Effects of nitrogen application combined with sulfur on the growth and nitrogen uptake of ginger

【Objectives】 Fertilizer application significantly affects the yield and quality of ginger. Rational sulfur addition based on nitrogen application can promote the synthesis and accumulation of dry matter by coordinating the ability of nitrogen metabolism to increase ginger yield. A field experiment was conducted in shajiang black soil to study the effects of nitrogen application combined with sulfur on dry matter accumulation, yield and nitrogen uptake of ginger at different growth stages, in order to provide a theoretical basis for the increase of ginger yield and nutrient uptake. 【Methods】 The treatments consisted of four nitrogen levels: N 0, 300, 450 and 600 kg/ha and two sulfur levels: S 0 and 50 kg/ha. Gingers were sampled in vigorous growth stage, rhizome expanding stage and harvest stage to measure dry matter weight and nitrogen contents of the stems, leaves and rhizomes. 【Results】 The stems and leaves of ginger mainly grow at early stage. Dry matter weights of the stems and leaves at rhizome expanding stage are 5.4-9.3 g/plant and 7.0-11.6 g/plant, respectively. The rhizomes quickly accumulate at the later stage, reaching 20.0-36.8 g/plant of dry matter weight at harvest stage. With the increase of nitrogen application amount, dry matter weights of the stems and leaves at different growth stages increase. Among suitable nitrogen application amounts, dry matter weights of rhizomes and ginger yields increase with the increase of nitrogen application amounts, and reach the highest in treatment N450S50. Compared with treatment N0S0 and N0S50, yield increasing rate of ginger in nitrogen treatments are 33.1%-74.3% and 25.4%-64.2%, respectively. Under the same application amount of nitrogen, higher dry matter weights and ginger yields are achieved through the addition of sulfur fertilizer. Nitrogen and sulfur combined application influences the nitrogen contents in the rhizomes, stems and leaves of ginger. The nitrogen contents in leaves are always higher than those in rhizomes and stems, reaching 24.3-28.4 g/kg at rhizome expanding stage. The highest nitrogen contents of rhizomes and stems are found at vigorous growth stage, reaching 18.3-24.5 g/kg and 16.3-22.2 g/kg, respectively. In different treatments, nitrogen content of rhizomes is highest in treatment N600S50 and the highest contents of stems and leaves are found in treatment N450S50. Nitrogen accumulation amount at the harvest stage is in the order of rhizomeleafstem. The highest nitrogen accumulation of rhizomes is found in treatment N450S50, and those in stems and leaves are found in treatment N600S50. Nitrogen accumulation in the whole plant increases with the increase of nitrogen application amount, and the highest is found in treatment N450S50 with the increase of 116.2% and 99.0%, compared with treatment N0S0 and N0S50, respectively. Excessive application of nitrogen fertilizer reduces nitrogen accumulation of ginger. The addition of sulfur fertilizer can increase nitrogen accumulation amount by 8.1%-15.8%. 【Conclusions】Rhizome dry matters of ginger are mainly accumulated at rhizome expanding stage, so nitrogen and potassium topdressing at this period is important to increase ginger yield in practice. There is a strong internal relation between nitrogen and sulfur, suitable nitrogen application combined with sulfur will further increase dry matter accumulation, ginger yield and nitrogen uptake by promoting the formation of assimilation products and transferring the nutrient to vigorous growth sites. Excessive nitrogen application or unsuitable nitrogen and sulfur application proportion will limit yield increase.