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Nitrogen Management

Effects of Compost and Nitrogen Fertilizer on Wheat Nitrogen Use in Japanese Soils

^a Integrated Soil Fertility Management Research Team, National Agricultural Research Center, 3-1-1 Kannondai, Tsukuba, 305-8666 Japan
^b Dep. of Primary Industries-VIDA, 110 Natimuk Rd., Horsham, VIC 3401, Australia
^c DA-Bureau of Soils and Water Management, SRDC Bldg., Elliptical Road cor. Visayas Ave., Diliman, Quezon City, The Philippines

^* Corresponding author (shigeru{at}affrc.go.jp)

Received for publication March 1, 2006.

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
Wheat (Triticum aestivum L.) grain yield (GY) and grain protein concentration (GPr) are influenced by N availability and supply. This study aimed to investigate wheat (cv. Ayahikari) response to compost and N fertilizer. A 3-yr field experiment was conducted on four Japanese soils varying in N mineralization potential with or without annual compost application (220 kg N ha^–1 yr^–1). Four N fertilizer treatments including a zero-N control were established each year, and equal amounts of N were applied at preplanting and stem elongation. A significant quadratic relationship of increasing GY with greater N uptake, and increasing GPr with greater N factor (aboveground N uptake, N_up, per unit of GY) occurred for the pooled data. From these relationships, the optimum N_up for appropriate GPr (105 g kg^–1) for Japanese ‘Udon’ noodle was estimated to be 139 kg ha^–1 and GY could be >5000 kg ha^–1. Fertilizer N rate for optimum N uptake in each soil–compost regime was estimated from a significant linear or quadratic relationship between N uptake and fertilizer N rate (N_f). The agronomic efficiency (yield increase per unit of fertilizer N) and apparent fertilizer N recovery at a given rate of fertilizer N tended to be lower in soils with annual compost than without. However, the fertilizer N requirement for an equivalent yield decreased, thus the fertilizer N surplus (N_f – N_up) at optimum N uptake was lower in soils with compost application than without.

Abbreviations: CA, Cumulic Andosol • GLS, Gray Lowland soil • GPr, grain protein concentration • GY, grain yield • LHA, low-humic Andosol • N_f, fertilizer nitrogen rate • N_up, aboveground N uptake • YS, Yellow soil

	INTRODUCTION

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JAPANESE UDON NOODLE is one of the most common foods made from wheat flour in Japan. Most of the wheat consumed in Japan is imported, and recent emphasis by the government and flour milling companies is to increase domestic production with an appropriate quality. Protein concentration is an important determinant of wheat quality expressed as Udon texture and color of wheat flour (Miskelly, 1984; Kowata et al., 1996; National Agriculture and Food Research Organization, 2006), and favorable GPr is between 100 and 110 g kg^–1 (Kimura et al., 2001; Takayama et al., 2004).

Wheat production, N uptake, and GPr can be influenced by N availability and supply (Eilrich and Hageman, 1973; Gauer et al., 1992; Whitfield and Smith, 1992; Bar-Tal et al., 2004). When the amount of available soil N limits yield potential, N fertilization can increase GY. However, GPr can decrease if the amount of N fertilizer is not adequate for potential yield (Olson et al., 1976; Grant et al., 1985). Recommended N_fs for proper GY and quality would vary depending on soil N status.

Nitrogen use efficiency is important in crop management systems (Mahler et al., 1994). Excess N could pose negative impacts on the environment (e.g., leaching, denitrification). For cereals such as wheat, N use efficiency is low (Raun and Johnson, 1999). Therefore, it is important to optimize N use efficiency while increasing wheat GY for sustainable production.

For sustainable agricultural systems, recycling of nutrients is a major component of nutrient management (King, 1990). Bar-Tal et al. (2004) found that organic matter content and net N mineralization increased over time in compost-treated soil. Applying composts to soil increases soil fertility, thus use of organic matter may decrease the need for application of mineral fertilizers (Honya, 1975). The aim of this study was to evaluate the effects of compost and N fertilizer on GY, N uptake, GPr, and N use efficiency by wheat in four Japanese soils.

	MATERIALS AND METHODS

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Experimental Site, Design, and Treatment
Field experiments were conducted at the National Agricultural Research Center (NARC), Tsukuba, Ibaraki, Japan (36°01' N, 140°01' E, 14 m elevation). Ayahikari winter wheat was grown for three crop years (2001, 2002, and 2003) on four characteristic soils from the region around NARC. The soils were Cumulic Andosol (CA, Pachic Melanudands), low-humic Andosol (LHA, Typic Hapludands), Yellow soil (YS, Typic Paleudults), and Gray Lowland soil (GLS, Typic Hydraquents). The CA, LHA, and GLS were collected from Ibaraki prefecture and YS from Aichi prefecture.

