IPI logo

Production and International Trade Conference, Shanghai, People's Republic of China

October 17-19, 2000

Strategies for Improving Balanced Fertilization


A.Krauss,PhD
Director, International Potash Institute (IPI)
Jin Jiyun,PhD
Deputy Director, PPI/PPIC China Program, and Professor, Soil and Fertilizer Institute, Chinese Academy of Agricultural Sciences

Contents

  • Population growth and urbanization result in more plant nutrient removal from soils
  • Use of mineral fertilizer is common practice in China, but its use is still out of balance
  • Some reasons for unbalanced fertilization
  • Consequences of continued soil K mining
  • Beneficiaries of balanced fertilization
  • Agronomic research provides a scientific basis for improving balanced fertilizer use
  • "Seeing is believing" - Field demonstrations move farmers towards more balanced fertilizer use
  • Using reliable soil testing and fertilizer recommendations provides information for balanced fertilizer use
  • Technology transfer
  • Using information technology to further improve balanced fertilization
  • Conclusion
  • References

Figure 1. Demographic evolution of PR China
FAOSTAT 1998
Figure 2. Grain balance of China as affected by income development and agricultural research.
Rozelle & Huang, 1999.
Figure 3. Fertilizer nutrient consumption (China).
IFA, 2000
Figure 4. Fertilizer use in relation to nutrient removal by crops (China).
FAO/IFA FYB'S
Figure 5. Evolution of the nutrient balance of Jiangsu Province, China.
Data source: 9th IPI/ SSAS Workshop Haikou, Hainan, 1999
Figure 6. Potassium dynamics in soils (simplified model)
Krauss, 0498
Figure 7. Potassium uptake and dry matter (DM) yield of sudangrass at sequential cropping
From Srinivasa Rao and Khera, 1995
Figure 8. Potassium release of soils as affected by cropping intensity
After Cheng Mingfang et al.,1999
Figure 9. Effect of potassium on nitrogen cycling in plants
After Marschner et al., 1996
Figure 10. Effect of potassium use on cotton yield
(ISSAS/IPI on-farm trials, China)
Figure 11. Safeguarding land use in China due to higher productivity
Datasource: FAOSTAT 1998
Figure 12. Effect of balanced fertilization on residual nitrate in subsoils (China)
After Härdter & Krauss, 1999
Table 1. Yield responses of selected crops to K application
Crops No of trials

Mean yield increase, %


Rice 667 11

Wheat 110 19

Corn 149 26

Rapeseed 94 30

Peanut 60 19

Cotton 56 21

Sugarcane 90 19

Banana 22 61

Potato 12 74

(Result of field trials carried out through cooperative projects of PPI/PPIC China Program in 1983-1994.)
Table 2. Effect of balanced fertilization on water-melon
(Hebei province, 1993)
Site Treatment

N-P2O5-K2O,
kg/ha

Yield,
kg/ha
Yield increase,
%
Net return,
Yuan/ha

1 FP* 990-405-55.5 74,025    
  BF* 255-210-180 84,375 14 4,140

2 FP 780-90-90 81,900    
  BF 315-105-135 84,075 2.7 1,785

* FP = farmer practice; BF = balanced fertilization

Population growth and urbanization result in more plant nutrient removal from soils

Forecasts by the Food and Agriculture Organization of the United Nations (FAO) show that the total population of China will increase more and will level within the next two to three decades at about 1.5 billion. At the same time, urbanization continues and will reach 50 percent by the end of the 2020s (Figure 1).

Increased population, and particularly more urbanites, suggests a need for both more and greater diversity of food. As a general observation, urbanites, having a higher income, eat more animal protein, fruits, and vegetables than their rural counterparts. As a consequence, low conversion rates of grains to animal protein and higher plant nutrient requirements of fruits and vegetables lead to higher plant nutrient uptake and removal from the soil. Also, the quality aspect of food becomes an important parameter at the market, which requires particular care in plant nutrient management.

Land to produce additional food is being reduced at a rapid rate in China, so horizontal expansion of agricultural production is hardly possible. In response to this, intensification of land use increased; for example, cereal grain yield increased almost five times in the last 40 years. To satisfy the growing demand for vegetables and fruits, production increased four and eight times, respectively, in the last 30 years.

