Fertilizer application decreased by 20%, forest growth increased by 23.78%, soil organic matter increased significantly, soil fertility was restored and can be maintained for a long time - Guangxi Academy of Forestry presided over the completion of "precision fertilization of timber forest and soil maintenance technology innovation and application" results subverted the convention, explored new methods, new technologies, new processes, developed new materials, new products and new results achieved, reached the international leading level of similar research.
The reporter specially interviewed Cao Jizhao, the project leader, vice president of the Guangxi Academy of Forestry Sciences, and a professor-level senior engineer in the second-level post.
Reporter: This set of precision fertilization and fertility maintenance technologies that subverts the conventional, where are the key innovations?
Cao Jizhao: The traditional fertilization method emphasizes that the fertilizer should be mixed with the soil. The disruptive innovation of precision fertilization and soil maintenance technology is the opposite, putting fertilizer into a paper cloth multi-layer bag that can be fully biodegradable, so that it can be scientifically separated from the soil and slowly release nutrients, this new product is called "bag controlled slow release fertilizer".
Experiments in the demonstration area proved that the average annual growth rate of timber forests was increased by 15.79%-33.81% and the nutrient loss rate of fertilizer was reduced by 29.84%-51.48% by the application of precision fertilization techniques such as bagged controlled slow-release fertilizer. Measured one year after the application of the bag-controlled slow-release fertilizer, the remaining nutrients of the fertilizer in the bag are 25.2%, and the fertility is valid for more than one year, which can maintain the stable, balanced and sustainable soil nutrients for a long time. Compared with the conventional fertilization method with fast nutrient release, bagged slow-release fertilizer is more environmentally friendly, more efficient, more time-saving and labor-saving, and is expected to become a new direction for the development of fertilizers in China.
Reporter: Judging from the management practice of Plantation Forests in Guangxi, which ranks first in the country, what are the defects in conventional fertilizers and their application methods?
Cao Jizhao: In the plantation forests of Guangxi, the timber forests dominated by pine cedar eucalyptus have sprung up, accounting for about 5% of the country's forest land area, producing more than 40% of the country's timber. Under the circumstance that the area of new forest land is very difficult, how to achieve high-quality development of existing timber forests? This is a major topic that needs to be studied urgently.
There are three prominent problems facing the operation of plantation forests in Guangxi: First, there is a widespread blindness in the fertilization of forest trees, the effectiveness of fertilizer in increasing production has not been fully utilized, and the principle and method of precision fertilization need to be systematically and deeply studied; second, the rate of fertilizer nutrient release does not match the nutrients required for forest growth, the fertilizer efficiency is not high, and the fertilizer utilization rate is low; the third is the operation mode of full land reclamation, pure forest planting, reuse of light culture, short-cycle rotation, etc., which is not conducive to the long-term maintenance of soil fertility.
Reporter: With regard to the above problems, where should we start to study them and what methods should be used to solve them?
Cao Jizhao: In view of the lack of basic data on soil nutrients in woodlands and the decline in soil fertility, based on the determination data of soil nutrients in forestland from 1983 to 2020 in Guangxi's main timber forests and WebGIS to develop the integrated application of soil big data in Guangxi and the regionalized formula fertilization system, different woodland nutrient status inquiry methods such as "point query", "surface query" and "forest class query" were formed, and different regions were formulated on the basis of soil nutrient supply, soil quality status, soil type, and forest tree nutrient fertilizer law 3. Precise fertilization formulas for timber forests of different tree species, different generations and different forest ages, and improve the precision fertilization mode of forest trees. At the same time, from the aspects of fertilizer raw material screening and element ratio, we will improve and optimize the formula fertilization technology, scientifically and rationally formulate fertilizer demand by zoning classification, build a scientific fertilization technology system for timber forests, and realize accurate fertilization of timber forests.
Aiming at the problem of the decline in the productivity of existing timber forests, the pathogenesis of soil barrenness under different soil types in guangxi's main timber forests was systematically studied, and the soil barriers of eucalyptus plantations were comprehensively studied from the regional scale (different production areas), time scales (different planting generations) and yellowing processes, and the soil barrier factor evaluation system of guangxi main timber forests was constructed, revealing that the main obstacles to eucalyptus yellowing in Guangxi were "low content or lack or lack or oxidation of Fe2+, Mn2+".
Reporter: In this way, to solve the problem of how to achieve high-quality development of timber forests, we must first start from "woodland (soil)" and "forest (timber forest)" to carry out basic research. Then, the next step is a breakthrough in the direction of new fertilizer and precision fertilization.
Cao Jizhao: Yes. In view of the problems of low fertilizer utilization rate, mismatch between the release and supply of fertilizer nutrients and the growth demand of forest trees, the principle of precise fertilization of forest trees is applied, the law of nutrient element demand and nutrition diagnosis technology of forest trees at different growth stages are systematically explored, the mathematical mode of precise fertilization of forest trees is improved, the multilayer bags of biodegradable and environmentally friendly kraft paper, nonwoven fabrics and bio-mineral materials are innovatively developed, and the "bag controlled slow release fertilizer" is developed to scientifically separate fertilizers from soil to achieve the nutrients of slow-release fertilizer throughout the year.
