This research investigated the effect of mature compost from cassava pulp and swine manure on soil chemical characteristics and growing greenhouse plants i.e., morning glory, Chinese cabbage and Chinese kale. Mature compost with an initial C/N ratio of 30/1 seeded with microbial activator p.d.1 was used in this study. Results revealed that compost in both ground and pelletized forms improved soil quality as indicated by significant increases in TOC content and macronutrients (NO- 3-N, available P, and K2O) in soil added with compost compared to control (no compost applied). Plants could use compost in ground form better than pelletized form in which ground compost added at 15.63 ton/ha was the most suitable in growing morning glory, Chinese cabbage, and Chinese kale as indicated by the highest shoot dry weight (1.63, 2.16, and 1.33 g/plant, respectively), and plant circumference (0.56, 3.07, and 0.61 cm/plant, respectively) obtained
Journal of Water and Environment Technology, Vol.4, No.1, 2006 - 9 - EFFECT OF CASSAVA PULP AND SWINE MANURE COMPOST ON GROWING PLANTS IN GREENHOUSE Nattipong Kamolmanit*, and Alissara Reungsang** *Department of Biotechnology, Graduate School, Khon Kaen University A.Muang, Khon Kaen 40002 THAILAND E-mail: kamolmanit@yahoo.com **Research Centre for Environmental and Hazardous Substance Management and Department of Biotechnology, Faculty of Technology, Khon Kaen University A.Muang, Khon Kaen 40002 THAILAND E-mail: alissara@kku.ac.th ; Correspondence author ABSTRACT This research investigated the effect of mature compost from cassava pulp and swine manure on soil chemical characteristics and growing greenhouse plants i.e., morning glory, Chinese cabbage and Chinese kale. Mature compost with an initial C/N ratio of 30/1 seeded with microbial activator p.d.1 was used in this study. Results revealed that compost in both ground and pelletized forms improved soil quality as indicated by significant increases in TOC content and macronutrients (NO - 3 -N, available P, and K 2 O) in soil added with compost compared to control (no compost applied). Plants could use compost in ground form better than pelletized form in which ground compost added at 15.63 ton/ha was the most suitable in growing morning glory, Chinese cabbage, and Chinese kale as indicated by the highest shoot dry weight (1.63, 2.16, and 1.33 g/plant, respectively), and plant circumference (0.56, 3.07, and 0.61 cm/plant, respectively) obtained. KEY WORDS : Cassava pulp, C/N ratio, Compost, Swine manure INTRODUCTION Composting is a biological decomposition process, wherein organic matter is decomposed to obtain inorganic nutrients, and stable organic material (compost) in the end. Composting is generally used for the treatment of organic wastes such as sewage sludge and animal manure. It is also used in agro-industrial process to achieve products which can be applied to soil to increase soil organic matter content as well as enhance soil structure and cation exchange capacity (Contreras-Ramos et al, 2004). As mentioned, compost products can increase soil organic matter content. Several studies showed that the application of food waste, sewage sludge and manure compost had positive effects on plant production. The organic matter and other compounds of swine manure were mineralized and immobilized by a group of bacteria, which had the ability to Journal of Water and Environment Technology, Vol.4, No.1, 2006 - 10 - supply nutrients for plant growth and improve the physical properties of the soil (Tiquia and Tam, 1998; Wong et al, 2003; Contreras-Ramos et al., 2004). Problems associated with the application of compost (in ground form) to soil include storage area, transportation, and preservation (Ta-oun