**7. Application of fertilizers**

**Pruning height of Pigeon pea**

Source: Agyare et al, 2002

in the northern Savanna zone of Ghana.

fallow for the mixed farmer.

the better the tree for agro-forestry system.

**6.5. Agroforestry**

same units.

to the higher quantity of litter fall from the pigeon pea.

**Dry Matter (litter)**

Pigeon pea (no pruning) 2.13 4.27 3.32 1.16 1.11

Pigeon pea (30 cm) 0.37 0.73 3.42 0.69 0.06

Pigeon pea (60 cm) 0.87 1.77 2.80 0.93 0.36

Pigeon pea (90 cm) 1.67 1.97 2.53 0.93 0.62

**Table 5.** Effect of pruning on leaf litter production, grain yield of pigeon pea and maize yield after two years of fallow

It was found that maize yield after two years of pigeon pea fallow was highest in 1998 at 30 cm pruning height which was followed by the pigeon pea not pruned at all in the trial. But maize yields from plots with pigeon pea pruned at 60 and 90 cm heights were similar in val‐ ue but significantly lower than the yield obtained from the plots with pigeon pea pruned at 30 cm. The high maize yields at no pruning and the pruning at 30 cm height were attributed

It was then concluded that biomass obtained from the pruning of pigeon pea up to 60 cm will be able to provide sufficient fodder that may be used to supplement livestock feeding in the dry season (Agyare et. al., 2002). This situation would not be sacrificing much in terms of soil fertility status, pigeon pea grain yield and yield of subsequent maize crop. This option makes pigeon pea a valuable leguminous shrub for short season

Agroforestry involves the integration of trees/shrubs and sometimes animal husbandry in the farming system. It combines annual crops with herbaceous perennials or trees on the

Both exotic and local tree species were screened for Agro-forestry purposes in SARI as from 1985 (Table 6). The results showed that *Gliricidia* and *Leucaena* which are both exotic tree spe‐ cies are better trees for soil fertility restoration than the local tree species like *Parkia.* Both the *Leucaena* and *Gliricidia* produced enough biomass much earlier for incorporation than the rest of the tree species, It was also found that the incorporation of pruned biomass from the tree species was responsible for the increase in soil nitrogen. This therefore suggest that the faster the growth and development of the tree species to produce biomass for incorporation,

**Grain yield of maize**

1997 1998 1998 1999 1998

**Seed yield of pigeon pea**

**(tons/ha)**

**Tons/ha**

**tons/ha**

**(Fallow )**

14 Soil Fertility

The most common of the materials used as soil fertility enhancing substances however, are the organic and in- organic fertilizers. The recommended rates of in-organic fertilizers for the production of cereals especially maize in Ghana are the basal application of compound fertilizer made up of 15 % each of Nitrogen, Phosphorus and Potassium (NPK) at planting or two weeks after planting of 2 fifty kilograms (50 kg) bags per acre. This is followed by the application of either sulphate of Ammonia or urea at 1 fifty kilogram bag (50kg bag) or twenty-five kilogram bag (25 kg bag) per acre respectively just before the tasseling of maize. However, the acquisition of these materials whether the organic or in-organic fertilizers by farmers have also been faced with a lot of challenges.

In the first place, most of the small scale farmers are poor and cannot afford the recommend‐ ed rates of the in-organic fertilizers to increase their crop yields. Most often, they just pur‐ chase the quantities that they can afford which are far below the recommended rates for the crops and therefore those quantities are unable to increase their yields. As a result, their crop yields still remain low and that explains why they remain poor.

Secondly, even though almost every farm family in northern Ghana possesses few livestock such as cattle, sheep, goats and or poultry, the dung (manure) they produce is highly inade‐ quate to fertilize an area of one acre. Most of these categories of livestock are also on free range thereby making the gathering of their dung very difficult. In addition, some of the farms are very far from their homes so carting these bulky materials to their farmlands pos‐ ses another challenge.

The above situation where farmers cannot afford recommended rates of in-organic fertiliz‐ ers because they are poor and they also do not have enough animal dung to fertilize their crops call for the combination of both.


The results showed that in some of the communities, the yields of maize under the animal manure and the household refuse were similar suggesting that both materials could contain similar quantity of nutrients. The use of these as soil fertility enhancing materials will not only increase crop yields but will also help to improve the sanitation status of these com‐

Enhancing Soil Fertility for Cereal Crop Production Through Biological Practices and the Integration of Organic...

