Research On The Nutrient Status And Conversion Characteristcs Of The Main Tobacco Planted Soils In Hunan

Through investigation to take soil samples, cultivation experiments and indoor simulation research methods, this article comparatively studied the nitrogen, phosphorus and potassium deficiency situation and biological effectiveness and efficiency of tobacco planted soils developed from5kinds of main parent material(limestone, shale, quaternary red clay and purple sand shale, purple shale)in Hunan. Due to the different soil available nutrients content and transformation characteristics, the biological efficiency showed a larger difference; the main conclusions are as followed:Soils developed from five kinds of parent material got the higher humus carbon content on the whole, the highest amount of humus carbon belonged to the soils developed from shale,25.91g/kg, and there was a significant correlation between the humin carbon and humus carbon. Hu/Fu rate of soils developed from limestone was high, and the activity of the organic matter was low. Acid nitrogen is the main soil mineralized nitrogen, and acid nitrogen content of different parent material was soils developed from shale> soils developed from quaternary red clay> soils developed from limestone> soils developed from purple sandy shale> soils developed from purple slate. On the nitrogen content, due to the impact of biomass, purple sandy shale and purple slate, respectively, showed the concentration effect and the dilution effect. Two quarters of tobacco seedlings nitrogen accumulation of soils developed from purple slate, limestone, purple sandy shale, slate, quaternary red clay were:120.34mg、129.84mg、133.17mg、161.35mg、142.32mg; from organic matter mineralization component, easy mineralization of organic nitrogen and culture test nitrogen mineralization, soils developed from slate had best soil conditions, then the soils developed from limestone, the purple slate、purple sandy shale parent material.Soils developed from five kinds of parent material had strongly effect of phosphorus fixation, soils developed from quaternary red clay got the largest phosphorus adsorption bonding energy and the strongest phosphorus fixation capacity, while the desorption rate was the lowest. Soils developed from purple slate had the maximum phosphorus adsorption saturation and the strongest desorption and highest desorption rate. Soils developed from limestone soil had the highest phosphorus pools and buffer capacity. In view of phosphorus bioavailability, two quarters of tobacco seedlings phosphorus accumulation of soils developed from purple slate, limestone, purple sandy shale, slate, quaternary red clay were:23.09mg、20.72mg、15.99mg、25.18mg、20.24mg. Generally speaking, soils developed from shale was the best on phosphorus biological effectiveness, followed by soils developed from purple slate, and soils developed from limestone was slightly better than soils developed from quaternary red clay, but the latter had strong ability to continue to provide for phosphorus, and soils developed from purple sandy shale was the worst on phosphorus bioavailability.Q/I characteristics of potassium showed that:soils developed from purple sandy shale, limestone, shale were better than soils developed from quaternary red soil and purple slate on buffering performance. After harvest, available potassium content of soils developed from limestone and purple sandy shale were maintained at a high level, but the amount of slowly available potassium decreased greatly. The slowly available potassium was an effective supplement for soil available potassium. These two kinds of parent material had stronger continued ability for potassium, and this is consistent with the potassium Q/I curve results, meanwhile the slate for sustainable potassium advantage was not significant. The potassium accumulated content of the two seasons of tobacco seedlings of soils developed from purple slate, limestone, purple sandy shale, shale, quaternary red clay were:157.76mg、152.06mg、100.25mg、148.33mg、148.54mg. In aggregate, the performance in potassium biological validity of soils developed from limestone, purple sandy shale were better, followed by soils developed from purple slate, and soils developed from slate was slightly better than quaternary red clay parent material, soils developed from purple sandy shale was the worst.In summary, soils developed from slate and purple slate had better performance on nitrogen and phosphorus nutrients, soils developed from quaternary laterite parent material ranked second, then soils developed from limestone and purple sandy shale; soils developed from limestone and purple sandy shale showed a better effect in potassium, then soils developed from purple shale, soils developed from slate is slightly better than the quaternary red clay parent material, soils developed from purple sandy shale was the worst.