Effects of mulch, N fertilizer, and plant density on wheat yield, wheat nitrogen uptake, and residual soil nitrate in a dryland area of China

Abstract

Understanding mulching influences on nitrogen (N) activities in soil is important for developing N management strategies in dryland. A 3 year field experiment was conducted in the Loess Plateau of China to investigate the effects of mulching, N fertilizer application rate and plant density on winter wheat yield, N uptake by wheat and residual soil nitrate in a winter wheat-fallow system. The split plot design included four mulching methods (CK, no mulch; SM, straw mulch; FM, plastic film mulch; CM, combined mulch with plastic film and straw) as main plot treatments. Three N fertilizer rates (N0, 0 kg N ha -1 ; N120, 120 kg N ha -1 ; N240, 240 kg N ha -1 ) were sub-plot treatments and two wheat sowing densities (LD, low density, seeding rate = 180 kg ha -1 ; HD, high density, seeding rate = 225 kg ha -1 ) were sub-subplot treatments. The results showed that wheat yield, N uptake, and N use efficiency (NUE) were higher for FM and CM compared to CK. However, soil nitrate-N contents in the 0-200 cm soil profile were also higher for FM and CM compared to CK after the 3 year experiment. Wheat grain yields were higher for SM compared to CK only when high levels of nitrogen or high planting density were applied. Mulching did not have a significant effect on wheat yield, nitrogen uptake and NUE when soil water content at planting was much high. Wheat yield, N uptake, and residual nitrate in 0-200 cm were significantly higher for N240 compared to N120 and N0. Wheat yield and N uptake were also significantly higher for HD compared to LD. When 0 or 120 kg N ha -1 was applied, HD had more residual nitrate than LD while the reverse was true when 240 kg N ha -1 was applied. After 3 years, residual nitrate-N in 0-200 cm soil averaged 170 kg ha -1 , which was equivalent to *40% of the total N uptake by wheat in the three growing seasons.

Response of nitrogen use efficiency and soil nitrate dynamics to soil mulching in dryland maize (Zea mays L.) fields

“…2). A similar result was also reported by Gao et al (2009), who found that wheat N accumulation was markedly increased under FM conditions. Crop N accumulation is closely related to plant growth rate and to environmental conditions, such as soil water and nutrient availability.…”

Nitrogen fertilisation of durum wheat: a case study in Mediterranean area during transition to conservation agriculture

“…This may reduce the availability of soil mineral N and may require an increasing in N fertilisation (Morell et al, 2011). Few studies indicate that slightly higher doses of fertiliser are required to achieve significant yields in winter wheat in presence of a layer of surface residues (Gao et al, 2009), especially under long-term periods (>10 years) of CA adoption.…”

Film fully-mulched ridge-furrow cropping affects soil biochemical properties and maize nutrient uptake in a rainfed semi-arid environment

“…Film mulch has increased soil microbial biomass and activity in wheat (Li et al 2004) and flooded rice (Oryza sativa L.) fields (Li et al 2006). Increased soil mineral nitrogen (N) has been observed in film-mulched wheat cropping (Gao et al 2009). However, despite being widely practiced, there is a lack of knowledge on changes in soil biological properties and nutrient status associated with improved soil temperatures and reduced evaporation under film mulching (Gan et al 2013).…”