**8. Effect of some soil fertility enhancing interventions on soil nutrients**

Table 9 shows the nutrient (NPK) values before and after some soil fertility enhancing inter‐ ventions initiated by scientists within the Savanna zone of Ghana. The initial values of N in particular show that the highest was 0.049% and the lowest was 0.022% within this zone. These values are percent total nitrogen and not available N which means that not all these will even be available to the plant. The low N content of these soils therefore explains why yields of cereal crops are very low and in some cases no yield is obtained if no soil fertility enhancing material is applied to the soil. Results from omission trials carried out in Nyank‐ pala for three consecutive years (2002-2005) showed that among the three major plant nu‐

> Initial Soil P

0.024 0.043 15.59 11.96 49.90 45.65

0.028 0.095 14.89 19.25 46.36 52.85

0.049 0.062 13.60 23.90 39.58 42.62

0.022 0.085 14.83 20.08 45.60 48.45

0.028 0.092 16.58 22.65 40.01 44.82

0.026 0.088 18.65 20.80 42.60 46.25

**Table 9.** Effect of different soil fertility enhancing interventions on soil NPK values within the Savanna zone of Ghana

With a minimum of two years of the various interventions however, there were increases in the nutrient (NPK) values which is indicative of the positive influence of these interventions on these elements in the soil. In most of the studies, the N values after the interventions

**N% P (ppm) K (ppm)**

**P After intervention** Initial Soil K

**K After intervention**

http://dx.doi.org/10.5772/53414

17

trients, nitrogen was the most limiting element for maize production (SARI, 2005)

**N After intervention**

munities since all these heaps would be carted to the farms.

**(NPK)**

**Type/period of intervention**

maize (6WAP)

fallow

hold refuse

(1 year)

The application of manure (cow dung)

Effect of pigeon pea pruned at 30cm

2 years of *callpogonium*.

The application of house

Improved fallow *Mucuna*

Intercropping *Mucuna* in

Initial soil N

**Table 7.** Effect of tillage and fertilizer on maize grain yields at Bunkpurugu, walewale and Karaga

Studies have been conducted on the effect of tillage and fertilizers on the yield of maize for three consecutive years in three communities of the northern part of Ghana by the Savanna Agricultural Research Institute (SARI). Results confirmed that the application of the combi‐ nation of half the rates of the organic and recommended in-organic fertilizers was as good as the application of the recommended in-organic fertilizers (Table 7) This suggests that, farm‐ ers with limited number of livestock or poultry can always supplement the manure they generate from these animals with half the rates of the recommended in-organic fertilizers to obtain high crop yields. The results however showed that there was no significant difference in yield of maize between the bullock and manual tillage systems indicating that any of the tillage systems will give similar maize yields.

Similarly, it has been found that the household waste generated and deposited outside the houses for several years are as rich in nutrients as the animal manure. Kombiok et al 1995 compared the yields of maize fertilized by animal dung and household waste in four com‐ munities of the East Mamprusi District of the Northern Region (Table.8).


**Table 8.** Effect of refuse and animal dung on the yield of maize at 4 sites in West Mamprusi District

The results showed that in some of the communities, the yields of maize under the animal manure and the household refuse were similar suggesting that both materials could contain similar quantity of nutrients. The use of these as soil fertility enhancing materials will not only increase crop yields but will also help to improve the sanitation status of these com‐ munities since all these heaps would be carted to the farms.

**Maize grain yields ( tons/ha)**

**Tillage** Bullock Manual **LSD** (0.05) **Fertilizers**

16 Soil Fertility

NPK

**LSD** (0.05)

Manure (6t/ha)

1/2 rates (manure &NPK) FP (No NPK/No manure)

Source: Kombiok et al 1995

Source: CSIR-SARI 2007 Annual report

tillage systems will give similar maize yields.

**Treatments Bunkpurugu Walewale Karaga**

**Table 7.** Effect of tillage and fertilizer on maize grain yields at Bunkpurugu, walewale and Karaga

munities of the East Mamprusi District of the Northern Region (Table.8).

Yaroyili 3.2 3.4 0.60 Bowku 2.7 2.8 1.33 Boayini 2.4 3.2 1.06 Tangbini 2.3 1.3 1.00 Average 2.65 2.68 0.99

**Table 8.** Effect of refuse and animal dung on the yield of maize at 4 sites in West Mamprusi District

**Community Yield ton/ha**

0.98 1.06 **0.29**

1.12 0.70 1.00 0.54 **0.27**

Studies have been conducted on the effect of tillage and fertilizers on the yield of maize for three consecutive years in three communities of the northern part of Ghana by the Savanna Agricultural Research Institute (SARI). Results confirmed that the application of the combi‐ nation of half the rates of the organic and recommended in-organic fertilizers was as good as the application of the recommended in-organic fertilizers (Table 7) This suggests that, farm‐ ers with limited number of livestock or poultry can always supplement the manure they generate from these animals with half the rates of the recommended in-organic fertilizers to obtain high crop yields. The results however showed that there was no significant difference in yield of maize between the bullock and manual tillage systems indicating that any of the

Similarly, it has been found that the household waste generated and deposited outside the houses for several years are as rich in nutrients as the animal manure. Kombiok et al 1995 compared the yields of maize fertilized by animal dung and household waste in four com‐

**R D(refused dump) A M (Animal dung) No fertilizers**

1.21 0.85 **0.58**

1.46 0.99 1.09 0.60 **0.31**

0.41 0.08 **0.38**

0.30 0.16 0.37 0.24 **0.33**
