长期施氮磷化肥对不同种植体系土壤有效硫累积研究

以22 a定位试验为基础,在黄土高原旱地研究了长期施用氮磷化肥,对不同种植体系土壤有效硫在剖面上分布与累积状况。结果表明,在60-80 cm土层各处理出现第一个累积峰,累积峰值为:玉米-小麦(2 a) 糜子轮作27.07 mg/kg,豌豆-小麦(2 a) 糜子轮作25.42 mg/kg,小麦(2 a) 糜子-玉米轮作24.23 mg/kg,豌豆-小麦(2 a) 玉米轮作22.61 mg/kg,小麦连作16.56 mg/kg,红豆草-小麦(2 a)轮作15.14 mg/kg;在120-180 cm土层又出现有效硫的第二个累积峰,累积峰值为:小麦(2 a) 糜子-玉米轮作34.20 mg/kg,豌豆-小麦(2 a) 糜子轮作32.16 mg/kg,豌豆-小麦(2 a) 玉米轮作31.00 mg/kg,红豆草-小麦(2 a)轮作30.32mg/kg,玉米-小麦(2 a) 糜子轮作29.16 mg/kg,小麦连作26.22 mg/kg。0-200 cm土层有效硫总累积量玉米-小麦 糜子轮作高达559.64 kg/hm2,其次是小麦 糜子-玉米轮作为538.88 kg/hm2,豌豆-小麦 糜子轮作为514.34 kg/hm2,豌豆-小麦 玉米轮作为489.58 kg/hm2,小麦连作为432.75 kg/hm2,红豆草-小麦轮作最小为423.68 kg/hm2。长期施用磷肥是不同种植体系有效硫在土壤中发生累积的主要因素,有效硫在土壤剖面上有向深层迁移的趋势。不同作物对硫的吸收利用差异和不同种植方式对有效硫的累积与分布产生影响。

Available Sulfur Accumulation in Soil Profile in a Long-term NP Chemical Fertilizer Experiment of the Different Cropping Systerms

Based on the long-time location exeriments,accumulation and distribution of available sulfur in soil of different cropping systerms under the condition of 22 years' continuous application of NP chemical fertilizer in Loess Plateau were studied.The results showed that there are two peaks of available sulfur in soil profiles.The first peak occurred in 60-80 cm soil depth with the values of 27.07 mg/kg,25.42 mg/kg,24.23 mg/kg,22.61 mg/kg,16.56 mg/kg and 15.14 mg/kg in maize-wheat(2 a) millet rotation,pea-wheat(2 a) millet rotation,wheat(2 a) millet-maize rotation,pea-wheat(2 a) maize rotation,wheat succession and sainfoin-wheat(2 a) rotation respectively.The second peak occurred in 120-180 cm soil depth and the values in maize-wheat(2 a) millet rotation,pea-wheat(2 a) millet rotation,pea-wheat(2 a) maize rotation,sainfoin-wheat(2 a) rotation,pea-wheat(2 a) maize rotation and wheat succession were 34.20 mg/kg,32.16 mg/kg,31.00 mg/kg,30.32 mg/kg,29.16 mg/kg and 26.22 mg/kg,respectively,which were higher than the first available sulfur peak value.The accumulation of available sulfur in soil profiles(0-200 cm) in maize-wheat(2 a) millet rotation,wheat(2 a) millet-maize rotation,pea-wheat(2 a) millet rotation,pea-wheat(2 a) maize rotation,wheat succession and sainfoin-wheat(2 a) rotation were 559.64 kg/hm2,538.88 kg/hm2 514.34 kg/hm2,489.58 kg/hm2,432.75 kg/hm2 and 423.68 kg/hm2,respectively.The results also showed that long-time application of P fertilizer was the principal factor influencing the distribution of available sulfur in soil profile at different cropping systerms.Additionally,available sulfur transported to deep soils in this study.The results suggest that the difference of sulfur uptake and utilization caused by different crops and cropping styles had effected accumulation and distribution of available sulfur in soil profiles.