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331.
From subsistence farming towards a multifunctional agriculture: sustainability in the Chinese rural reality 总被引:1,自引:0,他引:1
Prändl-Zika V 《Journal of environmental management》2008,87(2):236-248
The rural economic situation in China-with a living standard mostly at subsistence level-lags far behind the prosperous development in the cities and coastal areas. To balance this disequilibrium, comprehensive concepts and endeavors are necessary keeping in view all-not just economic-interests and needs that contribute to lively rural identities. In this context the role of agriculture, where still 50% of the Chinese population are working, will be newly defined, and sustainability concepts can help to find a readjusted position within the Chinese economy focusing on environmental health and food safety as main targets of political and other supporting measures. Within the SUCCESS project, a Concept of Sustainable Agriculture was developed and it drafts one conceivable relation between the exposure to natural resources and economy and tries to find new answers to the broad range of rural challenges in China. It is a qualitative model and, therefore, not always fully applicable, but in the concrete situation of villages, it shows possible directions of sustainability-oriented development by considering the typical local potentials. In the Chinese context that means identifying the different functions of agriculture-the well-known and the hidden-to make them explicit for the Chinese public and therewith to give them new significance. The article is based on a 3-years study within the EU-China Project SUCCESS with field research in four Chinese rural communities. It analyzes the agricultural sustainability potential of these selected villages against the background of massive structural changes within the next 20 years in rural China. Starting from the current agricultural reality, based on a qualitative analysis of the actual situation, local potentials and needs towards sustainable production and marketing are identified, and possible functions of the Chinese agriculture are formulated for the future. 相似文献
332.
A study was conducted in southern Ethiopia to evaluate the nutrient status on smallholder farms with respect to land use class
(garden, grassland, and outfield) and slope position (upper, middle, and lower). Soil physical and chemical properties were
quantified using soil samples collected at two depths (0–15 and 15–30 cm). Available phosphorous was significantly different
among the three land use classes. However, organic carbon and total nitrogen were lower in the outfield compared to the garden
and grass land but not significantly different. The lower than expected nutrient status of the garden and grassland, which
receive almost all available organic supplements, was attributed to the overall low availability of these inputs. Similarly,
pH and cation exchange capacity were not significantly different among the different land use classes. However, the sum of
the exchangeable cations was significantly higher in the garden compared to the outfields. Comparison at landscape level revealed
that the sand fraction was significantly greater, whereas the silt fractions were significantly smaller, on the lower slopes
relative to the middle slopes. Moreover, the organic carbon, total nitrogen, cation exchange capacity, Ca, and Mg values were
significantly less on lower slopes than upper and middle slopes. Perhaps this is because of leaching and the effect of deposition
of coarser sediments from the prevailing gully system. Overall, the fertility of the soil was adequate for supporting smallholder
farming, but consideration must be given to reducing pressure on the land resources, addressing erosion problems, and providing
a line of credit for purchasing inputs. 相似文献
333.
The Leaching Characteristics of Chromite ore Processing Residue 总被引:1,自引:0,他引:1
D. Deakin L.J. West D.I. Stewart B.W.D. Yardley 《Environmental geochemistry and health》2001,23(3):201-206
334.
气相色谱法测定水和土壤中苯醚甲环唑的残留量 总被引:2,自引:0,他引:2
研究并建立了气相色谱法测定水和土壤中苯醚甲环唑残留量的分析方法。实验结果表明:水中添加苯醚甲环唑的含量为0.005~0.500mg/kg时,平均回收率为97.9%~100.5%,相对标准偏差小于6.7%;土壤中添加苯醚甲环唑的含量为0.005~0.500mg/kg时,平均回收率为95.7%~109.5%,相对标准偏差小于7.5%。将该法用于水和土壤残留实验,土壤试样在拖药后10~88d进行采样分析,其残留消解动态回归方程为y=0.8803e^-0.0122x,相关系数为-0.915,消解半衰期为56.8d;水试样在施药后0~21d进行采样分析,其残留消解动态回归方程为y=0.2624e^-0.2539x,相关系数为-0.899,消解半衰期为2.7d。 相似文献
335.
336.
