Are China’s Farmers Using Too Much Fertilizer?

中国农民施肥太多？Linxiu Zhang, Jikun Huang, Ruifa Hu and Qiang Li

张林秀 黄季焜 胡瑞法 李强CCAP, CAS

Scott Rozelle and Fangbin Qiao罗斯高 乔方彬

UC Davis

Motivation 研究背景• Chemical fertilizer plays an

important role in increasing agricultural production in all developing countries, including China;

• China is now the largest fertilizer producer and consumer in the world ;

• Such high levels of fertilizer use in recent years have raised concerns about the overuse of chemical fertilizer and the negative environmental consequences that overuse would generate.

• 在发展中国家，化肥对于提高农产品产量有起了要作用，中国也不例外

• 目前中国是世界上最大的化肥生产国和消费国

• 最近几年，越来越关注化肥施用过量及其对环境的负面影响

Fertilizer use & grain production in China 化肥用量与粮食产量

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5

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30

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40

45

50

1978- 80 1981- 85 1986- 90 1991- 95 1996- 00 01- - 02

0

100

200

300

400

500

600

Fertilizer consumption (mt) Grain production (mt)

Fertilizer use intensity(4th highest in the world) 化肥施用强度（世界第四）

0

50

100

150

200

250

300

350

1965 1970 1975 1980 1985 1990 1995 2000

Chi naWorl d

kg/ha

Research Questions问题的提出• Whether farmers are

overusing fertilizer from economic point of view?

• If so, to what extent?• What have been the

factors determining the level of fertilizer use?

• In particular, what is the role of information in this process? [in other words, are farmers just making mistakes?]

• Whether there are measures or policies to reverse the trend? Does extension have a role?

• 从经济学的角度，农民是否过量施肥？

• 如果是，在多大程度上过量施肥？

• 决定施肥水平的因素？

• 信息？农民决策错误？

• 有没有什么措施、政策可以扭转目前的趋势？农业技术推广？

Plan of presentation 报告提纲• Testing extent of overuse

of fertilizer

• Determinants of fertilizer demand (why do they use the levels they do?)

• An intensive look at the role of information … and yield responses at greatly reduced levels of fertilizer …

• 检验过量施肥的程度

• 决定化肥需求的因素（农民为什么用那么多化肥？）

• 深入探讨信息的作用，大幅度降低施肥量是否对单产有影响？

Test of fertilizer overuse 过量施肥检验

• Data sources;

• Analytical methods;

• Empirical results;

• General discussions

• 数据来源

• 分析方法

• 实证分析结果

• 讨论

Data sources 数据来源• Jiangsu Household Survey (1

996): 69 households, 138 plots; input, output & price information

• Hebei & Liaoning Household Survey (1995): 275 households x 2 plots; same information

• China National Cost of Production Survey Dataset: more than 20,000 households; 1984 to 2000

• 江苏农户调查（ 1996）：69户， 138块地，投入、产出、价格信息

• 河北、辽宁农户调查（ 1995）： 275户， 550块地，投入、产出、价格信息

• 中国农业生产成本数据：2万多户， 1984－ 2000共 17年

Methodologies 研究方法

• Estimate Cobb-Douglas production function;

• Testing strategy: – VMP of fertilizer =

fertilizer price [or]

– VMP of fertilizer/fertilizer price = 1

• Bootstrapping for robustness check

• 估计柯布－道格拉斯生产函数

• 检验方法– 化肥边际产品价值＝化肥价格

– 化肥边际产品价值 /化肥价格＝ 1

• 通过 Bootstrapping检验稳健性

Estimated parameters for fertilizer use and output using Jiangsu and Hebei & Liaoning provinces

household survey data.