et al, 2003). In addition, dust and odor pollution could occur during the application of ground compost (Alberta Environment, 1996; Tiquia and Tam, 2002). Thus, the production of pelletized compost for agricultural use is of interest. Application of pelletized compost in agriculture reduces problems on storage area, transportation, dust and odor (Ta-oun et al, 2003). Ta-oun et al. (2003) demonstrated that the pelletized compost of 3 mm. size could be effectively used for growing morning glory with 97% efficiency compared to ground compost. This research examined the effect of ground and pelletized cassava and swine manure compost on soil properties and plant growth. The objectives of this research were to: 1) investigate the effect of compost forms (ground and pelletized) on soil chemical properties; and 2) investigate the effect of ground and pelletized compost on plant growth and macronutrient accumulation in plants. MATERIALS AND METHOD Raw materials Compost Compost was prepared from the mixture of cassava pulp and swine manure at an initial C/N ratio of 30:1 (dw/dw) seeded with a microbial activator p.d.1. at a p.d.1/composting pile ratio of 10 ml:500 g of compost. Every seven days, the moisture content of mixture was adjusted to 60% by adding water prior to start and during the composting process. Compost pile was manually mixed with a shovel by turning the pile for about 10 minutes to provide aeration. This was done every 3-4 days until the compost piles reached maturity. Table 1 shows the main characteristics of compost. Journal of Water and Environment Technology, Vol.4, No.1, 2006 - 11 - Table 1 Main characteristics of compost. Parameter Compost characteristics Moisture (%) 38.82± 4.30 a‡* Organic carbon (%) 25.05±0.38 a Total Nitrogen (%) 2.11±0.14 bc C/N ratio 11.91±0.99 a pH 7.39±0.57 a Total Phosphorus (%) 2.56±0.29 a Total Potassium (%) 1.97±0.08 a Final Day Temperature (°C) 28.83±1.53 ab Coliform Numbers (Log 10 MPN g -1 )/day at maturity 2.87±0.27 a /42 * Means followed by the same letter within the same row are not significantly different using Duncan’ s multiple range test at 0.05 level of significance. ‡ Mean ± standard deviation. Pelletized compost Ground mature compost was air-dried and sieved through a 2-mm sieve. Twenty percent molasse was used as a binder and mixed with ground compost at a ratio of 1: 2 (Ta-oun et al, 2003). The mixture was then pressed with the mincer and compressing machine to obtain the compost pellet. This machine consists of three main parts including 70x70x70cm mixing chamber, 12x135x50cm conveyor, and compressing mincer number 42 (giving compost pellet sizes at 3-8 mm range) (Ta-oun et al, 2003). Soil Soil used in the Greenhouse experiment was taken from a depth of 0-30 cm from the field of the Department of Land Resources and Environment, Faculty of Agriculture, Khon Kaen University. The particle size analyses of the soil samples were performed by the Department of Land Resources and Environment, Faculty of Agriculture, Khon Kaen University. Plants Morning glory (Ipomoea aquatica Forsk), Chinese cabbage (Brassica chinensis), and Chinese kale (Brassica albogloba Baileu) were used to examine the ability of ground and pelletized mature compost on plant yield and plant growth as well as to determine the optimum amount of mature compost to be added for the nutrient supply of plants. These three plants were chosen due to their short life cycles and that they are commonly used in Thai dishes. Journal of Water and Environment Technology, Vol.4, No.1, 2006 - 12 - Greenhouse study Plant cultivation Seeds of morning glory, Chinese cabbage, or Chinese kale were sowed in nursery pots and transplanted on Day 7. Each pot used was 15 cm deep and