Assessing the Effects of Fertilizer Applied to Soils with Different Soil Organic Carbon on Sorghum Varieties Yields

Abstract

Objective: To assess the performance of the newly registered varieties, TARISO-R1, TARISO-R2, and Macia (control variety) grown under unfertilized and fertilized soils differing in organic carbon (OC) levels on the loamy sand of Igunga and sandy soils of Tumbi, Tabora, and Tanzania. Methods: The experiment was laid out in a randomized split-split-plot design with treatments in sites (main-plot), varieties (sub-plot), and fertilizer (sub-sub plot) and was replicated three times for two cropping seasons. There were two sites, three varieties, and two rates of fertilizers, unfertilized and 10g plant-1 of Yaramila cereal fertilizer in two splits. Results: The two sites performance of TARISO-R2 was superior than Macia and TARISO-R1 varieties. Despite the low yields under unfertilized treatments, TARISO-R2 produced a significantly 1000 seed weight ranging from 20.47 to 21.83g, and under fertilized treatments, TARISO-R2 produced significantly 1000 seed weight ranging from 27.17 to 27.20g for both cropping seasons versus Macia and TARISO-R1. The Igunga site with 0.35% of OC produced significantly (P≤0.001) [F=40.57; 23.50, df 2] higher seed weight yields for TARISO-R2 ranging from 25.84 to 26.52g for both cropping seasons, while Tumbi site with 0.16% of OC produced seed weight yield at a lower rate with 21.80 to 22.51g. Conclusion: Organic carbon (OC), a key soil health indicator, contributed an increase of seed weight by 15.15 to 17.85% for TARISO-R2 variety than TARISO-R1 and Macia. The study recommends that sorghum stalks be incorporated in soils to build up soil organic matter (SOM) and recommends TARISO-R2 variety for use in both unfertilized and fertilized conditions due to its economic yield.