早熟区不同播期旱地玉米产量对施肥水平和种植密度的响应

Response of dryland maize yield to fertilization rate and planting density at different sowing dates in early-maturity areas

为明确早熟区不同播期旱地玉米产量对施肥水平和种植密度的响应特征及趋势,完善高产高效密植栽培技术,采用田间试验法,以传统耕种方式为对照,于2010—2011年连续2年研究了不同播期[秋耕早播和正常播种(对照)]、施肥水平和种植密度对旱地玉米主要产量性状的影响。结果显示,2010年(遭遇"卡脖旱")秋耕早播经济产量、收获指数和水分利用效率分别较对照增加9.0%、7.1%和6.4%(P<0.01),百粒重(P<0.01)和出籽率(P<0.05)显著大于对照。2011年(丰水年)增幅明显增加,经济产量、收获指数和水分利用效率分别较对照增加13.1%、8.8%和8.5%(P<0.01),穗粒数(P<0.05)和百粒重(P<0.01)显著大于对照。随着施氮水平增加,经济产量和生物产量都呈增加趋势,但2010年秋耕早播过量施肥造成明显减产,2011年施肥处理经济产量显著大于不施肥处理,而不同施氮水平间无显著差异。秋耕早播较低的施肥量可获得较高的产量。随着密度增加,2010年玉米经济产量和生物产量呈二次抛物线型,秋耕早播获得最高经济产量的种植密度为7.5万株·hm 2,该年型秋耕早播可通过适当增密获得高产,而对照增密会造成严重减产。2011年经济产量和生物产量随种植密度增加而增加,但当密度增加到7.5万株·hm 2时经济产量不再显著增加。受旱年份秋耕早播较对照缩小了密度效应,为增产奠定了一定基础,且施肥和密度对产量存在显著互作效应,而丰水年互作效应不明显。对照该生态区目前的玉米栽培措施,在适期早播的基础上,减少肥料用量和适当增密是该区实现玉米高产高效栽培的技术方向。

In order to determine the response of dryland maize sown at different dates to fertilization rate and planting density in early-maturity regions, consecutive field experiments were carried out in 2010 and 2011. The experiment studied the effects of sowing dates [autumn plowing and early sowing （APES） and conventional sowing （control）], fertilization rates and planting densities on the indicators of dryland maize yield. The study aimed to improve yield through highly efficient and compact planting techniques. Results showed that maize grain yield （GY）, harvest index （HI） and water use efficiency （WUE） under APES with a certain degree of summer drought in 2010 increased respectively by 9.0%, 7.1% and 6.4% over the control （P〈 0.01）. The 100-grain weight （HGW, P 〈 0.01） and kernel ratio （KR, P 〈 0.05） were also greater than those of the control. GY, HI and WUE under APES in the rainy year of 2011 significantly increased （P 〈 0.01） respectively by 13.1%, 8.8% and 8.5% over the control. Grain number perspike （P 〈 0.05） and HGW （P 〈 0.01） were significantly greater than those of the control. GY and shoot biomass （SB） increased with increasing fertilization rate. However, yield under APES in 2010 decreased with excessive fertilization rate. For the rainy year of 2011, GY under fertilization treatment was significantly greater than that under non-fertilization treatment, while no significant difference was noted in GY among different fertilization treatments. The results suggested that APES with low fertilization rate favored high yields. With increasing planting density, maize GY and SB dynamics in 2010 tracked a quadratic parabolic curve. Plant density of 75 000 plants.hm-2 gave the highest yield under APES. This suggested that while yields under APES increased at higher planting density in dry year, increasing planting density severely limited yield under the control. In wet year of 201 l, GY and SB increased with increasing planting density. However, as planting density was above 75 000 plants.hm 2, GY no longer significantly increased. In dry year of 2010, the effect of planting density on yield under APES was weaker than that under the control, which generally favored high yield under APES. While fertilization rate and planting density had a significant interactive effect on yield in dry year, such interactive effect was insignificant in wet year. Thus compared with present maize cultivation practices, early sowing during optimum period, low fertilization rate and appropriate planting density was an efficient maize cultivation technique for high yield.