ICAR AIEEA-PG — Agricultural Engineering & Technology (Major Subject Group 10) · India · National Testing Agency for ICAR
Original practice questions written to the published syllabus · not past papersEstimating erosion and designing the bunds, terraces, waterways, spillways, ponds and dams that control it.
In the exams: GATE AG Section 4 Soil & Water Erosion; ICAR AIEEA-PG Unit VII; ICAR AICE subject 40 Unit 5; NCEES PE erosion; PRC ABE land and water (32%); state PSCs
ICAR AIEEA-PG — Agricultural Engineering & Technology
Unit VII single-answer MCQs: definitions (unit plot, EI30, SDR, retardance), which structure suits which site, standard formulas (HI = 100 VI/S, VI = 0.3(S/3 + 2), A = (2/3)TD), and quick calculations under +4/−1 marking.
How our questions for ICAR AIEEA-PG spread across the units of Soil & Water Conservation Engineering. Difficulty: 29 easy, 31 medium, 1 hard.
| Mechanics of water erosion | 7 | |
| Soil loss estimation: USLE, RUSLE and MUSLE | 7 | |
| Earthen dams: seepage and stability | 6 | |
| Sediment yield | 5 | |
| Agronomic and biological conservation measures | 5 | |
| Bench and broad-base terraces | 5 | |
| Grassed waterways | 5 | |
| Wind erosion mechanics | 5 | |
| Wind erosion control and shelterbelts | 5 | |
| Contour and graded bunds | 3 | |
| Gully control | 3 | |
| Drop, drop-inlet and chute spillways | 3 | |
| Farm ponds | 2 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
Other factors being equal, which soil is usually the most erodible by water?
D. A silty, very-fine-sand soil low in organic matter with weak structure
Silt and very fine sand are easily detached and easily carried. Clays resist detachment through cohesion; coarse sands resist transport and absorb water quickly, so they produce little runoff.
Further reading: Wischmeier and Smith (1978), USDA Agriculture Handbook 537
In US usage, a tillage and planting system counts as conservation tillage when, after planting, crop residue covers at least:
A. 30% of the soil surface
The accepted US definition is at least 30% residue cover after planting. No-till, strip-till, ridge-till and mulch-till usually qualify.
Further reading: Schwab et al. / Fangmeier et al., Soil and Water Conservation Engineering
Contour farming becomes less effective as slope steepness and slope length increase mainly because:
B. runoff overtops the small tillage ridges and breaks through at low points
Contour ridges store only a little water. On long or steep slopes and in large storms, water overtops them, concentrates at low points and can cause rills. That is why AH 537 limits contouring to a maximum slope length and why the P value rises towards 1 on steep slopes.
Further reading: Wischmeier and Smith (1978), USDA Agriculture Handbook 537
Surface mulch reduces water erosion primarily by:
A. absorbing raindrop impact and slowing overland flow
Mulch in contact with the soil protects it from splash detachment and increases hydraulic roughness, so runoff slows and carries less. It acts through C in the USLE; R is a climatic property and does not change.
Further reading: Schwab et al. / Fangmeier et al., Soil and Water Conservation Engineering
Using VI = 0.3(S/3 + 2), with S in percent, the vertical interval between contour bunds on a 6% slope is:
D. 1.2 m
VI = 0.3 × (6/3 + 2) = 0.3 × 4 = 1.2 m. Forgetting to divide S by 3 gives 2.4; forgetting the 0.3 gives 4.0. Dropping the S/3 term gives 0.3 × 2 = 0.6 m.
Further reading: Suresh, R., Soil and Water Conservation Engineering
A broad-base terrace built by moving soil downhill from the upper side only, forming a relatively deep channel, is called a:
A. Nichols terrace
Nichols terraces take all soil from the upslope side. Mangum terraces take soil from both sides of the ridge. The conservation bench terrace is a runoff area plus a level storage bench.
Further reading: Schwab et al. / Fangmeier et al., Soil and Water Conservation Engineering
In a zoned earthen dam, the central core of clay serves mainly to:
D. reduce seepage through the dam
The impervious core controls seepage; the pervious shells provide weight and stability; riprap protects the upstream face.
Further reading: US Bureau of Reclamation, Design of Small Dams
The mode of transport that usually moves the largest share of soil in wind erosion is:
A. saltation
Saltation (short hops of particles about 0.1–0.5 mm) usually accounts for roughly 50–75% of movement. Suspension carries fine dust far but is usually a smaller share by mass; creep is driven by saltation impacts.
Further reading: Morgan, R.P.C., Soil Erosion and Conservation
For the longest effective zone of protection against wind erosion, a windbreak should have:
C. moderate porosity, roughly 40–50%
A solid barrier gives strong reduction just behind it but produces turbulence and a short sheltered zone. A moderately porous barrier lets some air through, reducing turbulence and extending protection. Gaps near the ground cause jetting under the canopy.
Further reading: Morgan, R.P.C., Soil Erosion and Conservation
Wind strip cropping controls erosion mainly by:
D. reducing the unsheltered distance along the wind with alternate strips of erosion-resistant crops
Strips of resistant crops laid across the wind break the field into short lengths, so soil flow cannot build up by avalanching. In the WEQ this reduces L.
Further reading: Woodruff and Siddoway (1965)
Ten here, 61 in the app. The Laisha app has every practice question we have written to ICAR AIEEA-PG in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
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