The Komati Downstream Development Project (KDDP), based upon the Maguga Dam has enabled 6,000 hectares of semi‐arid lowveld, in a region with low and highly variable rainfall to be converted from subsistence to irrigated commercial farming, mainly of sugar cane. This has transformed the Swazi sugar industry from one dominated by a small number of large‐scale commercial estates to one where more than 1,500 previously impoverished small‐scale Swazi farmers have been able to enter the industry by joining farmers’ associations and creating communally managed farms. Recent changes to the EU's Sugar Protocol have undermined the financial viability of the KDDP farms and undermined food security, especially for the poorest, due to the cut in sugar prices. However, some farmers’ associations have opted to keep some of their land as irrigated home gardens, rather than convert all their land to sugar cane. This model has improved food security at a time of low sugar prices and points to a more sustainable way of using water from large scale dams than the conventional model. It is argued that the EU should target support to members of the KDDP who have taken out large‐scale loans to pay for the in‐field infrastructure and encourage all farmers’ associations to adopt the food garden model. This would enable them to continue to benefit from the irrigation through improved production of subsistence crops, whilst they diversify their commercial production into novel markets. 相似文献
337.
338.
利用蜂窝煤灰渣和磷肥结合稳定铅污染贫磷(Olsen-P=2.50mg·kg-1)潮土中铅的可行性.采用盆栽试验,设置0和500mg·kg-1两个Pb用量,灰渣用量分别为干土质量的0%和2%,P:Pb分别为0和4.种植黑麦草,植物生长85d后收获,测定植物产量、土壤DTPA-Pb、Olsen-P含量、pH值和电导率(EC).结果表明,在两个Pb用量及两个P:Pb比例下,加入灰渣后,土壤的DTPA-Pb含量均降低,平均降低5.61%.其中加铅未加磷处理灰渣效果达到0.05的显著水平,各加Pb处理中,同时加入磷肥和灰渣处理土壤的DTPA-Pb含量最低;加入灰渣后处理土壤中的Olsen-P含量均增加,平均增加了2.71mg·kg-1,各处理土壤pH值上升约0.1个单位,加入灰渣也导致各处理土壤的EC增加.各处理条件下加入灰渣后植物产量均减小.在未加磷土壤中加入Pb后,土壤Olsen-P含量显著增加(p<0.05),表明高铅有效性下,植物可能通过根系分泌物增加了土壤磷的有效性.以上结果表明,蜂窝煤灰渣有可能用于降低污染土壤中铅的有效性,但其对植物生长的抑制作用需要克服. 相似文献
339.
We investigated the extent of Sb uptake by maize (Zea mays) and sunflower (Helianthus annuus) from nutrient solutions containing concentrations from 3 to 24 mg/L of potassium antimonate, with the aim of determining
the potential of Sb to enter the food chain. The maximum shoot Sb concentrations in Z. mays and H. annuus were 41 mg/kg and 77 mg/kg dry weight, respectively. There was no significant difference in Sb uptake between species. The
average bioaccumulation coefficients (the plant/solution concentration quotients) were 1.02 and 1.93 for Z. mays and H. annuus, respectively. Phosphate addition did not affect plant growth or Sb uptake. Antimony uptake by both Z. mays and H. annuus is unlikely to pose a health risk to animals and humans. 相似文献
340.
Tae Won Kim Kotaro Sakamoto Yasuhisa Henmi Jae C. Choe 《Behavioral ecology and sociobiology》2008,62(7):1139-1147
For males, courting and foraging are often behavioral alternatives, which take time and consume energy. When males have a
possibility of mating with receptive females, there may be a behavioral trade-off between courtship and feeding; the outcome
of which may be affected by male physiological condition and food availability. Although many mathematical models and empirical
studies suggest that the expression of male courtship signals are condition-dependent, decisions about courtship and mating
strategies in relation to food availability have not attracted much attention. In this study, we tested whether daily changes
in food availability affect males’ decisions about whether to court. We conducted experiments with the fiddler crab Uca lactea by providing males with additional food every other day. In food-supplemented enclosures, males did not increase courtship
activity on the days when food was supplemented. However, they built more courtship structures (semidomes) and waved more
on the days when they were not given additional food. Male size had a strong influence on the number of days the males courted.
We also tested whether the frequency of surface mating, as an alternative reproductive tactic, decreased when food was supplemented.
Contrary to our expectation, the number of males that exhibited the surface-mating tactic increased when food was supplemented
whereas the number of mate-searching females did not change. Our findings in this field study suggest that reproductive decisions
by male fiddler crabs are affected by fluctuating food availability and present body condition, and the alternative mating
tactic of this species may be more frequently used by males under good condition. 相似文献