Week 10 – SS2 First Term Agricultural Science Notes

 WEEK TEN
TOPIC: FARMING PRACTICES
CONTENT

• Types of farming practices
• Methods of Replenishing lost nutrients
• Factors influencing nutrient availability in the soil

FARMING PRACTICES
The following farming practices have consequences or effects on the soil;

1. BUSH BURNING

   This involves the setting of fire on the bushes to clear out the vegetation
   MERITS
   

2. It releases potassium and phosphorus as ash
3. It has some sterilizing effect on the soil
4. It stimulate the growth of fresh grass
5. It destroys soil borne pathogen or germs
6. It destroys the seeds of weeds

   DEMERITS
   

7. It destroys the organic content of the soil
8. It reduces the population of soil live organisms
9. It oxidase nitrogen and sulphur into gaseous forms
10. It exposes the soil to erosion and leaching
11. It may raise the PH level of the soil
12. It causes environmental pollution
13. It destroys the soil structure
14. It reduces soil water content

     

15. OVERGRAZING
    

    Overgrazing is a situation where more animals than can be supported on a particular pasture are put there to graze.
    MERIT
    

16. More feaces are dropped which could improve the fertility of the soil
17. Weeds can easily be eradicated from such land.

    DEMERITS
    

18. It depletes the vegetative cover of the soil
19. It causes poor growth and regenerative capacity of vegetation
20. It exposes soil to erosion
21. It destroys soil structure
22. It leads to soil compaction
23. Compacted soil reduces water infiltration
24. Pore spaces in the soil in the soil are reduced

     3.    CLEAN CLEARING
    This is the removal of the entire vegetation on a piece of land.
    MERITS
    

25. It gets rid of weeds from the land
26. It may leave land free of all obstacles

    DEMERITS
    

27. It leads to disturbance or removal of top soil
28. It leads to increase evaporation of water
29. It exposes the soil to erosion
30. It leads to reduction in organic matter
31. It leads to loss of soil nutrients
32. It leads to leaching
33. It destroys the soil structure

     

34. FERTILIZER APPLICATION

    This involves the application of certain chemical substance to the soil to increase its fertility
    MERITS
    

35. It supplements nutrients content of the soil
36. It enhances the productive capacity of the soil
37. It increases the population of microorganism in the soil
38. It stimulates vegetation growth

    DEMERITS
    

39. Excessive application of fertilizers can cause soil acidity
40. Excess application can also reduce the activities of soil organism
41. Excessive application may also hinder the growth of crops

     

42. ORGANIC MANURING

    It involves the application of manure e.g green manure, farm yard manure and compost manure to the soil in order to improve its fertility.
    MERITS
    

43. Organic manuring returns nutrients to the soil
44. It improves the texture and structure of the soil
45. It encourages the activities of soil organisms
46. It improves the water temperature fluctuations in the soil
47. It prevents soil erosion
48. It improves water holding capacity of the soil

    DEMERITS
    

49. The process may lead to introduction of pathogens to the soil
50. It may have adverse effects on crops, if not properly applied

     

51. CROP ROTATION

    Crop rotation is the system of farming whereby different crops are grown on the same piece of land year after year on a definite manner so as to maintain the fertility of the soil
    MERITS
    

52. It adds nutrient to the soil through nitrogen fixation
53. It increases the yield of crops
54. It controls the growth of weeds
55. It maximizes the use of available land
56. It control pests and diseases associated with soil
57. If controls erosion
58. CONTINOUS CROPPING

    This involves the growing of crops on the same piece of land every year without the application of manure or fertilizers
    MERITS
    

59. It enables different crops to be grown and harvested
60. It maximizes the use of available land

    DEMERITS
    

61. It depletes soil nutrients
62. It ensures the spread or multiplication of germs
63. It ensures the multiplication of pests and parasites
64. It results in low yields of crops

     

65. FLOODING: It is defined as the accumulation of an abnormal large quantity of water in an area which refuses to percolate or flows away.

