广西蔗区土壤肥力和叶片养分状况调查研究

Investigation on soil and sugarcane leaf nutrient status in Guangxi

广西是我国第一大甘蔗产地,了解广西蔗区土壤肥力及叶片养分丰缺状况,可对广西蔗区提出针对性的施肥建议。对广西南宁、崇左、来宾、百色、柳州、河池、贵港、玉林和防城港等主要甘蔗产区进行土壤和叶片调研,各采集了110份样品进行养分测定分析。结果表明:(1)广西蔗区调研土壤pH值平均为5.21,pH值<4.5的强酸性地块占比为40.91%;土壤有机质含量平均为24.43 g/kg,低于20 g/kg的缺乏地块占比为35.46%;碱解氮、有效磷、速效钾、交换性钙和交换性镁含量平均值分别为102.70、22.79、158.45、637.98和93.33 mg/kg,各自处于缺乏水平的地块占比分别为26.36%、30.91%、4.63%、45.46%和41.82%。(2)叶片大中量营养元素氮、磷、钾、钙和镁含量范围分别为14.80~25.50、1.30~2.50、9.90~19.70、1.30~7.50和0.40~2.80 g/kg,氮、磷和镁含量处于缺乏水平的地块占比分别为60%、91.82%和82.72%,而钾、钾含量普遍处于适宜或丰富水平;叶片微量元素铁、锰、铜、锌和硼含量范围分别为15.90~175.80、15.20~238.10、1.00~6.70、4.90~38.80和1.10~27.70 mg/kg,铁、锰、铜含量大多处于适宜或丰富水平,而锌和硼含量缺乏的地块占比分别高达50.09%和89.09%。(3)土壤pH值与土壤交换性钙和交换性镁含量呈极显著正相关关系,与土壤碱解氮含量呈显著负相关关系;土壤有机质含量与土壤碱解氮、速效钾、交换性钙和交换性镁含量均呈极显著的正相关关系。(4)土壤pH值与叶片钙含量呈极显著正相关关系,与叶片锰含量呈极显著负相关关系;土壤有机质含量与叶片磷、叶片钾含量呈显著正相关关系,与叶片锰含量呈显著负相关关系;土壤交换性镁含量与叶片镁含量呈极显著正相关关系。针对调研结果,提出的广西蔗区养分管理策略是重视土壤酸化治理,合理施用氮磷钾肥,增施有机肥和补施镁、锌、硼等中微量肥料。

Guangxi is the largest sugarcane production area in China.Understanding the nutrient abundance and deficiency status of soil and sugarcane leaf can provide rational nutrient management recommendations for Guangxi sugarcane production.This field survey was conducted in major sugarcane producing areas in Guangxi,including Nanning,Chongzuo,Laibin,Baise,Liuzhou,Hechi,Guigang,Yulin and Fangchenggang.110 paired samples were taken for soil and leaf,and nutrient contents were assayed.The results were as follows:(1)The average soil pH value was 5.21,with 40.91%of the samples having a pH value below 4.5.The average soil organic matter(SOM)content was 24.43 g/kg,and 35.46%of the samples was less than 20 g/kg.The average contents of alkaline hydrolysis nitrogen(AN),available phosphorus(AP),available potassium(AK),exchangeable calcium(ECa)and exchangeable magnesium(EMg)were 102.70,22.79,158.45,637.98 and 93.33 mg/kg,respectively,with the deficiency percentage being 26.36%,30.91%,4.63%,45.46% and 41.82%,respectively.(2)The contents of leaf N,P,K,Ca and Mg were 14.80~25.50,1.30~2.50,9.90~19.70,1.30~7.50 and 0.40~2.80 g/kg,respectively;while the deficiency percentage of leaf N,P and Mg accounted for 60%,91.82% and 82.72%,and most leaf K and Ca status were abundant.The content range of leaf Fe,Mn,Cu,Zn,B were 15.90~175.80,15.20~238.10,1.00~6.70,4.90~38.80 and 1.10~27.70 mg/kg,respectively;while most leaf Fe,Mn and Cu status were abundant,and deficient leaf Zn and B accounted for 50.09%and 89.09%,respectively.(3)The soil pH value showed significantly positive correlations with soil ECa and EMg,but a significantly negative correlation with soil AN.SOM was positively correlated with content of soil AN,AK,ECa and EMg.(4)The soil pH value was positively correlated with leaf Ca content,but negatively correlated with leaf Mn content.SOM showed positive correlations with leaf P and K,but a negative correlation with leaf Mn.A significantly positive relationship existed between soil EMg and leaf Mg content.According to these results,it is recommended that nutrient management in Guangxi major sugarcane production areas should pay attention to remediation of soil acidification,reasonably apply N,P and K fertilizers,increase application of organic fertilizers,and add some Mg,Zn and B fertilizers when needed.