Agriculture Paper 1 Questions and Answers - Form 4 Mid Term 2 Exams 2021

AGRICULTURE
PAPER 1
FORM 4 MID TERM 2

INSTRUCTIONS

This paper consists of THREE sections A, B and C.
Answer all questions in section A and B.
Answer any TWO in section C.

SECTION A
Answer all questions inthis section in the spaces provided.

State two roles of soil micro-organisms that are beneficial to plants.(1mk)
State two forms in which Nitrogen is available to plants.(1mk)
Name three negative parts that can be used to propagate pineapples.(1½mks)
State four factors that can increase the seed rate in crop production.(2mks)
State four reasons for deep ploughing during land preparation.(2mks)
What is meant by the following terms;
1. Mixed cropping.(1mk)
2. Mixed farming.(1mk)
Give two situations in which opportunity cost is equal to zero.(2mks) ____
State four qualities of crops which are used for green manure.(2mks)
Give four farming practices which can lead to increase in amount of light falling on leaves.(2mks)
State four factors which determine the stage and time of harvesting crops.(2mks)
Give the reason of using the following materials when preparing compost manure.
1. Wood ash ½mk
2. Top soil½mk
3. Dung ½mk
State five importance of mulching in crop production .(2½mks)
Give four roles of trees in soil and water conservation.(2mk)
List down the three types of land reform which have taken place in Kenya.1½mk)
State three effect of excess Nitrogen in tomato production.(1½mk)
Name two diseases of cabbages.(1mk)
Give four reasons of conserving forage crops.(2mk)
Differentiate between the following;
Top dressing and topping in pasture management. (1mk)

SECTION B
Answer all the questions in the spaces provided.

The diagram below illustrates a final seedbed after tertiary done during land preparation.
1. Name the tertially operation carried out on the seedbed.(1mk)
2. Give three reasons for carrying out the operation.(3mks)
3. Apart from the above operation name any other tertially operation.(1mk)
The following diagram represent a method of crop propagation .Study it carefully and answer the question that follows.
1. Identify the method of propagation.(1mk)
2. What is the importance of the above method of crop propagation?(1mk)
3. State three factors which influence rooting of cutting materials in vegetative propagation.(3mks)
A form four student was advised to apply a compound fertilizer 30:20:10 in a cabbage plot measuring 10 m long by 5 m wide at a rate of 300kg per hectare.
1. State the percentage of Phosphorus.(P2O5) .(1mk)
2. Calculate the amount of the fertilizer the student would require for the plot.(Show your working )(3mks)
The following is a photography showing maize crop growing in the filed .Study it clearly and answer the questions below.
1. Identify the field practices which have been carried out at point A.(1mk)
2. Give three reasons as to why it is important to carry out the practices.(3mks)
3. Apart from the crop above name any other two crops which require the practices in (a) above.(2mks)

SECTION C
Answer any two questions from this section in the booklet provided.

1. Explain five natural factors that influence soil erosion .(10mks)
2. State and explain five factors which may influence the spacing of crops.(10mks)
1. Give five cultural methods of weed control.(5mks)
2. Outline five ways in which pest influence agricultural production.(5mks)
3. Describe the importance of any five nursery management practices.(5mks)
4. 1. What is the meaning of economic injury level as it is used in pestmanagement.(1mk)
  2. Describe four physical measures of pest control in crop production.(4mks)
1. Explain the effects of land fragmentation in agricultural production.(5mks)
2. Describe the process of gulley formation.(4mks)
3. Outline the factors influencing crop rotation.(6mks)
4. Describe the importance of drainage in crop production.(5mks)

MARKING SCHEME

Role of soil living micro-organism
- Bring about decomposition of organic matter
- Fix free Nitrogen into the soil. 2x½mks
Forms in which Nitrogen is available to plants.
- Nitrate ion NO₃
- Ammonium
- ion ( NH₄⁴⁺) 2½mks
Vegetative parts used in propagating pineapple.
- Crown
- slip
- suckers 3x½mks
Factors which influence the seed rate
- Germination percentages.
- number of seeds per hole
- purity of seeds
- spacing of the crop 4x½mks
Reasons for deep ploughing
- To improve drainage
- To control all the perennial weed
- Facilitate the penetration of roots
- To break the hard pan
Mixed cropping different
- Growing of different crops on the same piece of land but in different plots.1mk
  Mixed farming.
- Growing of crop and rearing livestock on the same time. 1mk
  (Mark as a whole)
When opportunity cost is zero
- When goods &services are freely give
- when good are unlimited.
- when goods and services are freely given 2x1=
Characteristics of crop used for green manure.
- Decompose very fast
- Fast growth rate
- should be leguminous
- Highly vegetative
- Should be hard (grow well in poor soils) 4x½
Farming practices which leads to increase of amount of light falling on the leave
- Pruning
- Thinning
- Pricking out
- Weeding
- Proper spacing any 4x½mks
Factors determining the stage and time of harvesting.
- Chemical concentration required
- market demand
- purpose of the crop
- weather condition
- prevailing market prices any 4x½mks
- Ash- act as catalyst ½mk
- Top soil-provide micro-organism ½mk
- Dung- act as food for micro-organism ½mk
Importance of mulching
- conserve moisture in the soil
- protect the soil from the strong sun heat
- control of weed
- improve soil fertility after decomposition
- improve soil structure any 4x½mks
Role of trees in soil and water conservation.
- Act as wind breaks
- Reduce the impact of the rain drops
- Root hold the soil particles together
- Leaves fall down reducing the speed of the surface run off.
- Increase the infiltration of water into the soil.
- provide shade reducing the rate of evaporation. Any 4x½mks
Types of land reform
- Land consolidation
- Land adjudication and registration
- Settlement ad resettlement 3x½mks
Effect of excess Nitrogen in tomato production.
- Case blossom end rot
- Delayed maturity
- Excess leaves and few fruits
- Weak stems any 3x½mks.
Diseases of cabbages.
- Dumping off
- Black rot any 2x½mks
Reasons for conserving silage
- To sell
- To have feed through out the year.
- To use during the dry season
- Prevent wastage
- Ensure maximum utilization of the available land.
- Top dressing – application of Nitrogenous fertilizer /manure to the pasture
- Topping- it is the removal of stems and fibrous material left after a period of grazing.

