The effects of conservation tillage on soil physical and

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					 THE EFFECTS OF CONSERVATION TILLAGE ON SOIL HYDROPHYSICAL PARAMETERS AND
                   EARTHWORM ACTIVITY IN SANDY LOAM SOIL
                                                                                 1                                    2
                                                              Peter Laszlo , Csaba Gyurica
         1
          Research Institute for Soil Science and Agricultural Chemistry of the Hungarian Academy of
         Sciences (RISSAC), Hermann Otto u. 15, H-1022 Budapest; e-mail: laszlo@rissac.hu
           2
            Department of Soil Management, Institute of Crop Production, Faculty of Agricultural and
         Environmental Sciences, Szent Istvan University, Pater K. 1, H-2103 Godollo, Hungary; e-mail:
                                           gyuricza.csaba@mkk.szie.hu

In our long-term soil tillage experiment, the effects of conservation tillage systems on soil compaction
were examined in maize monoculture during ten years.
The research work was carried out at the experimental site of Pyhra Agricultural Secondary School in
Lower Austria. The weather is determined by continental and maritime climate influenced by the
closeness of the Alps as well. The soil is Endogleyic Fluvic Cambisol (Dystric, Siltic), with a base rock
of fine-graded silt deposited during floods. The soil has good structure and favourable water regime,
however it can be susceptible to compaction.
In the experiment three soil tillage systems were compared, namely direct drilling, ridge tillage and
conventional tillage with ploughing in maize (Zea mays) monoculture. To evaluate soil compaction soil
physical-, hydro-physical, earthworm activity and crop yield were used. Moisture content and soil water
retention curve (pF) were analysed for hydro-physical conditions. Earthworm activity characterized by
earthworm abundance, earthworm biomass and number of earthworm channels were measured.
The results of bulk density and penetration resistant measurements show that the soil is more
compacted in the topsoil in undisturbed direct drilling than in disturbed tillage treatments (Figure 1).


                                                         Soil bulk density (g.cm-3 )                                                      Penetration resistance (MPa)
                          1,3         1,4        1,5             1,6            1,7                           0,5             1,0                1,5               2,0
                      0                                                                                  0


                     10                                                                                  10
   Soil depth (cm)




                                                                                       Soil depth (cm)




                     20                                                                                  20


                     30                                                                                  30


                     40                                                                                  40


                     50                                                                                  50

                                No-till     Ridge-till         Ploughing                                            No-till         Ridge-till         Ploughing

                     Figure 1: Soil bulk density and penetration resistance at the soil profile (Pyhra, 1997–2006).

Even though slight soil compaction has been detected in direct drilling the crop yields were not
different considerable because soil moisture and plant available water content were almost the same
in the tillage treatments (Figure 2). In case of direct drilling earthworm activity was much more
favourable in contrast with tilled treatments (Figure 3).
                                                  Kruskal-Wallis test: H(2, N=30)=1,6504 p>0,05



                                         10


                                          9


                     Yield (t.ha-1 )      8
                                                                                                   Median
                                          7                                                        Quartiles
                                                                                                   Min-Max
                                          6


                                          5


                                          4



                                                        No-till        Ridge-till      Ploughing

                 Figure 2: Yield of maize in the tillage treatments (Pyhra, 1997–2006).


                                                  Kruskal-Wallis test: H(2, N=15)=7,992 p<0,05
                                         300



                                         250



                                         200
                     Density (db.m-2 )




                                                                                                   Median
                                         150                                                       Quartiles
                                                                                                   Min-Max

                                         100



                                          50



                                              0
                                                         No-till       Ridge-till      Ploughing


               Figure 3: Earthworm density of the tillage treatments (Pyhra, 1998–2006).

Consequently, physical evaluation itself is not suitable for the examination of the effect of soil tillage
systems on soil compaction. Within the experimental period, the effect of annual precipitation had an
important role regarding the effect of tillage systems on soil properties.

Keywords: ridge tillage, direct drilling, soil compaction, earthworm activity

				
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