The experiment was conducted at the Faculty of Agriculture,
University of Benin, Ugbowo Campus Benin City Nigeria. The experiment was conducted
under rain fed condition during the early cropping season (March to November)
of the year 2013.
The experimental design was the Randomized Complete Block
Design (RCBD) with yam and egusi-melon as the test crops. The trial consisted
of 4 levels of NPK 20:10:10 fertilizer (0, 200, 400, 600kg/ha) with 3 cropping
systems and replicated 3 times.
It was observed that yam did well in sole than in
intercropping. Average tuber yield of yam in fertilizer treatments was also
greater than that of unfertilized plants. Also the average tuber yield and
number of tubers were significant. The higher tuber yield of yam2.862t/ha and
2.991t/ha was obtained from 400kg/ha treatment in sole and in intercrop
planting system. Higher number of tubers of 21.66 was obtained from 200kg/ha
treatment in sole planting system.
The mean value of egusi-melon seed yield in intercrop and
sole melon was 0.0513t/ha and 0.0511t/ha respectively. And the mean value
obtained from average pods size was 28.97cm for sole and 34.0cm for intercrop.
From the experiment, plot which was measured 4×1.5m per sub-plot, the average
number of egusi-melon gotten was 34.0 for intercrop and 44.0 for sole.
The application of NPK 20:10:10 fertilizer at 400kg/ha had
the greatest influence on the yield of egusi-melon both as a sole and as
intercrop. The application of 400kg/ha at 6WAP influenced the pod number.
The application of NPK 20:10:10 at 600kg/ha had the greatest
influence on vine length and stem girth of egusi-melon both as sole and as
intercrop. Average stem girth of 1.19cm in sole and 1.33cm in intercrop was
obtained. Vine length of 154.3cm in intercrop as against 156.3cm recorded in
The longest vine and the widest stem girth of yam were
obtained at 400kg/ha of NPK 20:10:10 fertilizer. Average vine length of 236.2cm
in intercrop and 225.7cm in sole at 8WAP was obtained. Average stem girth of
1.55cm in intercrop as against 1.64cm recorded in sole planting.
Intercropping is an agricultural practice in which two or
more crops are grown together in the field (Onwueme, 1978). One advantage of
intercropping is that it increases yield: more can be grown on a single plot
Intercropping suppresses weed better than sole cropping. It
provides an opportunity to utilize crops themselves as tools for weed
management. In intercropping more complete crop coverage and high population
density cause some competition to weed and thus reduce the weed growth.
Compatible crop mixture which reduces weed competition viz a viz increases
total yield should be selected. Result of a large number of experiment have
indicated that short duration pulse like green grain, cowpea, soya beans as
intercrop effectively smothers weeds. Intercropping short season crops e.g.
maize and melon with large season crops like yam and cassava prevents weed from
adapting to the growth cycle of either crops. Low growing crops like melon,
sweet potato with maize, cassava, yam ass intercrops suppresses weed growth in
Nigeria (Akobundo, 1987).
For farmers who don’t have much land, it reduces farmers
risk because if one crop fails, other crop may continue to grow. Mixed
intercropping is common when cereals, grain legumes, and root crops are grown
together and when little or no tillage is practiced (Akinola and Agboola et’al
2007). Farmers in southern Nigeria plant two or more crops simultaneously in
association and on the same piece of land. The most dominant crop mixture is:
Yam + melon + maize + vegetable,
Cassava + melon
Maize + melon + cassava
Yam + melon intercrops.
However, intercropping root crop like yam (Dioscorea spp)
with egusi-melon (Colocynthis citrillus) is a common practice by farmers, as
egusi-melon serves as a weed suppressant in the first 6 weeks of yam growth
(Ogungbaigbe, et’al 1996).
1.1 YAM (Dioscorea spp)
Yam is an annual or perennial climbing plant with
underground tubers. Nigeria is by far the world largest producer of yams,
accounting for over 70-75 % of the world production (FAO, 2004). More than 95 %
of the world’s yams are currently grown in sub – Sahara Africa, with the
reminder grown in the West Indies and parts of Asia and South and Central
Yam, a tropical crop in the genus Dioscorea has as many as
600 species out of which 6 are economically important staple species. These
are: Dioscorea rotundata (white yam), Dioscorea cayensis (yellow yam),
Dioscorea alata (water yam), Dioscorea bubifera (aerial yam), Dioscorea
dumetorum (trifoliate yam), and Dioscorea esculanta (Chinese yam).out of these,
D. rotundata, D. cayensis and D. alata are the most common species in Nigeria
(Onwueme, 1978). Yam is in the class of roots and tuber, it is a staple of the
Nigerian and West African diet, which provide some 200 calories of energy per
capital daily. Yam have a cultural and traditional significance among many
communities in Nigeria, this is exemplified by the occurrence of rituals to
mark their harvest
Mono cropping is increasing in certain area of West Africa
and Caribbean. However, in producing area of Nigeria, mixed cropping with yam
and egusi melon with maize or yam with egusi melon is prevalent (Kurt, 1984).
1.2 EGUSI-MELON (Colocynthis citrillus)
Egusi-melon is a vegetable crop commonly cultivated in West
Africa (Vander-Vossen, et’al 2004). Because of its creeping nature and ability
to use its leaves to provide cover on the soil, farmers use it as weed
suppressant in mixed cropping (Achigan-Dako, 2008). Production of the crop is
more popular in the northern parts of Nigeria where there is abundance of
cultivable land which has made the practice of sole and mixed cropping
possible. This is unlike the eastern part of Nigeria, where the sandy area of
where scarcity of farm land has force majority of the farmers to raise the crop
in mixed crop farms. Despite the socio-ecological important of egusi-melon,
production output has been on the decline (Ugwumba, 2010).
Egusi-melon is grown for its seed, which is used in
preparing assorted foods, especially soup and stew. The seed is rich in oil and
protein and contains good quantities of most of the essential amino acids.
In traditional system of farming, egusi-melon is usually
planted as lich much and smothering crops in midst of other crops. The benefit
of intercropping yam with egusi-melon could possibly be harnessed by adjusting
the planting sequence of yam minisetts (Ikeorgu, 1991).
The importance of egusi-melon in conserving soil moisture
and reducing optimal soil temperature early in the growing season, earlier
reported by Ikeorgu (1991), suggest the crops suitability for intercropping
1.3 OBJECTIVE OF THE STUDY
The objectives were to determine:
the effect of NPK fertilizer on the growth and yield of yam
and egusi melon in sole and in intercrop
yield advantage, if any due to intercropping 0f both crops.