【作者】 张俊花；

【导师】 张凤路； 张立峰；

【作者基本信息】 河北农业大学 ， 作物栽培学与耕作学， 2009， 博士

【摘要】 近年来,随着冀西北高原生态环境的恶化,在国家政策的支持下,开始实行主动的退耕还林还草,使农牧交错带耕地面积显著下降,制约了该地区农民的经济收入。近十几年来,该地区在仅占耕地面积10%~15%的洼滩地上(草甸栗钙土)积极发展错季蔬菜,大大增加了农民的收入,但是,占耕地面积65%的坡梁地(岗梁砂质栗钙土)尚未得到高效开发利用。为了更加有效地利用当地的资源,积极开发该地区的坡梁地已成为当地政府部门和科技攻关者的首要任务。南瓜是粮菜兼用作物,经济产值较当地坡梁地主种作物莜麦高7~8倍。另外,其适合稀植,比较耐旱,因此,成为该地区开发坡梁地的首选作物。但该地区主要采用宽行稀植的栽培方式,这种栽培方式是否达到对该地区光水资源的合理利用有待于研究。本文应用田间试验与室内试验、定性分析和定量分析相结合等研究方法,系统研究了冀西北高原地区南瓜的光合特性,对南瓜//油葵间作的立体种植模式是否能高效利用该地区光水资源进行了探究和分析,并提出了南瓜合理的配套栽培措施,为当地南瓜的合理种植和高效利用该地区资源提供理论依据,为区域作物生产结构的调整与农田水土资源的高效利用提供理论与技术。研究结果表明:南瓜喜光,其苗期适宜的光照强度为887.82~2274.32μmol/m2.s;抽蔓期和结果期均为1402.74~2523.15μmol/m2.s,适合冀西北高原光照强的生态特点;南瓜苗期、抽蔓期和结果期的光补偿点(LCP)分别为257.91～330.88μmol/m2.s,181.25～229.2μmol/m2.s,67.96～72.81μmol/m2.s;而光饱和点(LSP)则分别为1828.57～1978.57μmol/m2.s,2110.00～2146.86μmol/m2.s,2128.57～2182.50μmol/m2.s;南瓜单个叶片从展开到衰老过程中,光合速率(Pn)随着叶片的生长呈先上升达最大值后再下降的趋势。晴天叶片Pn日变化无论生育期是否相同(苗期、抽蔓期和结果期)、品种是否相同(精品香栗和红太阳)、部位是否相同(顶部叶片、中部叶片和基部叶片),无一例外地表现为“双峰”曲线,存在光合“午休”现象,只是“午休”的时间和程度上有差异;叶片光能利用率(SUE)日变化呈下降→上升→下降趋势。南瓜//油葵间作效应的研究表明:通过根系及根冠比的分析,发现油葵在间作复合群体中处于竞争优势地位。间作南瓜的根系和其地上部的生物量均低于单作南瓜,而间作油葵的根系和其地上部生物量均高于单作油葵;南瓜行间种植两行油葵(J2)在南瓜生长中后期出现了油葵与南瓜争夺水分的现象,而南瓜行间种植一行油葵(J1)无此现象。各处理间水量平衡各分量有较大的差异,在整个生育时期降雨量为201.6mm的情况下,渗漏量占的比重非常小,并且土壤蓄水量变化均为负值,因此绝大部分水分都是以汽态水蒸散掉,但不同间作方式蒸散失水不同,其中J1较南瓜单作(ND)、油葵单作(YD)和J2分别少散失土壤水分36.33%、19.00%和34.87%。得益于油葵的偏利效应使南瓜经济产量下降30.00% ~71.42%,而间作油葵单株产量相对单作油葵提高190.71%~ 241.26%,虽其土地当量比(LER)和水分当量比(WER)分别达1.08~1.22和1.07~1.26,但复合群体的经济效益只能与南瓜单作田持平甚或降低20.69%。研究还表明,在南瓜//油葵间作复合群体内,油葵处于间作上位优势,在南瓜结果期内对南瓜冠层光合辐射和温度的影响程度随南瓜和油葵生育期的推进而降低,南瓜冠层越接近油葵,油葵对南瓜冠层光合辐射和温度的影响程度越大,且J1和J2对南瓜冠层光合辐射和温度的影响差异缩小。间作降低了复合群体内南瓜功能叶片的叶绿素含量,降低了南瓜对光能的吸收和转化效率,导致间作南瓜叶片的PSⅡ原初光能转化效率、潜在活性和光合速率明显低于单作南瓜。在冀西北高原雨养背景下,稀植高效的南瓜单作生产能够实现对区域光热资源的高效利用。栽培措施研究表明:在结果初期对南瓜减源,作为最直接源的瓜三叶(即瓜前叶、瓜叶和瓜后叶,瓜蔓伸长方向为前)光合有很强的补偿效应,但减源数量的不同使后期光合速率差异很大,大量减源(减少75%)瓜三叶出现早衰的现象提前,而适量减源(减少25%)于后期可以维持较好的光合性能。不同的源库比例其干物质积累数量不同,适量减源处理干物质积累较CK高18.66%;大量减源处理干物质积累较CK低36.25%。减源处理的叶面积载荷量高于CK,使源的光合产物向库输送的“流”更加通畅。南瓜比较耐旱,采用开沟覆膜、聚水集肥等措施,南瓜的定植密度可达14250~16500株/hm2;在此密度下,南瓜对地面覆盖的程度加大,减少了行间土壤水分的蒸发,提高了土壤水分利用效率,促进了南瓜光合速率的提高,从而有助于产量的提高。钾肥施用量的研究还表明,在南瓜栽培中,施用适量钾肥(121.5kg/hm2),可提高南瓜叶片的光合速率,一定程度上可以降低南瓜叶片的蒸腾速率,有利于保持叶片的含水量;也能使茎秆粗壮,可以有效地促进单位叶面积内干物质的积累,为南瓜的生育提供更多的养料,明显促进南瓜产量提高。在冀西北高原雨养旱作条件下,通过栽培技术措施(如土壤耕作、种植密度调整、源库搭配等)的改进来提高南瓜的光热利用率,通过土壤培肥来满足南瓜生长发育营养供应,这是稀植高效的南瓜单作生产能够实现对区域光水资源高效利用的一种切实可行的途径。更多还原

【Abstract】 In the recent years, accompany with ecological environment deterioration in the plateau in the northwest of hebei province, it begins to actively carry out returning farmland and restoring forest and grass under supporting of national policy; Because cultivated areas decreased significantly, peasants, economic incomes reduced. In the recent more than ten years, unseasonal conditions vegetables rapidly develop in meadow chestnut soil, which accounting for 10%~15% of total cultivated areas, and increasing peasants, economic incomes. But the areas of sand chestnut soil, which accounting for 60%~70% of total cultivated areas, donot perform highly exploitating and efficiently utilizing. To better utilize efficiently these resources, it has been become the most important task for local government and technology tackling patients to positively exploit the areas of sand chestnut soil. Pumpkin can be used as both vegetable and food crop. Its economic value is 7~8 times more than naked oats. As it has the characteristics of drought tolerance and suitability for larger