Effect Of The Soil Environmental Inorganic Nitrogen Content On Nitrogen Fixation And Growth Of Soybean (glycine Max L.)

The nodule nitrogen fixation, soil nitrogen and fertilizer nitrogen were the main resource of the growth in soybean. Due to the the nitrogen fixation can not satisfy the growth of soybean, so it necessary to applicate some fertilizer. However, the fertilizer can improved the soybean yield, inhibited the ability of nitrogen fixation. Actually the reaction of nitrogen on soybean was the reaction on symbiotic nitrogen-fixing system and root to soil environmental inorganic nitrogen. It means the fertilizer was put into the soil, it was dissolved and changed into the environmental nitrogen and which was together with the intrinsic environmental nitrogen affect the nitrogen fixation and growth of soybean. The content of soil environmental inorganic nitrogen derived from the sand and clay soil with the same N application rate is different. Meanwhile this is the reason for the ability of nitrogen fixation and development of soybean was different with the same N application rate. In this paper, a pot experiment was conducted to study the effects of the content of the environmental inorganic nitrogen content, which derived from different nitrogen application rate and style, on the ability of nitrogen fixation and development of soybean, and quantify their relationship. The main research results are as follows:1)Effect of soil environmental inorganic nitrogen content on nitrogen fixation of noduleIt was found that the nodule dry weight, number, nitrogenase activity and Lb content had the obviously negative related with the soil environmental inorganic nitrogen content, respectively. The nodule weight had the positive related with the nodule number in different growth stage of soybean. The nodule weight and number was lower before R2 stage of the soil environmental nitrogen content in the sowing date than the soil environmental nitrogen content derived from the continuous N supply style. However, it was higher in the R₆ stage. The nodule number and weight was inhibited by different soil environmental inorganic N derived from the uncontinuous N supply style, the trend showed: R₃ > V₂ > R₁ > R₅ > sowing. Meanwhile, the nodule number and weight was inhibited more seriously with the different environmental inorganic nitrogen content at V₂, R₁,R₃ and R₅ stage than the different environmental inorganic nitrogen content derived from continuous nitrogen supply style and in sowing date. The nodule number and weight was inhibited with the M3 and H4 treatment, by the soil environmental inorganic content was 264.10 and 238.88 mg·kg^-1 which was named as zero-nodulation content. And≥310.22 mg·kg^-1 with the M4 treatment causing death.The nitrogenase activity were obviously related with and Lb content. The nitrogenase activity and Lb content was inhibited more seriously with different soil environmental inorganic N derived from the continuous N supply style than the different soil environmental inorganic N derived from the N supply in the sowing date. The nitrogenase activity and Lb content was inhibited by different soil environmental inorganic N derived from the uncontinuous N supply style, the trend showed: R₃ > R₁ > V₂ > R₅ > sowing. It was found that the nitrogenase activity and Lb content was inhibited with the J4 treatment, by the soil environmental inorganic content was 219.99 mg·kg^-1 which was named as zero- nitrogenase activity and Lb content content.2) Effect of the environmental nitrogen content on the development of soybeanThe process of dry matter accumulation and root development showed the same change with"S". The dry matter accumulation had the negative related with the soil environmental inorganic content derived from the treatment with continuous nitrogen supply style, amd at V₂, R₁, R₃ and R₅ stage, and had positive related with the different soil environmental inorganic nitrogen in sowing date. The dry matter accumulation of different soil environmental inorganic N derived from the continuous N supply style and in sowing date was decided by the dry matter accumulation at R₆ stage, and the dry matter accumulation with the treatment of different soil environmental inorganic N derived from the uncontinuous N supply style was decided by the dry matter accumulation at R8 stage. The total dry matter accumulation was lower with the treatment of different soil environmental inorganic N derived from the continuous N supply style than the treatment of different soil environmental inorganic N derived from the uncontinuous N supply style, and the treatment of different soil environmental inorganic N at V₂, R₁, R₃ and R₅ stage. The dry matter accumulation was increased by different soil environmental inorganic N derived from the uncontinuous N supply style, the trend showed: R₅ > R₁ > R₃ > sowing > V₂. The dry matter accumulation was higher of the treatment at R₅ stage than the other treatment. The R/S was decreased with the growth of soybean increased. The root dry weight was lower with the treatment of N supply in sowing date than the treatment of different soil environmental inorganic N derived from the continuous N supply style. The root dry weight at R₆ stage with the treatment of different soil environmental inorganic N derived from N applicated in V₂, R₁, R₃ and R₅ stage was increased with the soil environmental inorganic N content inceased.It was found that the root length, surfarea and root volume had the obviously negative related with each other. The root length and root volume had the obviously negative related with the soil environmental inorganic nitrogen content, respectively. The optimal soil environmental inorganic nitrogen content was benefit to the increase of root length, surfarea and root volume. The root length, root surfare and root volume had the obviously negative related with the soil environmental inorganic nitrogen content, and the root average diameter had positive with the soil environmental inorganic nitrogen content.3) Effect of the environmental nitrogen content on N accumulation of soybeanThe total nitrogen accumulation had the obviously negative related with the soil environmental inorganic nitrogen content. The optimal soil environmental inorganic nitrogen content was benefit to the total nitrogen accumulation. The total nitrogen accumulation was higher with the treatment of different soil environmental inorganic N derived from uncontinuous N supply style, however, showed the decreased trend in the growth stage.4) Effect of the environmental nitrogen content on the yield of soybeanThe yield was lower with the different environmental nitrogen content in sowing date than the the different environmental nitrogen content of continuous N supply style. Meanwhile, the yield with the different environmental nitrogen content at V₂, R₁, R₃ and R₅ stage was higher than the treatment of different soil environmental inorganic N derived from continuous N supply style. The yield was increase by different soil environmental inorganic N derived from the uncontinuous N supply style, the trend showed: R₅ > R₃ > R₁ > V₂ > sowing. The yield with different soil environmental nitrogen content at the R₅ stage was higher than the other treatment. The G2 treatment was had the highest yield at 13.47 g·pot^-1 than the other treatment.