تأثير ثلاثة نظم حراثة و نوع و مستوى بقايا المحصول السابق في بعض الخصائص الفيزيائية و أجزاء الكاربون العضوي في تربة جبسية

الملخص EN

The preservative agriculture principle practice (crop rotation) was conducted under effect of different tillage systems to assess their effect on stability of the soil aggregates, moisture content and organic carbon fractions, ie.

particulate organic carbon (POC) and mineral associted organic carbon (MOC) in a gypsiferous soil.

Clover and Corn were planted in spring season (2018-2019)., under effect of no tillage system (NT), reduced tillage (RT), and conventional tillage (CT), keeping on levels (0 %, 50 % and 100 %) for their residues after ex harvesting.

In autumn season corn was planted in the same site of spring season, under the same effect of studied factors in the first experiment, besides factor of previous crop residues.

Soil samples were taken after harvest to study effect of these factors on aggregate stability.

Results showed the superiority of NT system significantly on CT system at a percent up to 8.4 % and not significantly superior over RT system.

No tillage was significantly superior on RT in moisture content by a percentage up to 22.8 % and 25.2 % over CT.

An increase in organic matter contant was noticed for NT and RT systems over CT by a percent up to 6.5 %.

NO-tillage system was significantly superior over RT and CT, their values reached 0.163 %, 0.155 and 0.149 %, respectively in POC content, while for MOC the values were 0.196 %, 0.192 % and 0.180 %, respectively, because of the positive relationship between organic matter content and organic carbon in soil.

Legume crop (clver) residues was significantly superior over spring corn with a value 1.483 mm in aggregate stability and with a value 14.38 % in moisture content, and 12.86 gm kg-1 soil in organic matter content, and 0.162 % in POC, and 0.195 % in MOC compared to the effect of corn spring residues which reached (1.357mm, 12.03 %, 12.11g kg-1 soil, 0.150 % and 0.183 %), respectively for the parameters..

By increasing level of residues from 0 % to 100 % values of the studied parameters increased significantly, aggregate stability from 1.372 to 1.468 mm, mositure content from 11.54 to 14.81 %, POC from 0.148 to 0.163 % , MOC from 0.183 to 0.194 % , organic matter content from 12.20 to 12.77 gm kg-1 soil.

Triple interaction treatment NT.C.C2 Re100 % was significantly superior over other treatments with values reached 17.34%, 13.46 g kg-1 soil , 0.185 % , 0.208 % for moisture content, organic matter content, POC, and MOC, respectively ; except for aggregate stability where there was no significant difference between RT.C.C2 Re100 % (1.560 mm) and NT.C.C2 Re100 % (1.553 mm).