Correct Answer: B. have excess negative charges

Correct Answer: A. Growing of crops one after the other in a particular sequence

Explanation

Choice A is correct. Crop rotation involves the growing of crops one after other in a particular sequence

Correct Answer: D. its efficiency on water distribution in steep slopes is poor

Explanation

(a) The law of diminishing returns as it apply to agricultural production states that as one factor of production increasingly applied in equal amounts to a fixed factor of production, e.g land, a stage will be reached where the add( application of the same factor adds less to the production output.

(b)

(c)(i)

ii) The curve reveals that: (1) with increase in fertilizer( yields increase at an increasing rate to the 20th bag of fertilizer; (2) further increase in fertilizer beyond the 20th bag results in increase at a decreasing rate to the 32nd bag of fertilizer; (3) after the addition of the 32nd bag of fertilizer, further increase in fertilizer fails to increase the yield of maize, i.e, yield remains constant; (4) beyond 34 bags of fertilizer, the yield of maize begins to decrease (5) the whole concept explains that beyond a certain stage (20 bags of fertilizer), addition of more fertilizer elicits less increase in maize yields, until yields begin to actually fall.

Correct Answer: D. remove sprouts and rotten tubers

Correct Answer: A) Coir, wood, bast, asbestos

Correct Answer: B. Thinning

Correct Answer: B. innoculation

Correct Answer: D. causing heavy rainfall

Explanation

(a)Definition of nursery in crop production: Nursery is a place where young plants are raised under intensive management practices for later transplanting into permanent fields/plot

(b)Reasons for establishing a nursery in crop production

- Promotes economy of seeds/efficient utilization of seeds

- Seedlings receive more intensive care e.g watering manuring and protection from animals, disease and pests

- Creates an opportunity for selecting healthy, vigorous and disease-free seedlings for transplanting

-Seeds that ate difficult to germinate in the field are better raised in the nursery e.g carrot, cabbage.

- Horticultural practices like budding, grafting are easily carried out in the nursery

- It is place for hardening delicate seedlings before transplanting them

(c)Characteristic of weeds that make them difficult to control

- Ability to produce many seeds

- Weed seeds have long period of dormancy

- Some weeds have deep root systems used for absorbing water from deeper horizons in dry soils

- Some weeds have modified root system for storing food which they thrive on for long periods e.g waterleaf

- A good number of weeds have very efficient means of dispersal

- Weeds survive under marginal/poor soil by virtue of profuse rooting systems and their minimum nutrient requirement status

- Some weeds have very fast growth rates

- Weeds survive under adverse environmental conditions by means of structures such as stolon, rhizomes

(d)Methods of controlling weeds

- Physical/Mechanical control

- Chemical control

- Biological control Cultural control

(e)Ways by which diseases are spread among crops

- Wind

- Water

- Contact(animal and human)

- Infected/diseased planting materials

- Infected soils

- Vectors

- Contaminated farm tools

(f)Effects of diseases on crops

- Reduced yield/output

- Reduction in the quality of produce

- Malformation of plant parts (gall formation, reduction in the leaf area)

- Death of plants

- Retarded growth of crops

- Reduced seed viability

- Deterioration of stored produce