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Huang W.,Hunan Meteorological Research Institute | Huang W.,China Agricultural University | Sui Y.,China Agricultural University | Sui Y.,CAS Institute of Atmospheric Physics | And 6 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2014

This study was based on daily precipitation data from standard meteorological stations in the 15 provinces (municipalities, or autonomous regions) in southern China. We adopted continuous days without available precipitation (Dnp) as drought index, also improved the critical values of available precipitation and drought classification standard during the data process, then calculated drought index values for crop (spring sowing-summer harvesting crop, spring sowing-autumn harvesting crop, summer sowing-autumn harvesting crop, and overwintering crop) during the most recent 50 years (from 1959 to 2009) in southern China. We analyzed the spatial distribution characteristics and inter-annual variation of crop drought frequency and crop drought duration days. In addition, we introduced daily drought frequency to study dynamic change of crop drought during the growing period. The results showed: spring sowing-summer harvesting crop drought occurred sometimes in the west of Southwest China and part of Huaibei Area during spring; spring sowing-autumn harvesting crop drought often affected the middle and lower reaches of Yangtze River, as well as the northeast of South China and the east of Southwest China during summer and autumn; summer sowing-autumn harvesting crop drought often occurred in the middle and lower reaches of Yangtze River during autumn, as well as the east and north of South China; overwintering crop drought took place in the north of Yangtze River and South China during autumn and spring, especially drought occurred frequently in the west of Southwest China during autumn to next spring. Generally, the distribution of drought duration days without available precipitation was basically consistent with the distribution of drought frequency, which meant drought lasted relatively longer in drought-prone area. The characteristics of drought change trend in southern China showed that: spring sowing-summer harvesting crop drought showed a decreasing trend in covering area as well as a reducing trend in intensity; spring sowing-autumn harvesting crop drought showed a slightly increasing trend in covering area yet a slightly reducing trend in intensity; summer sowing-autumn harvesting crop drought showed a significantly increasing trend in covering area and a slightly increasing trend in intensity with an exception of the Southwest China showing a reducing trend in intensity; overwintering crop drought showed a relatively more significantly increasing trend in covering area and an reducing trend in intensity with an exception of South China showing a increasing trend in intensity. From the perspective of daily drought frequency, early spring in the south and west of South China as well as the north of Yangtze River, together with spring in the west of Southwest China, showed a relatively higher drought frequency, hence affected spring sowing crops; midsummer drought in July and August in the middle and lower reaches of Yangtze River, autumn drought in September and October in South China, together with midsummer and autumn drought in the east of Southwest China mainly affected autumn harvesting crops; overwintering crop showed a relatively higher drought frequency in the whole study area, and the main drought period was in autumn and wintering period, however, early spring in the north of Yangtze River, as well as the south of South China, and Southwest China showed a relatively higher drought frequency. Source


Wang M.,Institute of Plateau Meteorology | Qu H.,China Agricultural University | Qu H.,Heilongjiang Meteorological Research Institute | Yang X.,China Agricultural University | And 2 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2012

In the 8 typical stations of agro-ecological zone in Sichuan Province, analysis study on the primary planting models was done to compare the yield reduction rate related with precipitation profit and loss, risk index of yield reduction rate, rainfall use efficiency(RUE) and economic efficiency of precipitation (EEP) of the primary cropping patterns. The results showed that: (1) The averaged yield reduction rates related with precipitation profit and loss significantly varied with regions, cropping patterns, crops and crop growth stages in Sichuan Province. Spatialy, the lowest value of 23% appeared in Ya'an station, the highest value above 50% appeared in Panxi station, and 30% -40% in other regions; in cropping patterns, the value of dry triple cropping pattern with wheat-maize-Chinese trumpet creeper was lower than that of the rotation pattern with wheat-rice; in crop species, the values of winter wheat, winter rape and autumn sowing potato et al. were generally higher than that of rice, maize, cotton, sweet potato and soybean; in growth stages, the values before and after flowering of winter wheat, winter rape and autumn sowing potato were generally higher; however, values at the end stage of each crop were relatively lower. (2) Based on natural precipitation, Panzhihua and Xichang encountered the highest risk of drought, but the risk index of yield reduction rate for the dry triple cropping pattern with wheat-maize-Chinese trumpet creeper was relatively lower; due to excessive staged precipitation in most basin regions like Ya'an, the waterlodgging disaster was more severe, resulting that the rotation pattern with wheat-rice was slightly supior to the dry triple cropping pattern with wheat-maize-Chinese trumpet creeper. Based on the rainfall use efficiency (RUE) and economic efficiency of precipitation (EEP), comparing results were great consistent at all stations: the superior cropping pattern was the double cropping pattern with wheat (rape or potato) -rice followed by the dry triple crooping pattern with wheat (rape) -maize-Chinese trumpet creeper (soybean). (3) Synthetically considering the risk of drought and flood, rainfall use efficiency, economic efficiency of precipitation and complex terrain factors, the double cropping rotation pattern with wheat (rape or potato) -rice was advised in croplands with well irrigation conditions, while dry triple cropping pattern with wheat (rape) -maize-Chinese trumpet creeper (soybean) was advised in dry lands without water guarantee. Source


Qu H.,China Agricultural University | Qu H.,Heilongjiang Meteorological Research Institute | Yang X.,China Agricultural University | Zhang X.,China Agricultural University | And 3 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2010

Seasonal drought has serious affections on agricultural production in Hunan Province, Developing an optimal cropping system to prevent and avoid drought disaster could provide scientific guidance for local agriculture production. In this study, adaptation and ensure index between precipitation and crop water requirement were analyzed using weather and crop phenological data of representative stations in Hunan Province from 1981 to 2007. Then optimal cropping systems based on precipitation were evaluated for the local agriculture to prevent and avoid local seasonal drought. Representative stations and cropping systems were selected according to the aridity and topography. And crop coefficients used in the study were amended using the time-averaged single-value approach recommended by FAO. Results showed that: (1) the optimal cropping systems were wheat-rice and potato-rice in humid low-altitude complex-terrain area of north Hunan Province and sub-humid medium-low altitude hilly area of northeast Hunan Province, (2) while in sub-humid low-altitude plains area of north Hunan Province, it was more suitable to adopt cropping systems of rape-cotton rape-rice and soybean-rice, (3) in sub-arid low-altitude plains and hilly transitional area of east Hunan Province, optimized cropping systems were rape-sweet potato, rape-cotton and rape-rice Similarly, for the other areas, it was, (4) rape-rice, wheat-rice and potato-rice in arid low-altitude hilly area of southeast Hunan Province, (5) rape-rice and rape-cotton in arid low-altitude basin area of middle- south Hunan Province, (6) potato-rice and rape-sweet potato in the humid high-altitude hilly area of northwest Hunan Province, (7) rape-sweet potato, rape-rice, wheat-rice and potato-rice in humid high-altitude hilly area of southwest Hunan Province, (8) and rape-sweet potato and rape-cotton in arid high-altitude hilly area of west Hunan Province. Source

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