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1．Project overview in Chongqing
Chongqing City, the youngest autonomous city in China, was founded in 1997. It directly governs 40 districts (counties/cities) with an area of 82,400 km2, dwelled 31.3 million residents (of which 31.3 million were farmers), cultivated 2.35 million ha of farmland with a sowing area of 3.3 million ha as grain crops, and produced 11-12 million t of staple food (45% of rice, 20% of corn and 25% of sweet potato) according to the Chongqing Year Book 2003. The major cash crop in the region is citrus grown in the Yangtze River Valleys (favor citrus growth and high quality production) with an annual production of 700,000 t.
The Chongqing General Station of Ag-Tech Extension is the technical section of the Chongqing Agricultural Bureau and responsible for demonstrations and extension of agricultural technology cross the city’s domain. The projects of IPNI and Canpotex undertaken by the Chongqing General Station of Ag-Tech Extension were initiated in 2000 and fall in two categories: balanced fertilization for different major crops and nutrient management for sustainable agriculture in China. Research and demonstrations have been carried out in several counties/ districts for several crops. The crops tested are rice, wheat, corn, sweet potato, vegetables, potato, forage, ect., totaling up to 37 field trials with a demonstration area of 85 ha. In average, balanced fertilization increased yields of grain crops by 8-12% and vegetable yields by 15-25%.
Through research and demonstrations, it is found that effects of potash on crop yields and quality are getting more pronounced on the so-called K rich purple soils. The results are updating and correcting the traditional understanding and practices of local ag-technicians and farmers who used to not apply potash to crops grown on the purple soils. Now, application of potash/compound fertilizers is becoming a common practice in crop production. Consumption K2O in Chongqing was 90,000 t in 2000 and increased to 140,000 t in 2004. This achievement would not be possible without the IPNI projects and educational programs. Under the sponsorship of IPNI, 11 harvest field days and 9 training courses for farmers have been conducted to accelerate the technology transfer in the past several years. During those activities, over 2000 technicians and smart farmers were trained in balanced fertilization program. Eighteen scientific articles dealing with proper use of fertilizers on different crops have been published on Better Crops China and domestic scientific journals. All the activities have contributed to build the concrete basis for us undertaking and better serving the Soil-testing Based Fertilizer Recommendations Project from the central government.
2. Projects implemented in Liangping county, Chongqing
(1) Background
Liangping County is located about 210 km, northeast Chongqing, with an altitude of 445-468 m above sea level. The field trials conducted on the yellow earth in the county were initiated in 2001 and continued to date. The major crop rotation systems are the single rice in the paddy soil and corn (sweet potato)-wheat in the upland soil. The annual crop production is 7,500 kg/ha for rice and 9,750 kg/ha for the uplands, typical of Chongqing’s crop systems and production levels.
Under the common practice of agricultural production, improper fertilizer use including rates, fertilizer ratios and application methods was the cause for ‘low productivity of high yield varieties’. This led to low fertilizer use efficiency and adverse effect to environment. Therefore, the objectives of the projects were to seek for balanced fertilizer techniques for different crops and rotation systems and the nutrient management strategies, and finally serve farmers to acquire high yield and income.
(2) Work conducted in the past five years
1) Monitored village
Soil nutrient variability and nutrient limiting factors in the monitored village in Liangping County were systematically studied. Digital map of soil nutrient status were developed and fertilizer recommendations for different crops were made and verified through field trials. It was found that soil K, N and Zn were deficient for rice and K, N and Mo deficient for the upland crops.
2) The fertilization practices and other agronomic activities, and crop yields were monitored and recorded every season.
3) Soil nutrient variation with time and locations horizontally and vertically in the profile has been studied for the two rotation systems since 2001.
4) Conduced BFDP field trials and demonstrations on rice, wheat, potato, vegetables, forage crops, etc., to determine effect of the enhanced fertilizer program on crop yield, quality and farmers’ income.
5) Education and extension
In the past five years, five field activities including harvest field days for rice, field inspections for leaders combined with training courses. Leaders from the Chongqing Department of Science and Technology, Chongqing Agricultural Bureau, the General Extension Centre of Ag-Tech. of Chongqing, Liangping Agricultural Bureau, Technicians from townships in Liangping county, media people fromChongqing TV Station, Chongqing Daily, village leaders and farmers of the village and nearby. All together, over 500 technicians and farmers were trained through the field activities and training courses. Handouts, posters, Better Crops China and other related materials were distributed. The knowledge contest was held for each field activity and the winners from the contest were awarded with Canadian pink potash. The activities are always welcomed by the farmers.
(3) Effect of balanced fertilization on crop yield and consumption of potash
Before 2000, K deficiency in soils was a serious problem that curtailed crop yields. According the statistics, the county had K deficient area of 12000 ha (28% of the farmland area) and yield loss was over 10 million kg annually. Through the balanced fertilizer research, it provided the evidence that K and P deficiencies were the major cause of low crop yield. The fact resulted from the field experiments and demonstrations further convinced local leaders, technicians and farmers. The problem of K and P deficiencies was corrected by the following up balanced fertilization with K and P. Since then, compound fertilizers have been getting popular in the county and widely used by farmers.
The research results are also used to develop BB fei by the local fertilizer factories. The agricultural station has developed a series of fertilizer practices for the major crops in the county which are used by the public. Liangping county along with its adjacent counties of Changshou and Dianjiang has a flat farmland area of 225,000 ha, are called as the Second Largest Plain after Chengdu Plain in the Sichuan Basin and are considered as the most important grain base in Chongqing.
(4) Work in 2006
1) Continued long term field research in two major cropping systems.
2) Demonstrations of balanced fertilizers on rice.
3) Enhanced balanced fertilizer research for maximum yield of paddy rice.
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