Bagged controlled slow-release fertilizer adopts bagged quantitative adjustable method, which can be personalized according to woodland soil data, forest tree varieties and their different growth stages. For the first time, PLC process control, touch-type man-machine interface and PID digital constant temperature control technology are integrated to realize the automation of bag control fertilizer out of the bag packaging, and form a complete new process and new equipment for bag control fertilizer production. Bag-controlled slow-release fertilizer eliminates the need for fertilizer granulation and drying, reduces production costs, and conforms to the development direction of energy conservation and emission reduction, chemical fertilizer reduction, and green and low carbon.
Reporter: What innovative achievements and application technologies have been achieved in the project research of "soil maintenance", which is closely related to "precision fertilization"?
Cao Jizhao: In view of the prominent problem of soil fertility decline in existing timbers, using specific substrate induction technology, 9 strains of penicillium chrysogenum L301 and 6 strains of cellulose decomposition bacteria (Trichoderma asperellum F01) were selected from the rhizosphere soils of pine and fir trees, and functional microbial bacterial fertilizers (fungal agents) were created to improve soil microecology and activate soil phosphorus. Promotes rapid decomposition and nutrient return of litter understory. For the first time, the application technology of green manure under the forest, the decomposition of litter under the forest, the biomass carbon and the bio-organic fertilizer were integrated to form a technical system for the maintenance of the main timber forest, improve the soil organic matter and fertilizer retention effect of the timber forest, and achieve an increase of 13.8%-22.6% of the soil organic matter content compared with before the implementation.
Reporter: It is understood that the innovative technology of precision fertilization and soil maintenance has not only been practically applied in plantation forests such as timber forests and economic forests, but also used in crops such as sugarcane.
Cao Jizhao: Yes. On December 30, 2020, Du'an Yao Autonomous County measured and compared the yield of newly planted sugarcane with a growth period of 7 months, and the results showed that the sugar content of sugarcane fertilized by conventional methods was 14.70%, the sugar content of sugarcane fertilized by bag control was 16.22%, and the sugar content was increased by 1.52 percentage points, which meant that the sugar production of the same amount of sugarcane increased by more than 10%. Moreover, the application of bag-controlled fertilizer can also increase the yield of sugarcane per mu by about 20%, and the increase in yield and efficiency is very obvious.
Reporter: "Precision fertilization of timber forests and technological innovation and application of soil maintenance" has achieved fruitful results, and has been highly praised by the expert group led by well-known academicians, please introduce its research process and achievements.
Cao Jizhao: "Precision Fertilization and Soil Maintenance Technology Innovation and Application of Timber Forest" project was led by guangxi academy of forestry, with the participation of key units such as Nanjing Institute of Soil Sciences of Chinese Academy of Sciences, Tropical Forestry Experimental Center of Chinese Academy of Forestry, Guangxi University, Guangxi Huawo Ecological Fertilizer Co., Ltd., Guangxi Tiandong Liyuanbao Technology Co., Ltd., and 13 district straight forest farms such as Guangxi state-owned Qipo Forest Farm and Gaofeng Forest Farm, as well as many county-level forest farms such as Linduo Forest Farm and Saltwater Forest Farm. More than 100 scientific and technological personnel and forestry engineers have collaborated in scientific research, joint research and application promotion for more than 10 years, aiming to promote the high-quality development of forestry in Guangxi, promote the realization of the goal of "reducing the use of chemical fertilizers to ensure zero or negative growth in the use of chemical fertilizers" in Guangxi and even the whole country, and help the high-quality development of plantation forests and the transformation and upgrading of the traditional compound fertilizer industry.
The project of "Precise Fertilization of Timber Forest and Technology Innovation and Application of Soil Maintenance" has been granted 10 patents and 3 software copyrights; 3 industry and local standards have been formulated; 1 400,000-word forest nutrition and scientific fertilization works have been published, 39 papers have been published; 3 new products have been developed; 1 new material and 2 new processes have been developed, 1 production line has been established, and 4 trademark registration certificates have been obtained. In the past three years, a total of 292,200 hectares of timber forests have been promoted, 317,700 tons of special fertilizers for forest trees have been produced, and the cumulative sales of wood and fertilizers in three years have been 1.482 billion yuan, and the new profits have been 825 million yuan. The comprehensive benefits of the project results are remarkable.
After the evaluation of the expert group headed by the well-known academician, the achievement reached the international advanced level of similar research, and reached the international leading level of similar research in the slow release nutrient technology of paper-cloth composite mineral materials and the realization of the precise fertilization effect of slow release of woodland. (Zhang Lei)
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