中国生态农业学报(中英文)

Effects of irrigation and nitrogen application on ammonia volatilization in solar greenhouse soils in winter-spring cucumber cultivation

LI Yin-Kun, MEI Xu-Rong, WU Xue-Ping, HAO Wei-Ping, CHEN Min-Peng, XIA Xu, LI Hao-Ru

2012, 20(11): 1413-1419. doi: 10.3724/SP.J.1011.2012.01413

Abstract(1345) PDF(1082)

Abstract:
Ammonia volatilization characteristics in fertilized and non-fertilized belts of greenhouse soils were investigated under different irrigation and nitrogen application treatments during winter-spring cucumber cultivation via the venting method. Also differences in ammonia volatilization among water-saving irrigation, reduced nitrogen treatment and traditional water/nitrogen treatments were analyzed and discussed. From the study, peak ammonia volatilization rate was on 7 days after basal fertilization in the solar greenhouse soil. Compared with traditional nitrogen treatment, the peak value for 25%-reduction in nitrogen fertilization dropped by 18.2%~34.3%. While peak ammonia volatilization rate was on the first day in the fertilization belt, it was on the fifth day in the non-fertilization belt after topdressing. Also compared with traditional treatments, the peak value for 25%-reduction in nitrogen fertilization also dropped by 12.3%~37.2% and that for water-saving irrigation treatment increased by 3.9%~47.0%. Ammonia volatilization and loss in the fertilization belt of greenhouse soils mainly occurred during cucumber blooming and initial fruiting periods, which were respectively 1.07~1.50 and 1.06~1.27 times those of the non-fertilization belt. No significant differences in ammonia volatilization and loss existed between fertilization and non-fertilization belts of greenhouse soils during cucumber full-fruit period and end-fruit periods. Ammonia volatilization rate increased with (0~10 cm) soil ammonium nitrogen content and improvement in (5 cm) soil temperature. However, a negative correlation existed between (0~10 cm) soil water content and ammonia volatilization rate. Cumulative ammonia volatilization was 11.4~26.6 kg·hm^-2 during the entire cucumber growth season. Compared with traditional nitrogen and irrigation treatments, cumulative ammonia volatilization in the 25%-reduction in nitrogen fertilization dropped by 20.8%~22.2%. Also water-saving irrigation treatments concurrently improved cumulative ammonia volatilization by 0~4.51%. The analysis showed that appropriate reductions in nitrogen fertilization significantly limited ammonia volatilization and enhanced irrigation/nitrogen fertilizer efficiency in solar greenhouse soils in Hebei Province. While water-saving also significantly improved irrigation/nitrogen fertilizer efficiency, it failed to significantly reduce ammonia volatilization. Irrigation water-use efficiency of the 25%-reduction in nitrogen fertilization improved by 2.6%~5.9% over traditional nitrogen treatment. Compared with traditional irrigation, agronomic efficiency of nitrogen in water-saving irrigation increased by 13.9%~75.0%.

Effect of irrigation and nitrogen supply on physio-morphologicalindices of broomcorn millet at seedling stage

WANG Hai-Ru, ZHANG Yong-Qing, DONG Wen-Xiao, YAN Jiang-Yan, FENG Xiao-Min, LI Peng

2012, 20(11): 1420-1426. doi: 10.3724/SP.J.1011.2012.01420

Abstract(1291) PDF(1202)

Abstract:
The effects of irrigation and nitrogen application on physio-morphological indices of broomcorn millet at seedling stage was studied in a pot experiment. The results indicated that plant height, leaf area, total root surface area, root volume and root length increased with increasing nitrogen supply at equivalent moisture. However, root to shoot ratio decreased with increasing nitrogen supply. All indices were similar in trends to the water and nitrogen supply, with each treatment significantly different from the control. Chlorophyll content of broomcorn millet at seedling stage remarkably changed under different water and nitrogen conditions. High water and nitrogen treatments [at soil moisture of 70%~80% field capacity and urea nitrogen at 4.6 g·kg^-1(soil), W3N3] had the maximum chlorophyll content while low water and nitrogen treatments [at soil moisture of 30%~40% field capacity and 0 g(urea)·kg^-1(soil), W1N1] had the minimum content. At constant moisture, chlorophyll content increased with increasing nitrogen supply. Also at constant nitrogen supply, chlorophyll content increased with increasing water supply. Hence water and nitrogen had an apparent synergetic effect on leaf chlorophyll content of broomcorn millet at seedling stage. Electrolyte leakage rate showed the reverse tendency. Root SOD activity of broomcorn millet at seedling stage was maximum [213.71 U·g^-1(FW)] under W1N2 [soil moisture of 30%~40% field capacity and 2.3 g(urea)·kg^-1(soil)] and minimum [72.93 U·g^-1(FW)] under W3N3. POD activity, MDA content and soluble sugar content decreased with increasing nitrogen at constant soil moisture and decreased with increasing water at constant soil nitrogen. The reverse was noted for root activity with each treatment significantly different. Under drought stress conditions, increase in nitrogen fertilizer proportionately improved chlorophyll content and root activity of broomcorn millet at seedling stage. It also increased total root surface area, root volume and root length. Increase in nitrogen fertilizer, however, reduced root MDA content. To a certain extent, increased nitrogen fertilizer responsively relieved the impact of drought stress.

