Effects Of Fertilization Level Under Drip Irrigation On The Soil Micro-Ecological Environment,Yield,Quality And Flavor Of Coffee Arabica In Dry-Hot Area

Coffea arabica is a special economic crop in Yunnan Province.Due to extensive nutrient management,coffee yield and quality and flavor are often not guaranteed.In order to find out the suitable drip irrigation and fertilization system for Coffea arabica,5-year-old Coffea arabica was selected as the test object through the field experiment in the dry-hot area for 2 years.Taking the CK treatment(F_Ⅰ0F_Ⅱ900F_Ⅲ0,fertilizing only in the fruit expansion period)with reference to the local fertilization habits as the control,five fertilization levels were set at three growth stages（flowering and fruiting period I,fruit expansion period Ⅱ,and fruit picking period Ⅲ）,respectively T1（FⅠ350FⅡ350FⅢ350）,T2（FⅠ300FⅡ300FⅢ300）,T3（FⅠ250FⅡ250FⅢ250）,T4（FⅠ200FⅡ200FⅢ200）,T5(FⅠ150FⅡ150FⅢ₁₅₀).The effects of different drip irrigation and fertilization levels on soil microecology,physiological growth,yield,quality and flavor of Coffea arabica were studied,and the following main conclusions were obtained:（1）With the increase of fertilization,the contents of nitrate nitrogen,available phosphorus and available potassium in the soil of Coffea arabica in the flowering and fruiting period and fruit expansion period showed an increasing trend.With the increase of fertilization amount,soil catalase activities of T5,T4,T3,T2 and T1 treatments were increased by 8.16%,12.23%,21.42%,29.82%and 29.69%respectively in the flowering and fruiting period compared with CK treatment.The activity of catalase increased first and then decreased with the increase of fertilization amount.With the increase of fertilization amount,the number of bacteria,fungi and actinomycetes gradually increased in the flowering and fruiting period,and the three microorganisms of T3treatment increased by 50.98%,25.84%and 21.98%respectively compared with CK treatment.（2）With the increase of fertilization rate,the daily average net photosynthetic rate,stomatal conductance and transpiration rate in flowering and fruiting period,fruit expansion period and fruit picking period increased first and then decreased,and the stomatal limit value decreased first and then increased.The daily average net photosynthetic rate,stomatal conductance and transpiration rate of T3 treatment were the highest in the three growth periods.With the increase of the total fertilization amount,the treatments with the largest increase in plant height,stem diameter and crown width during the growth period were all T3.In the three growth periods,with the increase of the fertilization amount,the light transmittance and extinction coefficient of the canopy it also showed a trend of first decreasing and then increasing,and all reached the lowest level in T3treatment.（3）In the 2-year experiment,with the increase of fertilization,the yield of Coffea arabica,fresh bean yield,coffee bean volume and fertilizer partial productivity increased first and then decreased.The total fertilization amount of CK treatment was equal to that of T2 treatment,but its dry bean yield,fresh bean yield,coffee bean volume and fertilizer partial productivity were lower than T2 treatment.The dry bean yield,fresh bean yield and coffee bean volume of T3 treatment were all at high levels,and the 2a average values were 6189.69 kg/ha,24814.63 kg/ha and 160.97ml,respectively.（4）From T5 treatment to T1 treatment,the total fertilization amount gradually increased during the growth period,and the content of protein,fat,caffeine,chlorogenic acid,and crude fiber increased first and then decreased.The comprehensive score of T3 treatment quality was 0.96,which was higher than other treatments.Dark roasting has higher relative contents of furans,ketones,aldehydes,alcohols,phenols,pyridines,pyrroles and other substances,and lower relative contents of ketones,esters,acids and pyrazine than medium roasting.In conclusion,T3 treatment(250 kg·ha^-1 fertilization in flowering and fruiting period,fruit expansion period and fruit picking period)can improve photosynthetic characteristics,increase growth index,build a reasonable canopy structure,and be conducive to a good soil micro-ecological environment.The formation of T3 treatment has the highest comprehensive quality score,and the yield is also at a high level.Therefore,from the perspective of improving quality and increasing production,T3 treatment is a more scientific fertilizer management system in terms of improving quality and increasing production.