| Based on the fact that the maladjustment of ecological factors, the obstruction of ecological circle, the decline of production profits and other situations existing in traditional agriculture, some new agri-ecological techniques were applied and the optimized agricultural eco-engineerings were constructed to solve these problems; By using positional observation and statistic investigation, the ecological function and comprehensive benefits of agri-ecological techniques were studied quantitatively; By analyzing the operation mechanism and operation process of these agri-ecological techniques, we could make a deeper understanding to their coupling-cooperation mechanism and their benefit amplification in sustainable development. The study will reveal the function and effect of agri-ecological techniques in the construction of agricultural eco-engigeering patterns, push the application and spreading of agri-ecological techniques, and promote the local agricultural sustainable development.The general study route and methods are as follows: According to the principle and method of agricultural eco-engineering, three techniques (the ecological loop-adding techniques, the ecological chain-prolonging techniques and the ecological interface-connecting techniques) were used respectively to design and assemble three different optimized agricultural eco-engineering patterns, including the apple tree-white clover interplanting, the integrated pig-biogas-vegetable greenhouse system and the planting-breeding-processing eco-system linked by biogas-fermenting. Here, taking traditional non-integrated units as experimental controls, the samples were collected from the experimentalspots and were assayed in the lab, and the data were investigated using the methods of positional observation, fargoing investigation and spot experiment. The substance circles, energy flows and value multiplications in eco-economic systems were studied by using systemic analysis methods; The Least Significant Difference Test was done with computer software, and the ecological function and Benefit amplification could be measured and evaluated quantitatively. While the operation mechanism and operation process of these agri-ecological techniques being analyzed, the mathematical formula were used to express the benefit amplification quantitatively, and the space geometry model was created to figure out the relationship between the ecological technique, economic technique and the sustainable development. While the study was going on, some results from it had been applied to the practice, and the agri-ecological techniques had been continually adjusted to make the eco-engineerings more perfect.The paper summarizes the theory proofs and the corresponding technical constitution of agricultural eco-engineering. The structure principles of agricultural eco-engineering include system components, diversity, domination, opening and self-adjusting; The function principles include energy flow and substance circle, value multiplication and message transfer, integrated effects, mutual dependence and mutual restriction, self-adaptability, circular economy, benefits harmony and ecological rehabilitation. The agri-ecological techniques, which correspond with certain eco-engineering, mainly include the loop-adding-removing techniques, the chain-prolonging-separating techniques, the interface-connecting techniques, the organic waste recycling techniques, and the agricultural eco-environment repairing techniques. The loop-adding-removing techniques can be divided into production-loop techniques, beneficial loop-adding techniques, consuming-loop removing techniques, processing-loop using techniques and complex loop techniques.Taking Shandong province as an example, the present agricultural eco-engineering system can be divided to 5-grade classifications, includingsocial-economic-natural complex system, the big agricultural system of farming-forestry-animal husbandry-produce processing-fishery, the subsystem of agriculture, the farmland (breeding field, fishery water, courtyard) resource utilization system and primary product production system; The present optimized patterns can be divided into six high level classifications: the restrictive factor control pattern for controlling natural disaster and improving eco-environment, the intergrowth and mutual benefit pattern for making full use of time-space resource and gaining high yield and profits, the pattern of fine substance circle which were used for utilizing waste and optimizing structure, the complex opening pattern for combining planting-breeding-processing and integratingagriculture-industry-commerce, the comprehensive development pattern being used in programming whole region and managing multi-industries, as well as the courtyard agricultural eco-engineering pattern. Each of these high level classification patterns can also be divided into many low level patterns. Using the principles and methods of agricultural eco-engineering, and according to the local ecological and economic situation, three new optimized agricultural eco-engineering patterns were constructed in Shandong province: By using the beneficial loop-adding techniques, the apple tree-white clover interplanting pattern was established to solve the ecological degeneration of soil caused by the traditional orchard-weeding method; By using the loop-adding and chain-prolonging techniques, the integrated pig-biogas-vegetable greenhouse system was established to solve the deficiency of greenhouse vegetable planting, pig breeding and biogas fermenting existing in traditional agriculture production; By using the ecological interface-connecting techniques, the planting-breeding-processing eco-system linked by biogas-fermenting was established to solve the question of ecological circle obstruction occurring in modern specialized agriculture.The comparable experiment results has shown: The application of all the three agri-ecological techniques has remarkably improved the local agriculturalecological condition, prevented the agricultural pollution from agricultural chemical material, increased the efficiency of nutrient cycle and energy flow, promoted the agricultural yield, saved the productive cost and raised the farmer's income. It has achieved considerable ecological, economic and social success, attained a beneficial ecological cycle and the mutual promotion of ecology with economy.