Effect Of Phosphate Application And Intercropping On Tomato And Tillered-onion’s Root Distribution And Phosphorus Uptake

Lots of studies confirmed that the main reason of the increasing yield in intercropping systems is due to the promotion of crop’s nutrient absorption, and the improvement of nutrient absorption always associated with the changes of root distribution. Our previous study has proved the tomato’s yield can be increased when it intercropping with tillered-onion, so on the basis of our preceding study we want to reveal the changed of root distribution and the nutrient absorption of tomato in tomato/tillered-onion intercropping system. And our study is so significant to build a high-efficiency nutrient utilizing root architecture and guide reasonable fertilization.Our study set insufficient and sufficient phosphorus levels, under the condition of soil culture, we studied whether the tomato/tillering intercropping system can increase the P uptake of tomato and how the available P in soil can be influenced after int ercropping with tillered-onion, and the monolith method is used to explore the root distribution in different combinations of tomato and tillered-onion, also in a non-destructive root box experiment under sand culture, we tested the root morphology and tendency under different interaction models.The main results are as follows:(1) Under the insufficient and sufficient phosphorus levels, intercropping with tillered-onion can significantly improves the aboveground and whole plant’s biomass and P uptake of tomato. Under the condition of phosphorus deficiency, intercropping with tillered-onion can significantly reduces the aboveground and whole plant’s P concentration of tomato, and a significant rise in underground’s phosphorus concentration. And under the condition of phosphorus deficiency, the tillered-onion’s underground biomass and phosphorus content were significantly higher than the intercropping system under phosphorus supply treatment. That’s to say, intercropping with tillered-onion can increace the P content of tomato, and the phosphorus concentration of tomato’s aboveground and whole plant can remain the same at the sufficient phosphorus level, but it can be reduced at insufficient phosphorus level.(2) At both phosphorus levels, the Resin P and Cowell P of tomato’s rhizosphere soil had no difference in tomato monoculture and tomato/tillered-onion mixture, even at insufficient P level the Resin P of tomato’s rhizosphere soil was significantly lower than tomato monoculture. It is illustrates that intercropping with tillered-onion can not improve the available phosphorus content in tomato rhizosphere soil.(3) Under the phosphorus deficiency condition, the root length density and root weight density became lager in tomato/tillerd-onion intercropping system and the root distribution scale was bigger than their monoculture, and the root of tillered-onion tended to be the tomato plants significantly. Whlie under the condition of P supply condition, the root length density and root weight density value is smaller than monoculture, but the range of root distribution became larger also, and the root growth direction away from tillered-onion on the soil surface and then tended to tillered-onion root at lower soil layer. That’s to say, intercropping with tillered-onion can change the root growth direction, and the tomato root system distribution range is increased, at the same time under the condition of phosphorus deficiency the root length density and root weight density of tomato can increased also.(4) In the non-destructive root box test, under different phosphorus levels the root interaction’s result is different at tomato and tillered-onion interspecific and intraspecific interaction models. At insufficient and sufficient phosphorus levels, the root tendency of tomato and tillered-onion are all changed, the root of tillered-onion tend to tomato plant, and the tendency is more obvious under the condition of phosphorus deficiency, and the root of tomato in intercropping system is avoid to cross with tillered-onion. And the intraspecific interactions result of two crops is affected by phosphorus levels significantly, the tomato’s root separated at sufficient phosphorus level and tend to cross at insufficient phosphorus level, while the root of tillered-onion is overlapped significantly at sufficient phosphorus level, but avoid cross at insufficient phosphorus level. That’s to say, the adjacent plant species and phosphorus levels can both affect the distribution of crop root niche.Above all, intercropping with tillered-onion can improve the biomass and P content of tomato, and can cause the crop’s root distribution and root tendency changes also, but the intercropping system can’t increase the Cowell P and Resin P content in tomato’s rhizosphere soil.