spacing planting, it is usually taken as the first candidate crop for increasing economic benefit in arid areas.The thesis adopted the research methods of field experiment combining laboratory experiment, qualitative analysis combining quantitative analysis. In this paper, photosynthetic characteristics of pumpkin was studied, and whether stereo planting pattern of pumpkin and oil sunflower can utilize efficiently light and water resources was studied and analyzed. Reasonable integrated cultural practices of pumpkin were put forward, too. This paper put forward theoretical basis for reasonable integrated cultural practices of pumpkin and utilizing efficiently light and water resources, at the same time, theory and technology was put forward for adjusting production structure of regional crop and utilizing efficiently farmland water and soil resources.The results showed as follow: pumpkin is positive vegetable, its optimum light intensity in seedling stage, vine-expending stage, fruit expansion stage was 887.82~2274.32μmol/m2.s , 1402.74~2523.15μmol/m2.s , 1402.74~2523.15μmol/m2.s, respectively; and it is suitable for ecological characteristics of intense light irradiation in the plateau in the northwest of hebei province, its light compensation point in seedling, vine-expending stage, fruit expansion stage was 257.91～330.8μ8mol/m2.s,181.25～229.2μmol/m2.s,67.96～72.81μmol/m2.s, respectively; its light saturation point in seedling, vine-expending stage, fruit expansion stage was 1828.57～1978.57μmol/m2.s,2110.00～2146.86μmol/m2.s,2128.57～2182.50μmol/m2.s. Pn of single leaf of pumpkin show the tendency of rising firstly and declining finally. The daily change trendency of Pn of leaves in pumpkin showed a double peak curve, and there was a significant“midday depression”at noon; the extent and duration of“midday depression”of pumpkin were stomatal factor more than that of non stomatal factor; whether growth periods, varieties, and leaf positions were or not the same. The daily change trendency of solar energy use efficiency of leaves in pumpkin showed declining firstly, rising, and declining finally.The study on the effect of pumpkin and oil sunflower intercropping system indicated that by analyzing roots and ratio of root to shoot, oil sunflower was dominant in this intercropping system.The root and the above-ground biomass of intercropped pumpkin with oil sunflower were lower than those in sole pumpkin cropping, while those of oil sunflower were just on the contrary; Oil sunflower competed for soil water with pumpkin during later growth stage of pumpkin about cropping two rows oil sunflower between pumpkin rows(J2), but there was no water competition with pumpkin about cropping one rows oil sunflower between pumpkin rows(J1).On condition that precipitation was 201.6mm during whole growth and development period, there was obvious difference between every gradient of water balance in different treatment. The ratio of water percolation was little; and all variations of soil water storage were negative, so almost all water was evapotranspirated by gaseous water, but the evapotranspiration of different treatment were different, the evapotranspiration of J1 was less than ND、YD and J2 for 36.33%、19.00% and 34.87%, respectively. Economic yield of pumpkin decreased from 30.00% to71.42%, but yield per plant of intercropping oil sunflower increased from 190.71% to 241.26% as