had a diameter of 8 inches. The pot was filled with 2 kg (dw) of soil. Five seedlings of morning glory, three seedlings of Chinese cabbage, and three seedlings of Chinese kale were transplanted per pot at a spacing of about 3-inches. Five replicates were made for each pot. The experiment was divided into two sets. The first set had pelletized compost manually mixed with soil in a pot at an application rate of 9.38, 12.5, 15.63, and 18.75 ton/ha. The second set of experiment was prepared in a similar manner but ground mature compost was mixed in each pot. Inorganic fertilizer (15-15-15) at 0.31 ton/ha (Panchaban, 2002) applied to the soil was used as reference. This rate was used according to the agricultural practice in the area. Neither compost nor inorganic fertilizer was added to the control pot. All pots were watered everyday and were placed in random on the greenhouse bench of the Faculty of Agriculture, Khon Kaen University and rearranged every 15 days to prevent the light effect. Morning glory and Chinese cabbage were allowed to grow for a period of 42 days and Chinese kale for 49 days. Every 15 days after cultivation, pots were gathered and determination of the number of leaves, plant height and plant circumference was done until the harvesting date (Day 42 for morning glory and Chinese cabbage or Day 49 for Chinese kale). After harvest, each plant was carefully removed from soil and washed with tap water 2-3 times to remove soil debris. The whole plant from each pot, including stems, shoots, roots and leaves, was measured for its dry weight by oven-drying method at 80° C for 24 h. The dried plant biomass (stems, shoots, roots, and leaves) was ground using a blender, passed through 2 mm sieve and analyzed for macro-nutrient content (total N, total P, and total K). Soil analysis Pots were gathered at Day 0, 15 and day of harvest (Day 42 for morning glory and Chinese cabbage or Day 49 for Chinese kale). After plants were removed, soil from each pot was sieved through a 2 mm sieve. Fifty grams of soil from each pot was used for the analysis of pH, nitrate nitrogen, available phosphorus, water-soluble potassium, and total organic carbon (Table 2). Journal of Water and Environment Technology, Vol.4, No.1, 2006 - 13 - Table 2 Physicochemical and biological parameters used for the analyses of soil samples Parameter Method Sampling date Reference pH pH meter Every 3-4 day Tiquia and Tam (1998) Temperature Thermometer Everyday Tiquia and Tam (1998) Moisture content (%) Oven dry method Every 7 day Page et al (1982) Total organic carbon (%) Walkley and Black method Every 14 day Walkley and Black (1934) Total Nitrogen (%) Micro-kjeldahl method Every 14 day Black (1965) Total Phosphorus (%) Spectrophotometric method Every 14 day Black (1965) Total Potassium (%) Atomic absorption technique method Every 14 day Black (1965) Faecal coliforms Most Probable Number Every 14 day AOAC (2000) Statistical analysis Mean and standard deviation values were reported for all parameters measured. Analysis of variance (ANOVA) and Duncan’ s multiple range test were performed using SPSS v. 11 statistical software for windows. One-way ANOVA was carried out to compare the means of different treatments where significant F-values at p≤ 0.05 were obtained. Differences between individual means were analyzed using the least significant difference test. RESULTS AND DISCUSSION Soil characteristics Soil texture was classified as loamy sand in Roi-et soil series (Aeric Paleaquults). Selected physicochemical properties of soil are shown in Table 3. Journal of Water and Environment Technology, Vol.4, No.1, 2006 - 14 - Table 3 Selected physicochemical properties of soil. Parameter Sand (%) 82.5 Silt (%) 12.5 Clay (%) 5.0 