Jiangsu dataset Hebei & Liaoning dataset

Dependent variable Log of output value Log of maize yield

FEa FE-IVa FEa FE-IVa FEa FE-IVa FEa FE-IVa

Log of output

value

Log of output

value

Log of

fertilizer Log of output

value

Log of output

value

Log of

fertilizer

Log of

yield

Log of

yield

Log of

fertilizer

Log of

yield

Log of

yield

Log of

fertilizer

Intercept 5.139 5.288 4.318 5.225 5.375 4.298 5.984 6.060 1.589 6.022 5.980 2.869

(20.69)*** (25.38)*** (5.76)*** (22.06)*** (26.60)*** (6.68)*** (36.04)*** (38.77)*** (3.77)*** (43.71)*** (41.54)*** (4.85)***

Log of total fertilizer 0.099 0.096 0.099 0.082

(1.68)* (2.64)*** (1.83)* (2.17)**

Log of nitrogen fertilizer 0.052 0.044 0.081 0.080

(0.87) (0.89) (2.02)** (2.85)***

Log of phosphate fertilizer 0.030 0.034 0.065 0.065

(0.67) (1.13) (1.84)* (2.63)***

Log of labor 0.089 0.090 0.289 0.104 0.108 0.259 0.017 0.020 0.188 0.013 0.013 0.199

(1.41) (2.32)** (3.23)*** (1.67) (2.68)*** (3.07)*** (0.39) (0.68) (5.57)*** (0.31) (0.45) (4.21)***

Irrigation dummy 0.078 0.077 -0.319 0.067 0.063 -0.422

(0.96) (1.55) (2.69)*** (0.82) (1.21) (3.91)***

Log of machinery expenditures 0.049 0.049 -0.006 0.050 0.050 0.010

(0.86) (1.40) (0.08) (0.86) (1.42) (0.13)

Wheat dummy 0.545 0.547 0.629 0.562 0.567 0.805

(7.64)*** (12.49)*** (7.04)*** (7.58)*** (11.16)*** (9.58)***

Log of organic fertilizer 0.087 0.089 0.068 0.100 0.100 0.016

(2.57)** (3.73)*** (2.51)** (2.95)*** (4.22)*** (0.43)

Log of other expenditures 0.019 0.020 0.065 0.022 0.022 0.020

(0.46) (0.69) (1.93)** (0.52) (0.75) (0.41)

Soil quality dummy 0.172 0.172 -0.012 0.170 0.170 -0.017

(5.55)*** (7.91)*** (0.48) (5.51)*** (7.89)*** (0.49)

Fertilizer price -0.384 -0.644 0.934 0.138

(1.31) (2.68)*** (3.78)*** (0.40)

Household dummy Omitted Omitted Omitted Omitted Omitted Omitted Omitted Omitted

R-squared 0.79 0.79 0.15 0.16

The rate of fertilizer overuse by China’s farmers in Jiangsu and Hebei & Liaoning

provinces, 1995 and 1996a.

Jiangsu dataset Hebei & Liaoning dataset

Total fertilizer used as

explanatory variable

Nitrogen fertilizer used

as explanatory variable

Total fertilizer used as

explanatory variable Nitrogen fertilizer used as

explanatory variable

FEb FE-IVb FEb FE-IVb FEb FE-IVb FEb FE-IVb

Output elasticity of

fertilizerc 0.10 0.10 0.05 0.04 0.10 0.08 0.08 0.08

t-valuec 1.68 2.64 0.87 0.89 1.83 2.17 2.02 2.85

Ratio of marginal output to

fertilizer price (VMP-price

ratio)

0.63 0.61 0.47 0.40 0.84 0.69 0.93 0.91

Results of bootstrapping analysis for VMP-price ratiod

Mean 0.53 0.56 0.46 0.51 0.72 0.60 0.75 0.67

0.41 0.44 0.29 0.27 0.58 0.45 0.58 0.49

95% confidence

interval

Minimum

Maximum 0.65 0.68 0.64 0.74 0.87 0.76 0.91 0.86

Teste

t-value 7.98 7.23 6.08 4.17 3.80 5.10 3.01 3.53

Probability 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Percentage of fertilizer

overuse (%)f 44 47 59 67 22 35 21 16

Output elasticities of fertilizer use (all are statistically significant)

化肥施用量的产出弹性（统计显著）Total fertilizer Nitrogen fertilizer

Jiangsu

江苏0.10 0.10 0.05 0.04

Hebei & Liaoning

河北＆辽宁0.10 0.08 0.08 0.08

National (84-90)

全国（ 84－ 90）0.13 0.10

National (91-00)

