| As the rapid development of our agriculture, we produce lots of agricultural wastes every year. But the way that we dispose of them is simple and rough.The agricultural wastea into soilless culture substrate through composting is not only a solution to the environment problem, but also a reduction of cost for soilless culture. The pathogenic bacteria would be killed because of the high temperature during composting. We selected corncob and bagasse our experimental material, which one of them is easily decomposed by microorganism, the other is hard to decompose. Under the condition of initial composting 25: l of C/N ratio, we focused on the change of stable components and physic-chemical properties during composting. The changes included the contents of lignin and cellulose, the activity of enzymes, microbe quantity and the contents of humus acid(HA), fulvic acid(FA) and humin. Then we used the product after composting which mixed with peat or vermiculite as grown media. And compared with control, we study on the height, stem diameter, ground fresh weight and ground dry weight of cucumber to see if the treatments could be accepted as an alternative to commercial substrate for cucumber seeding culture. The main results are as follows:1. Bulk density and water-holding porosity increased, as the same time total porosity and air filled porosity decreased during composting. Bulk density of bagasse increased a time, and bulk density of corncob increased about 1.2 times. Air filled porosity of bagasse declined by 69.31% and air filled porosity declined by 69.31%. Water holding porosity of bagasse rose about 2 times and water holding porosity of corncob rose 1.38 times. Both of bagasse and corncob declined about the contents of TOC,respectively24.14% and 34.14%.Compared with the corncob, total nitrogen of bagasse increased by 66.85% apparently, but the corncob only increased by 34.02%.Totalpotassium of bagasse rose 1.7 times and totalpotassium of corncob rose 1.1 times. Total phosphorus of bagasse increased more than corncob. Total phosphorus of bagasse increased by 97.71%.pH of bagasse changed little during composting.For corncob, pH and EC were increased markedly.2. The content of lignin of bagasse and corncob increased, but the activity of ligninolytic enzymes was different during composting.The amount of microorganisms was most in the initial of mesophilic(1~4d), but the amount of microorganisms decline with the temperature rising.The minimumamount of bagasse and corncob was respectively in 18 thday and 11 thday during the compost.For the bagasse, the activity of Mnp was increasing till 35 thday, 17.64IU/g. The activity of Lip was rising in the first four days, and then declined. From 11 th day, the activity of Lip was rising.The high activity of Lip was 12.43IU/g in the 35 th day.The activity of Lac of bagasse was rising. The high activity of Lac was11.69 IU/g in the 18 th day. For the corncob, the high activity of Mnp was 9.86IU/g in the 18 th day,and then declined. The activity of LiP increased a little in the first days and then declined. The high activity of LiP was 4.41IU/g in the 35 th day.The activity of Lac did not change in the first 4 days and then declined. The activity increased from 11 th day. The high activity of Lac was 4.46IU/g in the 27 th day.3. The content of cellulose increased in the first 4 days and decreased in the thermophilic phase(11~27d) but the activity of cellulose enzymes was different during composting. The amount of microorganisms was most in the initial of mesophilic(1~4d), but the amount of microorganisms decline with the temperature rising. The minimum amount of bagasse and corncob was respectively in 11 th day during the compost. For the bagasse, the activity of C1 was increasing till 35 th day. 17.64IU/g. The activity of CBwas rising in the first 11 days, and then declined. From 18 th day, the activity of Lip was rising. The high activity of CB was 12.43IU/g in the 35 th day. The activity of Lac of bagasse was rising. The high activity of Lac was26 IU/g and declined from 42 th day. The high activity of CMC 22.7 IU/g in the 27 th day and then declined.For the corncob, the activity of C1 was rising in the first 42 nd day. The high activity of C1 was 108.26IU/gin the 42 nd day. The activity of CB obviously increased in the 4 days and declined a little. The activity of CB increased from 11 day.The high activity of CB was 18.21 IU/g in the 35 thday. The activity of CMC did not change in the first 4 days and then declined. The high activity of CMC was 18.9 IU/g in the 42 nd day.4. The humus and humus acid(HA) were increased, but the fulvic acid(FA) and humin were declined. The humus of bagasse increased by 54.89%, and the humus of corncob increased by 34.46%; HA of bagasse rose 2 times, and HA of corncob rose a time during compost. FA of bagasse declined by 24.79%, and FA of corncob declined 28.54%.Humification coefficient(HR=HA/FA) of bagasse and corncob both increased. HR value of bagasse was greater than corncob. So we could say the humification of bagasse enhance more than corncob.5. The experiment showed us that the bagasse to vermiculite in a ratio of 1:1(T6) and corncob to peat and vermiculite in a ratio of 1:1:1(T4) could replace for commercial substrate on cucumber culture. After mixing with other materials, pH and EC of T4 and T6 were improved. By comparing overall evaluation coefficient of each treatment, T4 and T6 had a positive effect on the height, stem diameter, ground fresh weight and ground dry weight of cucumber. The comprehensive evaluation coefficient of T6 is the best of all. And there is no obvious difference between T4 and CK. So we concluded that T4 and T6 were horticulturally acceptable as an alternative to commercial substrate for cucumber culture... |
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