施肥对新垦绿洲风沙土肥力及碳积累的影响

利用2005年安排在临泽边缘绿洲沙地农田的长期施肥定位试验,研究不同用量有机肥、化肥、有机肥和化肥配施对绿洲沙地土壤肥力及有机碳积累的影响。试验包括高量有机肥单施(M3),氮磷化肥单施(NP3),低、中、高量氮磷钾化肥单施(NPK1,NPK2,NPK3),及低、中、高量氮磷钾化肥配施高、中、低量有机肥9个处理(NPK1M3,NPK2M2,NPK3M1),测定分析10年后不同施肥处理耕层(0~20 cm)土壤物理化学性状特征及有机碳动态。结果表明:施有机肥及有机无机配施处理较单施化肥处理容重下降0.13 g·cm^-3,田间持水量提高6.7%,单施有机肥、有机无机配施较单施化肥,土壤有机碳(SOC)和全氮含量分别提高64.8%、36.3%和64.9%、49.5%。高量施用氮磷化肥和氮磷钾化肥处理全磷含量最高,有机肥及有机无机配施较单施化肥有效氮含量显著增加,有机无机配施及高量施用磷肥土壤有效磷积累明显,高量施用有机肥能显著提升有效钾含量。连续施肥处理10年后,SOC含量提高了1.68~2.84倍,土壤全氮、全磷、碱解氮及有效磷均有一定程度的提高,但单施化肥及有机肥与氮磷化肥配施有效钾含量下降。SOC的积累速率单施化肥、有机无机配施、单施有机肥处理分别为0.27、0.59,0.87 g·kg^-1·a^-1。增施有机肥、适量减少化肥投入、氮磷钾化肥的平衡施用是绿洲沙地农田土壤肥力持续提升的施肥管理对策。

Effects of Long-term Different Fertilization on Soil Fertility and Soil Organic Carbon Accumulation in Psamments of Oasis Farmland

The objective of this study was to discuss the effects of long-term different fertilization treatments on soil fertility and soil organic carbon (SOC) accumulation in sandy soil of oasis farmland using a long-term field fertilization experiment started in 2005. The experiment treatments include 9 treatments with different amount of organic manure, chemical fertilizers, and combined application of different amount of organic and inorganic fertilizers. The characteristics in soil physical and chemical properties and dynamic changes in soil organic carbon (SOC) under different fertilization treatments were determined in tillage layer (0-20 cm). The results indicated that soil bulk density decreased 0.13 g·cm^-3 and field water capacity increased 6.7% in the treatments of manure application alone and combined application of different amount of organic and inorganic fertilizers compared with the treatments of chemical fertilizers application alone on average. SOC concentration in the treatments of manure application alone and combined application of organic and inorganic fertilizers increased by 64.8% and 36.3%, respectively, in comparison with the treatments of chemical fertilizers. Also, total nitrogen concentration increased by 64.9% and 49.5%, respectively. The treatments of high amount of NP fertilizers and NPK fertilizers showed a higher total phosphorus concentration than that of other treatments. Alkali-hydrolyzable N concentration was significantly higher in the treatments of manure application alone and combined application of organic and inorganic fertilizers than in the treatments of inorganic fertilizers. Available K concentration increased significantly under high amount of manure application. Under different fertilization treatments for ten consecutive years, SOC concentration increased by 1.68-2.84 times in comparison with the initial value. Total N, Total P, Alkali-hydrolyzable N and available P concentrations increased in different degrees. However, available K concentration declined under application of inorganic fertilizers alone and combined application of manure and NP fertilizers. On average, SOC accumulation rate was 0.27, 0.59 and 0.87 g·kg^-1·a^-1 under manure application alone, inorganic fertilizers application alone, and combined application of organic and inorganic fertilizers, respectively. Increasing organic fertilizer input, reducing moderately inorganic fertilizers input, and balanced application of manure and NPK chemical fertilizers were effective measures for improving soil fertility for oasis sandy farmland.