FORMULATION, CHARACTERIZATION AND APPLICATION OF SOIL-LIGNOCELLULOSIC COMPOSITE

Abstract

Soil faces many threats of degradation and over exploitation throughout the world. Ten of the nineteen states in Northern Nigeria and the Federal Capital Territory (FCT) are already affected by desertification. One of the challenges facing us as a nation is the need to increase food production so as to ensure food security and reduce dependence on imported food, and to also check desert encroachment in the northern part of the country. Soil conditioners, also called soil amendment, are materials added to soil to improve soil fertility / plant growth. Soil conditioners modify the properties of soils, thereby making water and plant nutrients more readily available to plant growth. The need to reduce the cost of food production and ensure the survival of higher percentage of trees planted in desert prone areas necessitated the search for more efficient soil conditioner. Soil samples collected from Guma-Benue (BG), Zaria-Kaduna (KZ), Akure-Ondo (OA), Bakura-Zamfara (ZB) and Zurmi-Zamfara (ZZ) were analyzed for physico-chemical properties essential for plant growth. Lignocellulosic materials: Chromolaena odorata (Siam weed, leaf (A) and stem (F)); Tithonia diversifolia (Sunflower, leaf (B) and stem (G)); Oryza sativa (Rice, husk (C)); and Arachis hypogaea (Ground nut, shell (D)) were collected, physically modified (dried and pulverized) and characterised. The samples were chemically modified by treatment with 300 gdm-3 of NaOH in isopropanol at 24 0C for 2 hours. The solution was then treated with monochloroacetic acid in isopropanol at 50 0C for 3 hours. Study of the surface morphology of chemically modified lignocellulosic materials was carried out using scanning electron microscope (SEM). Results indicated surface roughening and scissions compared to smoother surface of the physically modified lignocellulosic materials. FT-Infrared spectra of the chemically modified lignocellulosic materials showed a general shift of the ester carbonyl bands to lower frequencies in the chemically modified lignocellulosic materials compared to the physically modified carboxylic acid carbonyl bands. The effects of modified lignocellulosic materials from agricultural wastes and weeds on plant growth were studied. Soil-lignocellulosic composites formulated by treating soil samples BG, KZ, OA, ZB and ZZ with 0.25, 0.50, 0.75, 1.00, 1.25 and 1.50 % of both the physically modified (A, B, C, D, F and G) and chemically modified (AM, BM, CM, DM, FM and GM) affected plant growth in varying degrees compared to the untreated soil samples (control). Soil-lignocellulosic composites formulated with physically modified C. odorata leaf (A) with soil samples BG significantly increased plant biomass yield at 0.50 % (5.77 g), 0.75% (6.72 g) and 1.25% (7.76 g) treatments respectively over the control (4.74 g). KZ yield ranged from 0.47 to 5.26 g which were higher than the control (0.26 g). OA yields ranged from 5.20 to 9.52g in which all were higher than the control (4.51 g). ZB yield ranged from 0.57g to 2.76 g, showed all were higher than control (0.21 g). ZZ yield ranged from 0.44g to 4.53 g in which all were higher than control (0.17 g). The highest biomass yields of 7.76, 5.26, 9.21, 2.76 and 4.53 g, obtained from BGA1.25, KZA1.50, OAA1.00, ZBA0.75 and ZZA1.00 respectively, were the highest obtained for the respective soil sample investigated. For the chemically modified C. odorata leaf (AM), plant biomass yield significantly increased at OAAM0.25 (5.25g), OAAM1.00 (5.54g) compared to OACL (4.54 g); KZDM0.75 (1.42g), KZDM1.00 (1.59g) compared to KZCL (0.26g); ZBDM1.00 (0.93g) compared to ZBCL (0.21g); ZZDM0.75 (0.85g) compared to ZZCL (0.17g); BGFM0.25 (5.36g) compared to BGCL (4.74g). The significant increases, observed in growth parameters (shoot length, leaf number, root length and biomass) at some specific percentage treatment of soil samples with modified (physical and chemical) lignocellulosic materials were clear indications that physically and chemically modified lignocellulosic materials can serve as potential treatment methods to increase the rate of release of water and nutrient in the soils for plant growth and increased crop yield.