Author
(1)where A is the 15N natural abundance, B is the 15N atom percent excess in the plant or soil and C is the 15N atom percent excess in the fertilizer N.
(2)
(3)
(4)
(5)
(6)
For further details log on website :
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0153701
- Published: April 15, 2016
- http://dx.doi.org/10.1371/journal.pone.0153701
Abstract
A field micro-plot experiment using nitrogen isotope (15N) labeling was conducted to determine the effects of placement methods (broadcast and band) and N rates (60, 150 and 240 kg ha–1) on the fate of urea-15N in the wheat–soil system in Guangde County of Anhui Province, China. N fertilizer applied in bands increased grain yield by 15% compared with broadcast application. The N fertilizer application rate had a significant effect on grain yield, straw yield and aboveground biomass, as well as on N uptake and N concentration of wheat. The recovery of urea-15N was a little higher for broadcast (34.0–39.0%) than for band treatment (31.2–38.2%). Most of the soil residual N was retained in the 0–20 cm soil layer. At the N rates of 60 and 240 kg ha–1, the residual 15N was higher for band (34.4 and 108.7 kg ha–1, respectively) than for broadcast application (29.6 and 88.4 kg ha–1, respectively). Compared with broadcast treatment, banded placement of N fertilizer decreased the N loss in the wheat–soil system. Band application one time is an alternative N management practice for winter wheat in this region.
Figures
Citation: Chen Z, Wang H, Liu X, Liu Y, Gao S, Zhou J (2016) The Effect of N Fertilizer Placement on the Fate of Urea-15N and Yield of Winter Wheat in Southeast China. PLoS ONE 11(4): e0153701. doi:10.1371/journal.pone.0153701
Editor: Wenju Liang, Chinese Academy of Sciences, CHINA
Received: January 11, 2016; Accepted: April 3, 2016; Published: April 15, 2016
Copyright: © 2016 Chen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: All relevant data are within the paper and its Supporting Information files.
Funding: This work was supported by the National Basic Research Program of China (2013CB127401), the National Department Public Benefit Research Foundation of China (201203013), the National Natural Science Foundation of China (41271309), and the Program of the 13th Five-Year Plan in the Institute of Soil Science, Chinese Academy of Sciences (ISSASIP1649).
Competing interests: The authors have declared that no competing interests exist.
Introduction
Among the fertilizers, nitrogen (N) is the most important nutrient for wheat (Triticum aestivumL.) and can improve grain yield and quality of winter wheat [1, 2]. To obtain high yields of cereal crops, high rates of N fertilizer, especially manufactured N fertilizer, are applied by farmers in China [3]. However, the increase of crop yields is not proportion with the large increase of consumption of N fertilizer [4, 5]. Excess inorganic N and inappropriate application methods have led to low N use efficiency (NUE) and negative environmental impacts [6–9]. Efficient N fertilizer management is vital to maintain wheat production and soil fertility, and minimize environmental risk [10–12].
Efficient use of N fertilizer depends very much on timing, rates, resources and placement of N fertilizer application [13]. The placement method of fertilizer N influences crop yield and N uptake by cereal crops [14, 15]. Split application of N fertilizer has been shown to improve the yield, grain protein concentration and NUE of wheat, compared to a single surface application [16]. The uptake of surface-applied fertilizer depends on the following rain or irrigation [17], and in fields with limited rain or irrigation, broadcast-applied N fertilizer remains near the soil surface and does not move into the root zone where it can be absorbed by plants [18]. Compared with placement of N fertilizer on the soil surface, N fertilizer applied in bands can reduce N loss via ammonia volatilization and improve NUE of plants [19]. Banding of urea leads to high ammonium (NH4+) concentration in the fertilizer zone that can inhibit nitrifying bacteria, and so reduce N loss due to leaching [15, 20, 21]. Additionally, placing N fertilizer into soil can reduce the immobilization of N by soil microorganisms and increases uptake by plants [22, 23]. Banding of N fertilizer can also improve the competition of wheat with weeds compared to broadcast [18].
Appropriate N application rate is an important N management practice for winter wheat [24]. The increasing rate of wheat yield is not linear with increasing rate of N application; for example, when N was applied at 120 and 180 kg ha–1, the corresponding wheat yields were 3600 and 3000 kg ha–1 [1]. The economic yield of winter wheat is a maximum at the N rate of 210 kg ha–1 in Jiangsu Province, China [9]. The N recovery in wheat increased with increasing N rates in a pot experiment [25]. However, other researchers reported that the NUE of wheat decreased with increasing rate of N application under field conditions [24, 26]. Future increases in crop production must be achieved through improved N efficiency rather than increased N rates [27].
