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31.
In order to investigate the effect of tea tree rhizosphere soil acidification on yield and quality of tea tree, the pH value, yield, and quality index of fresh tea leaves of different ages were analyzed, and the correlation between rhizosphere soil acidification and ages, yield, and quality index were studied from nine tea plantations in Anxi county, Fujian Province. The results showed that 37.67% of the nine soils were acidified, and 10.03% of them were suitable for planting tea tree. Furthermore, the results indicated that the age of tea tree was significantly and negatively correlated with the soil pH value, as shown by a decrease in soil pH values associated with an increase in tree age. In addition, the yield of spring and fall crops of tea from these nine plantations were all significantly and positively correlated with the pH value, with correlation coefficients distribution values of 0.912-0.952 and 0.898-0.973, respectively. In addition, quality indices, including polyphenols, theanine, and caffeine for the nine tea plantations were all significantly and positively correlated with their soil pH values, and their correlation coefficient distribution values were 0.897-0.959, 0.908-0.974, and 0.907-0.975, respectively. Above all, as tea tree ages increased, rhizosphere soil acidity was significantly increased, and yield and quality of tea presented a statistically significantly up/down trend. © 2018 Science Press. All rights reserved. 相似文献
32.
The focus of the present study was to assess the ozone levels in a typical area of the Mediterranean basin, viz. Tuscany (central Italy). Eighty-thousand hourly mean ozone concentrations were recorded by 10 automatic analysers in the districts of Florence, Pisa, Lucca and Prato, from May to September 1995 to 1997. The highest daily mean concentrations were reached in Florence, with a maximum hourly average of 197 ppb. In Lucca and Pisa, the peaks were close to 100 ppb. Data from Prato were much lower. Long-term critical levels for vegetation, as set by United Nations Economic Commission for Europe (UNECE), were constantly exceeded in Florence and Pisa, occasionally in Lucca, never in Prato. The results were used to fit exposure/yield response relationships proposed by UNECE and US National Crop Loss Assessment Network for some important crops. The estimated yield losses varied in Florence from 8% for corn and alfalfa to 27% for soybean, in Pisa from 5% for corn to 24% for soybean, in Lucca from 3% for corn to 17% for soybean. A preliminary economic estimate for corn, wheat, barley, soybean, tomato and alfalfa, calculated annual damage to be 4.6 M Euro in Florence, 0.5 M Euro in Lucca and 3 M Euro in Pisa. The picture must be regarded as only partial, as exposure/yield response relationships for important Italian crops (such as grapevine and vegetables) are not available. 相似文献
33.
Qidong Wang Jiashou Liu Shengyu Zhang Yuxi Lian Huaiyu Ding Xue Du Zhongjie Li Sena S. De Silva 《Ambio》2016,45(3):361-373
Results of a survey of 156 Chinese mitten crab (Eriocheir sinensis) grow-out farms around Hongze Lake
(118.48–118.72°E; 33.36–33.38°N) are reported. Area farmed has remained relatively
unchanged but production (59 932 t in 2012)
increased steadily over the last 7 years, indicative of the viability and
sustainability of the farming system that has gradually replaced intensive Chinese
major carp polyculture around Hongze Lake. Results showed that production range was
135–2400 kg ha−1 cycle−1
(mean 1144 ± 34). Crab yields correlated linearly to stocking density and conformed
to a normal distribution curve, with 66.7 % of farms yielding
900 kg ha−1 cycle−1 or more.
Yield was negatively correlated to pond size and capture size (p < 0.01), and farms with macrophyte coverage rate
lower than 30 % of water surface were significantly (p < 0.05) lower than those exceeding 30 %.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-015-0722-0) contains supplementary material, which is available to authorized users. 相似文献34.
Victor Cucarella Ryszard Mazurek Micha? Kope? 《Environmental pollution (Barking, Essex : 1987)》2009,157(7):2147-2152
Reactive filter materials used for phosphorus (P) removal from wastewater can be disposed of as soil amendments after treatment, thus recycling P and other macro- and micro-nutrients to plants. In addition, materials with a high pH and Ca content, such as Polonite, are potential soil conditioners, which can be particularly beneficial for acid soils. Polonite previously used for on-site wastewater treatment was applied as a soil amendment to a mountain meadow. The amendment significantly increased soil pH and decreased the hydrolytic acidity, thus reducing Al toxicity risks. The effects were comparable to those of liming. No difference in yield and P uptake by meadow plants was observed. The uptake of metals was lower for amended soils, especially the uptake of Mn. Using Polonite after wastewater treatment as a soil amendment is thus a viable disposal alternative that can replace liming, when necessary, being capable of recycling P and other nutrients to meadow plants. 相似文献
35.
Crop Yield Gaps in Cameroon 总被引:2,自引:0,他引:2
Although food crop yields per hectare have generally been increasing in Cameroon since 1961, the food price crisis of 2008 and the ensuing social unrest and fatalities raised concerns about the country’s ability to meet the food needs of its population. This study examines the country’s potential for increasing crop yields and food production to meet this food security challenge. Fuzzy set theory is used to develop a biophysical spatial suitability model for different crops, which in turn is employed to ascertain whether crop production is carried out in biophysically suited areas. We use linear regression to examine the trend of yield development over the last half century. On the basis of yield data from experimental stations and farmers’ fields we assess the yield gap for major food crops. We find that yields have generally been increasing over the last half century and that agricultural policies can have significant effects on them. To a large extent, food crops are cultivated in areas that are biophysically suited for their cultivation, meaning that the yield gap is not a problem of biophysical suitability. Notwithstanding, there are significantly large yield gaps between actual yields on farmers’ farms and maximum attainable yields from research stations. We conclude that agronomy and policies are likely to be the reasons for these large yield gaps. A key challenge to be addressed in closing the yield gaps is that of replenishing and properly managing soil nutrients. 相似文献
36.