Although cereal production in China has grown substantially in the last decades, the current gap in supply is about 10 million tonnes (Mt), mainly due to shortage of high quality grain, including that for human consumption. The future cereal production/demand balance will depend on population growth, improvement in individual income, and agricultural research being given a high priority. Low investments in agricultural research would increase the import requirement of cereal grains from 10 Mt to more than 80 Mt. On the other hand, high investments in research, resulting in further improvement in the productivity of cultivated land, could turn China into a grain exporting country (Figure 2).

Research on balanced fertilization is one investment already paying dividends by providing food security in China, although much remains to be done.

Use of mineral fertilizer is common practice in China,but its use is still out of balance

Consumption of mineral fertilizers increased seven-fold in the last 30 years, from 4.6 Mt to about 35 Mt of nitrogen (N), phosphate (P2O5) and potash (K2O), as shown in Figure 3. However, fertilization is still highly unbalanced.

  • Even though the N:K ratio of mineral fertilizers 'improved' in the last 30 years from 1:0.02 to the current 1:0.15, it is still far from the ratio various crop plants absorb both nutrients: cereals 1:0.9, oil-seeds 1:1.3, and potato 1:1.7. This means plants take up as much or more K than N. However, in China much more N is applied than K.
  • The imbalance is more obvious when nutrient input is compared with nutrient removal by crops, as shown in Figure 4.
    • Use of N with mineral fertilizers appears to be well balanced; it exceeds N removal by crops;
    • Use of P2O5is in the same order of magnitude as phosphorus (P) removal by crops;
    • Potash application lags seriously behind K removal by crops. The gap in potassium (K) input increases annually by 250,000 Mt K2O.

The trend of an increasing imbalance in use of K2O is also obvious at the provincial level. Forty years ago there was a very positive nutrient balance in Jiangsu province (+818 kg/ha N, +745 kg/ha P2O5 and +504 kg/ha K2O), mainly due to extensive use of organic manure. In 1995, the N balance had declined to +241 kg/ha, but remained positive, whereas nutrient balance for P (-115 kg/ha) and especially K (-501 kg/ha) turned negative (Figure 5).

Based on a calculated estimate of total K removal by crops of 17.3 Mt K2O and assuming that use of 3.5 Mt K2O represents one-third of total K input, (with two-thirds from recycled K) the countrywide K deficit in fertilization is estimated at about 8 Mt K2O. This convincingly indicates substantial soil K mining and continuing loss in soil fertility.

Some reasons for unbalanced fertilization

  • Nitrogen demand, which is largely met by domestic N fertilizer production, improves and farmers have access to N fertilizers.
  • Nitrogen is the preferred nutrient in times of economic constraints due to its evident return.
  • Potassium, in contrast to N, affects plant growth in less visible ways through increased physiological efficiencies, which improve yield, quality and stress resistance.
  • Distribution logistics of imported potash restrict local availability and, hence, farmer use.
  • Quality based procurement of crops is now becoming important for marketing China's agricultural products domestically and internationally. The extent to which quality influences crop price, and in turn, fertilizer nutrient balance, is evident in India. For example:
    • South India's plantation crops such as tea, coffee, pepper, and cardamom are priced according to quality. Farmers know that K is the quality factor and that the desired N:K ratio of 1:0.25 had to be maintained, even when, during 1992, the potash price tripled, and they had to maintain the nutrient balance by lowering overall level of fertilizer use.
    • Conversely, in north India…the country's breadbasket…where wheat and rice are the major crops and cereals are paid only by weight and not by quality, N and P are the dominant fertilizer nutrients. The need to use K2O is less considered and will be sacrificed at the first sign of economic stress. The N:K ratio in North India is 1:0.03.
  • Lack of knowledge of the behavior of K in soils and its function in plants both explains and contributes to unbalanced fertilizer use.
  • Misinterpretation of soil test results and/or outdated fertilizer recommendations, which don't reflect the current soil K status or don't consider greater crop requirements resulting from improved varieties and crop management practices, reduce K2O consumption.
  • Use of organic manure and waste, and recycling of plant residues are insufficient to compensate for the K imbalance resulting from greater N and P inputs from mineral fertilization. Hence, the share of nutrients from organic sources declined in China from 100 percent in the 1950s to its current contribution of about 30 percent, even though the total quantity of organic manure use increased almost four-fold.

