Study specimens G (GOAT WEED), H (SIDA WEED), I (SPEAR GRASS), J (ELEPHANT GRASS), and K (PIG WEED) carefully and answer the following questions. (a) State ...

Answer Details

(a) Botanical names of the specimens

(b) One reason why each of I, J and K is difficult to control

• I (Spear grass): It reproduces by tough, deep, creeping underground rhizomes that resprout even after the shoots are cut.
• J (Elephant grass): It is a vigorous perennial that propagates readily from rhizomes and stem cuttings and also produces many seeds.
• K (Pig weed): It produces a very large number of long-viable seeds and grows and matures very rapidly.

(c) Two uses of specimen J (Elephant grass)

• Used as fodder/forage and for making silage for livestock.
• Used for mulching and for checking soil erosion (also for fencing/boundary marking).

(d) Five ways the weeds are of economic importance to farmers

1. They compete with crops for nutrients, water, light and space, thereby reducing crop yield.
2. They harbour crop pests and diseases, serving as alternative hosts.
3. They increase the cost of production through extra spending on weeding labour and herbicides.
4. They contaminate harvested produce, lowering its quality and market value.
5. Some (e.g. elephant grass and pig weed) are useful as fodder, mulch or vegetables/medicine, giving farmers additional benefits.