Pirjo Peltonen-Sainio Tapio Salo Lauri Jauhiainen Heikki Lehtonen Elina Sievil?inen 《Ambio》2015,44(6):544-556
The Finnish agri-environmental program (AEP) has been in operation for 20 years with >90 % farmer commitment. This study aimed to establish whether reduced nitrogen (N) and phosphorus (P) use has impacted spring cereal yields and quality based on comprehensive follow-up studies and long-term experiments. We found that the gap between genetic yield potential and attained yield has increased after the AEP was imposed. However, many contemporary changes in agricultural practices, driven by changes in prices and farm subsidies, also including the AEP, were likely reasons, together with reduced N, but not phosphorus use. Such overall changes in crop management coincided with stagnation or decline in yields and adverse changes in quality, but yield-removed N increased and residual N decreased. Further studies are needed to assess whether all the changes are environmentally, economically, and socially sustainable, and acceptable, in the long run. The concept of sustainable intensification is worth considering as a means to develop northern European agricultural systems to combine environmental benefits with productivity.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-015-0637-9) contains supplementary material, which is available to authorized users. 相似文献37.
Jos F. Andrade Kenneth G. Cassman Juan I. Rattalino Edreira Fahmuddin Agus Abdullahi Bala Nanyan Deng Patricio Grassini 《Ambio》2022,51(5):1158
Urbanization has appropriated millions of hectares of cropland, and this trend will persist as cities continue to expand. We estimate the impact of this conversion as the amount of land needed elsewhere to give the same yield potential as determined by differences in climate and soil properties. Robust spatial upscaling techniques, well-validated crop simulation models, and soil, climate, and cropping system databases are employed with a focus on populous countries with high rates of land conversion. We find that converted cropland is 30–40% more productive than new cropland, which means that projection of food production potential must account for expected cropland loss to urbanization. Policies that protect existing farmland from urbanization would help relieve pressure on expansion of agriculture into natural ecosystems.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01674-z. 相似文献
38.
Assessing current and future ozone-induced yield reductions for rice and winter wheat in Chongqing and the Yangtze River Delta of China 总被引:1,自引:0,他引:1
Dose-response functions from China were employed to assess ozone (O3)-induced relative yield loss (RYL) for rice and winter wheat in Chongqing and the Yangtze River Delta (YRD) in 1990-2020, based on monitored and simulated O3 exposures. It shows that RYL for rice in Chongqing from 1990 to 1995 was 1.1-5.8% and would reach 10.8% in 2020, while for winter wheat it was estimated to be 0.2-9.8% in 1990 and would reach around 12.0% in 2020. In the YRD, RYL for rice was 2.5-6.6% from 1990 to 1999 and would reach 9.2% in 2020, while for winter wheat, RYL was estimated to be 7.1-8.4% based on simulated O3 dosages, while based on monitored O3 dosages, it had surpassed 8.4% and reached about 12.0% in 1999. 相似文献
39.
Maggio A Chiarandà FQ Cefariello R Fagnano M 《Environmental pollution (Barking, Essex : 1987)》2009,157(5):1445-1452
Stomatal closure and biosynthesis of antioxidant molecules are two fundamental components of the physiological machinery that lead to stress adaptation during plant's exposure to salinity. Since high stomatal resistance may also contribute in counteracting O3 damages, we hypothesized that soil salinization may increase O3 tolerance of crops. An experiment was performed with alfalfa grown in filtered (AOT40 = 0 in both years) and non-filtered (AOT40 = 9.7 in 2005 and 6.9 ppm h in 2006) open-top chambers. Alfalfa yield was reduced by O3 (−33%) only in plants irrigated with salt-free water, while the increasing levels of soil salinity until 1.06 dS m−1 reduced both stomatal conductance and plant O3 uptake, thus linearly reducing O3 effects on yield. Therefore a reliable flux-based model for assessing the effects of O3 on crop yield should take into account soil salinity. 相似文献
40.
Xueling Li Joshua Philp Roger Cremades Anna Roberts Liang He Longhui Li Qiang Yu 《Ambio》2016,45(3):350-360
Understanding how the vulnerability of agricultural production to climate change can differ spatially has practical significance to sustainable management of agricultural systems worldwide. Accordingly, this study developed a conceptual framework to assess the agricultural vulnerability of 243 rural counties on the Chinese Loess Plateau. Indicators representing the climate/agriculture interface were selected to describe exposure and sensitivity, while stocks of certain capitals were used to describe adaptive capacity. A vulnerability index for each county was calculated and the spatial distribution was mapped. Results showed that exposure, sensitivity, and adaptive capacity occur independently, with most contributing indicator values concentrated in a narrow range after normalization. Within the 49 most vulnerable counties, which together encompass 81 % of the vulnerability index range, 42 were characterized by high exposure and sensitivity but low adaptive capacity. The most vulnerable area was found to be located in the central northeast–southwest belt of Loess Plateau. Adaptation measures for both ecological restoration and economic development are needed and potential adaptation options need further investigation.