氮肥运筹对陇中旱农区玉米光合特性及产量的影响

全膜双垄沟播技术使玉米成为了陇中旱农区主要作物之一,但该技术下玉米的高产出导致土壤养分耗竭,影响玉米生产的可持续性。本研究依托2012年布设在陇中旱农区的田间定位试验,研究4个施氮水平 (N₀:不施肥;N₁:100 kg·hm^-2、N₂:200 kg·hm^-2、N₃:300 kg·hm^-2)和2个施氮时期(T₁: 1/3基肥+1/3拔节期+1/3开花期、T₂: 1/3基肥+2/3拔节期)对玉米光合特性、叶绿素含量、叶面积指数、干物质积累和分配量及产量的影响。结果表明:1) 随着施氮量的增加玉米光合性能也在增强,而N₃和T₂N₂间差异不显著,T₂时期提高玉米光合特性;2) 全生育期内,N₃处理下叶绿素含量较N₂、N₁、N₀分别平均增加50.9%、17.0%、2.7%;叶面积指数也随施氮量的增加而增加,但N₂和N₃间无显著差异;T₂下的叶绿素含量和叶面积指数在生育后期显著高于T₁;3) 干物质积累量和籽粒分配量表现为:N₃>N₂>N₁>N₀,T₂下的干物质积累和籽粒分配量高于T₁;4) 籽粒产量和生物产量均随施氮量的增加而增加,N₂和N₃下的籽粒产量和生物产量显著高于N₀,其中N₃较N₀增加79.2%和68.4%,N₂较N₀增加65.9%和54.1%,T₂下的籽粒产量和生物产量分别较T₁显著增加9.9%和13.5%,而T₂N₂与N₃间无显著差异,因此,在陇中旱农区应用全膜双垄沟播技术种植玉米,施纯氮200 kg·hm^-2左右,按照1/3基肥+2/3拔节期配施,可以增强光合作用,从而提高玉米籽粒产量和饲料产量,促进玉米生产可持续发展。

Effects of nitrogen management on photosynthetic characteristics and yield of maize in arid areas of central Gansu,China

Maize has become one of the major cultivated crops in arid farming areas of central Gansu, China because of the adoption of complete film surface mulching and adoption of double ridge-furrow planting. However, the high output of maize using this technology results in exhaustion of soil nutrients negatively influencing the sustainability of maize production. The objective of this study was to determine the effects of different nitrogen application rates on the photosynthetic characteristics, chlorophyll content (SPAD), leaf area index, dry matter accumulation and distribution and yield of maize. The study relied on a field experiment that was conducted in 2012 at Dingxi, Longzhong region. The treatments included four nitrogen rates (N₀: 0 kg·ha^-1, N₁: 100 kg·ha^-1, N₂: 200 kg·ha^-1, N₃: 300 kg·ha^-1) and two nitrogen application times (T₁: 1/3 at sowing+1/3 at jointing+1/3 at flowering, T₂: 1/3 at sowing+2/3 at jointing). The photosynthetic characteristics improved with increased nitrogen application rate, but there was no difference between T₂N₂ and N₃; T₂ enhanced the photosynthetic characteristics. N₃ increased SPAD by 50.9%, 17.0%, and 2.7% respectively comparing N₀, N₁, and N₂ at all stages. Leaf area index also improved with increased nitrogen application rate, but N₂ and N₃ were not different. SPAD and leaf area index under T₂ were higher than T₁. Dry matter during all growth stages was highest at N₃ and lowest at N₀ (N₃>N₂>N₁>N₀) and T₂ was higher than T₁. Grain yield and biomass were significantly higher with increased nitrogen rates; for example, grain yield and biomass were 79.2% and 68.4% higher for N₃ than N₀ respectively, and 65.9% and 51.4% higher for N₂ than N₀ respectively. T₂ improved grain yield and biomass by 9.9% and 13.5% respectively, compared with T₁. However, T₂N₂ and N₃ were not different. The application of double furrow sowing technology, mulching with nitrogen applied at 200 kg·ha^-1 rate, 1/3 applied at sowing+2/3 at jointing is suggested as a means of more sustainable maize production systems in arid areas of central Gansu, China.