     EFFECTS OF TILLAGE IMPLEMENTS ON THE SOIL
    

66. PLOUGHING
    
67. It increases the soil organic matter content
68. It helps to mix the soil together
69. It improves water infiltration capacity
70. It improves the aeration of the soil
71. It leads to compaction of the soil
72. It spreads disease causing organism in the soil

     

73. HARROWING
    
74. It leads to fine tilth through the mixing of soil
75. It increases aeration and water infiltration
76. It increases root penetration
77. It leads to destruction of soil structure
78. It may lead to soil erosion

     

79. RIDGING
    
80. It prevents erosion and improves water penetration
81. It collects together rich top soil
82. It improves aeration and root penetration
83. It improves water conservation in the soil
84. It also facilitates the harvesting of roots crops

     EVALUATION
    

85. List five effects of bush burning on the soil
86. (a) Define Tillage

        (b) Explain Zero tillage

     METHODS OF REPLENISHING LOST NUTRIENTS
    

87. CROP ROTATION: It is a system of farming whereby different crops are grown on the same piece of land year after year in a definite manner so as to maintain the fertility of the soil.

     The layout of a four-year crop rotation plan is shown in this table

    YEAR	PLOT I	PLOT II	PLOT III	PLOT IV
    1	Yam	Cowpea	Cassava	Maize
    2	Cowpea	Cassava	Maize	Yam
    3	Cassava	Maize	Yam	Cowpea
    4	Maize	Yam	Cowpea	Cassava

     
     PRINCIPLES OF CROP ROTATION
    

88. Deep-rooted crops like yam and cassava should not follow each other
89. Shallow-rooted crops should not follow each other
90. Crops which have the same diseases should not follow each other
91. Crops which have the same pests should not follow each other
92. Crops of the same family should not follow each other
93. Crops which control weeds should be planted
94. Legumes should be included in crop rotation

     CONDITIONS NECESSARY FOR THE PRACTISE OF CROP ROTATION
    

95. Where land is scarce or limited in supply
96. Where population is high
97. The need to have different varieties of crops
98. The need to maintain soil fertility
99. Where the soil is exhausted of nutrient

     

100. ORGANIC MANURING
     

     Organic manure refers to the delayed plant and animal products which have been carefully prepared to supply nutrients to plants or crops.

      

101. BUSH FALLOWING
     

     This is the practice in which farmlands are left to lie fallow after one or two years of cultivation to allow the nutrients to revert to the soil.

      

102. COVER CROPING
     

     It is the process of planting certain plants mainly to cover soil surface to conserver the soil nutrient.
     Some common examples of cover crops are: mucuna pueraria, centro, clotalaria, calapogonium and cowpea

      

103. LIMING
     

     It is the process whereby Calcium or magnesium containing compounds are added to the soil to reduce soil acidity. Some common liming materials are: limestone, quicklime, slaked lime, basic slag, dolomite, gypsum, wood, ash etc.

      

104. APPLICATION OF INORGANIC FERTILIZERS
     

     Fertilizers are chemical substances in form of powder, granules, pellets, or crystals which can be added to the soil to increase fertility.

      EVALUATION
     

105. What is crop rotation?
106. List five principles of crop rotation

      FACTORS INFLUENCING NUTRIENTS
     Availability in the soil

107. Soil PH
108. Concentration of other nutrients
109. Leaching
110. Crop removal
111. Oxidation and Reduction of organic materials
112. Burning
113. Soil Texture
114. Erosion
115. Soil moisture content
116. Level or Organic matter/Micro Organisms in the soil

      WAYS IN WHICH SOIL NUTRIENTS CAN BE LEST
     

117. Crop removal
118. Erosion
119. Leaching
120. Soil Acidity
121. Excess of other nutrients
122. Oxidation and reduction of organic materials

      GENERAL EVALUATION
     

123. What is Bush burning?
124. State the merits of bush burning
125. What is crop rotation?
126. List five principles of crop rotation
127. State four effects of ploughing on the soil

      READING ASIGNMENT
     Essential Agricultural Science for Senior Secondary Schools, Chapter 18, pages 187 – 201

      WEEKEND ASSIGNMENT
     

     1. The following are pre planting activities except (a) ploughing (b) bush clearing (c) harrowing (d) thinning
     2. The following are types of manure except (a) green manure (b) farm yard manure (c) NPK (d) compost
     3. The following are methods of fertilizer application except (a) broadcasting (b) ring method (c) Top dressing (d) Eroding
     4. The following are liming materials except (a) limestone (b) Urea (c) quicklime (d) slaked lime
     5. Nutrients are lost through the following means except (a) crop removal (b) Erosion (c) leaching (d) mulching

      SECTION B
     1.    (a) State four demerits of bush burning
         (b) State four uses of lime in Agriculture
     2.    (a) Define soil organic matter
         (b) State five ways in which soil organic matter is important in Agriculture.