Each soil was placed up to an 80-cm depth within one concrete enclosure (20 by 25 m) without bottom in 1975. Although the soils were collected from farmers' fields, the top 0- to 15-cm depth was removed to exclude past agricultural practices. Thus, the top 0- to 30-cm depth in the enclosure was filled with the soil from the 15- to 30-cm depth layer and the following 30- to 80-cm depth with the soil from the 30- to 60-cm layer. Each enclosure was divided into two (10 by 25 m each) in 1983, and since then one half has received plant compost at the rate of 20 Mg fresh wt. ha^–1 yr^–1 and the other has not. The compost was made from crop residue mixtures consisting of corn (Zea mays L.), wheat straw, and vegetables, and had an average composition of 24 g N kg^–1 dry matter and a C/N ratio of 9. Application rate of N derived from the compost was 220 kg N ha^–1 yr^–1. Compost was surface spread and incorporated into soil 2 to 4 wk before sowing. Tilling the soil without compost was conducted in the same way as the soil with compost.

The field experiment design within each soil–compost regime was a randomized block with four replications in a total of 16 plots in 2001, and two replications in a total of eight plots in 2002 and 2003. Four N fertilizer treatments, including a zero-N control, were set up and randomly reassigned to new plots each year (Table 1). Fertilizer N rates in 2001 were determined by GY in the former experiments (2000, unpublished data) and modified in 2002 and 2003 based on GPrs of the 2001 season. Since N fertilization at heading and later is not recommended for Ayahikari wheat, equal amounts of N were applied at two timings (preplanting and stem elongation) as (NH₄)₂SO₄. Potassium was applied at preplanting as KCl at 83 kg K ha^–1. Phosphorus was applied at preplanting as superphosphate at the rates of 44 kg P ha^–1 for YS and GLS, and 87 kg P ha^–1 for CA and LHA since Andisols have high PO₄ retention capacity. Application rates of fertilizer K and P were sufficient to ensure that GY was not limited by K and P. After the harvest of wheat, sweet corn was grown without fertilizer N between late June and mid-September in an attempt to minimize carryover of residual N to the next wheat experiment.

Plant Sampling and Analysis
At maturity, a 0.9-m² (0.9 by 1 m) aboveground portion of each plot was sampled for analysis. Plant samples were separated into grain and straw, oven-dried at 70°C, weighed, and ground. Nitrogen concentrations in the plant materials were determined by an Autoanalyzer (TRACCS 800, Bran+Luebbe, Norderstedt, Germany) after digestion with H₂O₂–H₂SO₄ (Mizuno and Minami, 1980). According to Japanese protocol, GY (kg ha^–1) was recorded at 125 g kg^–1 moisture content (NARC, 1986) and GPr (g kg^–1) was calculated by multiplying N concentration by 5.7 and expressed at 135 g kg^–1 moisture content (Forestry and Fisheries Research Council, 1968). The following N-use efficiency parameters were calculated using terminology according to Good et al. (2004), where N_up and N_f are N_up (kg ha^–1) and N_f (kg ha^–1), respectively.

[5]

[6]

[7]

Agronomic efficiency for compost N was defined for the zero-N treatment as GY increase per unit of compost N. Nitrogen harvest index was calculated as the ratio of N in grain to N_up. Makowski et al. (1999) noted that GPr should be linked to the ratio of total N uptake to GY that was referred to as N factor by Alvarez et al. (2004). Makowski et al. (1999) calculated the N factor assuming that N in roots accounts for 20% of N_up. Here, we considered aboveground parts only and calculated the N factor (g kg^–1) as 1000 x (N_up/GY). Therefore, GPr is expressed as N factor x N harvest index x 5.7 x (0.865/0.875). In the present study, aboveground portions (grain and straw) were removed from the field and fertilizer N surplus was calculated as N_f minus N_up.