Consequences of continued soil K mining

Soils lose their potential to buffer demand of crops during peak growth and stress periods.

Soil K is subject to significant exchange processes (Figure 6). Potassium removed from soil solution by plant uptake or by leaching is replenished by K released from the exchangeable fraction when its quantities are sufficient. The readily available K fraction is in equilibrium with the 'non-exchangeable' K and the K reserves.

However, the intensity of K release decreases in the same sequence: high K release intensity from the exchangeable fraction, low from the non-exchangeable fraction, and very low from the reserves. With progressing soil K depletion, K release intensity decreases to the extent that plant K uptake becomes increasingly insufficient, and yields decline accordingly (Figure 7). Numerous long-term experiments have shown that yield loss due to declining soil K status may be as high as 40 percent in crops such as potato, sugar beet, or cotton, and up to 20 percent in cereals. Crop responses to K of this magnitude have been found in many parts of China.

Results of soil tests in north China by Cheng Mingfang et al. (1999) agree with world literature on changing K dynamics with soil K depletion (Figure 8). Soils subjected to high cropping intensity and thus high K removal suffer a considerable reduction in non-exchangeable content compared to soils with a low cropping intensity. Interestingly, the content of exchangeable K was only marginally affected by the cropping intensity in contrast to the K release intensity, which decreased substantially with increasing cropping intensity.

The rather minute change in the exchangeable K content shown in Figure 8 also points to the problem of interpreting soil tests. To get the true picture of the soil K status, routine soil analyses should consider the fraction of non-exchangeable K.

Cheng Mingfang et al. (1999) also showed that, with increasing cropping intensity, K adsorption increased three-fold, indicating K fixation. At the same time, fixation of ammonium (NH4) may also occur, thus lowering the use efficiency of N fertilizers.

Insufficient K supply impairs the plant's capacity to develop its yield.

Potassium is a multifunctional versatile nutrient, indispensable for plants, animals and humans. In plants, the function of K has several roles, such as:

  • enzyme activation,
  • stimulation of assimilation and transport of assimilate,
  • anion/cation balance,
  • water regulation through control of stomata.

Potassium plays a notable role in N uptake and metabolism. As schematically shown in Figure 9, nitrate-N (NO3-N) absorbed by the root travels with K as its counter-ion to the shoot. In the shoot, NO3-N is reduced and metabolized. At the same time, malate is produced in the shoot and part of the K travels as K-malate down to the roots where malate is oxidized, yielding K-bicarbonate (KHCO3), which exchanges HCO3 for potassium nitrate (KNO3 ). Lack of K, however, restricts NO3 transport and causes NO3 reduction in the root and amide accumulation. These conditions may produce a signal via feedback effect to the root, thereby restricting further N uptake, irrespective of its presence in soil solution. Impaired N uptake lowers N fertilizer use efficiency and, because more N remains in the rooting zone, there is increased potential for loss by leaching or volatilization. The plant cannot be forced to take up more N if K is in short supply.

Other important functions of K are:

  • to improve the quality of the crop,
  • to increase tolerance to drought, heat or frost,
  • to improve resistance to pests and diseases.

