2-Maruza Biosfera. Tabiiy resurslar, ulardan oqilona foydalanish va atmosfera muhofazasi. Suv va Tuproq resurslari va uni muhofazasi. O‘simlik, hayvonot dunyosi va ularni muhofaza qilish

Tuproq zararlanishi
Hosildor yerlar o‘simlik unib chiqishi uchun zarur hisoblanadi. Hosildor yerlar shakllanishi 
yuz ming yillarga borib taqaladi. Yomg‘ir yog‘ib, yerni bo‘shatib, uning ustki qismini oqizib ketadi, 
shamol ham uning ustki qismini ozi bilan uchirib ketadi. Tuproqning bir joydan ikkinchi joyga 
ko‘chib harakatlanishi- Eroziya deb ataladi. Eroziyaga uchragan yerlar daryo va kichik daryolar 
tomonidan yuvilib turiladi va quyosh nuriga to‘sqinlik qilib fotosintez jarayoniini sekinlashtiradi. 
Bu esa baliqlar, molyuskalarga va boshqa organizmlarga talofat keltiradi. Eroziya tabiiy jarayon,
lekin u insoniyat tasiri ostida kuchayib boradi, ekinzorlar haydalib, o‘rmonlar kesilishi oqibatida 

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yerlar ochiq holga kelib qolmoqda. Ochiq holdagi yerlarni esa shamol va yomg‘ir osonlik bilan 
yuvib oqizib ketadi.
1 
Soil Loss 
Fertile topsoil is important to plant growth. Newtopsoil takes hundreds or thousands of years to 
form.The Launch Lab at the beginning of this chapter showsthat rain washes away loose 
topsoil.Wind also blows itaway. The movement of soil from one place to anotheris called 
erosion 
(ih 
ROH zhun). Eroded soil thatwashes into a river or stream can block sunlight andslow photosynthesis. 
It also can harm fish, clams, andother organisms. Erosion is a natural process, buthuman activities 
increase it. When a farmer plows afield or a forest is cut down, soil is left bare. Bare soil ismore 
easily carried away by rain and wind. 
Figure 19
shows some methods farmers use to reduce soil 
erosion. 
Soil Pollution 
Soil can become polluted when air pollutants driftto the ground or when water leaves pollutants 
behindas it flows through the soil. Soil also can be pollutedwhen people toss litter on the ground or 
dispose oftrash in landfills. 
Solid Wastes
What happens to the trash you throwout every week? What do people do with old 
refrigerators,TVs, and toys? Most of this solid waste isdumped in landfills.Most landfills are 
designed to sealout air and water. This helps prevent pollutants fromseeping into surrounding soil, 
but it slows normaldecay processes. Even food scraps and paper, whichusually break down quickly, 
can last for decades in a 
landfill. In populated areas, landfills fill up quickly.Reducing the amount of trash people generate 
canreduce the need for new landfills. 
1
Peter Rillero, Dinah ZikeEcology, 2005 (109- bet)