Band application one time of N fertilizer would not only increase wheat grain yield, but also decrease the N loss, and still is time-saving. However, little information about effects of band application one time of N fertilizer on winter wheat in southeast China. The 15N tracer technique has been widely used to distinguish the plant N from fertilizer or soil N and the N fluxes in agroecosystems [26, 28]. This study aimed to determine the fate of urea-15N in the wheat–soil system as influenced by placement method and N rate in the Middle and Lower Yangtze River basin in southeast China, during 2014–2015.
Materials and Methods
Site Description
The field micro-plot experiment was conducted in Guangde County of Anhui Province (31°01ʹN, 119°26′E), China, during 2014–2015. The farmer had gave us permission to conduct the study in the site prior to the start of the experiment. The region is classified as sub-tropical with a monsoon climate. The soil at Guangde is an Alfisol (FAO classification), with topsoil (0–20 cm) properties as follows: soil bulk density 1.02 g cm–3, total carbon (C) 20.58 g kg–1, total N 1.12 g kg–1, Olsen- phosphorous (P) 25.51 mg kg–1, available potassium (K) 65.00 mg kg–1 and pH (water) 5.52. The rainfall and temperature data during the wheat season are shown in Fig 1. Rice–winter wheat rotation is used in the site. Total rainfall during the winter wheat growing season was 786 mm (Fig 1). Our study did not involve the endangered or protected species.
Fig 1. The monthly mean rainfall and mean temperature during the wheat growing season from 2014 to 2015.
Experiment Design
The micro-plots (0.5 m × 0.5 m) were bounded by plastic frames of 0.35 m high to monitor the fates of 15N-labeled fertilizer. The frames were pressed 0.3 m deep into the soil and protruded 0.05 m above the soil to prevent runoff and lateral contamination. The experimental design was a randomized complete block design with three replications. Two rows of wheat were planted in each micro-plot with row spacing of 25 cm. A local wheat cultivar, Yangmai 20, was sown in early November 2014 with the seed rate of 187.5 kg ha–1 and was harvested in early June 2015. The experiment was a factorial design with two placement methods (broadcast and band) and three N rates of 60, 150 and 240 kg N ha–1 termed N 60, N 150 and N 240, respectively. For fertilizer N banding, the 15N-labeled urea as basal fertilizer was side-banded by shovel 5 cm from wheat and 10 cm under the soil surface at one time. For fertilizer broadcasting, the 15N-labeled urea was broadcast and incorporated into soil at sowing, and was broadcast on soil surface at tillering and at jointing in split applications (with a ratio of base-N to topdress-N of 1:0.75:0.75). Wheat was planted around the micro-plot to reduce edge effects, with the placement method and N rate the same as in the corresponding micro-plot. The 15N-labeled urea (15N abundance was 10.15%) was provided by Shanghai Research Institute of Chemical Industry. The P fertilizer (150 kg P2O5 ha–1 as triple superphosphate) and K fertilizer (180 kg K2O ha–1 as potassium chloride) were applied to all micro-plots at sowing. No irrigation was applied due to abundant rainfall in the winter wheat growing season (Fig 1).
Plant and Soil Sampling and 15N Analyses
Plants were harvested by hand in each micro-plot after wheat maturity. Plant aboveground parts were divided into grain and straw. Roots of each micro-plot were all collected from the 0–20 cm soil layer and washed. The fresh grain, straw and root samples were dried at 75°C to constant weight for determination of dry weight. The dry samples were ground to powder and passed through a 150-μm screen before N content and 15N analysis.
Soils were sampled to a depth of 80 cm in 20-cm increments. The method of collecting soil sample for the banding treatment was described by Jayasundara et al. [29, 30]. Four soil cores (5 cm in diameter) were collected for the banding treatment: two from the fertilizer band and the others from the middle of two wheat rows. The same depth segments of four soil cores were mixed well as a single soil sample. The soil samples under broadcast treatment were randomly collected from four points and the same depth segments were mixed well as a single soil sample. The soil samples were air-dried and ground to pass through a 150-μm screen for 15N analysis. Soil bulk density was determined after harvesting the wheat using the cutting ring method [31]. Grain, straw, root and soil samples were analyzed for total N and 15N abundance using an elemental analyzer (Costech ECS4010, Costech Analytical Technologies Inc., Valencia, USA) coupled to an isotope ratio mass spectrometer (Delta V Advantage, Thermo Fisher Scientific Inc., USA).