Beneficiaries of balanced fertilization

  • The farmer benefits through higher yields and better quality, lower production costs, better profitability, and improved chances for producing a good yield under adverse climatic and soil conditions. There is also less biotic damage when soil K is ample.
    Yield increases with K of more than 800 kg/ha soy-bean, 1700 kg/ha groundnut, 2000 kg/ha maize, 8 t/ ha potato tubers, or 800 kg/ha cotton lint have been achieved in numerous PPI/PPIC and IPI trials supported throughout China (Figure 10). Each Yuan invested in K2O provides economic returns up to 24 Yuan because of the higher yield and quality achieved.
    Balanced fertilization with K and magnesium (Mg) has improved crop quality through, for example, higher contents of aromatic compounds in green and oolong tea as well as higher contents of amino acids in black tea (Wu Xun et al., 1997).
    Balanced fertilization reduces the incidence of plant diseases, such as red-leaf stem blight in cotton as found in both IPI and PPI/PPIC sponsored trials in various provinces of China. Natural improvements in the plant's ability to resist disease infections result in less need for insecticides and fungicides, which lowers production costs for farmers and reduces chances for negative environmental impact.
  • The nation benefits from balanced fertilization through increased food production, better food security, lower food import requirements and more export opportunities, especially when balanced fertilization improves quality. The higher income generated through higher yields also increases the purchasing power of rural areas, which attracts business, creates jobs, reduces migration and generally contributes to development and social stability of rural areas.
  • Natural resources are safeguarded through balanced fertilization by contributing to the preservation of soil fertility for future generations, by increasing water, nutrient, energy and land use efficiency, and by reducing pressure on land resources to prevent further deforestation and encroachment onto marginal land. Calculations using China's 1961 cereal yield of 1.21 t/ha, and the 1998 cereal production of 447 Mt, show that China would have had to utilize 280 million ha more, or three times the area currently under cereal cultivation, to achieve the 1998 production level (Figure 11).
  • The environment is improved as efficient fertilizer use increases N uptake (as described above) and thereby leaves less residual N free in the soil. This balanced fertilization mechanism protects both the groundwater from leaching and the atmosphere by reducing N volatilization losses. China research has documented that by applying balanced fertilization to cabbage, the content of residual NO3-N was decreased to 50 kg/ha compared to the farmer practice, which left 150 kg/ha NO3-N (Figure 12).
  • The domestic fertilizer industry will continue to be the target of environmentalists looking for someone to blame for nutrient leakage into the biosphere, either at production sites or in farmer fields. Advocating and promoting balanced fertilization by various extension techniques, such as field demonstrations, seminars, or through audio-visual systems, show that the fertilizer industry is taking positive steps to ensure a healthy environment. Further, it develops a positive image as a caretaker of the environment and the source of sustainable soil fertility. The benefits accruing to China's domestic fertilizer industry by adopting and supporting the message of balanced fertilization and its dissemination would indeed be substantial. The groundwork for much of this has been done through cooperation with the Ministry of Agriculture (MOA) and the PPI/PPIC and Canpotex Balanced Fertilization Demonstration Program (BFDP) conducted over the past 15 years. Some of the success of this program as well as initiatives by the MOA and others are given below and can serve as models for industry to expand this effort to support its own well being.

Agronomic research provides a scientific basis for improving balanced fertilizer use

To achieve greater balance in fertilizer use, agronomic research is the obvious first and a key step in understanding soil fertility evaluation, nutrient requirements of crops to achieve high yield and high quality, fertilizer placement and timing, etc. As indicated above, important achievements have been made through numerous research projects conducted and supported by the government of China and various Chinese and international institutions.

One good example is the Potash Agronomy Program which was supported by the Canadian International Development Agency (CIDA), China's Ministry of Foreign Trade and Economic Cooperation (MOFTEC) and Canpotex, and implemented by the MOA and PPIC. This 15-year program was a cooperative endeavor with agriculturally related national and provincial research institutions, academies, and universities. Three phases of the Canada/China Potash Agronomy Program, conducted between 1983 to 1998 and involving more than 20 provinces, supported more than 2,000 field trials using more than 40 crops. By adding only K fertilizer to traditional farmer fertilization practice – which usually applied only N and P – crop yields increased between 11 to 74 percent, depending on the crop. These field trials and demonstration plots covered an area of greater than 15,000 hectares, and balanced fertilization techniques have been adopted on over 12 million ha during the past 15 years, with accumulated profit of about 7 billion Yuan (Table 1).

The Potash Agronomy Program was initiated in the mid 1980s to advance the need of southern China's agriculture, where soil K was relatively low and K deficiency severe. The program's sphere of influence gradually moved northward in the early 1990s.

Research findings clearly show where soils are low in K supplying power, which crops are more sensitive to K application, and what the correct K ratio and needed quantities are, with respect to N and P use. These research results provided the provinces/regions a solid basis for adopting scientific use of K fertilizers in a more balanced and profitable manner.