全国（ 91－ 00）0.08 0.05

Consistent with findings by others本研究的结果与以往的研究一致

Authors Level of observation Crops Elasticity Period

Huang & Rozelle Province Grain 0.10 1975-90

Huang, et.al.(a) Province Rice 0.10-0.21 1984-90

Zhang and Fan Country GVAO 0.08-0.17 1979-96

Huang, et.al.(b) Household Rice 0.18 1986-91

Fang and Fan Household Crop 0.01-0.12 1978-90

Measures on overuse从经济学的角度判断是否过量施肥

• Condition for profit maximization:

– the value of the marginal product (VMP) of input use equals the price of the input

or– the ratio of VMP of

fertilizer and the fertilizer price (VMP-price ratio) equals 1

• 利润最大化条件下

– 投入品的边际产品价值＝投入品的价格

– 化肥边际产品价值 /化肥价格＝ 1

Measures on overuse（ con’t）从经济学的角度判断是否过量施肥（续）

• If VMP-price ratio is smaller than 1, then it means fertilizer use exceeds the optimal level

• 如果边际产品价值 /价格 <1，其经济学含义就是化肥施用量超过最优用量

VMP-Price Ratios边际产品价值 /价格比

Total fertilizer

（化肥）N fertilizer

（氮肥）Model/Sample

（模型、样本）Specification

1Specification

2Specification

1Specification

2

Fixed Effect

（固定影响） Jiangsu data 0.63 0.61 0.47 0.40 Hebei & Liaoning 0.84 0.69 0.93 0.08

Bootstrapping

Jiangsu data 0.53 0.56 0.46 0.51 Hebei & Liaoning 0.72 0.60 0.75 0.67

Percent of fertilizer overuseNational data

过量施肥的程度（全国数据）Crop

作物1984-90

(%)

1991-2000

(%)

Maize

玉米50 56

Wheat

小麦33 56

Rice

水稻36 61

Summary of findings小结

• Output elasticities of fertilizer are low, but still generate positive output at the margin– Regardless of crop, time p

eriod or specification

• Fertilizer overuse is pervasive– Regardless of crop, time p

eriod or specification

• 化肥施用的产出弹性低，但是边际产出仍然是正的（不论是从作物，时期还是从模型设定来看）

• 过量施肥是普遍现象（不论是从作物，时期还是从模型设定来看）

What are the determinants of the use of fertilizers by farmers?

什么因素影响农民的施肥决策？

Key hypotheses 重要假说• Good market environment

will help farmers to use fertilizer more rationally (if there is poor quality fertilizer on the market, farmers may respond by using more than needed)

• Good extension services will help farmers reduce fertilizer use

• 良好的市场环境有助于农民理性施肥（如果市场上有假化肥，农民会多施）

• 良好的农业推广服务有助于农民减少化肥施用量

Key hypotheses （ con’t）重要假说（续）

• More education helps farmers make fewer mistakes (and use less fertilizer)

• People with off farm jobs have high opportunity costs and will substitute fertilizer for labor (and management of careful fertilizer use), thereby leading to higher levels of fertilizer use

• 提高农民的受教育水平有助于农民科学决策施肥（减少化肥用量）

• 有非农就业机会的人劳动力的机会成本相对高，用化肥替代劳动力（施肥管理），从而导致化肥施用量偏多

Data source 数据• Household survey data

(2003/2004):

– 9 provinces

– 10 counties

– 400 households

– 800 plots

• 农户调查数据

– 9个省– 10个县– 400户– 800块地

Sichuan

ShaanxiJiangsu

Distribution of sample counties in China Total number of households: 401

Hebei

Henan

Shandong

Heilongjiang

Jiangxi

Liaoning

样本县的分布： 401 户

Information collected 调查数据• Fertilizer use (detailed)

• Control variables:– Wealth (to measure if

farmers faced capital constraint)

– Risk in gaining access to markets for grain

(ZERO problems in 2003!)

– Risk in gaining access to markets for fertilizer

(ZERO problem in 2003!)

– Other household/plot characteristics

• Soil quality• Access to irrigation• Etcetera

• 详细的化肥施用数据

• 控制变量– 财产（资本约束？）– 能否买到粮食的风险

（ 2003 年无）– 能否买到化肥的风险

（ 2003 年无）– 住户 / 地块特征

• 土壤质量• 灌溉条件• ……

Information on Variables of Interest for Testing Hypotheses 检验假说变量

• Marketing environment: there is one aspect of fertilizer markets that may be relevant that we discovered during our fieldwork … some farmers in the sample claimed that they had purchased low quality fertilizer (jia huafei or fake fertilizer) … we asked if the perception that the presence of jia huafei was increasing or not

• Extension (“Did any extension agents visit the village during the previous year?)

