Household Waste Collection and Composting Household waste (just a kitchen waste which includes fruit debris, vegetable, fish wastes, etc.) from Bangabandhu Sheikh Mujibur Rahman Agricultural University campus, Bangladesh, was collected and sorted. A biodegradable and agriculturally usable portion of household waste (HW) was placed in an earthen pit (5 × 2.5 × 1 m). About 30 cm household waste was placed in the pit weekly and thus 4 weeks were needed to make the pit full with waste. After each of the 4 weeks about 200 g of urea fertilizer was broadcasted over the surface of the waste and mixed well to accelerate the microbial degradation. A plastic shed was prepared over the pit to protect it from the direct sunlight and rainfall. When the pit was full with waste it was covered with soil; waste was composted for 4 months and then used in the experiment. One-month-old (accumulated in a pit and collected after 1 month) chicken manure (CM) and cow dung (CD) were procured from local poultry and dairy farms, respectively. Background nutrient concentrations of HW, CM, CD, and field soils were determined (Table 1). Total N was determined by Kjeldahl systems (Bremner and Mulvaney 1982), available P by Olsen’s method (Olsen and Sommers 1982), and K by ammonium acetate extraction method (Barker and Surh 1982). Available N [nitrate (NO3 −)-N plus ammonium (NH4 +)-N] was determined using the steam distillation method (Keeney and Nelson 1982). Experiments The first experiment with rice (BRRIdhan 29) was conducted from February to June 2008 (in wetland) and the second one with summer tomato (BARI hybrid tomato 4) was conducted from January to May 2009 (in upland) at the experimental field of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh, using HW, CM, and CD. There were 11 treatments in both experiments, which were laid out in a randomized complete block design using three blocks. Every treatment was assigned in each block randomly. The individual plot size was 4 m2 (2 m × 2 m). The treatments were (1) control; (2) recommended doses of N, P, and K; (3) HW 2.0 kg m−2; (4) HW 3.0 kg m−2; (5) HW 4.0 kg m−2; (6) CM 2.0 kg m−2; (7) CM 3.0 kg m−2; (8) CM 4.0 kg m−2; (9) CD 2.0 kg m−2; (10) CD 3.0 kg m−2; and (11) CD 4.0 kg m−2. The experimental site is located at 24.09? north latitude and 90.26? east longitude with an elevation of 8.4 m from the mean sea level. The site was situated in the subtropical climatic zone characterized by heavy rainfall during April to September and scanty rain during rest of the year. Soil of the experimental site belongs to the series Tejkunipara, and the family is clayey, Kaolinitic, and Ultic Ustochrepts under the order Inceptisols. The area is under the agro-ecological zone of Madhupur tract. Fertilizer Application, Transplanting, and Intercultural Operations The required amounts of N, P, and K for these two crops were determined using Eq. (1) (BARC 2005): Fr = Uf − (Ci/Cs) ∗ (St − Ls) (1) where Fr is fertilizer nutrient required for a given soil test value (kg ha−1), Uf is upper limit of the recommended fertilizer nutrient for the respective soil test value interpretation (STVI) class, Ci is unit of class intervals used for fertilizer nutrient recommendation, Cs is unit of class intervals used for STVI class, St is the test value of experimental plot soils, and Ls is the lower limit of the soil-test value within the STVI class. Recommended doses of N, P, and K of rice were 140, 39, and 66 kg ha−1, respectively, whereas for tomato these doses were 104, 47, and 88 kg ha−1, respectively. Using the data given in Tables 1 (soil-test value) and 2 (STVI class and nutrient recommendation) a calculation procedure is shown to get the recommended N for rice: Fr = 168 − (56/0.09) ∗ (0.095 − 0.091) = 140kgN/ha
The amount of inorganic fertilizer required for a 4-m2 plot was then calculated. Following the integrated plant nutrition systems (IPNS) as suggested by BARC (2005), the amounts of available N, P, and K in HW, CM, and CD as per the rates of treatments were then deducted from the total requirements to get application rates of fertilizers to each and every plots. The 50-day-old rice seedlings were transplanted in the plots on 2 February 2008. The full doses of P and K were applied using triple superphosphate (TSP) and muriate of potash (MP), respectively, at the time of final land preparation. Nitrogen as urea was applied in three equal splits in plots: 10 days after transplanting, at maximum tillering stage, and at booting stage of rice. Plant spacing for rice was 20 cm × 25 cm, and three seedlings were transplanted in each hill. After transplanting rice, 5–6 cm water was maintained in each plot throughout the growth period. The 30-day-old tomato seedlings were transplanted in the plots on 24 February 2009. The full doses of P and K were applied using triple superphosphate (TSP) and muriate of potash (MP), respectively, at the time of final land preparation. Nitrogen as urea was applied in three equal splits in plots: 10 days after transplanting, at maximum growth stage, and at maximum fruiting stage of tomato. The plant spacing for tomato was 40 cm × 40 cm. The number of rows and hills per plot was equal in all plots. Sulfur, zinc, and boron were not applied in rice or in tomato experiments as these elements were in very high levels in plot soils. Intercultural operations such as weeding and pest controls were done as and when required.
Statistical Analysis SPSS version 12.0 statistical software (SPSS Inc., Chicago, Ill.) was used to analyze the data. One-way analysis of variance (ANOVA) and univariate analysis were performed. Means were separated by least significant difference (LSD(0.05)).