Calculation Methods
All 15N was expressed as the atom percent excess corrected for background abundance (i.e. 0.366%). The bulk densities of 0–20, 20–40, 40–60 and 60–80 cm soil layers were 1.02, 1.17, 1.23 and 1.21 g cm–3, respectively.
The amounts of plant N derived from fertilizer (Ndff) and from soil (Ndfs), and the soil residual N were calculated as follows [16].
Statistical Analysis
Statistical analysis was conducted using SPSS 16.0 (SPSS Inc., Chicago, USA) for analysis of variance (ANOVA). Two-way ANOVA was conducted to assess the effects of N fertilizer placement and N rate on wheat yield, N uptake and fate of urea-15N. Significances among six treatments were compared by the least significance difference at P < 5% level.
Results
Crop Biomass
Placement method and N rate significantly affected grain yield, straw yield and aboveground biomass of winter wheat (Table 1). The grain yield of wheat was higher for band (3.83–5.42 t ha–1) than for broadcast treatment (3.32–4.74 t ha–1). The highest grain yield of wheat was 4.74 t ha–1 at N 240 for broadcast treatment and 5.42 t ha–1 at N 240 for band treatment. Both straw yield and aboveground biomass were also higher for band (mean of 6.57 and 11.4 t ha–1, respectively) than for broadcast treatment (mean of 5.15 and 9.34 t ha–1, respectively). The root biomass of winter wheat was similar across all treatments. Placement method significantly affected the harvest index (HI) of wheat. The HI was lower for band (0.41–0.43) than for broadcast treatment (0.44–0.46). This indicated that the increase of grain yield was not linear with increased aboveground biomass. The grain yield, straw yield and total aboveground biomass increased with increasing rate of N application, respectively (P < 0.001). The interaction of placement and N rate only significantly affected the HI (P < 0.05).
Table 1. Effects of N fertilizer placement and N rate on grain yield, straw yield, aboveground biomass, root biomass and harvest index (HI) of winter wheat.
N Concentration and N Uptake
The grain N concentration was higher at N 60, N 150 and N 240 under broadcast treatment (15.3, 18.3 and 22.5 g kg–1, respectively) than the corresponding N rates under band treatment (14.4, 15.3 and 18.3 g kg–1), but the grain yield was higher under band treatment, compared to broadcast treatment (Tables 1 and 2). This resulted in a similar N uptake in grain by wheat for broadcast and band treatments at the same N application rate (Table 2). The N concentration in straw and roots were not significantly affected by placement method. The wheat N concentration and N uptake increased with increasing N rate (P < 0.01) (Table 2). The N application method had no effect on the N uptake by wheat, but did affect the N uptake in straw. At N 150, the N uptake in straw was higher for band (22.6 kg ha–1) than for broadcast treatment (17.7 kg ha–1). The total N uptake by wheat was within the range of 66.5–136.3 kg ha–1 (mean 102.4 kg ha–1) for broadcast and 72.1–133.0 kg ha–1 (mean 104.1 kg ha–1) for band treatments.
Table 2. Effects of N fertilizer placement and N rate on N content and N accumulation in grain, straw and roots of winter wheat.
Distribution of Urea-15N and Soil N in Wheat Plants
Grain N uptake derived from 15N-labeled urea for broadcast and band treatments was in the range of 35.9–60.2% (mean 50.2%) and 33.2–57.0% (mean 47.0%), respectively. The total N uptake derived from fertilizer was 4–11% higher for broadcast than for band treatment. The average Ndff in grain (48.5%) and straw (46.3%) was higher than that in root (37.4%). The Ndff in wheat plant increased but Ndfs decreased with increasing N rate for both broadcast and band treatments (Table 3). The total N uptake by wheat from soil (43.1–58.2 kg ha–1) and that from urea-N (22.9–81.7 kg ha–1) increased with increasing N application rate (P < 0.001) (Table 4). At N 240, the Ndff in grain was higher for broadcast (64.4 kg ha–1) than for band treatment (56.6 kg ha–1). The N application method had no effect on Ndff in straw (except for N 150), roots and total plants. The highest Ndfs of straw for band treatment was 12.7 kg ha–1, significantly higher than the highest of 9.7 kg ha–1 for broadcast treatment. The total N derived from soil was within the range of 43.1–54.6 kg ha–1 for broadcast and 49.1–58.2 kg ha–1 for band treatment.
Table 3. Effects of N fertilizer placement and N rate on distributions of urea-15N in wheat plants.
Table 4. Effects of N fertilizer placement and N rate on N derived from fertilizer (Ndff) and from soil (Ndfs) of wheat plants.
