EFFECT OF MICROBIAL INOCULANTS AND EARTHWORM ON MICROBIOLOGICAL AND CHEMICAL CHARACTERISTICS OF ORGANIC FERTILIZERS PRODUCED FROM AGRICULTURAL RESIDUES

Abstract

Ten treatments were prepared as a trial to find out the optimal combinations of different materials to be added to rice straw in order to produce high quality compost. Treatments were arranged in piles according to the components of each one. The C/N ratio of the rice straw was adjusted in the start to be 30:1 either by adding cattle dung in the treatment nos. 7, 8, 9 and 10 or adding ammonium sulphate in the treatments nos. 1, 3 and 5. The rice straw in the other treatments (nos. 2, 4 and 6) was left without adjusting the C/N ratio. The effect of addition of N, P and K either in organic or inorganic form as well as addition of bio-accelerator (Trichoderma harzianum NRRL 13019 and Phanerochaete chrysosporium NRRL 6359) were studied. Another set of the same 10 treatments were prepared by adding Eisenia fetida, when the temperature steadily reached 30oC. The earthworms were added to each of the plastic bin, which containing the pre-composted materials. The composting process was continued for both sets up to 16 weeks. Four treatments namely 1, 3, 7 and 8 proved to be the best compared to the other tested treatments. These four treatments were used to prepare the teas. They were used, thereafter, with the selected compost and vermicompost to study their effects on the growth, oil, N, P and K (%) of common sage (Salvia officinalis L.). This was carried out under greenhouse condition. The obtained results could be summarized as follows: 1. Measuring the temperatures during the composting process revealed that the initial temperature in all the tested treatments, at zero time, was 21oC. The ten treatments under investigation could be divided according to the prevailing temperatures into two groups. The first group is comprised from the treatments 1 to 6, which were prepared without addition of cattle dung, while the second group is comprised from those prepared by adding cattle dung (nos.7, 8, 9 and 10). In the first group, the temperatures of the initial mesophilic phase ranged from 21 to 45 oC. The thermophilic phase started with a temperature ranged from 46 to 49oC then the temperatures gradually increased to reach 50 and 62oC, according to the composted materials. The period of thermophilic phase was ranged between 3 to 24 days. The third phase of the composting process is a mesophilic phase at which temperature gradually decreased to reach the ambient temperature. This phase took longer time as it ranged from 93-111 days. In the second group, the temperature degrees of the initial mesophilic phase ranged from 21 to 36oC and it continued three days. The thermophilic phase started from the fourth day with a temperature ranged from 55-60oC. The period of this phase ranged from 35-40 days. The highest temperature degree, recorded in this phase, reached to 65-67oC. In the following days, the temperature gradually decreased. The rate of such decrease was different depending on the composted materials.

2. Microbiological determinations during the composting process showed that the initial densities of total mesophilic bacteria, fungi and actinomycetes in all the tested treatments ranged from 9.477 to 11.246, 8.467 to 9.959 and 8.457 to 8.901 log10 CFU/ g compost. The viable counts of mesophilic bacteria decreased over time during the first weeks of composting process (4 to 6 weeks). In the finished compost, the total counts of mesophilic bacteria in all the tested treatments were lower than those recorded at zero time which ranged from 9.053 to 9.336 log10 CFU/ g compost. In the same time the total counts of mesophilic fungi were