• 市场环境：调查中有农民说他们买到过假化肥……农民预期市场上的假化肥是多了还是少了？

• 农业技术推广：去年有没有农技员来过本村？

Information on Variables of Interest for Testing Hypotheses （ con’t）检验假说变量（续）

• Education of household head / rest of family

• Opportunity cost (several measures of degree of participation of hh members in off farm labor market … tried to measure: are family members too busy to pay close attention to agriculture?)

• 户主 / 家庭成员的受教育水平

• 机会成本（家庭成员参与非农就业市场的程度，家庭成员是否太忙，无暇顾及农业生产？）

Descriptive information描述统计分析

High level of fertilizer / substantial variation across the sample

化肥施用量高 /作物之间差异大

Obs Mean S.d.

Wheat 269 395 31.31

Rice 262 404 25.12

Maize 238 296 32.83

Descriptive Summary of key Variables 描述统计Key explanatory factors MeanFarmer perception of changes in volume of low quality fertilizer that are inmarkets(1=increasing amounts; 0=non increasing amounts) 0.20Whether the agricultural extension agent visit the village in 2003 (1=yes; 0=no) 0.33Educational level of household head

Elementary school 0.38Lower middle school 0.41Completed at least high school 0.15

Whether household head has non-farm job (1=yes; 0=no) 0.47The proportion of households in which their labor force is in a non-farm job 0.47Household head is an owner-operator of a firm with assets that exceed 30thousand yuan (1=yes; 0=no) 0.03

Wealth of farm households

Household wealth less than 10000 yuan 0.32Household wealth greater than 40000 yuan 0.30

Whether suffered natural disaster (1=yes; 0=no) 0.58Soil quality (1=good: 0=no) 0.40

Key information (关键信息）

• There was at least some evidence that households had purchased low quality fertilizer in earlier years, nevertheless in 2004 only 20 percent of households believe the presence of low quality fertilizer on the market is increasing

• Also, level of extension is very low

• 农民觉得市场上化肥质量差是一个担忧 （ 20%）

• 另外，推广服务也不到位（ 33%）

Low quality fertilizer and level of fertilizer use（劣质化肥与施肥量）

Decr

ease

Decr

ease

Decr

ease

Incr

ease

Incr

ease

Incr

ease

0

50

100

150

200

250

300

350

400

450

Wheat Rice Maize

kg/ha

Extension and level of fertilizer use（技术推广与施肥量）

No No

No

Yes Yes

Yes

0

50

100

150

200

250

300

350

400

450

Wheat Ri ce Mai ze

kg/ha

Off-farm employment and level of fertilizer use（非农就业与施肥量）

No NoNo

Yes Yes

Yes

0

50

100

150

200

250

300

350

400

450

Wheat Ri ce Mai ze

kg/ha

Summary of descriptive analysis: Demand for fertilizer use小结：农民的化肥需求

• We have measures of proxies for factors that may explain why farmers are using such high levels of fertilizer

• Some are correlated with fertilizer use …

• Others do not appear to be correlated …

[need to examine in multivariate analysis]

• 可能解释农民施肥量过高的变量

• 一些变量与化肥施用量相关

• 另一些似乎不相关

• 需要多元回归分析

Multivariate analysis (Determinants of fertilizer use)多元回归分析（化肥施用量）

Fertilizer use=

f ( marketing environment extension education

off-farm employment

Other characteristics• Plot was affected by flooding or

drought• Household wealth• Other plot characteristics )

• 化肥施用量＝– f （市场环境、– 农技推广、– 教育、– 非农就业、– 自然灾害、– 家庭资产、– 其它的地块特征）

Estimation results All Rice Wheat Maize

ln_fert Coef. T Coef. T Coef. T Coef. T

Low quality fertilizer -0.006 (0.11) 0.015 (0.11) 0.084 (1.12) -0.024 (0.21)

Extension 0.082** (1.99) 0.014 (0.24) 0.094 (1.25) 0.250** (2.08)

Elementary 0.122 (1.37) 0.126 (0.89) 0.053 (0.37) 0.405* (1.67)

