Zhou chunxiang, Liu,

(Langfang Vocational and Technical College, Langfang, Hebei 06500 1)

Abstract: The changes of main animal species recorded in Langfang area in the past 25 years were investigated. The results show that the number of most animals is decreasing.

Small, some species even face a serious survival crisis. The important impacts of human activities and rural production and life on agricultural biodiversity were analyzed.

Keywords: Langfang; Biodiversity; Human activities; affect

China Library ClassificationNo.: S 18 1 Document ID: A DocumentNo.:100821631(2008) 0120093203.

2 Results and analysis

Statistical results of 2 1 1

The survey data show that the great changes of human activities and rural production and life have an important impact on agricultural ecological biodiversity. Since the reform and opening up 20 years ago, agricultural biodiversity has shown a serious downward trend, and the number of animal populations has generally decreased, and some of them are on the verge of extinction, which has a strong consistency (table 1). In addition to the stable population of magpies, the dominant populations such as sparrows, swallows and woodpeckers are decreasing. Bats, weasels, frogs, toads, snakes and lizards are facing a crisis of survival. In the investigation of nearly two months from September to June, 2006, frogs and toads were only found in three places with water sources in Wen 'an, Gu 'an 1 and Xianghe 1, and no amphibians were found in other places. As the geomorphological environment of Langfang tends to be consistent, the changes of animal resources in various counties and cities were compared, and it was found that the changes of ecological community diversity in various counties and cities were basically the same, that is, biodiversity showed a downward trend. Individual species, such as amphibians, have different requirements for the environment (water).

2 12 Impact of Rural Life Change on Agricultural Ecological Diversity

Changes in living conditions and environment have affected almost all animal types except agricultural insects, and changes in rural lifestyles have destroyed many animal habitats [6]. New buildings, mainly made of bricks, tiles and reinforced concrete, have made many creatures lose their habitat [4]. Bats and sparrows mainly nest in old houses with civil structures in rural areas, while hedgehogs and Yellow weasel are built in abandoned houses or haystacks in rural areas.

Bird's nests and old houses only exist in small quantities. Most domestic swallows (including golden swallow) live in inhabited halls, but now plastic-steel doors and windows are widely used in rural houses, making it impossible for domestic swallows and geckos to build nests. The lack of local buildings and the hardening of the garden floor make it impossible for rats and reptiles to survive.

2 13 Impact of Agricultural Production Activities on Agricultural Ecological Diversity

2 13 1 1 Impact of farmland environmental degradation on agricultural ecological diversity

Farmland is the largest and most important ecosystem in the plain area. A large number of chemical pesticides are used in agricultural production, which can effectively control pests and diseases, but also harm non-target organisms including natural enemies of pests. There are obvious adverse effects. Improper spraying of organophosphorus pesticides in wheat fields caused a large number of deaths of ladybug septempunctata, an important natural enemy of wheat aphids. As a result, the wheat aphid in chemical control area is 1 ~ 2 times higher than that in non-control area, which reduces the biodiversity of wheat field [5]. A large number of unscientific spraying of chemical pesticides will not only pollute soil, water and agricultural products, but also make farmland ecological imbalance, plant diseases and insect pests become more and more serious, and will also affect food safety and harm.

Human health.

Influence of Agricultural Farming System on Agricultural Ecological Diversity

Farming changes the physical environment of soil, such as moisture, air, compactness, porosity and temperature, thus affecting soil biota. The organisms in the soil include bacteria, fungi, actinomycetes, algae, protozoa, rotifers, nematodes, earthworms, mollusks, arthropods and some higher animals. In farmland ecosystem, the methods of less tillage and no tillage can improve farmland biodiversity [7]. Topsoil farming often hurts some nesting birds and small animals [8]. Most crops in Langfang are double cropping a year, with a high degree of agricultural mechanization and frequent farming (including arable land, sowing,

Intertillage weeding, etc. ) seriously affect the living environment of rabbits, rodents, amphibians and reptiles, annelids, burrowing insects, etc.

Effects of 2 13 13 irrigation methods on agricultural ecological diversity

Overirrigation, especially irrigation with reclaimed water, directly harms animals and affects the life and reproduction of burrowing animals such as rabbits, rodents, reptiles, annelids and burrowing insects [9]. Irrigation conditions of farmland in central and northern Langfang are good, and wheat is generally irrigated in one season.

Water it four times. Frequent floods have an impact on soil biota. Due to the shortage of water resources, sewage irrigation around the city is more common. Sewage irrigation water is mostly untreated urban sewage and industrial wastewater. Sewage irrigation leads to the accumulation of pollutants, which not only affects the living conditions of soil organisms, but also affects the quality of food and vegetables, directly or indirectly affecting human health.

