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81.
《Communications in Soil Science and Plant Analysis》2012,43(1-2):258-264
The improvement of water and nutrient efficiency leads to a production model that is more sustainable with less water, fewer fertilizer inputs, and less environmental damages. High-technology fertigation equipment permits high precision in the nutrient solution application. Besides, the field measurement of soil water content by tensiometers and the extraction of soil solutions by suction cups allow a dynamic methodology management in agreement with real crop requirements. This trial was carried out to compare this dynamic fertigation management method (using tensiometers and suction cups) for tomato crops (Lycopersicum sculentum Mill. Forteza) under Mediterranean greenhouse conditions with other methods: the local traditional model, based only on technical consulting, and the classical model, by means of estimation of Kc and nutrient extractions references. The parameters studied were tomato yield, water, and fertilizer amounts applied during the cultivation as well as water- and fertilizer-use efficiency. The water used to prepare the nutrient solution was classified as C4-S3 following the Riverside classification system. Plants were grown from 15 August to 20 April. The results show that the supply of fertilizers during the cultivation has been significantly lower with classical and dynamic models. Dynamic method shows greater efficiencies for all the elements, except for potassium, and also decreases the water consumption, not affecting total yield. 相似文献
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蓝靛果忍冬色素提取工艺的研究 总被引:2,自引:0,他引:2
以蓝靛果忍冬果实为原料,进行了天然色素提取工艺研究。结果表明:蓝靛果忍冬色素最佳的提取工艺条件为:提取剂采用无水乙醇效果较好,用量为35mL;提取pH 3、最适合的提取温度为80℃、60min为最佳的提取时间。 相似文献
85.
基于ARCENGINE空间分析的林业区划界线自动提取方法 总被引:1,自引:0,他引:1
使用ARCENGINE的空间分析接口,编程实现林业区划界线的自动提取。与传统方法相比,该方法极大地提高了林业区划界线提取的效率和准确度,且自动化程度高,极易推广。 相似文献
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N. R. Atkinson S. D. Young A. M. Tye N. Breward E. H. Bailey 《Soil Use and Management》2012,28(4):559-570
Urban waste disposal occurred on fenland to the west of Manchester, England, between 1900 and 1964. The reclaimed fenland, Chat Moss, is now used for mixed arable farming. A total of 1.92 Mt of waste including privy midden, street sweepings, clinkers and slaughterhouse refuse was incorporated into the moss resulting in a modified topsoil with raised pH and reduced organic matter content compared with the subsoil. Elevated levels of potentially toxic elements (PTEs) are observed in the topsoil beyond the typical depth of atmospheric contamination; Cd and As concentrations exceed soil guideline values (SGVs) at 1.8 and 43 mg/kg, respectively. Sequential extraction indicates that waste‐derived Pb, Zn and Ni remain predominantly in the residual fraction, whereas Cu was mainly organically bound. Arsenic was predominately found in oxide and organic matter fractions with Cd in carbonate, oxide, organic matter and residual fractions. Pot trials indicated limited uptake of PTEs by vegetables grown on the waste‐amended soil, with the exception of Cd uptake by lettuce (0.22 mg/kg FW) and Pb uptake by radish (0.16 mg/kg FW), which exceeded current EU limits of 0.2 and 0.1 mg/kg FW, respectively. Hazard quotients (HQs) identified no risks to adults from consumption of vegetables grown in these soils with the exception of lettuce consumption with a HQ of 1.4. Risks to children were slightly greater with HQs >1 for Cd in lettuce, spinach, carrots and onion, As in lettuce, parsley and onion and for Zn in spinach. 相似文献
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采用超临界CO2萃取技术,对极香罗勒芳香油进行了萃取,并利用气相色谱—质谱法(GC-MS)对芳香油成分进行了鉴定。结果表明:芳香油的主要成分为萜类物质共34种,占总芳香油的46.47%;脂肪酸类3种,占总芳香油的34.61%;芳香族醚类化合物有3种,总芳香油的7.84%;酯类有2种,占总芳香油的3.91%;烃类2种,占总芳香油的1.86%。芳香油中相对含量最高的是亚麻酸,占总芳香油的27.69%;其次是芳樟醇,占总芳香油的12.96%;其它含量较高的成分依次是(+)表-双环倍半水芹烯(7.53%)、m-丁香酚(5.88%)。 相似文献
90.
Weed seedbanks are the primary source of weeds in cultivated soils. Some knowledge of the weed seedbank may therefore be appropriate for integrated weed management programs. It would also be very useful in planning herbicide programs and reducing the total herbicide use. However, a number of problems are inherent in the estimation of the seedbank size for arable weeds that usually have annual life cycles. In a long-term research project we have investigated the dynamics of weed seedbanks in corn fields for the past 8 years. Specific studies have included (i) developing cheap and efficient methods for estimating the weed seedbank; (ii) developing guidelines for efficient soil sampling (including the number and size of samples); (iii) influence of cultivation methods on weed seed distribution; (iv) mapping the spatial variability of the seedbank; (v) estimating the rate of seedbank decline for certain weed species; and (vi) assessing the potential of using the weed seed content in the soil to predict future weed problems. This paper reviews and summarizes the results of our research on the above aspects. The strong correlation between seedlings emerged in the greenhouse and seeds extracted in the laboratory for the most abundant weed species has demonstrated the potential for using the weed seed content of the soil to predict future weed infestations. The next step is to establish correlations with field emergence under commercial conditions using the sampling guidelines developed in our studies. Subsequently, we aim to offer the weed seedbank estimation as a commercial service to farmers for planning the most appropriate weed management options. 相似文献