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

• Published in: Nutrient cycling in agroecosystems 2009-10, Vol.85 (2), p.109-121
• Main Authors: Gao, Yajun, Li, Yun, Zhang, Jianchang, Liu, Wenguo, Dang, Zhanping, Cao, Weixian, Qiang, Qin
• Format: Article
• Language: English
• Subjects: Agriculture; Arid zones; Biomedical and Life Sciences; Crop yield; dryland farming; Fertilizer application; fertilizer rates; Fertilizers; field experimentation; grain yield; Growing season; Life Sciences; Moisture content; Mulching; nitrate nitrogen; Nitrates; Nitrogen; nitrogen fertilizers; nutrient uptake; nutrient use efficiency; Original Article; plant density; Plant growth; plant nutrition; Planting; Planting density; plastic film mulches; Residual soils; Seeding; Seeding rate; soil fertility; Soil profiles; Soil properties; Soil water; soil water content; Straw; Triticum aestivum; Water content; Wheat; Winter wheat
• ISSN: 1385-1314; 1573-0867
• DOI: 10.1007/s10705-009-9252-0

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.