Profound harm [10].

2 14 Impact of Ecological Changes of Agricultural Natural Landscape on Agricultural Ecological Diversity

The agricultural landscape pattern in the plain area has an important impact on biodiversity, and hedgerows, woodland and farmland boundaries in the courtyard may be the most important landscape units to maintain biodiversity [7]. Langfang is located in the plain, where the primary natural environment is less preserved and the influence of relative changes is less, while the changes of secondary natural environment and man-made environment have the greatest influence on diversity. The secondary natural environment of Langfang is a semi-natural landform dominated by ecological forests in the north and natural depressions and depressions in the south-central part. In recent 20 years, the ecological forest land in Langfang has been greatly reduced, and most of the original natural small plates on the edge of farmland have been reclaimed as agricultural land. Rivers dry up and Wadian wetland disappears, which is harmful to agriculture.

Biodiversity poses a threat. Compared with the statistics of Langfang Land Resources Bureau in 20001year, the second national land survey in Langfang City 1986 showed that the forestland area in Langfang City decreased by1245112hm2, accounting for 38 122% of the original forestland area. Woodland, as an important ecological resource, is the place and territory where many animals and plants live, which is very important for protecting species and biodiversity.

The role of can not be underestimated. The decrease of forest land, especially ecological forest land, has destroyed animal habitats, especially amphibians, reptiles and birds. Since 1987, the Wadian area in the south has been basically in a long-term drought state, and the original secondary natural environment has disappeared, making most aquatic animals extinct and coexisting with amphibians and reptiles.

2 15 Effects of Plant Community Change on Agricultural Ecological Diversity

The simplification of vegetation has changed the habitat of related organisms and had a great impact on the diversity of some animals and microorganisms closely related to plant species. Diversified planting systems can keep the diversity of wild plants, which can obviously reduce the pest population and protect natural enemies [1 1]. Traditional agricultural models, such as intercropping, agroforestry system and transfer agriculture, are conducive to maintaining biodiversity because they imitate natural ecological processes and follow similar ecological models [7]. In recent years, the artificial vegetation in Langfang area is single, and the spatial heterogeneity of plant communities tends to decrease. Corridor greening, more than 90% of forest land is fast-growing poplar, and the original native tree species, such as willow, elm, locust, Toona sinensis and native poplar, have become scarce tree species; The planting management mode is single. Wheat is mainly planted in spring and summer, corn is mainly planted in summer and autumn, cotton is planted in a small amount, soybeans, sweet potatoes and peanuts are planted sporadically, and sesame, millet, sorghum, millet and miscellaneous beans are almost extinct. The use of herbicides leads to the decrease of plant diversity in woodland, garden and farmland.

2 16 Impact of environmental change on agricultural ecological diversity

Environmental pollution leads to the decline of local ecological environment quality, and the decrease of beneficial insects (such as bees and parasitic bees) and beneficial birds in the ecosystem [8]. Environmental pollution eventually leads to the deterioration of water bodies and affects biodiversity. The data of climate and water resources in Langfang 1964-2003 show that with the change of years, the temperature rises and the precipitation decreases. Especially since 1997, the dry year and normal year in Langfang city have appeared year after year, and the shortage of water resources has intensified [12]. Due to insufficient natural precipitation, groundwater overexploitation leads to water level drop, and there is no water supply in the upper reaches, which leads to the river drying up all the year round and the potholes are greatly reduced. A large number of chemical fertilizers and pesticides have caused water pollution, and the simple stacking of urban domestic garbage and industrial garbage is also the main factor of water pollution. "All the water is polluted" and "It turns sour when it rains" has become a serious ecological problem. Because there is no natural water surface and clean water surface for breeding, amphibians in central and northern Langfang have basically disappeared.

3 Conclusion

Biodiversity is the foundation for the survival and development of human society, not only the indispensable food source for human survival, but also the biosphere environment for human survival and development [13, 14].

(1) Due to the lack of primitive natural ecological environment, agriculture gives consideration to grain production and maintains ecological functions, and agricultural ecology is the most important ecosystem in the plain area; (2) The impact of human activities on agricultural biodiversity is inevitable, and the decreasing or even worsening trend of biodiversity will surely worsen the living environment of human beings, restrict or even seriously threaten their survival and development [14]; (3) Paying attention to biological survival means paying attention to human beings themselves. Under the premise of not affecting the improvement of people's quality of life, it is necessary to study how to adopt a more harmonious and reasonable lifestyle and agricultural measures to protect habitat diversity and biodiversity without affecting agricultural production. (4) Ecological agriculture is an effective way to protect biodiversity and promote the sustainable development of agriculture [15].