عنوان مقاله [English]
The ways of dealing with density include control of soil moisture control during tillage, the control of vehicle's traffic on the soil, weight reduction and vehicle's contact pressure with soil and changing of soil structure by adding organic material. In order to study of the effect of organic materials and zeolite and their mutual effect at different moisture stages on resistance to pentrometer penetration, organic material factor in four levels (0, 0.5, 1 and 1.5 percent), zeolite factor in four levels (0, 8, 16 and 24 tons per hectare), also soil moisture levels which are in two dry and wet stage at five levels (saturation, capillary crack, final crack, return final crack to capillary crack and when the crack have destroyed) were examined in three replicates as the factorial based on complete randomized blocks design in Rice Research Institute. The results showed that adding plant residues has increased resistance to pentrometer penetration in soil to 37 percent, the reason of increased resistance to pentrometer penetration in treatments containing plant residues, is the levels of plant residues which aren't decomposed. While adding plant residues causes reduced resistance to pentrometer penetration will accelerate in wet process. It was also found that resistance to pentrometer penetration with subsidence of soil, volume shrinkage of soil, Bulk density and soil moisture content highly correlated (0.7811- 0.9916). Finally it's recommended that in order to reduction of the resistance to pentrometer penetration, plant residues will be added to the soil for long time.