1. ridging 1x1=1mk
2. Reasons
  - To conserve soil and water
  - encourage tuber expansion
  - To make harvesting of tuber crops easier.
  - Provide open furrows for irrigation. Any 3x1 mks
3. Leveling
  - Sub soiling
  - Rolling any one 1x1mks
1. Trench layering 1mk
2. can produce more than one of planting materials. 1mk
3. Relative humidity
  - light intensity
  - temperature
  - leaf area
  - Oxygen supply any 3x1 mks
1. 20%
2. 1 ha 300kg of 30:20:10
  1000 m² – require 300 kg 1mk
  (10x5)m² 1mk 300 x 50 = 1.5kg1mk
  1000
1. earthling up. 1mk
2. - to conserve moisture
  - Provide support
  - Control soil erosion 3x1 mk
3. - Sweet potatoes
  - Carrots
  - Irish potatoes
    Any 2x1 mks
1. Natural factors influencing soil erosion.
  - Topography – the steeper the land the higher the erosive velocity
  - Soil types light soils are easily eroded.
  - Rainfall intensity –the high the rainfall intensity the higher the erosive power slashing the soil.
  - Soil depth- shallow soils are quickly and easily eroded.
  - Vegetables cover- forest protects the soil against erosion .Trees act as barrier protecting the soil erosion agent. 5x2mks
2. Factors influencing the spacing of crops
  - soil fertility –infertile soils crops are closely spaces.
  - Machine to be used – spacing should allow the movement of the machine to be used in between the rows.
  - Pest and diseases control –when crops are well spaced it is difficult for the pest to craw from one crop to another.
  - Soil moisture; in wet area crops are widely spaced.
  - Growth habit- spreading plants are widely spaced.
  - Purpose of the crop-when crops are grown for fodder they are closely spaced.
    Any 5x2 mks
1. Cultural methods of weeds control.
  - Crop rotation-control parasitic weeds
  - Clean planting method-planting should be free from weed seeds
  - Cover cropping-smothers the weeds
  - Mulching-smothers the weeds by denying the weeds sunlight
  - Clean seedbed
  - Flooding
  - Timely planting
2. Influence of pest to crop production
  - Transmit diseases
  - Increase the cost of production
  - Reduce the quality of produce
  - Some interfere with the transport system of the plant
  - Some introduce toxic substance to the crop
  - Lower the yield of the crops. Any 5x1mk
3. Importance of nursery management
  - Pricking out-to avoid over crowding in the nursery
  - Hardening off-ensure that the crop is well adapted to the condition in the main field.
  - Watering –ensure that there is enough moisture in the soil
  - Mulching-to modify the soil temperature and conserve moisture in the soil
  - Spraying using a appropriate chemical to control pest and diseases
  - Weeding to prevent competition of nutrients. Any 5x1mk
4. 1. The level at which the damage caused by the pest cannot be tolerated by the farmer and control measures must be put in place.1mk
  2. - Lethal temperature –This is use of extreme temperatures to kill the pest
    - Physical barrier-eg rat deflectors in a granary.
    - Trapping and killing physically.
    - Scare crows-Human like structures used to scare the pests
    - Use of radiation –which attracts and kills the pest. Any 4x1 mk
1. Effect of land fragmentation.
  - No sound planning
  - Small holding do Not allow mechanism
  - Soil and water conservation measure cannot be put in place
  - Wastage of time in movement from one place to another
  - Difficult to control weed, pest and diseases
  - Difficult to provide extension services
  - Poor supervision-due to the scattered land parcels all over. Any 5x1mk
2. Process of gulley formation
  - moving rain water
  - Formation of channel by water moving in them.
  - Widening of the channel
  - Scouring of the floor of the channel 4x1mk
3. Factors influencing crop rotation 4mks
  - Rooting characteristics –deep rooted crops should be alternated with shallow rooted crops.
  - Nutrient requirement –heavy feeder should be grown before the crops with low nutrition requirement.
  - Pest and diseases –crops of the same family should not follow each other in a crop rotation programme;
  - Weed association –crops associated with a certain weed should follow each other
  - Rest period-a fallow season should be provided in a crop rotation programme to improve soil structure.
  - Soil fertility a legume in order to fix free nitrogen into the soil
  - Availability of capital. Some programme may be so expense. Any 6x1mk
4. Importance of drainage in crop production.
  - Soil volume –increases soil volume
  - Increases the soil temperature
  - To reduce toxicity in the soil
  - Improve the activities of soil living organism
  - Reduce leaching
  - Reduce erosion rate of top soil.
  - Improve soil structure
  - It is a method of land reclamation any 5x1mk