水肥耦合对小粒咖啡苗木生长和水分利用的影响

Coupling effects of water and fertilization on growth and water use of Coffea arabica seedling

为探讨热带特色经济作物小粒咖啡苗木的节水抗旱和水肥资源高效利用模式，采用4个灌水水平（充分灌水、高水、中水和低水）和4个施肥水平（高肥、中肥、低肥和无肥）的完全处理组合，在智能控制温室内通过盆栽试验，测定在不同水肥处理下小粒咖啡苗木生长及耗水指标（株高、基茎、叶面积、生物量分配、日蒸散量、耗水量及水分利用效率），研究水肥耦合对小粒咖啡苗木生长、生物量累积及水分利用的影响规律.结果表明：小粒咖啡苗木的生长（株高、基茎、叶面积）和生物量累积随灌水和施肥的增加呈增加趋势.和低水处理相比，灌水增加生物量累积59.03％～369.77％.小粒咖啡苗木的根冠比和根质量比随灌水量的增加略有减小.小粒咖啡苗木的耗水量随施肥量的增加略有降低，而随灌水量的增加显著增加.和低水处理相比，增加灌水可提高小粒咖啡苗木的水分利用效率7.39％～128.96％.高水中肥处理（土壤含水量控制在田间持水率的65％～75％，施肥量为3 g/kg干土）能促进小粒咖啡苗木的生长并保证有较高的水分利用效率.

Water and fertilizer are very important for the growth and yield of Coffea arabica .C. arabica is an agricultural product with unique advantage in Yunnan Province , whose planting area and yield account for 90% of the whole country . However , its yield and quality are restricted because of seasonal drought and soil nutrient deficiency . To investigate the optimal mode of water-saving and high-efficient utilization of water and fertilizer ofC. arabica , the coupling effects of water and fertilization on growth and water use ofC. arabica were studied by using four irrigation levels , i .e . sufficient irrigation （ WS , soil moisture content was 75% 85% of soil field capacity） , high water （WH , soil moisture content was 65% 75% of soil field capacity） , middle water （WM , soil moisture content was 55% 65% of soil field capacity） and low water （ WL , soil moisture content was 45% 55% of soil field capacity） , and four fertilizer levels of NPK （ total nitrogen was 10% , P2 O5 was 30% and K2 O was 20% ） , i.e. high fertilizer （FH ,4.5 g/kg dry soil） ,middle fertilizer （FM ,3.0 g/kg dry soil） ,low fertilizer （FL ,1.5 g/kg dry soil） and no fertilizer （ FN , 0 g/kg dry soil） . A completely design of pot experiments ofC. arabica （ Kadimu P796 , a local variety） was conducted in intellectual control greenhouse from April to November in 2012 , in Faculty of Modern Agricultural Engineering , Kunming University of Science ＆amp; Technology in Kunming , Yunnan , China （102＆#176;79′E ,24＆#176;09′N） . Irrigation was controlled by weighing method . Experimental soil bulk density was 1.2 g/cm3 , field capacity （ FC ） of 24.3% （ mass by mass） . The temperature range of intellectual control greenhouse changed between 12 ℃ and 35 ℃ and air humidity range changed between 50% and 85% . Water-soluble NPK compound fertilizer （ total nitrogen was 10% , P2 O5 was 30% and K2 O was 20% ） was applied twice on May 26th and August 26th in 2012 . Morphological characteristics （ basal diameter , plant height , leaf area , root shoot ratio , root mass ratio and specific leaf area） and biomass accumulation and distribution were measured on November 11th , and daily evapotranspiration was measured on October 14th in 2012 , the day before irrigation in vigorous growth period ofC. arabica seedling . Results showed that the grow th （ plant height , basal diameter and leaf area） and biomass accumulation ofC. arabica seedling increased with the increase of irrigation and fertilizer , but the effect of fertilizer was inferior to irrigation . Compared with low water （WL） treatment , irrigation could increase biomass accumulation by 59.03%369.77% , and root shoot ratio and root mass ratio increased with the increase of irrigation slightly . Moderate increase of water and fertilizer could greatly increase biomass accumulation and water use efficiency （ WUE） under insufficient water and fertilizer , while marginal benefit significantly decreased while water and fertilizer supply increased under sufficient water and fertilizer . Daily evapotranspiration ofC. arabica seedling decreased with the increase of fertilizer slightly , while increased with the increase of irrigation significantly . Compared with low water （ WL ） treatment , irrigation could increase water use efficiency by 7.39% 128.96% . In conclusion ,faster growth and higher WUE could be obtained by high water and middle fertilizer （WHFM , soil moisture content was 65% 75% of soil field capacity and fertilizer was 3.0 g/kg dry soil） simultaneously .