Improving nitrogen fertilization in rice by site-specific N management.

A review*作者： Shaobing Peng , Roland J. Buresh , Jianliang 　　　Huang , Xuhua Zhong , Yingbin Zou , 　　　 Jianchang Yang ,Guanghuo Wang , Yuanying 　　　 Liu , Ruifa Hu , Qiyuan Tang , Kehui Cui , 　　　 Fusuo Zhang , Achim Dobermann出處： Agron. Sustain. Dev. 30 (2010) 649–656

報告人：陳筱鈞、莊豐鳴、陳伊蓉、吳昌烜

Outline

• Introduction － Nitrogen use efficiency － SSNM

Introduction

• Increase in fertilizer nutrient input, especially N fertilizer, has contributed significantly to the improvement of crop yields in the world .

• Over-application of N fertilizer may actually decrease grain yield by increasing susceptibility to lodging and damage from pests and diseases .

Introduction

• China is currently the world’s largest consumer of N fertilizer.

• In 2006, annual N fertilizer consumption in China was 31 million metric tons or 31.7% of the global N consumption.

• China’s national average N rate for rice was 193 kg ha− 1 in 2006, about 90% higher than the world average .

N-omission plots

• Fertilizer N use efficiency can be measured in different ways using N-omission plots.

1.Full fertilization:NPK applied2.N omission(–N):No N applied, PK applied3.P omission(– P):No P applied, NK applied4.K omission(– K):No K applied, NP applied

－ an N omission plot illustrates the deficit between the crop demand for N and indigenous supply of N, which must be met by fertilizers.

Nitrogen Use Efficiency

1. Total N rate.2. Agronomic N use efficiency.3. Recovery efficiency of fertilizer N.4. Yield response to N application.5. Partial factor productivity of apply N (PFP).

Nitrogen Use Efficiency(1)

• Total N rate ： － 單位面積的所施的氮肥量，單位 kg ha-1。

• Yield response to N application (N response)：　－ It is calculated as the difference between yields with and without N fertilizer.

N response = YT - Y0 in kg ha-1

Nitrogen Use Efficiency(2)

• Agronomic N use efficiency ：　－ The yield increase that results from N application in comparison with no N application . AEN = (YT - Y0 ) / FN = ΔY/ΔN in kg kg-1

= N response / total N rate

Nitrogen Use Efficiency(3)

• Recovery efficiency of fertilizer N ：　－ which is used to express the percentage of fertilizer N recovered in aboveground plant biomass at the end of the cropping season.

REN = ( UT - U0 ) / FN = ΔU/ΔN in kg kg-1

Nitrogen Use Efficiency(4)

• Partial factor productivity of apply N (PFP) ：　－ the ratio of grain yield to N applied and it provides an integrative index that quantifies total economic output relative to utilization of all N resources in the system, including indigenous soil N and fertilizer N . PFPN = YT / FN in kg kg-1

=Grain yield / total N rate

1. Zhu (1985) reported that recovery efficiency in China was less than 30% for ammonium bicarbonate and 30–40% for urea.

2. In China, agronomic N use efficiency was 15–20 kg kg− 1 N from 1958 to 1963 and declined to only 9.1 kg kg− 1 N between 1981 and 1983 (Lin, 1991).

3. Peng et al.(2006) reported that rice yield increases by only 5 to 10 kg for every kg of N fertilizer input by using farmers’ N fertilizer practice in China.

SSNM

• Site-specific N management ： SSNM was developed to increase fertilizer N

use efficiency of irrigated rice. In SSNM, N application is based on the crop demand for N.

－ N-omission plots － chlorophyll meter (SPAD) 、 leaf color chart

Leaf N status• During the growing season, leaf N status

measured with a chlorophyll meter (SPAD) or leaf color chart is a good indicator of crop N demand .

transplanting, midtillering, panicle initiation and heading

The N rate

• The pre-determined N rate is 30 kg ha− 1 at midtillering and 40 kg ha− 1 at panicle initiation.

• The actual rates of N topdressing at midtillering and panicle initiation are adjusted by ± 10 kg N ha− 1 according to leaf N status measured with a SPAD or leaf color chart.

The four steps about SSNM…

1. Set an attainable yield target based on 85% of yield Potential.

2. Estimate indigenous N supply – yield without N fertilizer.

3. Estimate N response – the difference between target yield and yield without N fertilizer.

4. Estimate N rate based on N response and agronomic N use efficiency.

Improving nitrogen fertilization in rice by site-specific N management.

A review

3. IRRI-CHINA COLLABORATION ON SSNMRESEARCH

Speaker:莊豐鳴

Journal: Agronomy for Sustainable Development 30 (2010) 649–656Author: Shaobing Peng et al.

