Effect of long-term integrated soil fertility management by | 15769
International Research Journals

Effect of long-term integrated soil fertility management by local farmers on nutrient status of a Typic Dystrandept under potato-based cropping system


Tabi1 FO, Bitondo D, Yinda GS, Kengmegne SSA and Ngoucheme M

Farmers in the western highlands of Cameroon use poultry and other animal manures with mineral fertilizers to increase crop yield. However, the effect of their practices on soil quality is not known. This study was designed to: identify the main cropping system; evaluate soil nutrient status; investigate relationships between nutrients and assess the suitability of farmers’ practices on soil quality. Cropping system survey was carried out using structured questionnaires and interviews. Baseline soil information was obtained from a representative Typic Dystrandept profile. An intensively cropped area (3 ha), was sampled at 0-25 cm soil depth and analyzed for soil chemical properties. Nutrient contents were compared with critical levels to declare sufficiency or deficiency. Suitability of farmers’ practices was assessed by comparing soil properties with those of the reference profile using Student’s T-test. Correlation analysis was performed among soil properties. The dominant cropping system was potatobased. pHw varied from 5.03 to 6.28 with a mean of 5.8; while organic carbon (OC), total nitrogen (N) and C/N ratio ranged from 5.0 to 8.13 %, 0.24 to 0.83 % and 7.29 to 31.92, with means of 6.73 %, 0.6 % and 12.55 respectively. Available P varied from 7.5 to 37.3 mg/kg; while Ca, Mg, K and CEC varied from 4.24 to7.84, 0.4 to 5.5, 0.3 to 0.7 and 26.7 to 36.0 cmol/kg; with means of 6.4, 2.2, 0.4 and 33.0 cmol+/kg respectively. All the nutrients were in medium concentrations and the soils were acidifying. ΔpH was less negative under current farmers’ practices. Apart from exchangeable Ca and CEC which decreased (p<0.05) and pHKCl and total N which increased (p<0.01 and p<0.05 respectively) significantly, no significant changes relative to the baseline were observed with other soil properties. Mg2+ was the most dominant cation. For an ideal cationic balance, 2.76 cmol+/kg Ca and 0.29 cmol/kg K are required under farmers’ practices. Available P and Ca were positively and significantly correlated (r=0.72**), while K was significantly and negatively correlated (r=0.50*) with Ca. Although poultry manure is a major source of Ca, the required quantity to combine with mineral fertilizers on a Typic Dystrandept is not known. We recommend that for high yields to be obtained and production sustained, farmers’ practice of ISFM should be encouraged and supported with recommendations of mineral fertilizers and animal manures from on-farm experiments and the use of ammonium sulphate, prohibited.

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