保水剂和氮肥对小粒咖啡生长及水分利用的互作效应

小粒咖啡生产经常受到季节性干旱和土壤营养不足的制约。为探讨小粒咖啡节水抗旱和水肥资源高效利用模式,采用3个保水剂水平和3个施氮水平,研究了保水剂和氮肥对小粒咖啡苗木生长及水分利用的影响。结果表明:低氮、低保处理可以获得小粒咖啡苗木的最大生长量(株高、茎粗及叶面积)。和对照(无氮处理)相比,低氮可使干物质累积量提高24.10%,而高氮减少干物质累积11.95%。和无保水剂处理相比,低保水剂提高干物质累积11.53%,而高保水剂抑制干物质累积8.65%。此外氮肥和保水剂能不同程度地降低日蒸散量,提高水分利用效率;施氮和保水剂可分别提高小粒咖啡水分利用效率2.72%~35.37%和8.48%~20.24%。小粒咖啡氮素累积量随着施氮量增加先增后降。过高水平保水剂和氮肥都会对小粒咖啡的苗木生长产生明显的抑制作用,而低氮低保处理可同时提高干物质累积和水分利用效率。

Interactions between Superabsorbent Polymers and Nitrogen on Growth and Water Use of Arabica Coffee

The production arabica coffee is frequently restricted by seasonal drought and soil undernutrition. The objectives of this study was to explore the optimal mode of water-saving, drought resistance and efficient use of water and fertilizer of arabica coffee. Using 3 levels of superabsorbent polymers(SAP) and 3 levels of nitrogen, the complete design experiments were conducted and effects of SAP and nitrogen nutrition on growth and water use of arabica coffee seedling were studied. Results showed that the growth(plant height, stem diameter and leaf area) and dry mass accumulation of arabica coffee seedling was the largest under low level of SAP and nitrogen. Compared to control(no nitrogen treatment), low level of nitrogen increased dry mass accumulation by 24.10%, while high level of nitrogen reduced it by 11.95%. In contrast to no SAP treatment, middle level of SAP increased dry mass accumulation by 11.53%, while high level of SAP reduced it by 8.65%. In addition, application of nitrogen and SAP reduced daily evapotranspiration but increased water use efficiency. Nitrogen and SAP increased water use efficiency by 2.72%-35.37% and 8.48%-20.24%, respectively. Arabica coffee nitrogen accumulation first increased and then decreased with the increase of nitrogen rate. Inhibitory effects of excessive application of nitrogen and SAP was obvious, and higher dry mass accumulation and water use efficiency could be obtained by combination of low level of nitrogen and SAP simultaneously.