Distribution of Residual Urea-15N in Soil
After winter wheat was harvested, the total residual urea-15N for broadcast treatment was 29.6, 84.9 and 88.4 kg ha–1 at N 60, N 150 and N 240, respectively, and correspondingly for band treatment was 34.4, 78.9 and 108.7 kg ha–1 (Fig 2). Most residual N remained in the 0–20 cm soil layer, accounting for 76.5–79.9% of total residual urea-N for broadcast and 76.0–91.2% for band application. The residual 15N in the 0–20 cm soil layer of band treatment for N 60 and N 240 was 26.2 and 99.1 kg ha–1, respectively, and was significantly (P < 0.05) higher than corresponding values for broadcast treatment of 22.7 and 67.7 kg ha–1. At N 150, there was no difference in topsoil (0–20 cm) urea-15N between broadcast and band treatments. In the 60–80 cm soil layer, the residual N was higher at N 60 for band than for broadcast treatment, but was lower at N 150 for band than for broadcast treatment. The 20–40- and 40–60-cm soil residual N was not significantly affected by the placement method. At higher N application rates (N 150 and N 240), more urea-15N moved to the deep soil for the broadcast treatment. Therefore, high rates of N fertilizer with broadcast application may increase the risk of N leaching.
Fig 2.
The distribution of urea-N residual in soil at (a) 60, (b) 150 and (c) 240 kg ha-1. ** Significant at p<0.01, * Significant at p<0.05, NS, not significant.
Fate of Urea-15N in Wheat–Soil System
The N placement method had no effect on N recovery in wheat (Table 5; Fig 3). The recovery of urea-15N in wheat decreased with increasing N rate. N recovery efficiency (NRE) in grain was within the range of 26.8–30.3% for broadcast and 23.6–30.6% for band treatment (Table 5). The NRE in straw was about one-fifth of that in grain. The N recovery in roots was much lower than that in grain and straw, and accounted for an average of 4% of total 15N recovery in wheat. The N loss increased with increasing N rate (Fig 3). For both N 60 and N 240, the unaccounted-N was significantly lower for band (5.0 and 23.5%, respectively) than for broadcast treatment (11.6 and 29.1%, respectively). The recovery in soil was within the range of 36.8–56.6% for broadcast and 45.3–56.8% for band treatment. The highest soil residual was 56.6% at N 150 for broadcast treatment, compared to 56.8% at N 60 for band treatment.
Fig 3. Percentages of N recoveries in wheat, and in soils (0–80 cm) and the unaccounted N losses.
Table 5. Effects of N fertilizer placement and N rate on urea-15N recovery in wheat.
Discussion
Grain Yield Affected by Placement and N Application Rate
In our study, the grain yield of wheat was 14.3–15.4% greater for band than for broadcast treatment. Rees, et al. [32] reported that banded application of N fertilizer increased the grain yield and aboveground biomass of wheat compared with surface application in the Guanzhong Plain, Northwest China. However, grain yield was not significantly affected by placement method under field conditions in Pakistan [33]. This may be explained by the differing climate conditions, wheat cultivars and soil fertility level in these study sites. The results of the present study demonstrated that grain yield, straw yield and aboveground biomass of wheat increased with increasing N rate (P < 0.001), as also found by other researchers [1, 7, 26, 34]. With banded application, wheat grain yield did not differ significantly when N rate was increased from 150 to 240 kg ha–1. Thus, the N rate of 150 kg ha–1 with band application could be the recommended N management practice for winter wheat in this region—this is similar to the optimal rate of 180 kg ha–1 for winter wheat in southeast China [35]. The HI of wheat was lower for band than for broadcast treatment. The reason was likely partly that the higher N rate accelerated the wheat growth rate in the early stage for band treatment compared to N split-application [36].
