Effects Of Fertilization On Soil Properties And Potato Yield

Fertilization has broad and deep impact on crop production and quality, soil physical and chemical properties and biological characteristics, as well as global climate change. The experiment used a randomized block design and researched the change of soil and potato Kexin 1 yield during the first 5-6 years continuous fertilization. The change of soil nutrients, moisture temporal change, soil enzymes, soil microbial biomass and greenhouse gas fluxes, as well as the response of biomass and yield of potato under seven fertilization treatments:organic manure combined with NPK (MNPK), organic manure (M), nitrogen and phosphorus and potassium fertilizers (NPK), nitrogen and phosphorus (NP), nitrogen and potassium (NK), phosphorus and potassium (PK), no fertilizer as control (CK), was analyzed. The main results are as follows.1. Fertilization, regardless of with balance or nutrient deficiency fertilizer, had a reduced effect on soil pH. The single application of sheep manure had a role to maintain or increase the soil pH. Nitrogen in MNPK fertilizer may have down leaching behavior. MNPK and M significantly increased soil organic matter to 0-20cm cultivated layer, significantly higher than that of NPK, nutrient deficiency treatments and without fertilization control. PK in 0-20cm soil layer had the highest available phosphorus content, followed by MNPK, the difference of between them was not significant.NK increased soil total phosphorus utilization intensity in 20-40cm soil layer than all other.Soil available potassium was related to application of potash and the content decreased with soil down. Available potassium in NK was slightly higher.2. In the case of two years of similar rainfall and different irrigation times,0-70cm layer the average water content of soil in 2015 increased compared with soil in 2014, in addition to the reduced production of NP, NK treatments, production of other treatment:-increase to some extent, especially MNPK significantly increased yields by 52.54%. The entire soil mean moisture content presented "O" type distribution,20-40cm soil layer had the largest soil water content, which had significant differences among all treatments during the growth period. Compared with partial fertilizer or no fertilizer, NPK and MNPK significant increased soil water retention capacity of 20-40cm soil layer.3. Soil invertase and urease activity presented similar response to fertilization, and were higher under treatments of MNPK and M than others. Nitrogen fertilizer has a slight activating effect on soil urease. Under the soil without fertilization had higher phosphatase activity, fertilization treatments had no significant effect on phosphatase activity or reduced to varying degrees. Catalase activity under PK and NPK fertilizer application appeared lower than no fertilization, and catalase activity of PK was the lowest.4. Soil microbial biomass C, N and P (simplified as SMBC, SMBN and SMBP) and SMBC/SMBN showed obviously seasonal fluctuating reduction with the advance of growth period. M or MNPK significantly increased SMBC, but chemical fertilizer had little effect on SMBC or partial fertilizer, such as NP appeared even a slight inhibition. M ’the minimum mean sampling period SMBC/SMBN, the value was 1.95, while MNPK had the maximum average of 2.82. Compared to no fertilizer and NK, the treatment with application of phosphorus fertilizer had the higher content of SMBP, while the application of organic fertilizer caused the highest SMBP content. But, the lack of nitrogen also constrained the content of SMBP.5. Soil respiration (soil carbon dioxide emission) of MNPK and M was higher than other treatments, and soil respiration of NPK and PK was relatively weak. Soil respiration and water correlation showed that in the case of less water was positively correlated, but when more moisture is a negative correlation. Inter annual temperature and soil respiration correlated with a large difference. In 2014, each treatment showed a significant positive correlation with temperature, while in 2015 the correlation was weak. 95% of the methane flux measurement records displayed as a negative value indicated that the potato field was mainly soil sinks CH4, and the absorption range was 10 ～45mμg·m-2·h-1. CH4 flux under all treatments appeared large annual differences and fertilization was not the main factors affecting soil CH4 uptake flux change. Among the two years of significant correlation records between CH4 uptake flux and soil moisture, the negative correlation was two-thirds. CH4 showed weak temperature dependence.N2O fluxes showed significantly influenced by the concentration of substrate. Compared to non-nitrogen fertilizer and control, nitrogen fertilization significantly increased soil N2O flux and decreased with decreasing nitrogen concentration. Soil N2O flux of non-nitrogen fertilizer and control remained low exhibit or weak absorption. May be subject to impact the substrate, N2O flux and soil water presented a weak correlation, which were more negative, and a little temperature correlation.6. MNPK, M and NPK potato had the highest dry matter accumulation and yield, and the yield of the three was not significant. Application of P and K and organic manure or had a significant effect of increasing the number of per plant tubers. Nitrogen fertilizer reduced the number of tuber; generated more assimilates used to increase the tubers. Compared with the no nitrogen fertilizer application, no phosphorus applied had the biggest influence on yield, followed by the influence of potassium.