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101.
102.
施氮对不同质地滴灌棉田土壤硝态氮分布及棉花产量的影响 总被引:2,自引:1,他引:2
为了探究施氮对不同质地滴灌棉田硝态氮分布及产量的影响,采用温室土柱模拟的方法,研究了滴灌条件下不同质地土壤硝态氮分布迁移特征,分析了施氮对NO_3-N和棉花产量的影响。结果表明,在灌水量一定的条件下,在砂土、壤土中施氮量分别为256.00、287.34 kg/hm~2时,相应的氮素积累量最大,皮棉产量最高,土壤硝态氮主要集中分布在30~40 cm土层,有利于棉花根系的吸收,且分别比不施氮增产43.87%和44.92%。一定施氮量下,壤土硝态氮分布的均匀性优于砂土,并且根层20~40 cm土层硝态氮量高于砂土,且比砂土平均增产6.16%。砂土、壤土中硝态氮量在各生育期总体呈现"降-增-降"的变化趋势,并且收获前期施纯氮340 kg/hm~2处理60cm土层砂土硝态氮量的第二个峰值较壤土提高15.98%,在生育期末端砂土在深层的氮素积累高于壤土,存在继续向下淋失的风险。 相似文献
103.
以春玉米品种金穗2号为材料,研究限量灌溉和施氮对春玉米生长及生理指标的影响。结果表明,较低的灌水量和施氮水平对春玉米苗期的叶面积和冠层的生长有一定的促进作用,但严重缺水会抑制其生长发育。灌水量适中(1012 m3/ha),春玉米苗期平均叶面积显著高于其他处理;施氮水平达75 kg/ha可以满足春玉米苗期生长的需要,而大量施氮会造成烧苗,说明高氮和充分供水不一定利于玉米的生长。 相似文献
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J. G. Wesseling C. R. Stoof C. J. Ritsema K. Oostindie & L. W. Dekker 《Soil Use and Management》2009,25(3):274-283
To gain more insight into the hydrological behaviour of coarse-textured soils, the physical properties of artificially created soil mixtures with different texture were determined. The mixtures were prepared according to the specifications of the United States Golf Association (USGA) for constructing putting greens. In addition, the effect of 10 vol.% organic matter addition was studied. The soil moisture retention and hydraulic conductivity relationships of the different mixtures were determined and their hydrological behaviour was studied using the numerical model SoWaM. Both texture and organic matter addition substantially affected the hydraulic properties. Hydraulic conductivity significantly increased with increasing coarseness while moisture retention decreased. On the other hand, organic matter addition reduced saturated hydraulic conductivity by a factor of 10 to 100 and distinctly increased moisture retention capacity. The amounts of total available water were increased by the addition of organic matter between 144% (slightly coarse texture) and 434% (very coarse texture). Results indicate that the mixtures can contain only 2–16% plant available water and therefore need frequent irrigation to maintain plant growth. Addition of organic matter seems a good solution to reduce the irrigation water requirements but it increases the risk of ponding or runoff because of large reductions in the saturated hydraulic conductivity sometimes to below the rate of 3.6 m/day recommended by the USGA. 相似文献
106.
发酵方法对柿果醋中香气成分的影 总被引:5,自引:2,他引:3
采用顶空固相微萃取法、结合气相色谱质谱联用技术,对自然发酵和常规发酵柿果醋中香气成分进行了分离与分析比较,分别从2种柿果醋中分离鉴定出挥发性化合物63种,均含有酯类、羧酸类、醇类、烃类、醛酮类、酚类及少量其他化合物.常规发酵柿果醋香气成分中含有酯类33.78%、醇类32.38%和烃类1.08%,高于自然发酵柿果醋的含量;自然发酵柿果醋香气成分中含有羧酸类61.25%、醛酮类9.66%和酚类6.13%,高于常规发酵柿果醋的含量.采用常规发酵法生产的柿果醋具有较好的感官质量. 相似文献
107.
畦田Philip入渗参数和田面综合糙率同步推求 总被引:5,自引:1,他引:4
以水量平衡原理为基础,通过对畦灌地表水面线的概化,并将Philip入渗公式等同为α=0.5的Kostiakov修正模型,由此建立了利用畦灌水流推进过程同步推求Philip土壤入渗参数和田面综合糙率的模型.结合文献资料和大田试验对所建模型进行验证,并采用Matlab软件求解,得出不同地表储水形状系数σh下的入渗参数和糙率,并分别对入渗参数和田面综合糙率的可靠性进行了验证,结果表明所建模型同步推求土壤入渗参数和田面综合糙率是可靠的,并且计算方便,精度较高. 相似文献
108.
河北省粮食两熟产区小麦冬前应变灌溉的气候分析 总被引:1,自引:1,他引:0
以选取的河北省山前平原区和黑龙港区的6个县(市)为样点,通过统计各地1973—2007年35年气象资料,分析了与灌溉决策有关的气候条件和冬前应变灌溉方案。结果表明:河北省小麦玉米两熟产区1/3年份的降水可满足播种出苗需要,这时趁墒播种应为首选。其他年份应尽量采取灌足底墒水播种的方式。若因农时紧张需适时抢播,播后应马上灌蒙头水。由于冬季气候变暖,越冬前的灌水应以保证越冬期和返青至拔节期水分供应为主,防御冻害为辅,应通过合理的冬前灌溉保证春季第一次肥水时间能推迟到拔节前后。 相似文献
109.
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The water-saving potential of using micro-sprinkling irrigation for winter wheat production on the North China Plain 下载免费PDF全文
Li-chao ZHAI Li-hua LÜ Zhi-qiang DONG Li-hua ZHANG Jing-ting ZHANG Xiu-ling JIA Zheng-bin ZHANG 《农业科学学报》2021,20(6):1687-1700
The shortage of groundwater resources is a considerable challenge for winter wheat production on the North China Plain. Water-saving technologies and procedures are thus urgently required. To determine the water-saving potential of using micro-sprinkling irrigation(MSI) for winter wheat production, field experiments were conducted from 2012 to 2015. Compared to traditional flooding irrigation(TFI), micro-sprinkling thrice with 90 mm water(MSI1) and micro-sprinkling four times with 120 mm water(MSI2) increased the water use efficiency by 22.5 and 16.2%, respectively, while reducing evapotranspiration by 17.6 and 10.8%. Regardless of the rainfall pattern, MSI(i.e., MSI1 or MSI2) either stabilized or significantly increased the grain yield, while reducing irrigation water volumes by 20–40%, compared to TFI. Applying the same volumes of irrigation water, MSI(i.e., MSI3, micro-sprinkling five times with 150 mm water) increased the grain yield and water use efficiency of winter wheat by 4.6 and 11.7%, respectively, compared to TFI. Because MSI could supply irrigation water more frequently in smaller amounts each time, it reduced soil layer compaction, and may have also resulted in a soil water deficit that promoted the spread of roots into the deep soil layer, which is beneficial to photosynthetic production in the critical period. In conclusion, MSI1 or MSI2 either stabilized or significantly increased grain yield while reducing irrigation water volumes by 20–40% compared to TFI, and should provide water-saving technological support in winter wheat production for smallholders on the North China Plain. 相似文献