| This study was carried out with the purpose of resolving the continuous cropping obstacles and producing forcing garlic at the same time by interplanting tomato/garlic under plastic tunnel. Different aspects were considered regarding the biological effects, researched on the sprouting date, agronomic characters, bulb characters, interplanting advantages and other indexes of different garlic cultivars by the different sowing dates. However, various aspects of ecological effects, researched on influence of interplanting tomato/garlic on soil microbial amount, soil enzyme activities and soil nutrients. In addition, regarding bacteriostatic effects of garlic root exudates on tomato bacterial wilt, vitro experiment was also analyzed. This article offered reference for establishing technology system by interplanting tomato/garlic. The main results and conclusions were as follows:(1) The experiment in 2008~2009 showed that sprouting duration for S1 (sowing on August 25) was much longer than that for S2 (sowing on September 9) and S3 (sowing on September 24), but the sprouting date for S1 was much earlier than that for S2 and S3. Garlic plant growth for S1 showed more advantages to the two later sowing treatments in the indexes of maximum leaf length, leaf width, sheath height, sheath width, plant height, root number and leaf number. Plant growth of cv. G64 appeared preponderant to the other three cultivars in maximum leaf length, leaf width, sheath width, plant height and root number. Early sowing promoted bulb development. Among four cultivars, cv. G64 ranked first and cv. G87 ranked the next in bulb characters of maximum width, minimum width, height and perimeter. Bulb weight of cv. G64 was very significantly heavier than that of the other three cultivars; the bulb yield of cv. G64 was the highest. Interplanting cv. G64 with tomato on the date of S1, garlic bulb harvest time was 30~35 days ahead to the conventional outdoor cultivation, and the garlic price enhanced 60%. Therefore, cv. G64 and August 25 were recommended as suitable cultivar and sowing date in the autumn tomato/garlic interplanting system under plastic tunnel in Guanzhong plain of Shaanxi Province.The experiment conducted in 2009~2010 further showed that cv. G64 had growth advantages among cultivars of G39, G64 and G87 by interplanting under plastic tunnel. When sowing garlic on August 31, sprouting rate of cv. G64 was 94.4% after 35 days, and sprouting rate of cv. G39 closely followed behind cv. G64 and G87. Garlic in the near row to tomato sprouted much earlier than that in the further row to tomato.(2) The experiment in 2008~2009 indicated that there had no significant influence on tomato (Jinpeng No.1 tomato) morphology and yield with interplanting different garlic cultivars in the different sowing date. And the experiment in 2009~2010 showed that there had no significant influence on tomato (Israel 1420) height, stem diameter and yield with interplanting different garlic cultivars and garlic sprouts. However, compared with the continuous monocropping tomato for two crops, interplanting garlic had some influences on tomato quality, and the contents of interplanting tomato nitrate and nitrite were lower, the ratio of sugar to acid and content of tomato soluble protein etc were higher.(3) The experiment in 2008~2009 showed that number of the soil bacteria, fungi and actinomyces presented the gradually rising trend. There were more microorganisms for sowing date S1 than that for S2 and S3, for cv. G64 and G87 than that of the other two cultivars, and for interplanting plots than that of monocropping plots in the symbiotic period of the tomato/garlic interplanting system. Activities of soil catalase, sucrase, urease, alkaline phosphatase showed a trend of rise first, and then fall.The experiment in 2009~2010 showed that changes of soil microbial amount and soil enzyme activities were same as that in 2008~2009 in the symbiotic period of the interplanting system. In the experiments of 2009~2010, size orders of soil microbial amount and soil enzyme activities were I-Gs>I-G64>I-G87>I-G39>M-T, which showed interplanting garlic sprouts of cv. G64 was more beneficial to improve the soil microbial amount and soil enzyme activities than the interplanting corresponding garlic bulbs. Contents of available N, P and K showed a trend of rise first, and then fall in symbiotic period of tomato/garlic. There were more of those nutrients in the early symbiotic period but less of those in the late symbiotic period in the interplanting plots than those in the monocropping plots. The three nutrients in the monocropping plots were the most among the five treatments on the November 27, 2009.(4) Garlic root exudates had bacteriostatic effects on tomato bacterial wilt. And with the increase of garlic root exudates concentration, the bacteriostatic effects increased. In the plating method experiment, the inhibitory rate of tomato bacterial wilt reached to 100.0% when the concentration of garlic root exudates increased to 0.4 mg/ml. All of bacteria were killed. |
