Effect Of Corn Stalks Substrate Soaked By Complex Broth On Watermelon Plug Seedling

Peat moss is the best soilless substrate in the world by far, but long-term and large number of mining will make the environment damaged, to seek new low-cost, environmentally friendly and renewable growing media has become a research focus at home and abroad. Corn stalks is a kind of newly developed horticultural substrate, but problems of low emergence and slow seedling growth in the early still exist in the nursery applications. This experiment had used composite agents of beneficial microorganisms to soak corn stalk matrix to explore the method and effect to improve the corn stalk substrate, and to provide a technical reference for the production of corn stalk substrate.In this experiment, two factors were used to study the immersion effect of different treatments on corn stalk substrates, one was the quantity of bacterial suspension A (A1: 0‰, A2: 5‰, A3: 10‰, A4: 15‰, 4 levels), and the other was soaking time B (B1: 5 d, B2: 10 d, B3: 15 d, 3 levels), 4 kinds of better treatment combination were screened out through the matrix of watermelon seed extract germination test. The optimal corn stalk matrix and 3 kinds of control matrix had been mixed with vermiculite by the volume ratio of 2:1 to study the effect on seedling morphological index, nutrient uptake and nutrient availability of substrate. The results showed that:1. With the increase of quantity of bacterial suspension and the prolongation of soaking period, the extracts had acceleration effects on the germination potential, germination index, vigor index and radicle length of watermelon seeds. The quantity of bacterial suspension and the soaking period did not have any interaction effects on the germination index and vigor index, but results shown there was a positive interaction effect on germination potential and radicle length. When corn stalk matrices were soaked by high quantity of bacterial suspension, the germination potential, germination rate, germination index and vigor index were significantly higher than the low quantity of bacterial suspension as time extended. But the extract of corn stalks matrix soaked 10 d by 10‰complex broth had a maximum radicle length of watermelon seeds. 2. When corn stalks substrates were soaked by complex broth, their total porosity and aeration porosity were significantly lower than the peat matrix (CK3), and bulk density, capillary porosity and water gas ratio were significantly higher than that of peat substrate. The pH values showed alkaline, and increased as time extended, and were significantly higher than the peat matrix. Low quantity of bacterial suspension had little effect on the EC values of corn stalks substrates , and the high quantity of bacterial suspension was able to significantly reduce the EC values of substrate, but their EC values were still significantly higher than the leaching corn stalks matrix (CK2) and the peat matrix.3. In the early growth stage, the form index, fresh and dry weight, and strength index of seedlings of different corn stalk media soaked by complex broth were all lower than leaching corn stalks matrix and peat substrate. In the late growth stage, the treatment A3B2's stem diameter, shoot dry weight, root volume and strength index were slightly higher than leaching corn stalk matrix, and significantly higher than peat substrate, the number of leaves and ground fresh weight were significantly higher than that of leaching corn stalk matrix and peat substrate, while, the height was slightly lower than leaching matrix, significantly lower than peat substrate, the ground fresh weight was significantly lower than leaching corn stalk matrix, higher than the peat substrate, the maximum root length and dry weight were significantly lower than leaching corn stalks matrix and peat substrate, and the dry weight per plant was lower than leaching corn stalk matrix, significantly higher than peat substrate.4. In the same immersion time, with the quantity of bacterial suspension increased, the utilization of N, P and K increased, and the percentage of residues decreased, and the proportion of loss increased gradually. In the same quantity of bacterial suspension, the N, P and K utilization of A3B2 (soaked 10 d) were higher than A3B3 (soaked in 15 d), whereas the percentage of residues and percentage of loss were lower than A3B3 (soaked in 15 d). The N, P and K absorption rate of peat matrix were all the highest, but the turnover rate lowest. In the early growth stage,the N, P and K uptake of A3B2 were relatively low, and relatively high in the late growth stage, while the peat substrate was opposite with A3B2. At the end of seedling growth, the totle N, P and K uptake of A3B2 were higher than peat matrix.