西北绿洲灌区水氮耦合对燕麦品种陇燕3号耗水特性及产量的影响

灌水和施肥,尤其是施氮肥,是调控作物生长和增加产量的两大重要技术措施,其互作是燕麦高产高效栽培中重要因素。2014—2015年连续2个生长季,在甘肃河西绿洲灌区的田间试验设3个定额灌溉和3个施氮(纯氮)水平,研究水氮耦合对陇燕3号农田0~150 cm土层耗水量、棵间蒸发、产量及水分利用效率的影响。3个灌溉处理的灌水量分别为270 mm(I_1)、337.5 mm(I_2)和405 mm(I_3),3个施氮水平分别为90 kg hm~(–2)(N_1)、120 kg hm~(–2)(N_2)和150 kg hm~(–2)(N_3)。从播种到成熟,燕麦阶段耗水强度呈先增后减趋势,抽穗至灌浆是最大耗水期,且同一施氮水平下,阶段耗水强度随灌水量增大而显著增加。在全生育期内,棵间蒸发量(E)及土壤水分蒸发量占总蒸发量的比例(E/ET)表现先降后升趋势,且相同施氮量下,拔节至灌浆期随灌水量的增大而增大,而灌浆至成熟期则随灌水量的增大而减小。相同施氮量下,燕麦产量随灌水量增加而显著增加,水分利用效率却随灌水量增加而降低。产量N_3I_3最高(5466.0~5727.5 kg hm~(–2)),N_3I_2次之(5428.5~5678.5 kg hm~(–2)),N_1I_1最低(4504.5~4804.3 kg hm~(–2));水分利用效率N_3I_2最大(12.11~12.82 kg mm~(–1) hm~(–2)),N_3I_1次之(12.04~12.63 kg mm~(–1) hm~(–2)),N_1I_3最小(9.79~10.58 kg mm~(–1) hm~(–2))。由此表明,水氮耦合对燕麦水分利用及产量具有显著互作效应。施氮量150 kg hm~(–2)、灌溉定额337.5 mm是西北绿洲灌区燕麦种植较佳的节水、高产水氮管理模式。

Interaction of Irrigation and Nitrogen on Water Consumption Characteristics and Yield in Oat Variety Longyan 3 in Northwest Oasis Irrigation Area

Irrigation and fertilization, particularly nitrogen (N) fertilization, are principal field practices to stimulate crop growth and increase yield,and their interaction plays an important role in high-yield and high-efficiency cultivation of oat. In the 2014–2015 oat growing seasons, a field experiment was conducted with three irrigation amounts and three nitrogen application rates to study the effects of water-nitrogen interaction on 0–150 cm soil water consumption, soil evaporation, grain yield and water use efficiency (WUE) of oat variety “Longyan 3”. The three irrigation amounts were 270 (I₁), 337.5 (I₂), and 405 mm (I₃), and the three N application rates were 90 (N₁), 120(N₂), and 150 kg ha^-1 (N₃). From sowing to maturity, the diurnal water consumption amount showed an increase–decrease trend, and the maximum consumption appeared at the duration of heading–filling. Under the same N application rate, the diurnal water consumption amount obviously increased with increasing irrigation amount. The soil evaporation (E) and the proportion of soil evaporation to evapotranspiration (E/ET) showed the decrease–increase tread in the whole growing period. Under the same N application rate, E and E/ET were enhanced with the increase of irrigation amount from jointing to filling stage, but declined from filling to harvest stage. The oat yield under a fixed N application rate had a positive relation to the irrigation amount, whereas, the WUE had the negative relation to the irrigation amount. For grain yield of oat, N₃I₃ ranked the top with yield of 5466.0–5727.5 kg ha^-1, followed by N₃I₂ with yield of 5428.5–5678.5 kg ha^-1, and N₁I₁ ranked the last with yield of 4504.5–4804.3 kg ha^-1. For WUE, N₃I₂ was the best treatment with WUE of 12.11–12.82 kg mm^-1 ha^-1, followed by N₃I₁ with WUE of 12.04–12.63 kg mm^-1 ha^-1, and N₁I₃ was the worst treatment with WUE of 9.79–10.58 kg mm^-1 ha^-1. Obviously, water–nitrogen interaction had significant effects on WUE and yield of oat. Our results suggest that N application at 150 kg ha^-1 coupling with irrigation amount of 337.5 mm is applicable in water-saving and high-yield production of oat in Northwest oasis area.