Effect of swine manure with different composting times onsoil fauna community and peanut yield

SHI Lin-Lin, CHANG Zhi-Zhou, SHEN Ming-Xing, YU Jian-Guang, LU Chang-Ying, WANG Hai-Hou, ZHOU Xin-Wei

2012, 20(11): 1427-1436. doi: 10.3724/SP.J.1011.2012.01427

Abstract(1323) PDF(1255)

Abstract:
To establish a standard for the maturity of swine waste compost, the performances of composts with different composting durations were analyzed in a 2010 to 2011 peanut-field experiment. The swine waste composting durations were 0, 10, 20 and 30 days, respectively. The controls were no fertilization and chemical fertilization. Soil fauna were isolated and trapped by hand and Tullgren collection methods. The highest peanut yield (6 713.4 kg·hm^{-2^{) was observed in the treatment of swine waste composted for 30 days. The 30-day compost yield was significantly higher (P < 0.05) than those for 0, 10 and 20 days and also that of the blank control. Variance analysis for the hand-collected macrofauna showed no significant difference among treatments in terms of individual number, group number, Shannon-Wiener index and evenness index. However, significant differences existed in individual number (F=2.69, P<0.05, df=5) and evenness index (F=6.40, P<0.001, df=5) for collected meshfauna via the Tullgren funnel method. The order of the treatments in terms of individual number was as follows: swine waste composted for 10 days > swine waste composted for 30 days > swine waste composted for 0 day > swine waste composted for 20 days > chemical control > blank control. Also the order in terms of evenness was as follows: swine waste composted for 0 day > blank control > swine waste composted for 20 days > chemical control > swine waste composted for 10 days > swine waste composted for 30 days. However, either by the hand or the Tullgren method did the four indices vary significantly among sampling dates (P < 0.01). S?rensen index and Whittaker index showed close similarities for both macro- and mesh-fauna communities across the treatments. Correlation analysis indicated that the numbers of macro-fauna individual and group were negatively correlated with swine compost total nitrogen (r= 0.951 and 0.967, respectively, P < 0.05). Individual number was also negatively correlated with peanut yield (r= 0.916,P < 0.1), and Shannon-Wiener index of micro-fauna community was positively correlated with humus matters (R=0.916,P < 0.1). However, meshfauna group number was negatively correlated with humic acid (r= 0.958,P< 0.05) and total phosphorus (r= 0.917, P < 0.1), and positively correlated with pH and fulvic acid (r=0.919 and 0.921, respectively, P < 0.1) in swine compost. Principle component analysis for fauna community showed that Orthoptera, Acariformes, Araneida, Diplopoda, etc. were the main macrofauna orders; and Collembala, Hymenoptera, Protura, Opiliones, Diplura, Coleoptera, Diptera, etc. were the main meshfauna orders in soils fertilized with swine manure composted for 30 days. Compared with low-maturity swine manure (composted for 10 days or 20 days), application of high-maturity swine manure (composted for 30 days) significantly improved peanut production. In soils with high-maturity swine manure, macrofauna individual and group numbers were low and community diversity and evenness indices high. However, meshfauna individual number was high, meshfauna group number low, community diversity index low and evenness index significantly low.}}

Effect of chicken manure with roxarsone on growth andarsenic accumulation in vegetables

HUANG Lian-Xi, YAO Li-Xian, HE Zhao-Huan, ZHOU Chang-Min, LI Guo-Liang, GUO Bin, YANG Bao-Mei

2012, 20(11): 1437-1442. doi: 10.3724/SP.J.1011.2012.01437

Abstract(1396) PDF(1084)

