Fig. 49. Poor plovfing up of a pond bottom. The clods, consisting of 

 the root systems of above-water plants, are turned only about 90°. 

 They grow out again later. An after-treatment with the cutter is 

 therefore desirable. The plow is here draT.Ti by a caterpillar tractor. 



Plows are especially suitable for the destruction of the above-water plants when a 

 not exactly very fertile subsoil is available. It is desirable here that the clods are 

 cleanly turned over about 180° and then somevchat pressed dovm if necessary by an 

 attached annulated roller (see Fig. ^8), Only then will the regrowth of the roots be 

 thoroughly prevented for about two years. Clods (see Fig. ^9) raised only 90° which in 

 strongly reeded ponds consist entirely of reeded root systems, readily sprout forth 

 again. Their unevenness also retards the reed mowing which should shortly follow the 

 soil cultivation. A lodgement of mud layers pla^/s no part in ponds with root sjfstems 

 of reeds, since mud occurring between above-water plants is hardly usable, and finally 

 a clean sandy bottom is always more favorable than a hopelessly reeded pond. Therefore 

 in reed control work, the ploughing may be done deeper (to 25 cm. = 10 inches) with 

 confidence, even though deep plowing in general is to be anxiously avoided. 



TThere the soil is not covered by a firm continuous layer of root systems of above- 

 water plants, grubbers, harrows v;j,th spring tines or comma tines, and disk harrov;s are 

 of much greater advantage than the plow. Also the tearing and cutting of thinner plant 

 covers, loosening and breaking up the soil and mixing the ingredients should be done 

 without carrying the valuable top layer of soil into the depths. 



In the regular care of 7;ell cultivated ponds such as carp brood-nursing ponds, 

 brood growing ponds, winter ponds, and natural trout ponds the use of the disk harrow 

 is in order. Unfortunately the vjorking breadth of many valuable implements such as the 

 disk harrow is not very large. It can be broadened by coupling several implements. 



The rotary cultivator is the soil cultivating implement which also belongs with 

 the future in pond industry. It crumbles the soil very finely, loosens it uniformly and 

 well, breaks up the root covering into the smallest pieces, mixes everj'-thing carefully 

 and thoroughly and with the subsoil, and leaves behind it a completely smooth soil, with- 

 out carrying fertile top layer into the depths or sterile soil to the top. In cases of 

 soft soils, "marsh extensions" or the wheel rims give good services. Lime can be mixed 

 in vdth the soil during the same v/ork run. In many pond industries, the machine is not 

 well liked, because the hooks and knife clavjs too frequently break. It should also be 



160 