"Seeing is believing" - Field demonstrations move farmers towards more balanced fertilizer use

Balanced fertilization techniques derived from research findings are useless until farmers adopt them. Therefore, technology transfer of new techniques to farmers is a critical step for realizing balanced fertilization as common practice.

Most farmers are very realistic and will not change their farming practice until they see – with their own eyes – the real benefits of a new practice. But they are also eager for new technology to improve their production and profitability, so as soon as they see the significant benefits an improved technique offers, they will adopt it. In 1993, scientists in the Soil and Fertilizer Institute (SFI) of the Chinese Academy of Agricultural Sciences (CAAS) found that farmers in Yutian county of Hebei province applied too much N (> 800-900 kg/ha) to their watermelon crops, but very little P and K. Field trials based on soil testing and fertilizer recommendations from the CAAS-PPIC Cooperative Soil and Plant Analysis Laboratory in Beijing indicated that balanced fertilization treatments resulted in an increased net profit of 1,785 to 4,140 Yuan/ha. The next year, all farmers in the region followed the balanced fertilization practice, making it virtually impossible for researchers to get a small plot to demonstrate the effects of unbalanced use of N (Table 2).

Field trials and demonstration plots are useful tools for farmer education. The PPI/PPIC China Program has conducted its market development activities by working with Chinese scientists and extension personnel to set up field trials and demonstration plots to show the beneficial effect of balanced fertilization practices - based on sound science - on correcting nutrient deficiencies and their effect on lowering crop yield and product quality. The number of participants at field activities such as farmer meetings, field visits, leaders' field inspections, and harvest field days held for farmers, local technicians, local and national leaders, scientists, and the media ranged from several dozen to several thousand. With these activities, the message was out, and farmers learned the new technology for their next season's crop production. Fortunately, new research information is constantly being developed, so these types of activities are continuously needed and offer good opportunity for industry to develop product identity by farmers while improving customer profitability.

Using reliable soil testing and fertilizer recommendations provides information for balanced fertilizer use

Reliable soil testing is essential for developing balanced fertilizer recommendations. A large number of soil testing laboratories have been established in China and much work done to develop calibrations correlating soil tests to fertilizer needs. Unfortunately, soil testing and related field experiments were often not completed, or they focused on only two or three nutrients while ignoring the others. Balanced fertilization must consider all essential plant nutrients because if any nutrient is deficient, it will affect both crop yield and quality, as well as use efficiency of other applied plant nutrients. Generally speaking, China's farmers tend to use more N than is needed and insufficient P and K, while ignoring secondary nutrients and micronutrients. The environmental and economic consequences of having excessive N in the system were explained previously in this paper.

To solve this problem, a Systematic Approach for soil nutrient evaluation and balanced fertilizer recommendations was introduced to China and was further developed by the PPI/PPIC China Program in cooperation with CAAS and other organizations. The systematic technique evaluates the soil's status for all macro, secondary and micro-nutrients, and a fertilizer recommendation is developed, so that all nutrients are supplied in a balanced manner. Knowledge on the capability of soils to fix or complex certain plant nutrients is needed so these considerations can be taken into account when developing the fertilizer recommendation.

To detail the nutrient status of individual soil types, both greenhouse and field experiments were established using an optimum treatment (OPT) with all essential plant nutrients supplied and adjusted to an optimum level. Thus, no plant nutrient in this treatment limited crop yield during the experiment. In other treatments, each suspected deficient nutrient was left out individually and tested against the optimum. Plant nutrients testing adequate in the soil test are not added to the OPT to avoid toxic levels, but are left out of one treatment each, to verify that the soil test interpretation was correct.

A semi-automatic operation procedure using a multi nutrient extraction solution was developed which significantly improved the working efficiency of the soil testing laboratory. Based on the large set of results and information from soil testing, greenhouse pot experiments and field trials, PPI/PPIC established a soil and crop nutrient requirement database, a data management system, and a computerized fertilizer recommendation system.