Abstract:
A pot experiment was carried out under greenhouse conditions to study biomass and arsenic contents of four vegetable crops (flowering Chinese cabbage, turnip, lettuce and crown daisy) at difference harvest stages. The aim of the study was to validate the effect of roxarsone in chicken manure on growth and arsenic accumulation of vegetables. Treatments with roxarsone-free chicken manure were used as control experiment. The results showed that biomass and arsenic contents of vegetable shoots and gross arsenic uptake in the four vegetable crops were enhanced with increasing growth period. However, arsenic contents of vegetable roots or tubers reduced with increasing growth period. At the same harvest stage, chicken manure with roxarsone reduced flowering Chinese cabbage, lettuce and crown daisy biomass but increased turnip biomass. Total arsenic content and gross arsenic uptake of the four vegetable crops treated with chicken manure with roxarsone were (significantly) higher at harvest stage than in the corresponding control treatment. Compared with the control, shoot arsenic contents of the four vegetable crops at final harvest stage treated by chicken manure with roxarsone increased by 10.53%, 5.56%, 11.11% and 11.11% and those of the roots increased by 52.94%, 46.67%, 39.22% and 28.00%, respectively. Also the gross arsenic taken up by the four vegetable crops under treatment of chicken manure with roxarsone increased by 7.07%, 30.88%, 15.25% and 5.57%, respectively. The results suggested that chicken manure with roxarsone somehow influenced the growth of vegetable crops. Although chicken manure with roxarsone increased vegetable arsenic uptake and accumulation, its effects on different vegetables were different. Arsenic intakes into edible parts of the vegetable crops treated by chicken manure with roxarsone were respectively 10.53%, 46.67%, 11.11% and 11.11% higher than that of the control if the same weights of the same vegetables were consumed in daily life. The result of this study provided important support data for vegetable growth in terms of the effect of adding roxarsone to livestock manure. It also laid the scientific basis for food safety of crops cultivated on livestock manure containing roxarsone.

Photosynthetic characteristics and yield of potato in potato/maize intercropping systems with different row number ratios

HUANG Cheng-Jian, ZHAO Si-Yi, WANG Ji-Chun, WANG Long-Chang, ZHAO Yong, CAI Ye-Mao, TENG Yan, GAO Xu

2012, 20(11): 1443-1450. doi: 10.3724/SP.J.1011.2012.01443

Abstract(1432) PDF(1336)

Abstract:
Intercropping of potato with maize has been a traditional cropping system in China widely practiced in mountain regions. However, yields of potato/maize systems have been limited by inappropriate potato-maize row ratios. A potato/maize intercropping field experiment with two different potato-maize row ratios was carried out to determine dynamic changes in a range of potato features. The elements analyzed included leaf area index (LAI), special leaf weight (SLW), chlorophyll a (Chla), chlorophyll b (Chlb), total chlorophyll (Chla+Chlb) and chlorophyll a/b ratio in potato at different developmental stages. Also gas exchanges at potato tuber development and yield stages were studied using monocropped potato as the control. The ratio 2︰2 meant two rows of potato to two rows of maize and that 3︰2 meant three rows of potato to two rows of maize. The results showed that while intercropping significantly reduced LAI, SLW and Chla/b, it increased Chla, Chlb and Chla+Chlb of potato at all growth stages. Compared with the 2︰2 intercropping system, the 3︰2 intercropping system had significantly higher LAI at all developmental stages; lower SLW at tuber initiation stage; higher SLW at vegetative growth and starch accumulation stages; higher Chla, Chlb and Chla+Chlb at tuber development stage; lower Chla, Chlb and Chla+Chlb at starch accumulation stage; and higher Chla/b at both tuber development and starch accumulation stages. Also Chla and Chla+Chlb declined much slowly in the 3︰2 than in the 2︰2 potato/maize system. Furthermore, intercropped potato induced declines in net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) and stomatal limitation (Ls). It, however, increased intercellular CO₂ concentration (Ci) and water use efficiency (WUE). Variations in Pn, Gs and Ci suggested that intercropping limited photosynthetic activity in potato due to non-stomatal processes. Significantly higher Pn, Gs, Tr and Ci and lower WUE were noted in the 3︰2 than in the 2︰2 intercropping system. Also in comparison with monocropping, both the number and weight of big tubers (fresh tuber weight >50 g) per plant markedly dropped under intercropping. The number and weight of small tubers (fresh tuber weight ≤50 g) per plant also dropped in the 2︰2 cropping system. However, while the number of small tubers per plant improved, the weight of the small tubers largely remained unchanged in the 3︰2 cropping system. Both the number and weight of small tubers per plant were higher in the 3︰2 than in the 2︰2 intercropping system. No significant difference was noted in the number and weight of big tubers per plant between the 3︰2 and 2︰2 intercropping systems. This suggested that increasing potato rows more or less affected small tubers and not big tubers in potato/maize systems. In conclusion, intercropping substantially decreased tuber yield at harvest due to changes in photosynthetic characteristics of potato in potato/maize systems. The land equivalent ratios were 0.88 and 1.24 in the 2︰2 and 3︰2 intercropping systems, respectively. This suggested that the 3︰2 row ratio performed better than the 2︰2 row ratio in potato/maize intercropping systems.

