hii Presentation haipo kwenye lugha yako, kuangalia kwa: English (en),
au tumia ufasiri wa google:  

 

Mtangazaji: Roland Bunch

Tukio: ECHO East Africa Highlands Symposium 2014 (27-10-2014)

A-frame levels can be used to trace contour lines for soil conservation, or irrigation ditches at ½ % slope. They are highly accurate, and cost nothing.