基于根区土壤质量指数优化小粒种咖啡滴灌施肥方案

Optimization of drip fertigation scheme for Coffea arabica based on soil quality index

开展3个施肥量(以单株计,F_(H) 190.8 g,F_(M) 127.2 g,F_(L) 63.6 g)和3个灌水量(以单株计,W_(H) 190.63 L,W_(M) 158.86 L,W_(L) 132.90 L)的2因素3水平完全组合试验,选取小粒种咖啡(Coffea arabica)根区土壤硝态氮、有效磷、速效钾含量,细菌、真菌、放线菌数量,以及过氧化氢酶、磷酸酶、脲酶活性构建土壤质量指数,基于各处理的土壤质量指数,筛选出适宜的滴灌施肥方案。结果表明,增加灌水量会降低土壤养分含量,而增加施肥量会提高养分含量。F_(H)W_(L)处理的土壤养分含量最高,与F_(L)W_(L)相比,硝态氮、有效磷、速效钾含量分别显著(P<0.05)增加185.7%、422.9%、95.9%。土壤微生物数量和酶活性随着灌水量的增加而增加,随施肥量的增加呈现先增后减趋势。与F_(L)W_(L)处理相比,F_(M)W_(H)在增加土壤微生物数量和提高土壤酶活性上的作用最明显,细菌、真菌、放线菌含量分别显著(P<0.05)增加176.4%、73.3%、49.2%,过氧化氢酶、磷酸酶、脲酶活性分别显著(P<0.05)提高45.1%、24.6%、146.6%。土壤质量指数在F_(M)W_(H)处理下最高。据此认为,在试验条件下,适宜的滴灌施肥模式为高水中肥(F_(M)W_(H))。

In the present study,a full combination test with 2 factors(fertilization level and irrigation level)of 3 levels was carried out.Three fertilization levels(based on single plant)were set as F_(H) 190.8 g,F_(M) 127.2 g,F_(L) 63.6 g,and three irrigation levels(based on single plant)were set as W_(H) 190.63 L,W_(M) 158.86 L,W_(L) 132.90 L.Based on the contents of soil nitrate nitrogen,available phosphorus,available potassium,number of bacteria,fungi and actinomycetes,and activities of catalase,phosphatase and urease,soil quality index(SQI)was constructed.Based on SQI in the root zone of Coffea arabica under different treatments,the suitable drip fertigation scheme was screened out.It was shown that the increasing irrigation level could decrease soil nutrients contents,yet soil nutrients contents increased with the increasing fertilization level.Among all the treatments,soil nutrients contents under F_(H)W_(L) was the highest,and its nitrate nitrogen,available phosphorus,available potassium contents were significantly(P<0.05)increased by 185.7%,422.9%,95.9%,respectively,than those of F_(L)W_(L).The microbial(including bacteria,fungi and actinomycetes)quantity and soil enzymes activities increased with the elevated irrigation level,yet increased first and decreased later with the elevated fertilization level.Compared with F_(L)W_(L),F_(M)W_(H) showed the best performance in increasing microbial quantity and improving soil enzymes activities,as the number of bacteria,fungi,actinomycetes,and activities of catalase,phosphatase,urease were significantly(P<0.05)increased by 176.4%,73.3%,49.2%,45.1%,24.6%,146.6%,respectively.The highest SQI was recorded under F_(M)W_(H).Therefore,the most suitable drip fertigation scheme was high irrigation level coupled with medium fertilization level(F_(M)W_(H))under experiment conditions.