N Uptake Affected by Placement and N Application Rate
Our field experiment showed that increasing N application rates could improve the N concentration of winter wheat. A similar trend was also observed by Tran and Tremblay [1], who found that the N concentration increased from 22 to 28 g kg–1 when increasing the N application rate from 0 to 180 kg ha–1. The plant N concentration was higher for broadcast than for band treatment. The N concentration in grain was within the range of 15.3–22.5 g kg–1 for broadcast and 14.4–18.3 g kg–1 for band treatment. The wheat growing season is about seven months in Southeast China [26], thus the topdressing of N fertilizer would increase the grain concentration compared with a single application [37]. The placement method of N fertilizer did not affect the N uptake by grain and the whole plant, likely because band application of N fertilizer increased wheat yield but decreased the N concentration, compared with broadcast application. The whole-plant N derived from fertilizer N with broadcast and band application was within the range of 35.2–59.9% and 31.8–56.3%, respectively, while the whole-plant N derived from soil was 40.2–68.2%. This was similar to results reported by Jia et al. [26], who found that the total N uptake by wheat from soil was within the range of 45–66% in the North China Plain. Some researchers found that 15–31% of total N uptake by wheat was derived from fertilizer and the plant N uptake from soil accounted for more than 70% of total N content [38, 39]—apparently, a higher N application rate for wheat negatively affects mineralization of soil organic N. Tran and Tremblay [1] suggested that, with a low application rate of N fertilizer, soil indigenous N was important for wheat production. A micro-plot 15N-labeled experiment carried out in the North China Plain showed that Ndff in the total wheat plant increased with increasing N application rate, while Ndfs decreased [26].
Fate of Urea-15N Affected by Placement and N Application Rate
The total N uptake by winter wheat derived from fertilizer was within the range of 18.2–64.4 kg ha–1 for broadcast and 18.3–56.6 kg ha–1 for band treatment. Rees et al. [32] found, with increasing the N rate from 75 to 150 kg ha–1, that the Ndfs in wheat plants increased from 20 to 37 kg ha–1 with surface application and from 25 to 58 kg ha–1 with band application. In the present study, the recovery of 15N in grain and wheat were within the range of 23.6–30.6% and 31.2–39.0%, respectively. Some researchers reported that the N recovery for wheat was within the range of 33.0–49.0% in the Middle and Lower Yangtze River Region [31, 40], which was higher than the results for the present study; the reason was that the wheat grain yield in our experiment was lower (5.7 vs. 6.7 t ha–1) due to sowing 10 d later. The N recovery is closely related to wheat cultivars, soil fertility and climate conditions [39]. With broadcast application of N fertilizer, the total N recovery in wheat was not significantly affected by the N application rate. Because the N application rate increased, and the N uptake by wheat derived from fertilizer increased correspondingly (Table 4). Similarly, Zhao et al. [40] reported that the fertilizer N recovery of wheat did not differ significantly when the N application rate increased from 100 to 250 kg ha–1. This trend was also observed in a micro-plot experiment in Canada in which the N application rate had no effect on the N fertilizer recovery in wheat [1]. However, the N recovery in plants was higher at low (60 kg ha–1) than that at high N application rate (240 kg ha–1) for band treatment. Ju, et al. [43] found that the N recovery in wheat was 54% at 120 kg N ha–1, and 32% at 360 kg N ha–1.
After the winter wheat was harvested, 37–57% of applied N fertilizer remained in the 0–80 cm soil layer for broadcast treatment, and 45–57% for band treatment. In a wheat–wheat rotation under Mediterranean conditions, 65% of applied-N remained in the 0–80 cm soil profile [41]. Liang et al. [3] reported that 40–80% of applied urea-N was recovered in the 0–100 cm soil layer after wheat harvest in the North China Plain. N fertilizer can move into the deep soil after wheat harvest [42]. Liang et al. [3] showed that urea-15N moved into the 60–100 cm soil layer and Wang et al. [34] even found that N fertilizer moved to a depth of 200 cm. In our study, the urea-15N in all treatments moved into the 60–80 cm soil layer (Fig 2). Nevertheless, most residual 15N remained in the 0–20 cm soil layer, accounting for 76–91% of total urea-N in soil. Fan et al. [4] also found that above 67% of total soil residual N was retained in the topsoil (0–20 cm) in southwest China. About 90% of the residual N can be immobilized in soil organic matter [43]. The residual N in the topsoil layer can be mineralized and then be taken up by the following crop [3, 26, 41].
Our results showed that band application reduced the unaccounted-N compared with broadcast application. The higher NH4+ concentration with band application has toxic effects on nitrifiers and then inhibits nitrification, and so increases the soil residual N [20, 21, 44]. Higher N application rate (240 kg ha–1) caused more N loss compared to the lower N rates (60 and 150 kg ha–1) irrespective of placement method. This trend was similar to the findings of Jia et al. [26] that the unaccounted-N increased from 13 to 27% when increasing the rate of N application from 150 to 270 kg ha–1.
The results from our study showed that N loss was lower with band application of N fertilizer; however, the N recovery in wheat was lower and the residual N was higher in the middle and lower Yangtze River basin. This indicates that the best time for band application requires further examination and banding coupled with split applications may be an alternative pattern of N management for winter wheat with a seven-month growing season.
