arable productivity, including wheat production (Fig.…”

“…In the largest wheat planting area, Henan province, in central China, the average fertilizer application amount is 792.3 kg ha −1 , which is more than twice the average national level of 375.0 kg ha −1 . This has inevitably led to an over‐fertilizing problem that has resulted in major concerns about environmental pollution and has resulted in lower fertilizer use efficiency and therefore lower wheat production profits for farmers . In 2005, China consumed around 38% of the global supply of N fertilizer, but the average N recovery efficiency in the wheat–maize double cropping system was very low (only 16–18%) .…”

“…In the winter wheat fields in NCP, a loss of 20% of the N application amount appears as N application rate maintains a higher level of 325 kg N ha −1 . Although winter wheat production increases by increasing N application in moderate amounts (from 0 to 300 kg ha −1 of N application rate), yield NUE obviously decreases with continually increasing N input (40.6–32.8 kg grain kg −1 N with an optimum irrigation regime: 60 mm irrigation amount at sowing and at jointing), indicating that an optimum level of N application may exist . Excessive N application in crop fields, particularly in higher‐intensity cropping systems such as greenhouse vegetable systems, has led to a great N enrichment and consequent environmental pollution to groundwater, as indicated by a very high nitrate level – a source of the main contamination .…”