SSNM in IRRI

SSNM experiment design

• IRRI and China cooperation since 1997• Data sources: -on-farm field trails in 5 provinces -on-farm demonstration in 6 provinces (J.G. Richardson, 2003)

-farmer’s participatory research in 5 provinces (Rice knowledge bank, IRRI )

1997200120032005

http://wenwen.soso.com/z/q176122474.htm

Distribution of experimental provinces

2001-2007 on-farm trails

• 2001-2003 in Zhejiang(浙江 )、 Guangdong(廣東 ) 、 Hunan(湖南 )及 Jiangsu(江蘇 ) (Peng et al, 2006)

A. 2001-2007 on-farm trails

• 2005-2007 in Hubei(湖北 )、 Guangdong(廣東 )、 Hunan(湖南 )及 Jiangsu(江蘇 )

Other treatments explanation

(1)Real-time N management Below critical N level with SPAD

(2)Farmer’s N fertilizer practice N rate based on farmer’s decision

(3)Modified farmer’s N fertilizer practice

Reducing total N rate by 30% within 10 days after transplanting

(4)Three fixed –N split treatment N rates of 60,120,180 kg/ha(35% basal,20% midtillering, 30% panicle initiation, 15% heading )

2003-2005 Farmer participatory research(FPR)

• 2003-2005 in Hubei(湖北 )、 Guangdong(廣東 )、 Hunan(湖南 ) and Jiangsu(江蘇 ). (Hu et al., 2007)

1. Farmer participatory research:12-15 farmers in each study village and total 144 farmers.

2. Farmer-modified SSNM: Decrease N topdressing, and increase basal N.

Site selection Exp. Design and decision making

Implementation and evaluation

B. 2003-2007 on-farm demonstrations

1. Six provinces: Zhejiang(浙江 )、 Guangdong(廣東 )、 Hunan(湖南 )、 Jiangsu(江蘇 )、 Hubei(湖北 )and Heilongjiang(黑龍江 )

2. One location is selected in each province, and 10 farmers are selected in each location.

3. Experimental design:SSNM with N omission plot

Farmer’s N fertilizer practice

http://www.knowledgebank.irri.org/ericeproduction/bodydefault.htm#pop_up_nutrient_omission_plot.htm

Data analysis• Pooled the data from 2001 to 2007 in 6

provinces (544 observations)• Compare SSNM with other N treatments• Analytic parameters: -yield -N response -Agronomic N use efficiency -Partial factor productivity of applied N(PFP)

Improving nitrogen fertilization in rice by site-specific N management.

4. Key research findings

Speaker：陳伊蓉

Table 1

a. 107 farmers form six provinces in China between 2003 and 2007

b. average grain yield of zero-N control was 5.69 t ha-1 across the 107 farmers

SSNM

Grain yield

N rate

N response

Agronomic N use efficiency

PFP

a. 25 on-farm field experiments conducted in five provinces in China between 2001 and 2007

b. average grain yield of zero-N control was 5.69 t ha-1 across the 25 experiments

Table 2

SSNM

Grain yield

N rate

N response

Agronomic N use efficiency

PFP

Grain yield and N rate of site-specific N management and other N treatments

site-specific N management other N treatments

Six provinces in China form 2001-2007

Relationship between grain yield with and without N fertilizer

y = 2.16 + 0.886x (r = 0.70; n = 544)

Six provinces in China form 2001-2007

5.77

7.2

Relationship between yield response to N application and N rate

• Six provinces in China form 2001-2007

• 544 observations

• N response average 1.5 t ha-1 1.5

Relationship between yield response to N application and grain yield with N fertilizer

Six provinces in China form 2001-2007

Relationship between agronomic N use efficiency and N rate

Six provinces in China form 2001-2007

Relationship between agronomic N use efficiency and grain yield with N fertilizer

Six provinces in China form 2001-2007

5. Remarks on site-specific N management

報告學生 : 吳昌烜

Remarks on site-specific N management

1. High indigenous N supply capacity in China.– Reduce N rate during early vegetative stage

2. Total N rate is based on N response and AEN.– Experimental results– Indigenous N supply capacity

3. Adjustments of topdressing N rate by ±10 kg/ha at critical time based on leaf N status.

Charlie fong

The Limitations of the SSNM

1. N response varies with the location across seasons.– Cropping history, variety, climatic condition

2. Total N rate can not be very accurate.– N response and AEN

3. Tillering capacity and early growth vigor.– Varietal differences

4. In-season adjustment of N rate by ± 10 kg/ha may be inadequate.

– the magnitude of N response

Charlie fong

Conclusion

1. SSNM is a matured technology.– AEN and yield of irrigated rice crop

2. For a better performance of SSNM.– N response and AEN

3. In-season adjustment on N rate.– Location, season and variety

Charlie fong

Conclusion

1. Simplify the procedure of SSNM.

2. To convince policy-makers.

3. To develop SSNM based on remote sensing technology for large scale practice.

Charlie fong

推廣

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