Junior 0.088 (0.98) 0.090 (0.62) 0.110 (0.77) 0.285 (1.22)

Senior 0.108 (1.14) 0.102 (0.65) 0.097 (0.64) 0.395 (1.63)

Boss 0.261** (2.42) 0.396** (2.29) 0.336** (2.02) 0.183 (0.61)

Wealth -0.004 (1.40) 0.000 (0.05) -0.024*** (3.46) -0.030 (1.52)

Disaster -0.149*** (3.90) -0.086 (1.63) -0.146** (2.10) -0.449*** (4.00)

Distance to water -0.0985** (2.17) -0.0403 (0.43) -0.1175** (2.05) 0.1404 (0.82)

Quality good 0.066* (1.75) 0.008 (0.15) 0.136** (2.11) 0.189* (1.88)

Wheat dumy -0.130** (2.36)

Maize dumy -0.592*** (9.39)

North 0.218*** (4.00)

Constant 5.816*** (61.34) 5.809*** (39.71) 5.873*** (38.71) 5.220*** (22.01)

Observations 657 249 237 171

R-squared 0.2 0.05 0.11 0.17

Absolute value of t statistics in parentheses

* significant at 10%; ** significant at 5%; *** significant at 1%

Summary of findings 小结（ 1）• Models generally perform well

(in R-square sense)

• Many of control variables have expected signs:– For example: When farmers face

higher flood/drought risk, they use less fertilizer

• Level of wealth does not matter (insignificant)– The finding of no capital

constraint by farmers in the purchase of agricultural inputs is consistent with findings of a much bigger study on credit by Park and Wang

• 总体上模型的拟合程度好（ R－平方）

• 多数控制变量的系数符号跟预期一致– 农民面临自然灾害的话，

他们少用化肥• 资产水平对施肥量没有显著影响– 农民购买农业生产投入时没有资产约束，这与 Park and Wang的研究结果一致

Summary of findings 小结（ 2）

• Marketing environment

• Extension *

• Level of education

• 市场环境• 农业技术推广• 受教育水平

Do not matter in explaining high fertilizer use!

* 实际上，在一些回归中，农业技术推广反而增加农民的施肥量

不能解释农民施肥量为什么这么高 !

* In fact, in many specifications, extension leads to higher use

Summary of findings 小结（ 3）

• Off-farm employment effect is complicated:– Does have significant impact

(for some crops / but not others)

– In general, however, does not appear to have a large effect (magnitude-wise)

– Most prominent effect appears when variable is measuring those households with most extreme opportunity effects

• 非农就业对农民施肥量的影响– 对一些作物的施肥量

没有显著影响，但是对另一些作物有显著影响

– 总体而言，即便有显著影响，其影响程度也不大

– 对于某些非农就业机会变量，影响显著

Overall findings, however, appear to be less than satisfactory

但是，总体研究结果不满意• We admit that some of our

proxies of determinants of fertilizer use may not be very good measures …

• Especially for information …

• There is a perception by some that the real problem in Asian agriculture is that farmers just do not understand the current generation of technology …

• 我们承认有些控制变量不太好

• 尤其是信息变量

• 一些人认为亚洲农业的真正问题在于农民不了解新一代的技术

Overall findings, （ con’t）• Story:

– Green Revolution began … new varieties demanded fertilizer

– Over first years, farmers discovered that if they put on more fertilizer, yields and income increased

– Extension agents and officials main objective: how to convince/allow farmers to use more fertilizer

• 故事– 绿色革命，新品种需要化肥

– 绿色革命初期，农民发现增加化肥用量就能增加单产＆收入

– 农技推广人员＆官员的主要目标：如何让农民多用化肥

Overall findings （ con’t）• Story:

– However, later generations of GR varieties have become more efficient in their need for fertilizer … fertilizers, in general, have become better (e.g., urea vs. ABC) …

– Farmers / extension agents / officials, however, still are in the habit of thinking: more fertilizer, the better!

