春秋季红壤旱地氨挥发对氮施用量、气象因子的响应

AMMONIA VOLATILIZATION IN RELATION TO N APPLICATION RATE AND CLIMATE FACTORS IN UPLAND RED SOIL IN SPRING AND AUTUMN

通过红壤旱地种植牧草马唐和蔬菜冬萝卜轮作试验,研究了在春秋二季红壤旱地氨挥发对不同施氮量和气象因子的响应。结果表明,红壤旱地春季牧草实验,氮肥处理N90、N160和N230,氨挥发持续10～17d,在施肥后6～8d达到峰值,峰值（扣除对照N0）分别为N0.11、0.57和1.84kg hm^-2d^-1。秋季氮肥处理N70、N130、N190和N250以基肥和以水带肥追施（基/追比为7∶3）氨挥发持续时间均为10～11d,基肥氨挥发峰值（扣除对照N0）分别为N0.02、0.05、0.06kg hm^-2d^-1和0.09kg hm^-2d^-1;追肥氨挥发峰值（扣除对照N0）分别为N0.05、0.22、0.38kg hm^-2d^-1和0.72kg hm^-2d^-1。不同施氮处理,春季累计氨挥发量为N0.67～5.16kghm-2,占施入肥料N的0.74%～2.24%;秋季累计氨挥发量为N0.37～3.04kghm-2,占施入肥料N的1.31%～3.69%。红壤旱地春秋二季氨挥发量（y）均随施N量（x）的提高而指数递增,其关系式分别为：y=0.1576e^0.0146x和y=0.1826e^0.0112x。显著性检验表明,春秋两季不同施氮量处理之间,土壤氨挥发量及挥发通量差异均达到显著水平。春秋二季基肥氨挥发总量和通量均与气温、气压、蒸发量和土温等环境气象因子有较好的相关性（p〈0.05）。

Ammonia volatilization in relation to N application rate and climate factors was studies through field experiment in red soil under the crop rotation of Smooth Crabgrass （ Digitaria ischaemum） in spring and Winter Radish （ Raphanus sativus） in autumn. Results indicate that ammonia volatilization in Treatments N90, N160 and N230 in spring dragged on for 10 ～ 17 days, and peaked at the 6th ～ 8th day after urea application, reaching N 0.11,0.57 and 1.84 kg hm^-2 d^-1, respectively, and the total amount of N loss through ammonia volatilization was N 0.67 ～ 5.16 kg hm^-2, accounting for 0.74% - 2.24% of the total N applied. In autumn, in Treatments N70, N130, N190 and N250 （the ratio of basal and sidedressing is 7：3） ammonia volatilization occurred both after application of basal fertilizer and tillering fertilizer and lasted 10- 11 days, with peaks reaching N 0.02, 0.05,0.06 and 0.09 kg hm^-2 d^-1 for the basal fertilizer, and N 0.05, 0.22, 0.38 and 0.72 kg hm^-2 d^-1 for the tillering fertilizer respectively. The total amount of N loss through ammonia volatilization was N 0.37 ～ 3.04 kg hm^-2, accounting for 1.31% ～ 3.69 % of the total N applied to Winter Radish （ Raphanus sativus ）. The total N loss through ammonia volatilization（y） enhanced with the increase in N application rate（ x ） （ p 〈 0.05） and expressed as y = 0. 157 6e^0.0146x and y = 0. 182 6e^0.011 2x respectively. Meanwhile, for basal fertilizer application, the N flux and total N loss through ammonia volatilization in Spring and Autumn is significantly correlated with the climate factors, such as air temperature, atmospheric pressure, soil temperature and evapora- tion rate （p 〈 0.01）.