Theory question 105
Crop Propagation(a) Define the term nursery as used in crop production.
(b) Give three reasons for establishing a nursery in crop production.
(c) Mention three characteristics of weeds that make them difficult to control.
(d) List two methods of controlling weeds.
(e) State three ways by which diseases are spread among crops.
(f) Mention three effects of diseases on crops.
Show the model answer
(a) A nursery is a specially prepared place where seeds are sown and seedlings raised and cared for before transplanting to the field.
(b) Any three: small seeds need special care; easier to water, shade and protect young plants; only healthy, vigorous seedlings are transplanted; saves seed; gives the crop a head start in the season.
(c) Any three: produce many seeds; seeds stay viable/dormant for long; spread by many means; grow fast and compete strongly; deep roots or underground stems/rhizomes; resistant to drought and trampling; resemble crops.
(d) Any two: manual/mechanical (hoeing, slashing, hand-pulling); chemical (herbicides); cultural (mulching, cover crops, rotation); biological.
(e) Any three: wind; water/rain splash; insects (vectors); infected planting materials; farm tools and man; soil; animals.
(f) Any three: reduce yield; reduce quality and market value; death of plants; increase cost of production; reduce photosynthesis; make produce unsafe.
Weeds are hard to control because of their seeds and roots – explain both.