1171. Depending on the percentage of sand, silt, clay, soils are divided into _______ textural classes:
A. 12
B. 13
C. 14
D. 09
1172. Based on their diameters, soil pores are divided into:_________?
A. Macro pores
B. Meso pores & Micro pores
C. Both A & B
D. The above statement is wrong
1173. Water is the major constituent of all living creatures. Biomass of plants is composed of ________% water:
A. 65 – 75%
B. 72 – 62%
C. 85 – 95%
D. 75% – 80%
1174. The planned development, distribution and use water resources:
A. Water distribution
B. Water management
C. both A & B
D. None of the above
1175. Conservation agriculture improves the water use efficiency of dryland systems. It has components:
A. Reduced soil disturbance through no-till or minimum till
B. Residue return to keep at least 30% of soil covered
C. Crop rotations for better utilization of available water & nutrients
D. all of the above
1176. Losses of soil water not includes_________?
A. Direct evaporation from the soil & transpiration from vegetation
B. down-ward drainage
C. Hydroponics loss
D. Surface run-off from the field
1177. In Pakistan there is general deficiency of rainfall. It varies from 125 mm annually in upper Sindh to about 900 mm in the sub-mountainous of northern Pakistan. In Balochistan the mean annual rainfall is about 200 mm, diminishing to ________ mm in the desert of Kharan:
A. 100 mm
B. >70 mm
C. <50 mm
D. None of these
1178. _________ erosion is the removal of a thin layer of soil by water acting over the whole surface. This type of erosion damaged very fertile lands located on slopes, some of which have been eroded to a depth of about 15 cm.
A. Rain splash rill erosion
B. Stream bank erosion
C. Sheet erosion
D. Gully erosion
1179. Soil samples are collected:
A. From the field with immediate application of fertilizer or amendments
B. Field with upper white layer of salts
C. Boundaries of the field
D. None of these
1180. Clay and humus particles are referred to as colloids and are less than 0.002mm. Due to their small size, colloids have ________________ surface area which provides surface for adsorption, catalysis, precipitation and microbial colonization:
A. Extremely low
B. Extremely high
C. Very little
D. None of these