Thumbnail Image

Theses

Browse

19991
Reset filters
Subject: Agricultural Engineering × Author: KAU × Author: Sajeena, S × Start date: 1994 × Type: Thesis ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    Erodibility and runoff potential of laterite soils under simulated rainfall conditions
    (Department of Irrigation and Drainage Engineering, Kelappaji College of Agricultural Engineering and Technology, Tavanur, 1999) Sajeena, S; KAU; Kurien, E K
    Soil erosion is one of the most serious environment degradation problems. However reliable measurement of erosion remains limited and estimates of soil productivity are even rarer. Assessing the extent and seriousness of erosion therefore remains a difficult task Nevertheless, identification and assessment of erosion problems could have an important role in influencing better land use and conservation practices. Rainfall simulators are considered as an effective tool in soil conservation research. Simulators make it possible to produce predetermined storms at any desired time and location. They make the replication of research easier and facilitate the study of storm sequences. Laterite soils are by far the most important soil group occurring in Kerala and cover the largest area. The objective of this study was to estimate the erodibility and runoff potential of laterite soils of three well defined series under simulated rainfall conditions. The rainfall simulator designed and fabricated by Kurien and George (1998) was modified for better performance. The modified simulator could produce rainfall intensities varying from 741 to 23.00 cmlh. Also uniformity of the rainfall produced could be increased to higher values of 88.10 and 91.53 per cent, thus giving a better performance. Intensity of rainfall increased as the 11 pressure of supply water to the simulator increased and a relationship was established between intensity and the supply pressure of water as 1= -87.205 p2 + 108.61 P - 10.786 (R = 0.99) Experiments were also conducted to study soil loss and runoff from three different series of laterite soils, i.e.Mannamkulam series, Naduvattom series and Vellanikkara series. The soil loss and runoff increased with increase in the rainfall intensity for all slopes studied for each series of soil. A general trend of increase In soil loss and runoff with increase in the slope was observed for all the three series of soils. Empirical equations were developed for estimating soil loss (E) and runoff (0) for various intensities of rainfall and land slopes for the three series of soils selected for the study. The equations are: Mannamkulam series E = 1167.797 I + 835.109 S - 21686.07 (R = 0.90) Q = 65.0161 + 16.747 S - 235.923 (R = 0.99) Naduvattom series E = 324.766 I + 112.799 S - 3912.219 (R = 0.97) Q = 74.542 1+19.434 S - 394.323 (R = 0.99) Vellanikkara series E = 115.662 I + 431. 064 S - 11512.284 (R = 0.98) Q = 58.742 I + 26.837 S - 310.019 (R = 0.99) ii1