International Journal of Plant & Soil Science <p style="text-align: justify;"><strong>International Journal of Plant &amp; Soil Science (ISSN: 2320-7035)</strong>&nbsp;aims to publish high quality papers (<a href="/index.php/IJPSS/general-guideline-for-authors">Click here for Types of paper</a>) in all areas of ‘Plant &amp; Soil Science research’. The journal also encourages the submission of useful reports of negative results. This is a quality controlled, OPEN peer reviewed, open access INTERNATIONAL journal.</p> SCIENCEDOMAIN international en-US International Journal of Plant & Soil Science 2320-7035 Soil Organic Carbon and Acid Phosphatase Enzyme Activity Response to Phosphate Rock and Organic Inputs in Acidic Soils of Central Highlands of Kenya in Maize <p><strong>Aims:</strong> To evaluate the effects of phosphate rock and organic inputs on soil organic carbon and acid phosphatase activity.</p> <p><strong>Study Design:</strong> The experiment was laid in Randomized Complete Block Design with seven treatments replicated thrice.</p> <p><strong>Place and Duration of Study: </strong>The study was conducted at Kigogo Primary school in Meru South Sub-county, Tharaka Nithi County, Kenya. The experiment ran for two consecutive seasons the short rains of 2017 (October to December) and long rains of 2018 (March through June).</p> <p><strong>Methodology:</strong> There were seven treatments replicated thrice. The treatments included <em>Tithonia diversifolia</em>, Phosphate rock (PR), Goat manure, <em>Tithonia diversifolia</em> + Phosphate rock, Goat manure + Phosphate rock, Triple superphosphate + Calcium ammonium nitrate and a Control (no soil external inputs). The test crop was maize (<em>Zea mays </em>L.) H516 variety. Soil organic carbon followed modified Walkley and Black oxidation method while acid phosphatase enzyme activity was essayed following the method by Tabatabai and Bremner.</p> <p><strong>Results:</strong> Goat manure + phosphate rock, sole phosphate rock and use of goat manure significantly (<em>P</em>= .0001) increased soil organic carbon by 198, 100 and 71% compared to the control. <em>Tithonia diversifolia</em> reported a 3.4-fold increase in soil organic carbon compared to the control in short rains of 2017. Goat manure gave higher soil organic carbon by 135% compared to the control in the long rains of 2018. Goat manure + phosphate rock treatment significantly (<em>P</em>= .0002) increased the phosphatase activity by a difference of 1.12% compared with the control, with 2.14% decreases under TSP+CAN treatment compared to the control.</p> <p><strong>Conclusion:</strong> The results showed that integration of phosphate rock and manure could have a far-reaching influence on soil organic carbon and acid phosphatase activity thus could be recommended for improved soil productivity in <em>humic nitisols</em> in similar agro-ecological zones.</p> J. A. Omenda K. F. Ngetich M. N. Kiboi M. W. Mucheru-Muna D. N. Mugendi ##submission.copyrightStatement## 2019-10-04 2019-10-04 1 13 10.9734/ijpss/2019/v30i230169 Residual Effect of Different Sources of Nutrients on Available NPK in Soil after Harvest of Maize in Rice Fallow Maize Cropping System <p>A field experiment was conducted for two consecutive years (2011-2012 and 2012-2013) on fine texture soils of Agricultural college farm, Bapatla. The experiment was laid out in a randomized block design in <em>kharif</em> season with four treatments. The treatments consisted of M<sub>1</sub> (RDF (Recommended dose of fertilizers) - Control), M<sub>2</sub> (10t FYM (Farm Yard Manure) ha<sup>-1</sup> + RDF), M<sub>3</sub> (1.5t vermicompost ha<sup>-1</sup> + RDF), M<sub>4</sub> (Green manuring + RDF). During the immediate <em>rabi,</em> the experiment was laid out in a split-plot design without disturbing the soil for succeeding maize with the four treatments given to <em>kharif</em> rice as main plot treatments and each of these divided into five sub-plots to receive five levels of fertilizer NPK application <em>viz.</em>, N<sub>1</sub> - 75% NPK, N<sub>2</sub> - 100% NPK, N<sub>3</sub> - 125% NPK, N<sub>4</sub> - 150% NPK and N<sub>5</sub> - 175% NPK for succeeding maize.</p> <p>Data collected on available NPK after harvest of maize crop were significantly increased with the application of 100% NPK in combination with FYM @10t ha<sup>-1</sup> to preceding rice crop, irrespective of the NPK levels applied to succeeding maize crop. However, it was on par with that of green manuring together with 100% NPK during both the years of the study.</p> Mohana Rao Puli P. R. K. Prasad P. Ravindra Babu K. L. Narasimha Rao G. Subbaiah ##submission.copyrightStatement## 2019-10-14 2019-10-14 1 11 10.9734/ijpss/2019/v30i230170