• 故事：– 但是，后来研制出

的新品种的化肥利用率高……而且总体上化肥本身的质量也提高了（如尿素 V.S. ABC ）

– 但是，农民 / 农技推广人员 / 官员还是习惯性地认为施肥越多越好

Joint policy experiment 多方参与的政策试验

• CCAP and IRRI are collaborating:– on trying to better

understand whether or not it is poor information that is causing the overuse of fertilizer

– how to help farmers reduce their fertilizer use

• 农业政策中心与国际水稻研究所合作– 是不是因为信息方面的原

因导致农民过量施肥？

– 如何帮助农民减少化肥施用量？

Joint policy experiment （ con’t）多方参与的政策实验 (续 )

• In 2003, began experiments in rice growing areas of Guangdong and Hunan

• Main package of new technology called: Site Specific Nutrient Management (SSNM) … basically asks farmers to use less fertilizer but applying at the right time …

• 2003年开始在广东＆湖北的水稻产区开展试验

• 试验的新技术：适时适地施肥技术（ SSNM），该技术主要是要减少化肥施用量，而且适时

Specific Objectives 具体目标• To determine appropriateness of

SSNM technology for sample rice farmers;

• To investigate the willingness of farmers to adopt SSNM;

• Impact of SSNM on fertilizer use and yields

• To explore new approaches that can be incorporated into the extension system;

• 确定适合于样本农户的 SSNM技术

• 分析农户采用 SSNM技术的意愿

• SSNM对化肥施用量＆作物单产的影响

• 结合现有的农技推广体系，探索新的切入点

Experimental Design 试验设计（ 1）

1. Randomly select sample of farmers to participate in an extension training program for SSNM (this training session is more “traditional” in that it involved mainly a lecture-like presentation of the material to the farmers)

[type C farmers are those not selected to participate in training session)

• 1. 随机抽取一些农户参加 SSNM的培训（传统意义上的培训，主要是给农民介绍一些材料）

– C 类型农户指没有参加培训的农户

Experimental Design 试验设计 （ 2）

2. Selected subset of farmers to participate in a intensive, scientist-guided experiment in the fields of selected farmers

[type B farmers are those not selected for scientist-guided experiments]

• 从参加培训的农户中选出一部分农户，在这部分农户的地里进行一项有科学家指导的试验

– B 类型农户是指没有参加有科学家指导的试验的农户

Experimental Design 试验设计 （ 3）

3. Scientist-guided experiments in fields of selected farmers:

[type A farmers are those in scientist-guided experiments]

-- cultivated one plot using SSNM technology [plot “1”]

-- cultivate one plot in traditional manner [plot “2”]

• 对于有科学家指导的试验– A 类型农户是指参加有

科学家指导的试验的农户

– A 类型农户在一块地上用 SSNM 技术（地块1 ）

– A 类型农户在另一块地上沿用他原来的技术（地块 2 ）

CCAP’s role as economists 经济学家在这项政策试验中的作用

• Do household interviews of:– Farmers A– Farmers B– Farmers C

• Information on:– Yields– Fertilizer use– Other households and

plot characteristics

• 农户访谈– A 类型– B 类型– C 类型

• 收集以下信息– 单产– 化肥施用量– 农户＆地块特征

Tests of New Technologies检验新技术作用

• Effect of technology (lower bound):– Plot A1 versus plot A2 [lower bound because of

unintended learning effect by Type A farmer … he/she was supposed to use traditional ways of applying fertilizer on plot A2, but, if anything, may have used less after exposure to the new information

[Can also compare Plot A1 versus Farmer C]

• 技术的影响（下限）

– 比较地块 A1 与 A2

– （下届是因为 A 类型农户无意中的学习效应，该类型农户应该在 A2地块上用原有的技术，但是他 / 她有可能在接触到新技术后减少化肥用量）

– （也可以比较 A1 地块＆ C 类型农户的地块）

Tests of New Technologies (con’t) 检验新技术的作用（续）

• Effect of scientist-guided experiments– Plot A1 versus Farmer B

• Effect of extension training (traditional style)– Farmer B versus Farmer C

• 有科学家指导的试验的影响– 比较 A1 地块＆ B

类型农户的地块

• 推广培训（传统方式）– 比较 B 类型农户＆

C 类型农户

A Quick Tour of the Experiment试验现场“传真”

Farmers selected for training session …（农户培训）

Never heard this! 从没听说过

Traditional Extension Training … （传统的推广培训）Using Lecture-like format to teach farmers about SSNM