pH 5.61 ± 0.02 ‡ Bulk density (g/cm 3 ) 1.42 ± 0.05 Moisture content (%) 19.07±1.23 Total organic carbon (%) 0.39 ± 0.05 Total Nitrogen (%) 0.031 ± 0.1 Total Phosphorus (%) ND Total Potassium (%) ND Nitrate nitrogen (mg/Kg) 0.66 ±0.10 Available Phosphorus (mg/Kg) 9.95 ± 1.02 Water soluble K (mg/Kg) 38.54 ± 5.33 C/N ratio 12.46 ± 0.52 ‡ Mean ± standard deviation. ND: not determined Effect of compost on soil chemical properties The finest compost, with an initial C/N ratio of 30/1 and a seeding of p.d. 1, was examined (both in ground form and pelletized form) for its effect on soil chemical properties. Controls used were soil without amendment and soil with inorganic fertilizer. Results revealed that soil pH values were between 5.2 and 6.5 (Table 4, 5, 6). This range was found suitable for plant growth based from the optimum pH range of 5.8-6 suggested by Miller and Donahue (1990). The pH values relatively increased with an increase in the amount of compost added both in ground and pelletized form. Addition of fertilizer did not affect the soil pH as indicated by similar pH value recorded in the soil without fertilizer. Increasing the soil pH up to the optimum for crop planting by adding compost into soil could improve the growth of the plants as compared to the soil without amendment (Mkhabela and Warman, 2005; Mungprom, 1998). Total Organic Carbon (TOC) analysis at day 0 and 15 (before plant cultivation), indicated that TOC in soil was increased by the addition of compost in both ground and pelletized forms (Table 4, 5, 6). Addition of 18.75 ton/ha of ground and pelletized compost to the soil cultivated with morning glory increased the TOC from 0.47% to 0.93% (Table 4). However, addition of inorganic fertilizer into soil did not increase the TOC content of the Journal of Water and Environment Technology, Vol.4, No.1, 2006 - 15 - soil (Table 4). As seen in Table 1, compost contained high amount of TOC (25.05%) which could increase the TOC content when added to the soil. Soumare et al. (2003) reported that TOC in soil increased with an increase in municipal solid waste compost added from 25 to 100 ton/ha. However, significant improvement occurred at the highest compost application rate of 100 ton/ha mixed with inorganic fertilizer. It resulted to the highest organic carbon content of 15.7 g/kg whereas the control (soil without compost added) had only 8.5 g/kg. Organic carbon is considered a soil quality index (Ta-oun et al., 2003) and is known to increase the nutrients and water holding capacity of the soil (Organic matter management, 2002). In the same treatment i.e., an addition of 18.75 ton/ha of ground and pelletized compost to the soil grown with morning glory, TOC contents in soil were not significantly different at day 0 and day 15 (Table 4). However, TOC contents in soil were found to increase slightly after 42 days of plantation. These may be explained that soil with vegetation had carbon containing compounds such as sugars, alcohol, and acid exudated from plant roots resulting to an increase in TOC content of the soil (Schnoor et al., 1995). Garcia et al (2005) found that after 6 years of plant growing, nutrients and number of microorganisms as organic contents were increased compared to non-vegetated soil. Analysis of nitrogen (NO 3 ), phosphorus (available P), and potassium (K 2 O) contents in soil revealed that the addition of fertilizer and compost in both ground and pelletized forms increased NO 3 , available P, and K 2 O contents in soils (Table 4, 5, 6). The NO 3 , available P, and K 2 O contents of soil increased upon increasing the amount of compost added (Table 4, 5, 6). This suggests that the increase in NO 3 , available P, and K 2 O contents of soil were from