(1) The white clover (Trifolium repens L.) is an ideal species for interplanting with apple trees, because it has a long life circle, wide adaptability, and effective fertilization ability, and its roots distribute in the upper soil layer whereas the apple tree's in the deeper layer, so they can get along very well On the one hand, the apple tree-white clover interplanting can improve the soil ecological condition by increasing soil nutrient, and regulate soil temperature and enhance soil-water conservation ability. Three years later after the white clover was interplanted with apple trees, the soil organic matter content below soil surface 0-30 cm increased 3.3 g kg'1 on average, the nutrient content of Nitrogen, Phosphorus and Potassium in soil increased too. Compared with traditional orchard-weeding land, the soil moisture below soil surface 0-25 cm was 4.2% higher averagely in the summer, and the average soil temperature below soil surface 5 cm was 4.1 °C lower in the summer but 2-3 "C higher in the winter. On the other hand, the apple tree-white clover interplanting promoted the growth of apple trees, controlled the diseases, insects and weeds to a degree. It increased the fruit yield and improved the fruit nutrition quality, and it had a higher economic benefits. The fruit yield increased by 7.04% on average, the annual pasture yield reached 2130 kg hm'2, and the total economic income increased 5328 RMB hm'2 each year. The content of total sugar, dissolvable solid substance and Vitamin C in apple fruit increased, while the total acid substance and apple rot rate decreased. In addition, the experimental results in the saltwater intrusion area of Laizhou Bay have shown that there were very manifest ecological sheltering benefits of jujube-soybean (peanut) interplanting. It could improve the farmland microclimate significantly, make the daily or annualchanges of temperature and humidity more gentle during crop growth period, slow down the wind speed, reduce surface soil evaporation and crop transpiration, and save irrigation water.(2) The integrated pig-biogas-vegetable greenhouse organically combined vegetable planting, livestock feeding and biogas fermentation techniques together, attaining a beneficial ecological cycle which of high nutrient-energy conversion efficiency in a single greenhouse. It successfully solved the limiting factors existing in traditional production patterns in the winter of North China. The pigs' growth, biogas production and vegetable production were all effectively improved, and the considerable ecological, economic and social benefits were simultaneously achieved. The daily net weight increase for a pig in the ecological greenhouse averaged 0.82 kg, 0.57 kg higher than in the roof-less pigsties, while its average consumption of grain feedstuff in the eco-greenhouse decreased by 19.1%; The biogas digesters in the eco-greenhouse operated more days in a whole year and produced 400-500 m biogas. which was increased by 32.3% over the traditional household digesters, more observably in the winter; The average yield per hectare of cucumbers and tomatoes increased by 18.4% and 17.8% over their ordinary greenhouses respectively, and the vegetable quality was also improved. The average annual net income of a standard eco-greenhouse was 10,900 RMB, with an increase of 58.0% over its traditional non-integrated parts. It could use up 14 t fresh pig dung and produce 10 t organic manure one year for the improvement of soil fertility. It provides a new way to make full use of organic wastes (such as crop stalks and livestock excrements) and produce pollution-free agricultural products.(3) The agricultural eco-system of Xishan village was integrated with crop planting, livestock breeding and primary product processing by the two ecological interface-connecting components of biogas-fermenting and forage-feedstuff production. Its substance-energy flow was highly efficient and reasonable, the ecological efficiency and economic benefits were promoted each other, and theecological, economic and social benefits increased simultaneously. The utilization efficiency of organic energy in livestock excrements increased by more than 57%, the ratio of grain energy to chemical fertilizer energy rose from 3.55 to 6.33. After' the livestock excrements, were fully fermented in the digester, the residual dreg and liquor was used as organic manure, and it could replace the chemical fertilizer to a certain degree, reduce the pollution from chemical fertilizers and pesticides; The use of biogas improved the living energy structure (The biogas energy accounted for 63.8% of the family living energy), solved the conflict between the farmer living energy and the stockbreeding fodder in crop stalk resource successfully. The forage-feedstuff processing production increased the livestock's feedstuff energy conversion rate and the farnland's nutrient substance returning rate. The total feedstuff energy conversion ratio reached to 38.5%, and the entire crop stalk resource in Xishan village was used reasonably. The nitrogen input on farmland was greater than its output (the ratio of output to input averaged 0.745), and the soil organic matter content in the crop field rose from 11 g kg"1 to 13 gkg1.The agricultural eco-engineering is an improving process of the present agri-economic system, and it is also an ecological reconstruction process of the degenerative agricultural eco-system. In this process, the agri-ecological techniques plays the role of assembling and optimizing the system structure, integrating the system function, promoting the ecological circle, enhancing the production efficiency and ecological efficiency, and realizing the synchronization of ecological, economic and social benefits. Among the different units (structural component and structural chain) connected with agri-ecological techniques, there is a relationship of coupling-cooperation and positive feedback, which makes the function and benefits of eco-systems increasing and magnifying. The benefit amplification of one integrated unit can be calculated by the summation of every index's weight multiplying its increasing rate of the integrated unit's function-benefit value to non-integrated unit's, and the total benefit amplificationof an eco-system can be calculated by the summation of every unit's weight multiplying its benefit amplification value. By calculation, the total benefit amplification is 16.2% for the beneficial loop-adding technique of interplanted orchard with white clover, and it is 72.8% for the loop-adding and chain-prolonging technique of eco-greenhouse. In an independent eco-economic system with fine circle, its economic development presents a progress of dynamic movement in a cone-like helix, which means it moves up in a helix line along the conical surface from the cone peak. Hereby, the analytic geometry model of cone-like helix is created to illustrate the relationship between ecological technique, economic technique and sustainable development, in which the peak angle of the cone represents the ecological technique factors and the inclination of the helix with the circumference of cone cross section represents the economic technique factors, which means the two impetuses for realizing the agricultural sustainable development.The agri-ecological techniques are always related with certain natural, social and economic conditions, and they have strong regional characteristics and timely characteristics. They may play a very important role within a certain region and a certain time, but their ecological function and ecological effect may decrease and finally disappeare when the certain region and certain time changes. The suggestion about this paper are as follows: The ecological function and benefit amplification of three agicultural eco-techniques should be observed and studied positional ly in more aspects and a longer period, the operation techniques should be improved continuously, and the structure of agri-ecolological economic system should be optimized further. Based on the local practical conditions, the three optimized agricultural eco-engineering patterns, including the apple tree-white clover interplanting pattern, the integrated pig-biogas-vegetable greenhouse system and the planting-breeding-processing eco-system linked by biogas-fermenting, should be spread to gain more ecological, economic and social benefits.
|
PDF Full Text Request