Soil Sampling and Analysis
For determination of soil properties after the third harvest, soil sampling was conducted from the plow layer (0- to 15-cm depth). Twelve soil cores (3-cm diam.) were collected in each soil–compost regime and mixed to form a composite sample from that regime. The samples were air-dried, passed through a 2-mm sieve and used for the determination of pH, organic C, total N, N mineralization potential, and available P (Table 2). Soil pH was determined with a glass electrode for 1:2.5 soil–water suspensions. Organic C and total N were determined by dry combustion with a NC-Analyzer (model NC-95A, Sumica Chemical Analysis Service, Japan). Nitrogen mineralization potential was determined by the difference in inorganic N before and after soil incubation for 28 d at 30°C and 60% water holding capacity (aerobic incubation method, Matsumoto et al., 2000). Inorganic N was extracted with 2M KCl and inorganic N concentrations were determined colorimetrically by an Autoanalyzer (TRACCS 800, Bran+Luebbe, Norderstedt, Germany). Available P was determined by the modified Bray2 method (Shoji et al., 1964) by extracting 1 g of air-dried soil with 20 mL of Bray2 solution for 1 min. Phosphorus concentration in the filtrate solution was determined colorimetrically (Murphy and Riley, 1962).

	RESULTS AND DISCUSSION

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Soil Properties
Organic C concentrations ranged from 7.1 to 67 g kg^–1 in the soils without compost, and from 14 to 75 g kg^–1 in the soils with annual compost (Table 2). Nitrogen mineralization potentials ranged from 14 to 32 mg kg^–1 in the soils without compost, and from 26 to 49 mg kg^–1 in the soils with annual compost. Bray2 P levels ranged from 65 to 538 mg kg^–1 in the soils without compost, and from 146 to 640 mg kg^–1 in the soils with annual compost.

Yield, Grain Protein, and Nitrogen Uptake
In the zero-N treatment, mean GY without compost ranged from 903 kg ha^–1 in YS to 2636 kg ha^–1 in GLS (Table 3). Mean GY in each soil was greater with annual compost than without. Country-wide average GY in Japan is around 4000 kg ha^–1 at present, and tentative yield target by researchers is 5000 kg ha^–1. Mean GY in LHA and GLS with annual compost was about 5000 kg ha^–1, even in the zero-N treatment (Table 3). Mean GY was significantly correlated to N mineralization potential (r = 0.88, P < 0.01). Thus, GY in the zero-N treatment likely reflected the difference in soil N supply.

View larger version (22K): [in this window] [in a new window]   Fig. 1. Relationship between wheat grain yield and aboveground N uptake for 2001 to 2003 on four soils with or without annual compost application (+ comp and – comp, respectively). The regression was performed by setting the intercept = 0 using data pooled over 3 yr.

[3]

Assuming GPr of 105 g kg^–1 (mean of appropriate range for Udon), N_up is estimated to be 139 kg ha^–1 from Eq. [2] and [3], and then GY is 5149 kg ha^–1 from Eq. [1]. By the split N application method used in this study, therefore, proper grain quality and GY can be achieved at optimum N_up (139 kg ha^–1). In the present study, N fertilization timing was fixed (preplanting and stem elongation) since late-season N topdressing is not recommended for Ayahikari wheat. Studies have demonstrated that late-season N applications increased GPr more than earlier applications (Vaughan et al., 1990; Wuest and Cassman, 1992; Knowles et al., 1994). If late-season N application is allowed, proper GPr may have been obtained with a lower N_up than the present result.

View larger version (21K): [in this window] [in a new window]   Fig. 2. Relationship between wheat grain protein concentration and aboveground N uptake for 2001 to 2003 on four soils with or without annual compost application (+ comp and – comp, respectively).

View larger version (19K): [in this window] [in a new window]   Fig. 3. Relationship between wheat grain protein concentration and N factor for 2001 to 2003 on four soils with or without annual compost application (+ comp and – comp, respectively). N factor is g of aboveground N uptake per kg grain. The regression was performed by setting the intercept = 0 using data pooled over 3 yr.

View larger version (25K): [in this window] [in a new window]   Fig. 4. Relationships between wheat aboveground N uptake and fertilizer N rate for 2001 to 2003 with and without annual compost. + comp and – comp, with and without annual compost, respectively. See Table 1 for fertilizer N rates in each year. CA, Cumulic Andosol; LHA, low-humic Andosol; YS, Yellow soil; GLS, Gray Lowland soil.

Nitrogen Utilization Efficiency
Utilization efficiency (GY/N_up) was expressed as Eq. [4] stemming from Eq. [1]. This means that utilization efficiency decreased linearly with increasing N_up.