the fertilizer and compost added. A slight increase in NO 3 , available P, and K 2 O contents of soil in all treatments at day 15 after adding amendment confirmed that compost in both ground and pelletized forms released plant nutrients to soil during these 15 days. In contrast, after plant cultivation, amounts of NO 3 , available P, and K 2 O in soil decreased significantly suggesting that these nutrients were taken up by plants and used for their growth. Soumare et al. (2003) reported the same findings. An increase in the amount of compost added to the soil resulted to an increase in N, available P, and K 2 O in soil indicating that compost supplied these nutrients (Table 4, 5, 6). A study on the effect of compost on the improvement of degraded sandy soil revealed that N, P, and K increased with an increase in the amount of compost added (Puttaso, 2003). Total organic matter, macronutrients (N, P, and K) and micronutrients (Na, Ca, Cu, Zn, and Mg) in the soil (amended with swine manure compost) increased when the amount of added compost was increased. Compost improved soil physical properties by increasing soil porosity and hydraulic conductivity (Wong et al., 1999). Tam and Wong (1995) reported that the utilization of “age” spent pig litter as fertilizer enhanced the growth and plant production of Brasssica parachinensis through the increase of nutrients in soil. Our results suggested that the form of compost (ground ad pelletized) did not significantly affect the soil chemical properties. Both forms of compost when added to soil caused an Journal of Water and Environment Technology, Vol.4, No.1, 2006 - 16 - improvement in soil chemical properties. However, pelletized compost has an advantage over ground compost. Aside from the ease of transportation, pelletized compost could reduce storage area, amount of generated dust, and odor pollution when applied to soil (Ta-oun et al, 2003). Nutrient accumulation in harvested plants Although both forms of compost could significantly improve soil chemical properties, the nutrient uptake of plants were not known. Therefore, in this study we examined the nutrient accumulation in different parts of plants to determine the extent of nutrient uptake from compost added. Results indicated that there were significant differences in N, P, and K contents between the plants cultivated in soil with and without amendment (Table 7, 8, 9). Plants harvested from pots added with ground and pelletized composts had similar levels of N, P, and K contents but relatively higher than in plants harvested from pots with inorganic fertilizer added. This suggests that compost is a better soil conditioner than fertilizer. Wong et al. (1996) reported a similar observation. The amount of compost added did not strongly affect the amount of N, P, and K that accumulated in the harvested plants (Table 7, 8, 9). These results were in contrast with Tam and Wong (1995) who reported that plants (Brassica parachinenesis) collected from pots with high percentage of spent pig litter (40%) had higher amounts of N, P, and K in plant tissue than the plants collected from pots with low percentage (10 %). In addition, N, P, and K contents in rye grass grown in soil treated with municipal solid wastes compost increased as the amount of compost added to the soil increased (Soumare et al., 2003). Journal of Water and Environment Technology, Vol.4, No.1, 2006 - 17 - Table 4 Soil chemical properties at Day 0, Day 15 (after adding amendment) and Day 57 (Morning glory harvest day). Control – soil without amendment Values followed by the same letter within the same column do not differ significantly at 5% level of significance according to the least significant different test. ‡ Mean ± standard deviation. Day 0 (initial) Day 15 (after adding amendment to soil) Day 57 (day of harvest) Treatment pH TOC NO - 3 N (mg/kg) Avai.P (mg/kg) K (mg/kg) pH TOC NO - 3 N (mg/kg) Avai.P (mg/kg ) K (mg/kg) pH TOC NO - 3 N (mg/kg ) Avai.P (mg/kg) K (mg/kg) control 5.73± 0.23 e‡ 0.47± 0.07 c 0.65± 0.14 e 13.0± 1.36 d 50.06± 3.96 d 5.93± 0.20 b 0.48± 0.07 c 0.75± 0.89 d 110.18± 00.48 e 52.44± 5.02 e 5.83± 0.22 cd 0.59± 0.11 d 0.58± 0.22 d 10.11± 1.89 e 38.24± 5.66 f fertilizer (0.31 ton/ha) 5.80± 0.08 cde 0.46± 0.11 c 1.56± 0.27 bc 386.7± 134.70 c 262.18± 142.32 cd 5.28± 0.09 c 0.44± 0.07 c 1.43± 0.13 c 244.66± 78.30 d 307.30± 23.29 d 5.57± 0.30 d 0.55± 0.07 d 0.81± 0.18 cd 271.14± 157.80 cd 62.38± 10.52 ef pelletized compost (9.38ton/ha) 5.79± 0.25 de 0.56± 0.14 c 1.41± 0.29 cd 341.27± 212.17 c 290.84± 164.44 cd 6.02± 0.16 b 0.63± 0.13 c 1.47± 0.11 c 290.39± 130.50 d 296.12± 91.17 d 6.06± 0.11 bc 0.73± 0.10 cd 1.21± 0.15 b 241.41± 98.42 d 120.18± 26.96 def pelletized compost (12.5ton/ha) 6.00± 0.09 cde 0.87± 0.32 ab 2.00± 0.27 a 601.99± 244.20 bc 428.34± 166.10 bc 6.08± 0.06 b 1.15± 0.37a 2.36± 0.27a 756.6± 146.81 bc 289.06± 166.35 d 6.24± 0.31 abc 1.37± 0.22 a 1.71± 0.31 a 465.70± 259.53 abc 166.44± 105.82 cde pelletized compost (15.63 ton/ha) 5.90± 0.11 abcde 0.64± 0.08 bc 2.23± 0.31 a 762.45± 308.57 ab 665.53± 104.21 b 6.06± 0.41 b 0.75± 0.18 bc 1.87± 0.17 b 906.57± 92.40 b 807.34± 228.38 bc 6.21± 0.16 abc 0.91± 0.07 bc 1.84± 0.40 a 398.41± 249.56 bcd 411.69± 148.24 a pelletized compost (18.75ton/ha) 6.04± 0.06 ab 0.93± 0.23 a 1.88± 0.49 ab 725.59± 492.24 ab 1071.50± 475.01 a 6.15± 0.25 b 1.05± 0.44 ab 2.26± 88.85 a 609.93± 153.18 c 846.66± 104.72 bc 6.34± 0.08 ab 1.36± 0.17 a 1.32± 0.28 b 612.74± 153.67 a 380.96± 116.06 ab Journal of Water and Environment Technology, Vol.4, No.1, 2006 - 18 - Table 4 (cont.) Soil chemical properties at Day 0, Day 15 (after adding amendment) and Day 57 (Morning glory harvest day). Day 0 (initial) Day 15 (after adding amendment to soil ) Day 57 (day of harvest) Treatment pH TOC NO - 3 N (mg/kg) Avai.P (mg/kg) K (mg/kg) pH TOC NO - 3 N (mg/kg) Avai.P (mg/kg) K (mg/kg) pH TOC NO - 3 N (mg/kg) Avai.P (mg/kg) K (mg/kg) ground compost (9.38ton/ha) 5.84± 0.10 bcde‡ 0.50± 0.05 c 1.08± 0.33 d 505.75± 239.00 bc 295.28± 149.81 cd 5.97± 0.27 b 0.63± 0.16 c 1.29± 0.19 c 607.63± 156.88 c 277.30± 47.10 d 6.30± 0.54 ab 0.74± 0.23 cd 1.09± 0.28 bc 353.01± 63.06 bcd 137.20± 62.65 def ground compost (12.5ton/ha) 5.96± 0.21 abcd 0.56± 0.14 c 1.42± 0.20 cd 563.80± 156.40 bc 651.34± 150.94 b 6.14± 0.35 b 0.64± 0.15 c 1.38± 0.23 c 662.11± 179.39 c 687.14± 134.05 c 6.31± 0.19 ab 0.78± 0.16 cd 1.22± 0.20 b 309.13± 70.75 bcd 199.04± 53.68 cd ground compost (15.63 ton/ha) 66.09± 0.09 a 0.82± 0.17 ab 2.11± 0.30 a 766.65± 139.27 ab 1177.41± 288.80 a 6.12± 0.36 b 0.75± 0.11 bc 2.15± 0.11 a 867.08± 79.00 b 959.70± 339.65 ab 6.53± 0.57 a 1.00± 0.29 bc 1.06± 0.25 bc 217.94± 67.86 d 333.06± 142.99 ab ground compost (18.75ton/ha) 6.11± 0.11 a 0.93± 0.18 a 2.21± 0.13 a 1019.17± 91.92 a 1082.95± 106.74 a 6.62± 0.54 a 0.76± 0.38 bc 2.24± 0.16 a 1088.39± 196.84 a 1122.9± 119.09 a 5.85± 0.23 cd 1.10± 0.45 ab 1.24± 0.44 b 485.84± 135.12 ab 263.56± 70.02 bc Values followed by the same letter within the same column do not differ significantly at 5% level of significance according to the least significant different test. ‡ Mean ± standard deviation. . 1. 84 0 .40 a 398 .41 ± 2 49 .56 bcd 41 1. 69 148 . 24 a pelletized compost (18.75ton/ha) 6. 04 0.06 ab 0 .93 ± 0.23 a 1.88± 0 . 49 ab 725. 59 49 2. 24 ab 1071.50± 47 5.01. 10 19. 17± 91 .92 a 1082 .95 ± 106. 74 a 6.62± 0. 54 a 0.76± 0.38 bc 2. 24 0.16 a 1088. 39 196 . 84 a 1122 .9 1 19. 09 a 5.85± 0.23 cd 1.10± 0 .45 ab 1. 24 0 .44 b 48 5. 84