compared with sole oil sun-flower, because of oil sunflower had laterality effect. The Land Equivalent Ratio (LER) of pumpkin-oil sunflower were 1.08~1.22, and the Water Equivalent Ratio (WER) of pumpkin-oil sunflower were 1.07~1.26, but economic benefit of compound population was similar to sole pumpkin or decreased 20.69%.The results from pumpkin and oil sunflower intercropping system showed that oil sunflower was dominant in this intercropping system.The influenced degree to PAR and temperature of canopy in fruit expansion stage of pumpkin was decreased company with the propulsion of growth period in pumpkin and oil sunflower; The shorter the distance from pumpkin to oil sunflower, the greater the influenced degree to PAR and temperature of canopy in pumpkin, and there was no obvious differences between J1 and J2. Pumpkin and oil sunflower intercropping system decreased the contents of Chl in functional leaves, absorption and transformation efficiency of light energy, which led to Fv/Fm, Fv/Fo and Pn of intercropping pumpkin lower than sole pumpkin. On the background of rain-fed and dry farming, slope pumpkin of sparse planting and efficient could realize regional light and heating resource using efficiently in the plateau of northern Hebei province.The study on the cultural practices for pumpkin showed that the photosynthetic rates of three leaves had very strong compensation effects when source-reduced in fruit early stage. The photosynthetic rates of three leaves had great differences in fruit later stage because of different source-reduced quantities; premature senility phenomenon advanced for the photosynthetic rates of three leaves when 75% source-reduced; photosynthetic characteristics could be maintained well in fruit later stage when 25% source-reduced. The quantities of accumulated dry matters varied as defferent source-sink proportions, The quantities of accumulated dry matters were more than those of CK when 25% source-reduced, less than those of CK when 75% source-reduced. Loading amounts of leaf areas were higher than the treatments of source-reduced, which led to more fluency when photosynthates were transported from source to sink.As pumpkin has the characteristics of drought tolerance, planting density is 14250~16500 plantlets per hm2, which increasing the mulching degree to the ground, decreasing soil water evaporation between rows, improving WUE and the photosynthetic rate and yield. Study on the potassium fertilizer applying rate for pumpkin showed the potassium fertilizer improved the photosynthetic rate, decreased the transpiration rate in leaves, and maintained water contents in leaves; this study also showed the potassium fertilizer promoted stem overstriking and dry matter in per leaf area accumulating, which providing more nutrients and improving obviously yield for pumpkin.On the background of rain-fed and dry farming in the plateau in the northwest of Hebei province, light and heat use efficiency in pumpkin could be increased by improving cultural control methods such as farming soil, adjusting the planting density, collocating optimal source-sink,et al. In addition, supplying nutrients for growth and development of pumpkin by fertility betterment, which could be a real and feasible way to realize regional light and water resource using efficiently for sole cropping pumpkin in the plateau of northern Hebei province.更多还原