[4]

The highest utilization efficiency has been found to be associated with zero fertilizer N applications in bread wheat (López-Bellido et al., 2005) and durum wheat (López-Bellido et al., 2006). Since N_up usually increased with fertilizer N application as indicated in Fig. 3, the zero-N treatment should give the maximum agronomic efficiency from Eq. [4]. Utilization efficiency was estimated to be 36.9 kg kg^–1 when N_up = 139 kg ha^–1. Miyama et al. (1989) reported a similar utilization efficiency value (37 kg kg^–1) for Japanese Udon wheat (cv. Norin 61) at GY of 5000 kg ha^–1.

The agronomic efficiency (yield increase per unit of fertilizer N) tended to decrease with greater N_fs (Fig. 5). In 2001, the agronomic efficiencies at the lowest N rate (N1) for YS and GLS without compost were low and counter to the trend. This should be related to the relatively lower apparent fertilizer N recovery of these treatments (Fig. 6) but we cannot explain these results at present. Apparent fertilizer N recovery was quite variable with no clear trends apparent with respect to N rate (Fig. 6).

View larger version (33K): [in this window] [in a new window]   Fig. 5. Comparison of agronomic efficiency (AE) of wheat with and without annual compost at the same fertilizer N rate for 2001 to 2003 with one-to-one line shown for reference. Agronomic efficiency (AE), grain yield increase per unit of fertilizer N. + comp and – comp, with and without annual compost, respectively. Bars indicate standard error. See Table 1 for fertilizer N rates in each year. CA, Cumulic Andosol; LHA, low-humic Andosol; YS, Yellow soil; GLS, Gray Lowland soil.

View larger version (30K): [in this window] [in a new window]   Fig. 6. Comparison of apparent fertilizer N recovery between with and without annual compost at the same fertilizer N rate for 2001 to 2003 with one-to-one line shown for reference. Apparent fertilizer N recovery (ANR), percentage of N uptake increase per unit of fertilizer N. – comp and + comp, with and without annual compost, respectively. Bars indicate standard error. See Table 1 for fertilizer N rates in each year. CA, Cumulic Andosol; LHA, low-humic Andosol; YS, Yellow soil; GLS, Gray Lowland soil.

When a linear relationship between N_up and N_f is observed, apparent fertilizer N recovery should be constant regardless of N_f and estimated by 100 x slope of the equations indicated in Fig. 4. The estimated apparent fertilizer N recoveries from linear equations were 62, 53, and 51% for CA, LHA, and YS without compost, respectively, and 44, 42, and 44% for CA, YS, and GLS with annual compost, respectively. This is evidence of the reduced apparent fertilizer N recovery with annual compost application. However, apparent fertilizer N recovery in each soil regime was not constant (Fig. 6). This conflict with the relationships based on Fig. 4 may depend on whether data were regarded pooled over years or not.

When a quadratic relationship between N_up and N_f is observed, 100 x d[N_up]/d[N_f] as N_f approaches zero gives the (virtual) maximum apparent fertilizer N recovery. The estimated maximum apparent fertilizer N recoveries were 116% in GLS without compost and 82% in LHA with annual compost, which were similar to the measured values of maximum apparent fertilizer N recovery. The quadratic term in soil–compost regimes other than GLS without compost and LHA with annual compost was not significant; in some cases, this may have been due to a narrow range of N_fs and/or variability of N_up among years.

	CONCLUSIONS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 
A significant quadratic relationship of increasing GY with greater N_up, and increasing GPr with greater N factor occurred for the pooled data over the 3 yr. The optimum N_up for proper GPr for Udon noodle production and GY was estimated to be 139 kg ha^–1 for Ayahikari wheat. The agronomic efficiency and apparent fertilizer N recovery at a given rate of fertilizer N tended to be lower with annual compost than without. However, estimated N_f for optimum N_up indicated that annual compost application contributed to reduction of chemical N fertilizer need and deceased fertilizer N surplus at optimum N uptake.

	ACKNOWLEDGMENTS

 
We thank Dr. Toshiro Nakatsuji, Ms. Yumiko Nemoto, and Ms. Tsuyuko Komatsu for their field and laboratory assistance. We are also grateful to Dr. Takashi Nishio for providing the chemical composition data of compost. This work has been supported by the Brand Nippon Project from MAFF of Japan.

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS RESULTS AND DISCUSSION CONCLUSIONS REFERENCES

 

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This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Takahashi, S. Articles by de Vera, S. G. Search for Related Content PubMed Articles by Takahashi, S. Articles by de Vera, S. G. Agricola Articles by Takahashi, S. Articles by de Vera, S. G. Related Collections Nitrogen Wheat Soil Fertility and Productivity