Effects Of The Different Plant Density On Plant Temperature And Growth Vigor Of Tomato

The efficient cultivation greenhouse tomato not only need suitable density, but also need reasonable environment regulation, especially the meticulous management of temperature, reflecting the body temperature of plant as accurately as possible, so that the plants was in optimum condition, in order to achieve the harvest yield of tomato.This paper attempts to build different canopy structure through the regulation of planting density, research effects of planting density on the body temperature of plant, to accurately direct the management of daily temperature of tomato.The experiment uses Organic soil cultivation pattern and set up two treatments of planting density which were6plants/m2and3plants/m2(plantling distance was22cm, row distance were75cm and150cm) in2012. The experiment studies the effection of planting density on tomato growth, leaf-air temperature, root-soil temperature, conclusions were as follows:1-. Judging from the plants,Vegetative growth between75cm processing and150cm processing is no obvious difference. From May12to June16, which is more than a month’s time, plant height was up to1.6m; flower panicles; leaf numbers was up to24; leafing rate was0.3spikes/d; the size of leaf (product of leaf width and length) was no obvious difference. Stem diameter of150cm processing was significantly higher than75cm processing,which was12.9mm and11.9mm respectively at the end of measurement.Leaf area index is closely related to dry matter production and distribution. In later period of experiment,including August and September, the LAI of75cm processing maintained more than6.9m2/m2, the highest up to8.23m2/m2,and the LAI of150cm processing maintained at the appropriate range of4m2/m2. The dry matter content of leaf、stem、root、fruit and whole plant reduced with density increasing. The dry matter content of stem were extremely difference significantly, the dry matter content of the rest organs were no significant difference. The density also affect the distribution ratio of the dry matter of each organ, the dry matter distribution ratio of leaf and stem of75cm processing were higher than that of150cm processing,but,the dry matter distribution ratio of root and fruit was lower than that of150cm processing. The variation tendencies of fruitset percentage between75cm processing and150cm processing were same, that was the first four fruitset percentage was higher, and after that the fruitset percentage depressed. From the third spike fruit, the fruitset percentage of150cm processing was higher than that of75cm processing. From the fifth spike fruit, the fruitset percentage of150cm processing was13%higher than that of75cm processing. In addition, the fruitset percentage of the9th spike fruit of150cm processing was26.6%higher significantly than that of75cm processing.The yield of each flower cluster of150cm processing was higher than that of75cm processing, in which of them, the fourth and the eighth spike were significantly different; the ninth and the tenth spike were extremely significant difference. Because the fruit number of per plant were38/plant of150cm processing and30.5/plant of75cm processing respectively; the average fruit weight were99.4g of150cm processing and87.9g of75cm processing respectively, leading to the yield of per plant decreased with density increasing, the yield of per plant were3.78kg of150cm processing and2.68kg of75cm processing respectively. Although the plot yield and per mu yield of75cm processing were1.4times higher than that of150cm processing, but its number of plants per unit area was the double of150cm processing and the output value was not higher, and as such, the150cm processing could save cost and gain relatively high yield and value.2^For the leaf-air temperature, leaf temperature was varied with the change of air temperature at the same part of plant synchronously and they basically coincided.During determination days, the leaf-air temperature difference was always negative.On sunny day,the leaf-air temperature difference changed greatly; but, on cloudy day, it was almost no fluctuation, maintained at about-2to-3℃.From the comparison of the leaf-air temperature difference of75cm processing and that of150cm processing,we found that when the air temperature in the greenhouse was between20～35℃, the leaf-air temperature difference of75cm processing centered largely between-1.5℃and-3.5℃; when the air temperature in the greenhouse was between20～32℃, the leaf-air temperature difference of150cm processing centered largely at-3℃; when the air temperature was over32℃, air temperature was3℃higher than leaf temperature; when the air temperature was over35℃, air temperature was5℃higher than leaf temperature;when the air temperature was up to40℃, the leaf-air temperature difference was up to-8℃. when the leaf-air temperature difference was over3℃, because the energy consumption of transpiration increases, the growth of plant became weaker, so that when the air temperatures was greater than32℃,it was not suitable for tomato growth.The planting density, plant parts could affect the change of leaf temperature. In the condition of high er temperature,150cm processing could more effectively regulate body temperature than75cm processing, leaf temperature was smaller.The leaf temperature for plant with plant space75cm between rows was higher than that of the central and lower.However, the leaf temperature for upper part with plant space of150cm was smaller than that of the central and lower.3、During the measurement period, the variation tendencies of air temperature, soil temperature, diurnal variation of root temperature between75cm processing and150cm processing were same. Root temperature changed with soil temperature, which had virtually no hysteretic phenomenon. The average root-soil temperature difference was-1.3℃to-1.4℃. Unlike75cm processing, the soil temperature, root temperature of150cm processing changed much; the root-soil temperature difference was smaller, the variation tendency was contrary to the75cm processing and the magnitude of change was smaller; the temperature increase quickly in the morning and cool earlier in the afternoon. In addition, the root-soil temperature difference changed greatly on sunny day; but, it was almost no fluctuation on cloudy day.To sum up,150cm processing which was low-density processing was propitious to plant for heat exchange with the surrounding environment, efficiently regulated body temperature, could maintain the root temperature of plant at a suitable range which was optimal for the growth of plant by reducing the root-soil temperature difference, stimulateing the sufficient absorbent of water, speeding up leaf transpiration, reducing the difference temperature between leaf and air, stimulateing growth of tomato plants.