The effect of fertilizer placement on nitrogen uptake and yield of wheat and maize in Chinese loess soils

Abstract

Field trials were carried out to study the fate of 15N-labelled urea applied to summer maize and winter wheat in loess soils in Shaanxi Province, north-west China. In the maize experiment, nitrogen was applied at rates of 0 or 210 kg N ha-1, either as a surface application, mixed uniformly with the top 0.15 m of soil, or placed in holes 0.1 in deep adjacent to each plant and then covered with soil. In the wheat experiment, nitrogen was applied at rates of 0, 75 or t50 kg N ha -3, either to the surface, or incorporated by mixing with the top 0.15 m, or placed in a band at 0.15 m depth. Measurements were made of crop N uptake, residual fertilizer N and soil mineral N. The total above-ground dry matter yield of maize varied between 7.6 and 11.9 t ha-I. The crop recovery of fertilizer N following point placement was 25% of that applied, which was higher than that from the surface application (18%) or incorporation by mixing (18%). The total grain yield of wheat varied between 4.3 and 4.7 t ha -I . In the surface applications, the recovery of fertilizer-derived nitrogen (25%) was considerably lower than that from the mixing treatments and banded placements (33 and 36%). The fertilizer N application rate had a significant effect on grain and total dry matter yield, as well as on total N uptake and grain N contents. The main mechanism for loss of N appeared to be by ammonia volatilization, rather than leaching. High mineral N concentrations remained in the soil at harvest, following both crops, demonstrating a potential for significant reductions in N application rates without associated loss in yield.

Crop residue, manure and fertilizer in dryland maize under reduced tillage in northern China: I grain yields and nutrient use efficiencies

“…Locally recommended maize varieties were used, i.e., Yandan No.12 in 1993-1997, Shandannong No.1 in 1998, and Jindan No.34 in 1999-2004. The N and P fertilizers were urea (46% N) and superphosphate (7% P) in a ratio of N to P of 1:0.44.…”

“…These practices commonly lead to soil drying and severe wind erosion in early spring. Erosion of fertile top soil, removal of crop residues (to feed animals and to be used as fuel for cooking with only partial return of manure and ashes to the cropped land) and burning of crop residues have led to nutrient depleted soils on various places (Rees et al 1997;Cai et al 2002;Peng et al 2006). Soil conservation and improved nutrient management practices are gaining interest of Chinese research and policy communities (Wang et al 1999(Wang et al , 2001(Wang et al , 2003Ju et al 2005).…”

Reducing ammonia volatilization in a no-till soil by incorporating urea and pig slurry in shallow bands

“…The use of trailing hose systems or surface banding for slurry application has been demonstrated to reduce NH 3 -N loss (Smith et al 2000) particularly when in conjunction with soil aeration (Bittman et al 2005). In the case of urea, application in bands at a minimum depth of 5 cm (Fenn and Miyamoto 1981) is recommended to improve N use efficiency (Rees et al 1996;Malhi et al 2001;Sommer et al 2004). Accordingly, ammonia emissions from urea incorporated in bands at 2.5 cm were 3% of applied N compared to 19% from broadcasted urea (Bouwmeester et al 1985).…”

Effects of Fertilizer Placement and Nitrogen Forms on Soil Nitrogen Diffusion and Migration of Red-Yellow Soil in China

“…Similarly, Ling et al [6] found that the inorganic N concentration in the 6 -16 cm layers of paddy soil showed the following sequence: point deep fertilization > mixed fertilization with 3% soil > mixed fertilization with 10-cm top soil > broadcast. Rees et al [11] showed that the mineral nitrogen ( Cheng et al [15] found that with which the N fertilizers were mixed [6]. This is shown by the greater yields and NUEs after large particles of urea were applied compared with small particles of urea in rice field experiments [18].…”

“…An optimum fertilization model can reduce N loss, and increase crop yield and the NUE [11] [12] [13]. Rees et al [11] indicated that in the point-placement (hole-source fertilization) application were significant greater than in the corresponding surface-application and mixed-incorporation treatments. Wang et al [14] found that point deep placement can reduce the N fertilizer loss and improve the NUE.…”