Conclusion
Under the field conditions of this study, band application one time of N fertilizer increased the yield of winter wheat and soil residual 15N, and decreased the N loss, compared to surface application three times. Nevertheless, placement method had no effect on N recovery in wheat. Split application of N fertilizer increased the grain N concentration. The yield of wheat increased with an increased N rate. At the N rate of 240 kg ha–1, the unaccounted-N was much higher than that at 60 and 150 kg ha–1. The root biomass was not affected by the placement and N rate. It was concluded that band application one time is a recommended N fertilizer management practice for winter wheat in southeast China.
Author Contributions
Conceived and designed the experiments: ZMC HYW. Performed the experiments: ZMC XWL YZL SSG. Analyzed the data: ZMC HYW JMZ. Contributed reagents/materials/analysis tools: HYW. Wrote the paper: ZMC HYW JMZ.
References
- 1.Tran TS, Tremblay G (2000) Recovery of N-15-labeled fertilizer by spring bread wheat at different N rates and application times. Can J Soil Sci 80(4):533–539. doi: 10.4141/s99-098
- 2.Ma BL, Subedi KD, Dwyer LM (2006) Timing and Method of 15Nitrogen-Labeled Fertilizer Application on Grain Protein and Nitrogen Use Efficiency of Spring Wheat. J Plant Nutr 29(3):469–483. doi: 10.1080/01904160500525065
- 3.Liang B, Yang X, Murphy DV, He X, Zhou J (2013) Fate of 15 N-labeled fertilizer in soils under dryland agriculture after 19 years of different fertilizations. Biol Fert Soils 49(8):977–986. doi: 10.1007/s00374-013-0789-3
- 4.Fan M, Lu S, Jiang R, Liu X, Zeng X, Goulding KWT, et al (2007) Nitrogen input, 15N balance and mineral N dynamics in a rice–wheat rotation in southwest China. Nutr Cycl Agroecosys 79(3):255–265. doi: 10.1007/s10705-007-9112-8
- 5.Shen J, Li C, Mi G, Li L, Yuan L, Jiang R, et al (2013) Maximizing root/rhizosphere efficiency to improve crop productivity and nutrient use efficiency in intensive agriculture of China. J Exp Bot 64(5):1181–1192. doi: 10.1093/jxb/ers342. pmid:23255279
- 6.Zhou SL, Wu YC, Wang ZM, Lu LQ, Wang RZ (2008) The nitrate leached below maize root zone is available for deep-rooted wheat in winter wheat-summer maize rotation in the North China Plain. Environ Pollut 152(3):723–730. pmid:17692443 doi: 10.1016/j.envpol.2007.06.047
- 7.Zhao S, Qiu S, Cao C, Zheng C, Zhou W, He P (2014) Responses of soil properties, microbial community and crop yields to various rates of nitrogen fertilization in a wheat–maize cropping system in north-central China. Agric Ecosyst Environ 194:29–37. doi: 10.1016/j.agee.2014.05.006
- 8.Peng Y, Li X, Li C (2012) Temporal and spatial profiling of root growth revealed novel response of maize roots under various nitrogen supplies in the field. PLoS One 7(5):e37726. doi: 10.1371/journal.pone.0037726. pmid:22624062
- 9.Shi Z, Li D, Jing Q, Cai J, Jiang D, Cao W, et al (2012) Effects of nitrogen applications on soil nitrogen balance and nitrogen utilization of winter wheat in a rice–wheat rotation. Field Crop Res 127:241–247. doi: 10.1016/j.fcr.2011.11.025
- 10.Grant CA, Brown KR, Racz GJ, Bailey LD (2001) Influence of source, timing and placement of nitrogen on grain yield and nitrogen removal of durum wheat under reduced- and conventional-tillage management. Can J Plant Sci 281(1):17–27. doi: 10.4141/p00-091
- 11.Guo R, Li X, Christie P, Chen Q, Jiang R, Zhang F (2008) Influence of root zone nitrogen management and a summer catch crop on cucumber yield and soil mineral nitrogen dynamics in intensive production systems. Plant Soil 313(1–2):55–70. doi: 10.1007/s11104-008-9679-0
- 12.Zhu ZL, Chen DL (2002) Nitrogen fertilizer use in China—Contributions to food production, impacts on the environment and best management strategies. Nutr Cycl Agroecosys 63(2–3):117–27.
- 13.Wang H, Zhou J (2013) Root-zone fertilization-A key and necessary approach to improve fertilizer use efficiency and reduce non-point source pollution from the cropland Soils 05:785–790.(In Chinese)
- 14.Duan W, Shi Y, Zhao J, Zhang Y, Yu Z (2015) Depth of nitrogen fertiliser placement affects nitrogen accumulation, translocation and nitrate-nitrogen content in soil of rainfed wheat. Int J Plant Prod 9(2):237–256.
