施氮深度对旱地小麦耗水特性和干物质积累与分配的影响

为确定黄淮冬麦区旱地小麦施氮技术的最佳施肥深度，2010-2012连续两年度在大田条件下设置氮肥表面撒施(D1)，施氮深度10 cm (D2)、20 cm (D3)和30 cm (D4) 4个处理，研究了施氮深度对旱地小麦山农16和烟农0428耗水特性和干物质积累与分配的影响。与D1和D2处理相比，D3和D4处理在拔节至开花期和开花至成熟期的耗水量显著提高，40~120 cm土层土壤贮水消耗量显著增加，在降水量较丰富的2011-2012年度，D3和D4处理120~160 cm土层土壤贮水消耗量也显著高于D1和D2处理(高4.0~5.3 mm), 说明20~30 cm施氮肥有利于提高土壤水分的利用, 尤其是土壤深层贮水的利用，满足小麦拔节后的水分需求; D3和D4处理拔节至开花期和开花至成熟期干物质积累量均显著高于D1和D2处理，成熟期和开花后干物质积累量分别高642.1~2006.8 kg hm^-2和394.5~723.1 kg hm^-2。D3的籽粒产量和氮肥偏生产力与D4无显著差异，均显著高于D1和D2，水分利用效率较高。因此，20 cm是黄淮冬麦区旱地冬小麦的适宜施氮深度。

Effects of Nitrogen Application Depth on Water Consumption Characteristics and Dry Matter Accumulation and Distribution in Rainfed Wheat

To raise a suitable nitrogen application depth for rain-fed wheat in the Yellow-Huai Rivers Zone in China, we tested the water consumption characteristics and dry matter accumulation amounts and distribution ratios of wheat cultivars Shannong 16 and Yannong 0428 under different nitrogen application depths in 2010–2011 and 2011–2012 growing seasons. The nitrogen application depths were designed in four levels, which were surface application (D1) and application depths of 10 cm (D2), 20 cm (D3), and 30 cm (D4). Compared to D1 and D2, D3 and D4 exhibited significantly greater water consumption amounts in the periods of jointing–anthesis and anthesis–maturity and soil water consumption amounts in 40–120 cm soil layers (P < 0.05). In the 2011–2012 growing season with sufficient precipitation, the 120–160 cm soil water consumption amounts of D3 and D4 treatments were 4.0–5.3 mm greater than those of D1 and D2 (P < 0.05). These results indicated that nitrogen applied in 20–30 cm of soil depth could increase the utilization of soil water, particularly deep soil water, to meet the water requirement of wheat plant after jointing stage. Besides, D3 and D4 treatments also showed dramatically higher dry matter accumulation amounts from jointing to maturity than D1 and D2 treatments (P < 0.05). After anthesis, the dry matter accumulation amounts in D3 and D4 were 394.5–723.1 kg ha^-1 higher than those in D1 and D2, and at maturity stage, the increments were 642.1–2006.8 kg ha^-1. The grain yields and partial factor productivities of nitrogen in D3 and D4 were significantly higher than those in D3 and D4, and no significant difference between D3 and D4. Besides, D3 had relatively higher water use efficiency. Therefore, we suggest that 20 cm is the optimal soil depth of nitrogen fertilizer application for rain-fed wheat in Huang-Huai Rivers Zone.