The technique is well established and recognized in China. In 1995, the Systematic Approach was selected by the MOA as one of the major agricultural technology achievements made during the Eighth-Five-year period (1991-1995), and it was suggested for future extension throughout China. From 1995 to 1997, the technique was applied to a total of 30,000 ha of wheat, corn, cotton, rice, and other crops in Shandong, Hebei, Henan, Jilin, and Liaoning provinces, resulting in an economic benefit of 1,450 million Yuan. Its use has been expanded to more than 20 provinces and is a primary contributing factor for improving fertilizer use in China. The technique has also been used by some fertilizer companies as a basis for production of crop and soil-specific complex fertilizers.

Technology transfer

Agriculture is a complex system involving people in various disciplines with various responsibilities. To promote balanced fertilizer use, it is essential to disseminate scientific findings and related techniques to the farmers as well as decision makers, using a variety of technology transfer methods and venues.

  1. Meetings: Scientific meetings, workshops, training courses, farmer meetings, etc. are important means of technology transfer. The MOA and scientific organizations in China, such as CAAS, the Soil Science Society of China, and the Chinese Society of Plant Nutrition and Fertilizer Sciences, together with international organizations such as IPI, PPI/PPIC, and The Sulphur Institute (TSI), have done much to advance knowledge on the need and use of fertilizers in China. Several large scale international or country-wide scientific conferences, symposia and workshops have been organized. Successful examples include the International Balanced Fertilization Symposium in 1988, the International Symposium on the Role of Sulphur, Magnesium and Micronutrients in Balanced Plant Nutrition in 1991, the International Symposium on Maximum Yield in 1992, the International Symposium on Fertilizer and Environment in 1994, the International Symposium on Fertilizer and Sustainable Agriculture in 1996, and the Workshop on Nutrient Cycling and Management in Cropping Systems of Different Agro-Eco Regions of China in 1999.
    Workshops and training programs for different groups were also carried out for the particular purpose of focusing on specific techniques. For example, in order to systematically approach soil nutrient evaluation, more than 200 training courses, including hands-on training in laboratories, greenhouses and the field, were held from 1993 to 1997 with a total of over 20,000 participants. A more recent example is the first IPI training course on fertigation, conducted this year in cooperation with the National Agro-Tech Extension and Service Center (NATESC) in Hangzhou, Zhejiang.
  2. Publications: Printed material is a traditional and efficient means of technology transfer. These include scientific publications of professional societies, proceedings of symposia and workshops, special publications with focuses on important issues, hand-books, and leaflets for farmer guidance, etc. In 1991, the PPI/PPIC China Program started a publication series on Modern Agriculture and Fertilizers to popularize proceedings, lectures, special publications, and leaflets. In 1997, the PPI/PPIC China Program adapted its banner publication – Better Crops with Plant Food – to its Chinese readership and produces two issues each year of Better Crops China. All publications are distributed to more than 8,000 technicians, agricultural researchers, extension specialists, policy makers, fertilizer suppliers, and other fertilizer industry personnel. Other international organizations, including IPI, issue relevant scientific material in the Chinese language.
  3. Videos: More and more farmers are receiving information on new technologies via television. And television is becoming an important means for transferring technology. To speed new technologies to farmers, the government of China created a special 'agricultural' channel, CCTV-7, and is supporting this initiative through the Central Agricultural Broadcasting School to develop agricultural education programs for farmers using both television and radio. It is estimated that the TV programs and other educational activities of the Central Agricultural Broadcasting School reach at least one third of the rural population.
    More then 20 television and video programs have been developed through the PPI/PPIC cooperative programs in China. All have been used by central or local television stations. One example was the 135-minute video program on soil fertility management, based on the PPI/PPIC International Soil Fertility Manual, but including the Chinese experiences. This program, split into nine lectures, has been used by the Central Agricultural Broadcasting School several times.