- 15.Engel R, Liang DL, Wallander R, Bembenek A (2010) Influence of urea fertilizer placement on nitrous oxide production from a silt loam soil. J Environ Qual 39(1):115–125. doi: 10.2134/jeq2009.0130. pmid:20048299
- 16.López-Bellido L, López-Bellido RJ, Redondo R (2005) Nitrogen efficiency in wheat under rainfed Mediterranean conditions as affected by split nitrogen application. Field Crop Res 94(1):86–97. doi: 10.1016/j.fcr.2004.11.004
- 17.Petersen J, Mortensen J V (2002) Dry matter production and 15N recovery in spring wheat as affected by placement geometry of the fertilizer band[J]. Communications in soil science and plant analysis 33(1–2): 163–178. doi: 10.1081/css-120002385
- 18.Petersen J (2001) Recovery of N-15-ammonium-N-15-nitrate in spring wheat as affected by placement geometry of the fertilizer band. Nutr Cycl Agroecosys 61(3):215–221.
- 19.Malhi SS, Nyborg M, Solberg ED (1996). Influence of source, method of placement and simulated rainfall on the recovery of N-15-labelled fertilizers under zero tillage. Can J Soil Sci 76(1):93–100. doi: 10.4141/cjss96-013
- 20.Hartmann TE, Yue S, Schulz R, He X, Chen X, Zhang F, et al (2015) Yield and N use efficiency of a maize–wheat cropping system as affected by different fertilizer management strategies in a farmer's field of the North China Plain. Field Crop Res 174:30–39. doi: 10.1016/j.fcr.2015.01.006
- 21.Yang J, Li X, Xu L, Hu F, Li H, Liu M (2012) Influence of the nitrification inhibitor DMPP on the community composition of ammonia-oxidizing bacteria at microsites with increasing distance from the fertilizer zone. Biol Fert Soils 49(1):23–30. doi: 10.1007/s00374-012-0692-3
- 22.Mooleki SP, Malhi SS, Lemke RL, Schoenau JJ, Lafond G, Brandt S, et al (2010) Effect of form, placement and rate of N fertilizer, and placement of P fertilizer on wheat in Saskatchewan. Can J Plant Sci 90(3):319–337. doi: 10.4141/cjps09075
- 23.Yevdokimov I, Gattinger A, Buegger F, Munch JC, Schloter M (2008) Changes in microbial community structure in soil as a result of different amounts of nitrogen fertilization. Biol Fert Soils 44(8):1103–6. doi: 10.1007/s00374-008-0315-1
- 24.Haile D, Nigussie D, Ayana A (2012) Nitrogen use efficiency of bread wheat: Effects of nitrogen rate and time of application. J Soil Sci Plant Nut 12(3):389–409. doi: 10.4067/s0718-95162012005000002
- 25.Blankenau K, Kuhlmann H, Olfs HW (2000). Effect of increasing rates of N-15-labelled fertilizer on recovery of fertilizer N in plant and soil N pools in a pot experiment with winter wheat. Journal of Plant Nutrition and Soil Science 163(5):475–480. doi: 10.1002/1522-2624(200010)163:5<475::aid-jpln475>3.0.co;2-w
- 26.Jia S, Wang X, Yang Y, Dai K, Meng C, Zhao Q, et al (2011) Fate of labeled urea-15N as basal and topdressing applications in an irrigated wheat–maize rotation system in North China Plain: I winter wheat. Nutr Cycl Agroecosys 90(3):331–346. doi: 10.1007/s10705-011-9433-5
- 27.Cui Z, Zhang F, Chen X, Li F, Tong Y (2011). Using In-Season Nitrogen Management and Wheat Cultivars to Improve Nitrogen Use Efficiency. Soil Sci Soc Am J 75(3):976. doi: 10.2136/sssaj2010.0117
- 28.Dai X, Xiao L, Jia D, Kong H, Wang Y, Li C, et al (2014) Increased plant density of winter wheat can enhance nitrogen–uptake from deep soil. Plant Soil 384(1–2):141–152. doi: 10.1007/s11104-014-2190-x
- 29.Jayasundara S, Wagner-Riddle C, Parkin G, von Bertoldi P, Warland J, Kay B, et al (2007) Minimizing nitrogen losses from a corn-soybean-winter wheat rotation with best management practices. Nutr Cycl Agroecosys 79(2):141–159. doi: 10.1007/s10705-007-9103-9
