526 IOWA DEPARTMENT OF AGRICULTURE. 



that no specific figures can be followed in all cases but the problem will be 

 greatly simplified if landowners and engineers can come into possession of 

 reliable data regarding even a few areas which have been drained economic- 

 ally and successfully. 



So far as we have been able to learn , landowners have practically the same 

 problems and the same experiences with gumbo that they have with clay. 

 One farmer states that he tiled a tract of gumbo with the result that the 

 water was removed very slowly the first season. The drain was much more 

 effective the second year and drew the water from a greater distance, and it 

 did still better the third year. Apparently the gumbo was affected by the 

 drain just as the clay described previously. There are extensive tracts of 

 gumbo in Iowa, and doubtless the best methods to adopt in draining soils of 

 this type are those which have been recommended for clayey soils. We 

 trust that landowners and engineers who are present will state their experi- 

 ence with gumbo for the benefit, not only of those in attendance at the con- 

 vention, but also through the reports for the large number of farmers in the 

 State who are seeking information in regard to the drainage of these lands. 



The gumbo soils, to which we refer are loams with sufficient clay mixed 

 with them to make them exceedingly sticky or adhesive when wet. When 

 these soils are properly drained and cultivated they are fertile. 



Muck is another type of soil which it is often difficult to drain successfully. 

 This is a black soil, composed largely of vegetable matter and is found in 

 swampy areas. Muck is quite often unproductive because the permanent 

 water level is too near the surface. There are several factors which make 

 this a difficult soil to drain and therefore we refer briefly to some drainage 

 plans which have been found to be well adapted to muck areas. One well 

 known authority says, ' 'In raw muck lands the water will not readily enter 

 a tile, and the water moves through such soil with great difficulty. On the 

 unproductive lands the water level is maintained by some source of water in 

 the surrounding higher ground and reaches the muck soil through a water- 

 bearing sand or gravel layer below the muck. The water moves very readily 

 through the gravel, and if we can devise some plan of drainage by which a 

 portion of the tile will pass through this gravel layer a permanent water 

 level will be reduced to the level of the tile. Whenever this can be done at 

 reasonable expense it is the simplest and most satisfactory solution of the 

 problem." 



The recommendation is offered that a preliminary drainage survey should 

 be made when it is proposed to drain a muck soil. Holes should be bored 

 in the muck bed to determine the character of the stratum below the surface 

 and the depth at which it is found. We use for this purpose a one and a 

 half inch auger welded to a piece of one-half inch gas pipe with a T screwed 

 on top to hold the cross handle, which is also a piece of one-half inch pipe. 

 When the distance from the surface to the water-bearing gravel has been 

 determined, by the use of the auger, at several points in the area to be 

 drained, usually it is possible to plan a drainage system which will reduce 

 the permanent water level to a sufficient depth and which will require only a 

 comparatively few short lines of tile in the gravel. 



There are cases where water-bearing gravel is found at a depth of forty 

 to fifty feet below a layer of muck which rests upon thirty or forty feet of 

 clay. Whenever such a muck area can not be drained economically in any 



