施用氮肥对砖红壤硝态氮和盐基离子淋失特征的影响

摘要

Reasonable selection of different nitrogen fertilizers has an important influence on the increases of crop yield and rural incomes and the improvement of soil acidification.Taking the latosol in Haikou,Hainan province as research object,a soil column leaching experiment was conducted to study the leaching characteristics of NO3--N and Ca2+,Mg2+,K + and Na +.The results show that the cumulative leaching amounts of NO3--N are in order,ammonium sulfate ＞ ammonium nitrate ＞ urea ＞ N0,and have a positive correlation with fertilizer rate in a linear equation,y =3.3064x + 315.74 (R2 =0.8848).The cumulative leaching amounts of base cations of all treatments are in order Ca2+ ＞Mg2+ ＞ K+ ＞ Na+,and the total cumulative leaching amounts of base cations (kg/ha) are in the tendency of ammonium sulfate (1821.12) ＞ ammonium nitrate (1080.27) ＞ urea (872.24) ＞ NO (417.23).The migration rates of base cations of latosol are in order:ammonium sulfate (26.28％) ＞ ammonium nitrate (13.37％) ＞ urea (11.78％),and the best fitting equations for the base cations migration rates of latosol in the urea,ammonium nitrate and ammonium sulfate treatments are linear equation,y =0.1178x + 123.18 (R2 =0.9121),power equation,y =15.634x0.4423 (R2 =0.9259),and logarithmic equation,y =128.38e0.0007x (R2=0.9244),respectively.%氮肥品种的合理选用对作物增产增收、土壤酸化改良有重要的影响.本文以海南省海口市观澜湖采集的砖红壤为研究对象,采用室内土柱模拟试验,对尿素、硝酸铵和硫酸铵3种氮肥处理下砖红壤硝态氮及盐基离子(Ca2+、Mg2+、K+、Na+)淋失特征进行了研究.结果表明,1)硝态氮累积淋溶量表现为硫酸铵＞硝酸铵＞尿素＞N0,且硝态氮的淋溶量与施肥量呈正相关关系,整个淋溶过程中硝态氮累积淋溶量(y kg/hm2)与施肥量(x kg/hm2)之间满足线性方程y =3.3064x +315.74(R2 =0.8848)；2)尿素、硝酸铵、硫酸铵处理整个淋溶过程的盐基离子淋溶量均表现为Ca2+＞ Mg2+＞ K+＞ Na+,且盐基离子淋溶总量(kg/hm2)表现为硫酸铵(1821.12)＞硝酸铵(1080.27)＞尿素(872.24) ＞N0(417.23)；3)砖红壤盐基离子迁移速率表现为硫酸铵(26.28％)＞硝酸铵(13.37％)＞尿素(11.78％),尿素、硝酸铵和硫酸铵处理分别以线性方程y =0.1178x+ 123.18(R2 =0.9121)、乘幂方程y=15.634x0.4423(R2=0.9259)和对数方程y=128.38e0.0007x(R2=0.9244)的拟合度最高.