Effects Of SAP On Water And Nitrogen Regulation Of Arabica Coffea

The production arabica coffea is frequently restricted by seasonal drought and soil undernutrition. The study for the hydrothermal regimes problem of arabica coffea, using3levels of superabsorbent polymers (SAP) with3levels of nitrogen and3levels of irrigation combination, and the primary research of this paper concentrates mainly on the effect on arabica coffea growth characteristics, physiological property, water and nitrogen utilization. The main results of this study as follows:(1)Under the complete design of SAP and nitrogen nutrition, the results showed that the growth (plant height, stem diameter and leaf area) and dry mass accumulation of arabica coffea 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 by24.10%, while high level of nitrogen reduced it by11.95%. In contrast to no SAP treatment, middle level of SAP increased dry mass accumulation by11.53%, while high level of SAP reduced it by8.65%. In addition, application of nitrogen and SAP reduced daily evapotranspiration but increased water use efficiency. Nitrogen and SAP increased water use efficiency by2.72%-35.37%and8.48%-20.24%, respectively. Arabica coffea 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.(2)Under the complete design of SAP and irrigation, the results showed that, compared to SN, SL increased chlorophyll (Ch1), carotenoid and root activity by11.8%,13.4%and52.2%, and reduced soluble sugar (SS), malondialdehyde (MDA) and proline(Pro) by24.9%,24.3%and55.8%, and increased total dry mass and water use efficiency (WUE) by31.0%and35.9%simultaneously, while SH reduced Chl, carotenoid, MDA and root activity by3.1%,2.4%,13.5%and6.3%, and increased SS, and MDA by3.7%and75.1%, and reduced total dry mass by21.3%, and increased WUE by8.6%simultaneously. Compared to WL, WM increased total dry mass, water consumption and WUE by89.8%,44.5%and33.2%, and WH increased total dry mass, water consumption and WUE by172.8%,104.8%and34.0%. Compared to CK (SNWL), SLWM had the largest increase of WUE by112.7%, and increased total dry mass by158.9%, and increased leaf relative water content, Chi, carotenoid and root activity by24.4%,19.5%,25.8%and149.9%, and reduced SS, MDA and Pro by38.3%,36.4%and68.7%, simultaneously. Considering high efficiency water saving, SLWM was optimum experiment combination.This experiment results could provide practice reference for water and nitrogen use efficiency of arabica coffea, which have certain theoretical and practical significance. Due to the study was conducted under the condition of potted simulation, the result still need field experimental verification.