Effects of mineral levels and leaf extracts of some plants on soil pH and growth rate of selected non-leguminous plants

Abstract

Abstract. Njogu MJ, Murungi JI, Wanjau RN. 2021. Effects of mineral levels and leaf extracts of some plants on soil pH and growth rate of selected non-leguminous plants. Cell Biol Dev 5: 76-89. The purpose of this study was to determine the effect of growth rate on non-leguminous plants such as wheat (Triticum aestivum L.), kale (Brassica oleracea var acephala), and coriander (Coriandrum sativum L.) grown on acidic soils treated with leaves and leaf extracts of plants known to have a high buffering capacity and mineralization capacity, i.e., Jacaranda mimosifolia D. Don, Cordia africana Lam, Croton macrostachyus Hochst. ex Delile, Vitex keniensis Turril, Tithonia diversifolia (Hemsl.) A.Gray, Manihot esculenta Crantz, Carica papaya L., and Helianthus annuus L. For this investigation, the leaves and leaf extracts were applied to the soil with a pH of 4.75. Leaf extracts and leaves of eight species were combined according to the macronutrient content and mineralization of chosen plants discovered in Nyandarua County, Kenya. Wheat, kale, and coriander growth rates were determined by comparing the dry mass of uprooted seedlings from the trial and control studies every fourteen days for 60 days. Flame photometry, atomic absorption spectrometry (AAS), UV/visible spectroscopy, and turbidimetry were used to determine macronutrients in leaf extracts. The analysis of variance (ANOVA) and Student-Newman-Keuls (SNK) tests were used to analyze the data. For 60 days, the mean pH value of leaf extracts ranged from 4.580.27a to 7.440.04d. K+; 189.95±0.17c, Ca2+; 367.33±0.67e, Mg2+; 114.33e±0.33, PO43-; 55.38±0.23f, NO3-; 322.25±0.40f, and SO42-; 56.48±0.23e had the greatest mean levels in leaves (?g/g). Macronutrient levels were significantly different in soil treated with leaves and leaf extract (Le), commercial NPK fertilizers (Cf), and untreated soil (Us). Wheat (dry mass) grew at a mean rate of 1.27±0.13b g/wk (Le), 1.26±0.12b g/wk (Cf) and 0.32±0.02a g/wk (Us), while in (height) was 7.29±1.43b cm/wk (Le), 6.20±1.95b cm/wk (Cf), 3.98±0.97a cm/wk (Us). For kales 0.20±0.01a g/wk (Le), 0.30±0.02a g/wk (Cf), and 0.03±0.01b g/k (Us), while in (height) 2.15±0.85c cm/wk (Le), 2.57±0.88b cm/wk (Cf), and 1.04±0.02a cm/wk (Us). The mean growth rate for corianders was 0.16±0.01a g/wk (Le), 0.17±0.02a g/wk (Cf), and 0.10±0.01a g/k (Us), while in (height) 1.85±0.56b cm/wk (Le), 1.86±0.58b cm/wk (Cf) and 0.79±0.18a cm/wk (Us). This study's findings show that the plant's leaves and leaf extracts can be used in place of inorganic fertilizers and should be recommended for agroforestry in low-pH environments.