Using information technology to further improve balanced fertilization

Information technology is developing rapidly world-wide and is having significant impact on various disciplines, including agriculture. It is believed that information technology along with biotechnology will lead to new breakthroughs in agricultural production and that information technology will influence fertilizer use in two aspects:

  1. Information sharing and technology transfer: As computerized information networks develop, they will provide an excellent 'highway' for sharing information and effecting technology transfer. In China, CAAS is leading a program to establish the China Agricultural Science and Technology Information System to serve technology transfer in all fields in agriculture. Scientists in its Soil and Fertilizer Institute are developing the Soil and Fertilizer Information System of China database, which includes data and information from statistics, surveys, field research, etc. The development of these information systems will certainly help transfer technology to leaders, farmers, technicians, and the associated agricultural industries.
  2. Improvement of soil management and fertilizer application techniques: Information technology such as Geographic Information Systems (GIS), when linked with the global positioning system (GPS) and remote sensoring (RS), is providing the capability to improve both soil management and rational fertilizer application. Related new concepts and techniques, such as site-specific nutrient management, site-specific fertilization, variable rate fertilization, precision agriculture, etc., initiated in developed countries are now being introduced into China. These newly developed information-based technologies, when further developed or modified to fit China's conditions, will certainly stimulate improvement in soil fertility management and fertilization.

Realizing the importance of information technology for future improvement in soil and fertilizer management, the newly started China-Canada cooperation project Nutrient Management and Strategies for Sustainable Agriculture in China places the introduction and use of information technology in both technology transfer and agronomic research (improvement of soil and fertilizer management techniques) activities as key components of the project. Supported by the Chinese government (MOFTEC, MOA), CIDA, CANPOTEX, and PPI/PPIC, and implemented by the PPI/PPIC China Program in co-operation with CAAS and related research and educational institutions, the project functions in all provinces (cities and regions) of China to stimulate and support research and education programs to improve soil management and fertilizer use. With successful implementation of this project, regional and national soil fertility and fertilizer information systems will be established for decision-making by governments and farmers to accomplish rational fertilizer distribution, technology transfer, farmer education, and collectively, the effort will further improve soil and fertilizer management in China.

Conclusion

Imbalanced fertilizer use is a hidden time bomb, and this is particularly true for China's agriculture. If it is not corrected, the progress in soil productivity and thus the welfare of China's rural population and ultimately food security for China are in grave jeopardy. Numerous results from soil tests and field trials are available, as indicated in this paper, which substantiate the need for fertilizers in China and the opportunity the fertilizer industry can realize. However, it is up to the fertilizer industry to support activities which will utilize this invaluable asset and fortify ongoing efforts to transfer the knowledge to farmers. At the same time, the fertilizer industry should add its voice to those alerting politicians and decision-makers on the continuing soil degradation due to imbalanced fertilizer use and the need to develop policy and economic framework for implementation of balanced fertilization. And finally, it should be mandatory for the domestic fertilizer industry to stimulate and sponsor scientifically based research in soil fertility in addition to 'common product' promotion.

Agronomic research is always important for generating useful information from which reliable techniques for improvement of soil management and the rational use of fertilizers are developed. However, the findings of a research program will be useless unless the 'new ways' are accepted by farmers and become farmer 'common practices' in agriculture production. Technology transfer must be directed in many ways and by a variety of venues to leaders, farmers, scientists, technicians, fertilizer distributors, and fertilizer producers, to ensure the 'right' production, distribution and use of fertilizers. Traditional means of technology transfer, such as meetings, training courses, publication, video programs, etc. will continue to play important roles in future technology transfer. New developments in information technology will certainly speed technology transfer in soil and fertilizer management.

The fertilizer industry in China needs to support these efforts by cooperating with scientists, extension personnel, and others to magnify the intensity of research and technology transfer of soil fertility and fertilizer use.

Selected References

Cheng Mingfang, Jin Jiyun, and Huang Shaowen (1999). Release of native and non-exchangeable soil potassium and adsorption in selected soils of North China. Better Crops International, Vol. 13, No. 2.

Chinese Society of Plant Nutrition and Fertilizer Sciences, Potash & Phosphate Institute of Canada. 1996. Proceedings of International Symposium on Fertilizer and Sustainable Agriculture, edited by Lin Bao et al. China Agri. Scientech Press. (in Chinese and English).

FAOSTAT 1998. Food and Agriculture Organization, Rome, Italy.

Härdter, R. 1997. IPI internal report.

