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

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


**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 were significantly (p< 0.05) higher than the initial N values but for P and K, there were no significant differences between the initial and after two years of intervention. The significant increases of percent N in the soil as a result of the various interventions also show how lim‐ ited nitrogen is in the savanna soils.

the Ministry of Food Agriculture in different parts of the country. Some of these practices are either new to the farmers such as conservation Agriculture, Agro-forestry and Alley cropping or they are the improved versions of farmers' practices such as crop rotation (alter‐ nating cereal and legumes), intercropping cereal and legumes, root crops with cereals and legumes, cover cropping. Despite the benefits demonstrated to farmers from the use of these technologies, adoption rate is very low. Some of the challenges militating against the adop‐

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

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

19

Most of the farmers in Ghana do not own the land they farm on and they are therefore described as settler or migrant farmers if they come from other parts of the country and settle at that particular place. The amount of money to invest on such rented lands by these farmers will therefore depend on the length of time the land is rented for farming. A farmer with one year rent period will not be willing to invest so much on that land for farming compared to a farmer who is renting the land for over ten years. Secondly, the land owners may not even allow farmers to introduce long term investments on such short term rented lands. It will therefore be difficult for such farmers to adopt soil fertili‐ ty enhancing techniques such as Agro-forestry system or even the cultivation of tree crops since this will take a long time to yield benefits to the farmer. However, It was found that the system of land tenure in the forest or the transitional zones where the farmers are allowed to use a plot for several years for farming may not have difficulties in adopting no-till as part of soil fertility management practices. This, according to Ek‐ boir et al. (2002) if these farmers are allowed to use such lands for several years it will enable them to recoup the profits of their investments. Also, data collected on the farm‐ ers adopting any particular tillage system showed that farmers using their own lands adopted CA practices more easily than farmers on rented lands (Adjei et al. 2003).

Farmers in the forest and transition zones where share cropping arrangements exist between the settler or migrant farmer and land owners, they are encouraged to practice CA and other related practices because increase in the productivity of their crops will lead to an increase in their share of the harvest. Unlike in the north, lands are almost given out free to settler farmers and can also be seized back at anytime by land owners without any notice as there is no agreement signed between the farmers and their land owners. There are certain times land owners even seize back their lands when they find increases in crop yields of the settler farmers. In such situations, farmers in the northern Savanna zone will definitely be discour‐ aged from adopting any of these soil fertility improving practices since the land owners do not benefit from such increases and there is also no agreement signed between them to pro‐

One of the three pillars CA is hinged on is the provision of adequate soil cover and it is one of the several ways of enhancing soil nitrogen. Unfortunately, it is very difficult to provide soil cover in the northern Savanna zone of Ghana because of rampant bush fires during the

tion of these practices by farmers include:

tect the farmers from their lands being seized back.

**10.2. Difficulties in maintaining soil cover**

**10.1. Ownership of land**
