内蒙古西部旱区机采棉膜下滴灌水氮耦合效应

为探明内蒙古西部旱区机采棉膜下滴灌水氮耦合对棉花生长发育、产量、品质,以及水分与氮素利用效率的影响,在内蒙古阿拉善盟阿拉善左旗,设置3种灌溉定额(216、288、360 mm,分别记为W₁、W₂、W₃)和3种施氮水平(127.5、195、262.5 kg·hm^-2,分别记为N₁、N₂、N₃)的完全组合处理,进行了大田棉花膜下滴灌试验.结果表明: 水分是膜下滴灌棉花生长的决定因素,增加灌水量可以促进棉花株高增加,提高棉花各部分干物质积累量,但降低生殖器官与地上部干物质比例.W₃处理单株成铃数较W₁和W₂分别提高25.4%和17.5%,单铃质量分别降低5.8%和4.6%,籽棉产量分别增加18.1%和11.9%;单株成铃数提高是籽棉产量增加的主要因素.水氮调控对籽棉产量的互作效应显著,W₁与W₂灌水量下N₁处理籽棉产量最高;W₃灌水量下N₂处理较N₁、N₃籽棉产量分别增加8.5%和31.9%.水氮调控对纤维品质整体无显著影响.W₁N₁处理水分利用效率最高,为1.37 kg·m^-3,与W₃N₂处理差异不显著;W₃N₁处理氮肥偏生产力最高,为51.35 kg·kg^-1.在本试验条件下,灌水增产效应显著,施氮则在水分充足条件下对籽棉产量形成有促进作用.其中,灌水360 mm、施氮195 kg·hm^-2处理显著促进地上部干物质积累,籽棉产量最高,水分利用效率和氮肥偏生产力分别达1.30 kg·m^-3和36.41 kg·kg^-1,节水增产效果显著,是内蒙西部旱区较理想的机采棉水氮调控模式.

Coupling effect of water and nitrogen on mechanically harvested cotton with drip irrigation under plastic film in arid area of western Inner Mongolia,China

In order to understand the main and interactive effects of water and nitrogen on crop growth and development, yield, fiber quality, and water-nitrogen use efficiency of mechanically harvested cotton with drip irrigation under plastic film in arid area of western Inner Mongolia, a two-factorial experiment with irrigation water amount and nitrogen dosage in completely randomized block design was conducted in Alxa Left Banner of Alxa League in Inner Mongolia. The levels of water irrigation were 216 mm (W₁), 288 mm (W₂) and 360 mm (W₃), and the nitrogen dosages were 127.5 kg·hm^-2(N₁), 195 kg·hm^-2(N₂) and 262.5 kg·hm^-2(N₃). The results showed that water was the decisive factor for cotton growth, and plant height and dry matter accumulation increased rapidly with increasing the water irrigation level, but the ratio of reproductive organs to shoot biomass decreased. Compared with the treatments W₁ and W₂, the average boll number per plant in W₃ was increased by 25.4% and 17.5%, the seed cotton yield was improved by 18.1% and 11.9%, but the single boll mass was decreased by 5.8% and 4.6%, respectively. It indicated that an increase in boll number per plant was the determining factor in achieving high seed cotton yield. Moreover, there was also a significant interactive effect between water and nitrogen affecting the seed cotton yield. Under the condition with low-level irrigation (W₁ and W₂), the highest seed cotton yield was measured in N₁; while for the condition in W₃, the seed cotton yield in N₂ was greater than that in N₁ and N₃ by 8.5% and 31.9%, respectively. In general, the regulation of water and nitrogen had no significant effect on fiber quality. Water use efficiencyin W₁N₁ was 1.37 kg·m^-3, which was not significantly different with the value in W₃N₂, and the nitrogen partial factor productivityin W₃N₁ was the maximum (51.35 kg·kg^-1). Therefore, irrigation had a significant effect on yield increasing, but nitrogen application promoted the seed cotton yield only under well-watered conditions. The treatment with irrigation amount of 360 mm and nitrogen fertilizer of 195 kg·hm^-2 could promote the shoot biomass accumulation significantly and achieve the highest seed cotton yield, and its water use efficiency and nitrogen partial factor productivity were 1.37 kg·m^-3 and 36.41 kg·kg^-1, respectively, indicating the potential of water-saving and yield increasing. Therefore, it was recommended as a suitable water and nitrogen management for the mechanically harvested cotton in arid area of western Inner Mongolia.