تأثير الزراعة الطويلة للرز على بعض الصفات الفيزيائية و الكيمائية للترب

الملخص EN

Rice cultivation for long periods has a clear impact in soil physical and chemical properties this effect is shown due to the nature of soils that cultivated by rice that can logged as ( soil water saturated).

The results shows that the rule of separate soft (silt and clay) in soil cultivated with rice and sand values ranged between (46.0- 875) g.

Kg-1 and silt (73.0-776) g.

Kg-1 and clay (52.0-520.0) g.

Kg-1.

The results indicated a decline in the proportion of sand/silt and sand/clay in cultivated soils than uncultivated soils also results shows decreased the proportion of silt/clay in the prospects under the surface, and increased the bulk density of soil cultivated by rice with depth.

the results shows that pH indicated in soil cultivated with rice compared with uncultivated soils, EC decreased in cultivated soils as a result of melting and movement of salts out of the soil Pedon, the range of soil CEC between cultivated (11.2-33.5) cm.

Kg-1.

soils shows different in calcium carbonate content and this is belong to the situation of seasonal water and melting of limestone and redistribute in soil body, where calcium carbonate content increased with depth as a results of de calcification process and deposition in the lower horizons.

It was noted a decrease in calcium sulfate content in cultivated soils compared with uncultivated soils, because of the case of water in wet lands, which works to melt gypsum.

The results also pointed to increased in organic matter in soil cultivated by rice, and to the low content of total Nitrogen in cultivated soils by rice, and it was noted a convergence of values of phosphorus in cultivated and uncultivated soils.

and increase in potassium values in cultivated soils by rice as a result of water conditions that increase the weathering process of minerals that containing potassium.