Härdter, R. and A. Krauss. 1999. Balanced fertilization and crop quality. In: Proc. IFA Conference on 'Managing plant nutrition - towards maximum resource efficiency', Barcelona, Spain, June 29 - July 2, 1999.

IFA 2000. International Fertilizer Industry Association, Paris, France.

9th IPI/ISSAS Workshop on 'Nutrient cycling and management in cropping systems of different agro-eco regions of China', Haikou, Hainan, PR China, December 6-8, 1999.

Marschner, H., E.A. Kirkby, and I. Cakmak. 1996. Effect of mineral nutritional status on shoot-root partitioning of photoassimilates and cycling of mineral nutrients. J. Exp. Botany 47: 1255-1263.

Potash & Phosphate Institute of Canada, Beijing Office. 1992. "A Systematic Approach for Soil Nutrient Status Study", edited by J. Jin, China Agricultural Scientech Press, 117 pages. (in Chinese).

Potash & Phosphate Institute of Canada, Beijing Office. 1995. "Balanced Fertilization and Agriculture Development-Twelve years of PPI/PPIC cooperative program in China. (both in Chinese and English).

Rozelle, S. and Jikun Huang. 1999. Supply, demand and trade of agricultural commodities in China. Marketing opportunities: World trade competition. Agricultural Outlook Forum, February 23.

Science and Technology Bureau, Ministry of Agriculture. 1991. "Potassium in Agriculture in South China". Agricultural Publishing House. 328 pages (in Chinese with English abstracts).

Science and Technology Bureau of Ministry of Agriculture, Soil and Fertilizer Institute of Agricultural Sciences, Beijing Office of Potash & Phosphate Institute of Canada. 1992. "Soil Potassium and Potassium Fertili-zation", edited by J. Jin, China Agricultural Scientech Press, 177 pages. (in Chinese).

Soil and Fertilizer Institute of Chinese Academy of Agricultural Sciences. 1988. Proceedings of the International Symposium on Balanced Fertili-zation, November 7-11, Beijing, China, organized by PPI/PPIC, CAAS and MOA, Published by Agricultural Publishing House.

Soil and Fertilizer Institute of Chinese Academy of Agricultural Sciences, Potash & Phosphate Institute of Canada. 1994. "Proceedings of Symposium on Fertilization and Environment", edited by J. Jin, China Agricultural Scientech Press, 95 pages.

Soil and Fertilizer Institute of Chinese Academy of Agricultural Sciences, Beijing Office of Potash & Phosphate Institute of Canada. 1994. "Soil Potassium and Potassium Fertilization in Northern China", edited by J. Jin, 171 pages.

Soil and Fertilizer Institute of Chinese Academy of Agricultural Sciences, Beijing Office of Potash & Phosphate Institute of Canada. 1995. "Proceedings of Systematic Approach for Soil Nutrient Status Study", edited by Jin Jiyun et al. China Agri. Scientech Press. 190 pages (in Chinese).

Srinivasa Rao, Ch. and M.S. Khera. 1995. Consequences of potassium depletion under intensive cropping. Better Crops, Vol. 79, No. 2, pp. 24-27.

Wu Xun, Ruan Jianyun and Wu Binghua. 1997. Potassium and magnesium for better tea production. Tea Research Institute, TRI, CAAS, Hangzhou, China, and International Potash Institute, IPI, Basel, Switzerland.

Acknowledgement

The authors gratefully acknowledge the editorial and linguistic assistance provided by Dr. Mark Stauffer and staff of PPI/PPIC.

About the Authors

Dr. A. Krauss
Director
International Potash Institute (IPI)
P.O. Box 1609
CH-4001 Basel, Switzerland
Phone: 41 61 261 29 22
Fax: 41 61 261 29 25
Email: ipi@ipipotash.org
Website: http://www.ipipotash.org
Dr. Jin Jiyun
Deputy Director, PPI/PPIC China Program, and
Professor, Soil and Fertilizer Institute,
Chinese Academy of Agricultural Sciences
Room 316-317, 12 South Zhongguancun Street
Beijing, 100081, China
Phone: 86-10-68975873
Fax: 86-10-68975266
Email: jyjin@ppi.caas.ac.cn