Performance and Dry Matter Accumulation of Groundnut in an Ultisol Amended with Phosphorus and Lime.

&lt;b&gt;Background and Objective:&lt;/b&gt; Adequate yield improvement in groundnut may not be achieved in acid sand Ultisol through the application of mineral phosphorus alone, however, a combined application of lime and phosphorus fertilizer may be a better management option in such soils. Hence, this study evaluated the effects of four levels of lime (0, 2.0, 4.0 and 8.0 t ha&lt;sup&gt;1&lt;/sup&gt;) and four phosphorus (P) levels (0, 25, 50 and 75 kg ha&lt;sup&gt;1&lt;/sup&gt;) on the performance of groundnut (&lt;i&gt;Arachis hypogaea &lt;/i&gt;L.) in the humid rainforest of South Eastern Nigeria. &lt;b&gt;Materials and Methods:&lt;/b&gt; The study was a factorial experiment laid out in a Randomized Complete Block Design (RCBD) and consisted of sixteen treatment combinations replicated three times each. &lt;b&gt;Results:&lt;/b&gt; The result obtained showed that the application of phosphorus fertilizer and lime had a significant (p<0.05) effect on plant height, number of leaves per plant, number of branches per plant, 75 kg ha&lt;sup&gt;1&lt;/sup&gt; P and 8.0 t ha&lt;sup&gt;1&lt;/sup&gt; lime resulted in the highest growth parameter. Similarly, 75 kg ha&lt;sup&gt;1&lt;/sup&gt; P and 8.0 t ha&lt;sup&gt;1&lt;/sup&gt; lime significantly improved the number of pods per plant 30.67, pod yield 3.58 t ha&lt;sup&gt;1&lt;/sup&gt;, biomass yield of 4.68 t ha&lt;sup&gt;1&lt;/sup&gt;, seed yield of 2.1 t ha&lt;sup&gt;1&lt;/sup&gt; and 100 seed weight of 44.58 g, seed yield of groundnut while curtailing the number of unfilled pods 2.33. &lt;b&gt;Conclusion:&lt;/b&gt; Application of phosphorus and lime at 75 kg ha&lt;sup&gt;1&lt;/sup&gt; P and 8.0 t ha&lt;sup&gt;1&lt;/sup&gt; lime is a beneficial agronomic practice that could enhance the productivity of groundnut in the Calabar rainforest zone of Cross River State.