- 30.Jayasundara S, Wagner-Riddle C, Parkin G, Lauzon J, Fan MZ. (2010) Transformations and losses of swine manure N-15 as affected by application timing at two contrasting sites. Can J Soil Sci 90(1):55–73. doi: 10.4141/cjss08085
- 31.Shi Z, Jing Q, Cai J, Jiang D, Cao W, Dai T. (2012) The fates of 15N fertilizer in relation to root distributions of winter wheat under different N splits. Eur J Agron 40:86–93. doi: 10.1016/j.eja.2012.01.006
- 32.Rees RM, Roelcke M, Li SX, Wang XQ, Li SQ, Stockdale EA, et al. (1997) The effect of fertilizer placement on nitrogen uptake and yield of wheat and maize in Chinese loess soils. Nutr Cycl Agroecosys 47(1):81–91. doi: 10.1007/bf01985721
- 33.Hamid A, Ahmad M (1995) Interaction of N-15-Labeled Ammonium-Nitrate, Urea and Ammonium-Sulfate with Soil N during Growth of Wheat (Triticum-Aestivum L) under Field Conditions. Biol Fert Soils 20(3):185–9. doi: 10.1007/bf00336556
- 34.Wang Q, Li F, Zhao L, Zhang E, Shi S, Zhao W, et al (2010) Effects of irrigation and nitrogen application rates on nitrate nitrogen distribution and fertilizer nitrogen loss, wheat yield and nitrogen uptake on a recently reclaimed sandy farmland. Plant Soil 337(1–2):325–339. doi: 10.1007/s11104-010-0530-z
- 35.Xue LH, Yu YL, Yang LZ (2014) Maintaining yields and reducing nitrogen loss in rice-wheat rotation system in Taihu Lake region with proper fertilizer management. Environ Res Lett 9(11). doi: 10.1088/1748-9326/9/11/115010
- 36.Mahler RL, Koehler FE, Lutcher LK (1994) Nitrogen source, timing of application and placement effects on winter wheat production. Agron J 86(4):637–642. doi: 10.2134/agronj1994.00021962008600040010x
- 37.Fuertes-Mendizábal T, Aizpurua A, González-Moro MB, Estavillo JM (2010) Improving wheat breadmaking quality by splitting the N fertilizer rate. Eur J Agron. 33(1):52–61. doi: 10.1016/j.eja.2010.03.001
- 38.Lam SK, Chen D, Norton R, Armstrong R (2012) Nitrogen demand and the recovery of 15N-labelled fertilizer in wheat grown under elevated carbon dioxide in southern Australia. Nutr Cycl Agroecosys 92(2):133–44. doi: 10.1007/s10705-011-9477-6
- 39.Wang D, Xu ZZ, Zhao JY, Wang YF, Yu ZW (2011) Excessive nitrogen application decreases grain yield and increases nitrogen loss in a wheat-soil system. Acta Agr Scand B-S P 61(8):681–92. doi: 10.1080/09064710.2010.534108
- 40.Zhao X, Xie YX, Xiong ZQ, Yan XY, Xing GX, Zhu ZL. (2009) Nitrogen fate and environmental consequence in paddy soil under rice-wheat rotation in the Taihu lake region, China. Plant Soil 319(1–2):225–234. doi: 10.1007/s11104-008-9865-0
- 41.Ichir LL, Ismaili M, Hofman G (2003) Recovery of N-15 labeled wheat residue and residual effects of N fertilization in a wheat—wheat cropping system under Mediterranean conditions. Nutr Cycl Agroecosys 66(2):201–7. doi: 10.4314/acsj.v11i1.27527
- 42.Ottman MJ, Pope NV (2000). Nitrogen fertilizer movement in the soil as influenced by nitrogen rate and timing in irrigated wheat. Soil Sci Soc Am J 64(5):1883–1892. doi: 10.2136/sssaj2000.6451883x
- 43.Ju XT, Liu XJ, Pan JR, Zhang FS (2007) Fate of 15N-Labeled Urea Under a Winter Wheat-Summer Maize Rotation on the North China Plain. Pedosphere 17(1):52–61. doi: 10.1016/s1002-0160(07)60007-1
- 44.Angus JF, Gupta VVSR, Pitson GD, Good AJ (2014) Effects of banded ammonia and urea fertiliser on soil properties and the growth and yield of wheat. Crop and Pasture Science 65(4):337–352. doi: 10.1071/cp13337
For further details log on website :
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0153701
No comments:
Post a Comment