长期施用磷肥和有机肥黄壤微生物量磷特征

【目的】研究玉米不同生育时期长期不同施肥处理下土壤微生物量磷(MBP)的动态变化与周转特性,探究长期施用磷肥和有机肥对土壤磷转化与供应能力的影响。【方法】依托贵阳黄壤肥力长期定位试验,选取不施肥(CK)、氮钾化肥(NK)、氮磷钾化肥(NPK)、有机肥(M)、1/2有机肥+1/2氮磷化肥(0.5MNP)、全量有机肥+全量氮磷钾化肥(MNPK)6个处理,在玉米播种前、苗期、拔节期、开花期、收获后分别采集0—20 cm土层样品,测定土壤微生物量磷含量、有效磷含量、酸性磷酸酶活性,并计算微生物量磷周转期和周转量。【结果】与NK处理相比,施用磷肥和有机肥各处理土壤微生物量磷(MBP)和微生物含磷量(MPC)分别显著提高了123.9%—446.2%和85.0%—268.2%,均以MNPK处理增幅最大。施磷量基本一致的条件下,M和0.5MNP处理MBP含量较NPK处理显著提高了26.7%—32.7%;NK处理MBP和MPC含量均在开花期最低,施用磷肥和有机肥各处理MBP含量在玉米生长期均较高,MPC含量则随生育时期变化呈"双峰"曲线,苗期和开花期最高;与CK相比,NK处理MBP周转期缩短了405 d...

Characteristics of Microbial Biomass Phosphorus in Yellow Soil Under Long-Term Application of Phosphorus and Organic Fertilizer

【Objective】 The seasonal dynamics of microbial biomass phosphorus (MBP) in yellow soils under different long-term fertilization treatments were studied to understand the influence of long-term application of P and organic fertilizer on P nutrients cycling and P nutrients available for plant uptake. 【Method】 Six treatments, including CK, NK, NPK, M, 0.5MNP and MNPK, were investigated in a 22-year (1995-2016) long-term fertilization experiment at Guiyang (Guizhou Province) of China. 0-20 cm soil layer was collected at before sowing, seedling stage, jointing stage, flowering stage and after harvest of maize, respectively, and to determine MBP, soil available P (AP), acid phosphatase (ACP) activity, and calculate the MBP turnover time and turnover amount. 【Result】 The results showed that, compared with NK treatment, the mean value of MBP content and microbial P content (MPC) in different maize growing periods under the treatments of P and organic fertilizer application were significantly increased by 123.9%-446.2% and 85.0%-268.2%, respectively, with MNPK treatment increasing the most. Under the same amount of P application, the MBP content under M and 0.5MNP treatments was 26.7% and 32.7% higher than that of NPK treatment. MBP and MPC of NK treatment were the lowest at flowering stage, while the MBP content of P and organic fertilizer application treatments were the highest in maize growth period. The MPC showed a "double peak" curve with the growth period, and the highest content was at seedling stage and flowering stage. Compared with CK, the MBP turnover time of NK treatment was shortened by 405 days, and the MBP turnover amount was increased by 50.9%. Compared with NK treatment, the MBP turnover amount increased by 19.2%-156.4%, and MBP turnover time was prolonged by 248-391 days under the treatments of P and organic fertilizer application, which indicated that application of P and organic fertilizer could increase MBP storage capacity and decrease its turnover rate. The amount of soil available P and P uptake of maize plant under the treatments of P and organic fertilizer application were 3.63-7.27 times and 1.77-1.97 times of NK treatment, respectively. The acid phosphatase activity in each treatment was ranked as NK>M, MNPK>CK, NPK, 0.5MNP, and the mean value of NK treatment increased by 10.2%-21.0% compared with other treatments. Correlation analysis showed that soil available P was the most important soil factor affecting the MBP content and MBP turnover amount, while acid phosphatase activity was the most important soil factor affecting the MBP turnover time. 【Conclusion】 To sum up, soil MBP could reflect the P supply level, and the storage and turnover of MBP were of great significance for improving the potential P supply capacity of yellow soil. Long-term application of P and organic fertilizer could increase soil available P sink, soil P cycling and P available for plant uptake, increase P uptake of maize plants.