不同供氮水平对夏玉米养分累积、转运及产量的影响

Effects of different N rates on nutrients accumulation,transformation and yield of summer maize

通过田间小区试验,研究了高肥力土壤上施N 125、250、375 kg/hm^2对夏玉米生物量、子粒产量、N、P、K养分累积动态、及氮肥表观利用率、养分转运的影响.结果表明,不同施氮量只影响夏玉米不同生育时期养分的阶段累积量,而对累积趋势基本无影响.植株生物量及N、P、K养分累积量随生育期的延长而增加,且它们的累积趋势相似,都呈“S”型曲线.各处理的子粒产量在7000～7700kg/hm^2之间,只有N250处理增产达显著水平;氮肥表观利用率在10%～18%之间,随施氮量的增加略有降低.施氮可提高子粒中的氮素累积量,而对磷的累积量影响不大.随着施氮量的增加,氮素的转运量、转运效率及其在子粒中的比例都降低,磷的转运与氮表现出类似的趋势.综合考虑产量、氮肥利用率、养分转运及环境污染等因素,该地区夏玉米的推荐施氮量应控制在125 kg/hm^2以内.

Rational N fertilization could improve the yield and quality of crop production, but over-application may cause groundwater and atmosphere pollution. Based on the characteristics of N, P, K uptake, accumulation and transformation, applying fertilizer at appropriate time and dose can increase crop yield and nitrogen use efficiency. A summer maize field experiment was carried out in high fertility soil of Guanzhong of Shaanxi province in 2004 to investigate effects of N fertilization on biomass, yield, accumulation dynamic of N, P and K, N use efficiency and nutrient transformation. The experiment design was the randomized complete block with four replications. The area of each plot was 33.6 m^2（6m ×5.6m）. Four nitrogen fertilization levels were employed including 0, 125, 250 and 375 kg/ha, one third of nitrogen fertilizer and total P （P 45 kg/ha） and K （K 216 kg/ha） was used as basal fertilizer, and two third of nitrogen fertilizer used as topdressing fertilizer at ear premordia stage. The results showed that N application rates affected the nutrient accumulate at different growth stages, but no influence on the tendency of nutrients accumulation in plant. Biomass and N, P and K accumulate increased with the prolongation of growth stages, and the accumulation tendencies were very similar, and could be described by ＂S＂ curve. The grain yield of different treatments was ranged from 7000 to 7700 kg/ha. The yield of treatment N250 was significant higher than other treatments, among which no significant difference on yield was observed. Fertilizer N recovery ranged from 10% to 18% ,which decreased slightly with increasing of N rates. N application could increase N accumulation in grain, but the effect on P in grain was neglected. N transfer amounts, transfer efficiency and its proportion in grain decreased with increasing of N application rates, P transformation showed the similar tendency at different N fertilization. Comprehensive the yield, fertilizer N recovery, meat pollution, the recommendation of fertilizer N rate for summer maize was less area. nutrients transformation and environthan 125 kg/ha in the experimental area.