(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)

Size of farm (ha)	Qty of fertilizer used (bags)	Yield of maize (bags)	Change of Qty of fertilizer	Change in yield of maize (bags)
2	0	8	-	-
2	8	24	8	16
2	12	48	4	24
2	26	80	4	32
2	20	120	4	40
2	24	150	4	30
2	28	170	4	20
2	32	180	4	10
2	34	180	2	0
2	36	170	2	-10

(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.