底部渗灌下施肥对华北落叶松容器苗生长和养分状况的影响

采用完全随机区组设计,以华北落叶松(Larix principis-rupprechtii Mayr.)1年生播种苗为研究对象,底部渗灌下设置3个梯度施肥量(0.36、0.72、1.08 g·株~(-1))。通过观测生长末期(11月25日)苗木的形态指标和氮、磷、钾等养分状况,确定了华北落叶松容器苗底部渗灌条件下最佳缓释肥施肥量。结果表明:底部渗灌缓释肥能有效促进华北落叶松的生长。当施肥量为0.72 g·株~(-1)时,1年生华北落叶松容器苗开始进入奢养阶段,此时的苗高、地茎和生物量达到最大,分别为34.60 cm、3.86 mm和1.36 g。为培育造林效果好的华北落叶松容器苗,底部渗灌技术下缓释肥较佳施肥量为0.72~1.08 g·株~(-1)。     

Growth and Yield Responses of Two Soybean Cultivars Grown under Controlled Groundwater Level in Southwestern Japan

Abstract

One of the limiting factors of soybean yield in southwestern Japan is soil moisture fluctuation from flooding to drought. The Farm-Oriented Enhancing Aquatic System (FOEAS), which consists of underdrain and sub-irrigation systems and can keep groundwater levels stable, was developed in 2005 to solve this problem. To obtain basic information on soybean cultivation using the FOEAS in southwestern Japan, we examined the growth response to groundwater level by using two cultivars (cv. Fukuyutaka and Sachiyutaka) in 2008 and 2010. Plant growth, yield, yield components and seed components (protein and oil contents) were analyzed. We also studied the effect of sowing time (normal or late). The groundwater level was controlled at depths of 20 and 35 cm or not treated (NT) as a control. The groundwater level could be kept at the target depths (20 and 35 cm) by FOEAS throughout the experimental period, but that in the NT plot fluctuated greatly. The growth and yield of Sachiyutaka might be increased by FOEAS, especially in late sowing, but the yield of normal sown Sachiyutaka was decreased in the 20-cm plot in 2010. Yield of late-sown Fukuyutaka tended to be decreased in the 20-cm plot. These results suggest that (1) the optimum groundwater level for yield of Sachiyutaka is between 20 and 35 cm, regardless of sowing time and (2) the groundwater level should not be kept at 20 cm for late-sown Fukuyutaka. Further studies are needed to determine the optimum groundwater level for each cultivar.     

底部渗灌对华北落叶松容器苗水肥利用状况及生长、光合特性的影响1）

以华北落叶松播种容器苗为研究对象,采用完全随机区组设计,设5个灌水梯度、3个施肥量,共15个水肥处理,探讨不同水肥条件与苗木质量及光合特性间的关系,以期找出华北落叶松容器苗底部渗灌的最佳灌水梯度及缓释肥量。结果表明：与上方灌溉相比,底部渗灌节水68％,苗高提高了6．1％～14．6％;苗木生物量、净光合速率、水分利用效率及叶绿素质量分数随灌水梯度及施肥量的增大呈先增加后降低的趋势;底部渗灌条件下,华北落叶松当年生容器苗最佳水肥组合为75％灌水梯度、施氮量100 mg·株－1,此处理下苗木水分利用效率、净光合速率及总叶绿素质量分数达到最大,分别为0．89 g·L －11、0．37μmol· m－2· s－1及1．85 mg· g－1,平均苗高为23．73 cm、地径为3．03 mm、总生物量为0．68 g·株－1,比上方灌溉处理分别提高了19．42％、7．44％、15．25％。     

渗灌土壤水分运动数值模拟软件设计方法研究

数值模拟是认识渗灌条件下土壤水分运动规律的重要方法之一,其可为渗灌工程的实施提供理论指导。为降低渗灌条件下土壤水分运动数值模拟研究的成本,在渗灌条件下土壤水分运动数值模拟软件的设计方法上进行了探讨,分析了软件实现的功能,提出了一种渗灌条件下土壤水分运动数值模拟软件的开发模型,并采用面向对象的方法和迭代-增量式的开发过程实现了该软件。本软件能够应用于渗灌条件下土壤水分运动数值模拟,能够模拟土壤初始条件、灌水压力、渗灌管特性和计算区域边界条件对土壤水分运动的影响,能模拟渗灌条件下土壤水分的再分布过程。软件运行可靠、操作方便,具有一定的通用性。