Research On Relationship Between Tomato Roots Distribution And Soil Water Variation Area

Water is an important factor that influence tomato growth in greenhouses, water can impact the growth of the plant and the distribution of tomato roots in soil layers. What’s more, the amount of irrigation can directly influence soil water capacity of tomato root soil layer. If water is lack of, the quality of tomato may be reduced and its output may be influenced seriously. As a result, research on the impact of soil water to tomato roots growth in greenhouses has great significance. At present, domestic scholars have conduct wide research on tomatoes growth in greenhouses. They mainly focus on upper and lower irrigation limit of tomatoes in greenhouses, irrigating indexes and institutions of tomatoes in greenhouses, water consumption laws of tomatoes, influence of low water capacity that has on tomato growth character. Researches on tomato roots distribution mainly concentrate on influences that different irrigation amount and methods to tomatoes in greenhouses. However, researches on the relationships between soil water variation and tomato roots growth and distribution were relatively few.This experiment is aim to conduct research on the influence that soil water capacity has on tomato roots growth condition and distribution of tomato roots in soil layer, so as to find out area in root soil layer that can best represent soil water capacity. Meanwhile, we are aiming to definite best soil water message collecting points. Consequently, scholars can bury the least soil water information sensor to get the most representative soil water condition. Through this research, we can offer reliable soil water information to intelligent irrigation diagnosis and control system. Certainty, precise irrigation of tomatoes in greenhouses can also be achieved.In tomato growing period, we use EM-50 data collecting machine to collect soil water data. We set 15 water collecting points to every plant, they are located in 5 centimeters、15 centimeters、25 centimeters to the plant in level direction respectively and 5 centimeters、15 centimeters、25 centimeters、35 centimeters、45 centimeters in vertical direction underground respectively. The frequency of this method was once every hour. During blossom and full bearing period, we use TREME water data sensor to detect soil water capacity. We excavate tomato roots regularly and to survey tomato roots parameters. Detecting points concerning this method were a little different, that are 5 centimeters、15 centimeters、25 centimeters to the plant in level direction respectively and 5 centimeters、10 centimeters、20 centimeters、30 centimeters、40 centimeters 、50 centimeters in vertical direction underground respectively. And frequency of this method was once every day and one more after irrigation.All data collected were processed and analyzed through Excel and Sigmaplot. Results are as follows:1)The majority of tomato roots distributed in areas 5 centimeters to the plant in level direction and less 10 centimeters underground. And the length of roots were mostly less than 10 centimeters. During growing period, soil water capacity ranging extent decreased as level distance from the plant increased. The minimum soil water capacity 5 centimeters in level direction from the plant is located 10 centimeters underground, this was perfectly in accordance with roots length. Within this period, we can use soil water variation data that exists in areas 5 centimeters to the plant in level directions in 0 to 10 centimeters soil layer, as evaporation figure calculated by this data in accordance with evaporation figure calculated through Penman-Monteith formula based on this figure.2)In blossom period, soil water capacity decreased as horizontal distance to the plant increased. With time passing by, roots weight increased and its length extended. The majority of root length were 5 centimeters to 15 centimeters. Meanwhile, low soil water capacity area expanded to 0 to 9 centimeters horizontally and 8 to 28 centimeters under surface vertically. During this period, we can use soil water variation data that exists in areas 5 centimeters to the plant in level directions in 0 to 30 centimeters soil layer for evaporation figure calculated by this data in accordance with evaporation figure calculated through Penman-Monteith formula based on this figure.3)In full bearing period, tomato roots grew continue onward and roots length mainly distributed from 5 centimeters to 15 centimeters. During this period, soil water changed significantly in area 15 centimeters to the plant horizontally in 0 to 30 centimeters soil layer. In this area, as soil depth increased, soil water capacity and variation range of soil water capacity decreased. Low soil water capacity most likely existed in 0 to 10 centimeters to the plant horizontally and 15 to 25 centimeters underground surface. As time passing by, low soil water capacity area expanded gradually.4)When tomato plants were grew in greenhouses and land were protected by plastic membrane, taking soil texture into consideration, soil moisture sensor should be buried 5 centimeters underground in growing period and 10 centimeters underground in later tomato growth period. Certainly, that conclusion also take roots growth and soil water capacity in root soil layer into account. Data obtained from this method can best represent soil water condition in tomato root soil layer in different growing period and can be applied to guide intelligent irrigation in green houses.