(both Type A and Type B farmers attended) A、B 类型农户

Choosing Farmers to Participate in Scientist-guided experiments

(choosing Type A Farmers) 选 A 类型农户

Farmer A（ A 类农户）Plot 2 （地块 E）Traditional Practices （传统施肥方式）

Farmer A （ A 类农户）Plot 1 （地块 1）SSNM technology （ S

SNM技术）

Field of Type B Farmer (only attended training session) B 类农户的地块

Findings on Fertilizer Reduction (1)对减少施肥量的影响（ 1）

• Full impact of technology

• SSNM reduces fertilizer use by 30% （减少 30％）

• Same difference when doing either set of comparisons (i.e., the check plots work well in providing a measure of traditional practices) 各组的施肥量差异大体如此

020406080

100120140160180

Pl otA1

Pl otA2

Pl otA1

FarmerC

SSMN SSMN

Traditional

Findings on Fertilizer Reduction (2)对减少施肥量的影响

• Impact of traditional extension approach（传统农技推广方式的影响）

• Getting the right message does lead to fall in fertilizer use （得到正确信息确实减少化肥施用量）

• But reduction is far less – only reduces fertilizer use by 14% （但只减少 14％）

0

20

40

60

80

100

120

140

160

180

Farmer B Farmer C

Traditional

SSNM thru training only

Findings on Fertilizer Reduction (3)对减少化肥施用量的影响（ 3）

• Weaknesses of traditional extension approach (compare those who get message only through lecture against those that get hands-on-guidance by scientists)传统推广方式的不足（简单培训与“手把手”的指导）

• When farmers adopt the “complete package” of technology (with the help of scientists) the reduction is much greater (falling an additional 19%)如果完全掌握该技术，化肥用量减少 19 ％

020406080

100120140160180

Pl ot A1 FarmerB

FarmerC

Traditional

SSNM thru training only

SSNM

19%

Yield Effects of SSNM SSNM对单产的影响

0100020003000400050006000

Pl ot A1 Pl ot A2 Farmer B Farmer C

Kg / ha

Statistical Tests Show that there are no differences among yields … in other words, farmers on plot A1 reduced fertilizer use by 30% and had no loss of yields （统计检验结果表明不存在单产差异，即减少化肥用量并不减产）

Conclusions 结论（ 1）

• Fertilizer overuse is an issue; farmers in China appear to be systematically overusing fertilizer

(may be a source of reduced income, low productivity and non-point source pollution)

• 存在化肥过量施用的问题，目前中国农民过量施肥– 可能会因此减少农民

的收入，降低生产率水平，造成面源污染

Conclusions 结论（ 2）Reasons for high demand are com

plicated:

– Part of reason (small part) may be related to high opportunity cost of labor

– Traditional extension system, if anything encourages overuse

– Poor control on the quality of fertilizer would induce farmers to use more fertilizer

• 农民化肥需求高的原因是多方面的– 一小部分原因可能在

于劳动力的机会成本高

– 传统的农技推广体系从某种程度上讲促使农民多施肥

– 化肥质量控制不严也促使农民多用化肥

Conclusions 结论（ 3）Intensive collaborative

research with IRRI and domestic scientists provide evidence that:

– Information is a key factor in overuse of fertilizer

– Fertilizer were reduced by 30% in the sample rice-growing households with no loss of yield!

– Extension agents and farmers alike admitted to “being surprised”

• 与 IRRI以及国内科学家的深入合作研究表明

– 信息是农民过量施肥的一个关键因素

– 种水稻的样本农户将化肥用量减少 30％并没有减产

– 农技推广人员＆农民对此都感到“震惊”

Conclusions 结论（ 4）• Promoting such technology,

however, may not be easy

• Extension agents need to be convinced first

• Traditional extension approaches are not enough:– Although “getting the message”

right helps, the full benefits from the technology were not realized

• 但是，推广这种技术绝非易事

• 首先要让农技推广人员相信这样的技术

• 仅有传统的农技推广方式还不够– 虽然得到正确的信息有所帮助，但是这种技术的效果并没有充分实现

Conclusions 结论（ 5）• There needs to be

more research on the appropriateness of SSNM technology for the general population (e.g., as China’s farmers get busier and busier, is this an easy technology to use?)

• 需要进一步研究 SSNM技术对广大农民的适用性（如果农民越来越忙，这项技术的进一步大量推广容易吗？）

Thanks!谢谢！