Soil physical and chemical properties of cacao farms in the south western region of cameroon

Authors: NKENGAFAC, NJUKENG - Institute Of Agricultural Research For Development (IRAD); Baligar, Virupax

Submitted to: International Journal of Plant and Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2016
Publication Date: 6/24/2016
Citation: Nkengafac, N., Baligar, V.C. 2016. Soil physical and chemical properties of cacao farms in the south western region of cameroon. International Journal of Plant and Soil Science. 16:1-10.

Interpretive Summary: Cacao (Theobroma cacao L) is a major cash crop for Cameroon, contributing substantially to the national economy in terms of employment and foreign exchange earnings. Cameroon is the fifth largest producer of cacao in the world and low soil fertility under cacao is one of the major causes for the poor cacao yields. A better understanding of soil fertility will assist improved nutrient management for higher cacao yields. This research reports the important soil physical (texture) and chemical [pH, N, C content, exchangeable bases (K, Ca, Mg), and the exchangeable properties (Al, CEC and % BS)] of major cacao growing soils from the South Western Region of Cameroon. The soils evaluated generally contained adequate amounts of required nutrients but could become easily deficient in N, K, and P nutrient contents, since there are no current fertilizer applications being practiced. Further increases in yields might deplete these essential nutrients and such a situation could lead to soil infertility in this region. Such information will be useful to cacao farmers, extension workers and decision makers to formulate and follow best nutrient management strategies and maintain adequate soil nutrient status for sustainable cacao bean production in this important cacao growing region.

Technical Abstract: The low macro nutrient content (K, Ca and Mg) in soils under cacao is one of the major causes of the poor cacao (Theobroma cacao L) yields. Efforts were made to assess the major physical and chemical properties of soils from some important cacao zones of the South West Region of Cameroon in order to develop proper nutrient management strategies for optimum cacao bean yields. The soils of the studied sites were slightly acidic, with pH range of 4.6 - 6.2. The soils were clayey in texture, ranging in clay content from 19.8 % to 76.6 % and sand content from 4.3 % to 64.4%. The total nitrogen levels for all the studied sites ranged between 0.11 and 0.82% with an average of 0.30% and 0.65 % being very close to the critical levels. This indicates need for N fertilization. Soil organic carbon levels were quite good for crop production (1.02 – 7.75 %). The exchangeable potassium and magnesium levels ranged between 0.11 – 0.67 cmol/kg and 0.31 – 2.41cmol/kg respectively. The exchangeable calcium levels in these soils ranged from 1.11 – 18.00 cmol/kg while available phosphorus levels ranged between 0.25-26.00.mg/kg. The soils evaluated were generally adequate in required nutrients but could become deficient in nutrient content in the near future especially as there is no fertilizer application being practiced and further increase in yields might deplete the essential nutrients and such a situation could lead to soil infertility in this region. Therefore it is essential to formulate and follow best nutrient management strategies for this cacao growing region to maintain adequate soil nutrient status for sustainable cacao bean production.