Effect of maize row spacing on yield of pea/maize intercropping system

ZHAO Jian-Hua, SUN Jian-Hao, LI Long, LI Wei-Qi

2012, 20(11): 1451-1456. doi: 10.3724/SP.J.1011.2012.01451

Abstract(1616) PDF(1669)

Abstract:
Crop row spacing in intercropping systems affects interactions of crop species and subsequent crop yields. In a field experiment, the response of crop yield to different maize row spacing (0~80 cm) in pea/maize intercropping system was investigated. The results showed that land equivalent ratio (LER) of each treatment exceeded 1, indicating a significant yield advantage. When maize row spacing changed from 0 cm to 80 cm, the system yield first increased to a threshold and then declined. Positive quadratic relations between maize row spacing and yields of intercropping system or intercropped maize were observed in the field experiment. The highest yield occurred when maize row spacing was 40 cm and intercropped maize yield reached 10 118 kg·hm^-2. Since intercropped pea yield never changed significantly, yield of the intercropped pea/maize system was dependent on maize yield. The change in maize row spacing significantly influenced maize yield components and especially grain number per spike. Grain number per spike (549 grains per spike) was highest when maize row spacing was 60 cm. Maize aggressive dominance over pea in terms of yield gradually strengthened with increasing maize row spacing. When maize row spacing was within 60 cm, its aggressive dominance over pea was below zero. This indicated that maize had a stronger competitiveness than peas. However, when maize row spacing was 80 cm, its relative aggressive dominance was 0.14 - which suggested that pea was more competitive than maize. Hence adjustment of maize row spacing effectively enhanced maize yield in pea/maize intercropping system. This increased production output of pea/maize intercropping system.

Effects of used plastic film disposal patterns on dry matter productionand water use efficiency of oil flax in arid areas

WU Bing, GAO Yu-Hong, ZHAO Li, CHEN Yong-Jun, LING Peng, ZHANG Qiang, WANG Wang-Tian, NIU Jun-Yi

2012, 20(11): 1457-1463. doi: 10.3724/SP.J.1011.2012.01457

Abstract(1260) PDF(1235)

Abstract:
Field experiments were conducted to investigate how disposal patterns of used plastic films in field and mechanism of oil flax production enhance in arid areas. The study compared the influences of 6 used plastic film disposal patterns on oil flax soil water amount, leaf area, dry matter accumulation and distribution, water use efficiency and yield. The 6 patterns included field-kept film and no-tillage sowing the next year (T1); field-kept film, earth mulching and no-tillage sowing the next year (T2); field-kept film, straw mulching the current year and no-tillage sowing after straw clearing the next year (T3); field-kept film replaced with new plastic film and no-tillage sowing the next year (T4); film collection, land preparation, new plastic film mulching just after harvest and sowing the next year (T5); and collected just after crop harvest, land reparation and no-mulch sowing the next year (T6, control). The results showed that keeping used plastic films in fields till the next year had the same film mulch effect on soil moisture and temperature, thereby promoting photosynthetic area and favoring assimilation product accumulation. Soil moisture conservation effect under different disposal patterns of used films was strong before budding stage, ensuring the full and sound flax seedling growth. Leaf area response to the treatments had the same trend as soil water storage. Leaf areas in the five treatments were higher than in the control before budding stage. Treatment T4 was the best at momi fir pattern stage and budding stage, but T5 was the best at flowering stage. Accumulated amount of dry matter, amount and distribution proportion of dry matter, contribution of dry matter assimilation amount after anthesis to grain under T4 and T5 were higher than T6 (CK). And dry matter proportions in stem, spike axis and kernel husk also decreased. Also the values of these variables under T1, T2 and T3 were between those for T4 and T5. Yield of T1 to T5 treatments were significantly higher than T6, treatment T4 had the highest grain yield (1 509.52 kg·hm^-2) with T5, T1, T2, T3 and T6 yields of 1 370.77 kg·hm^-2,1 171.84 kg·hm ^-2,1 158.47 kg·hm^-2,1 011.36 kg·hm^-2 and 620.52 kg·hm^-2, respectively. The trend in water use efficiency was the same as that in yield, which increased respectively by 153.63% (T4), 129.82% (T5), 97.49% (T1), 85.71% (T2) and 64.41% (T3) over CK. Therefore the study recommended T4 as the most appropriate tillage practice in high-yield and water-saving oil flax production. However, optimal reuse pattern of used plastic film also needed considerations of local soil physical conditions and disposal method selection.

Impact of nighttime warming on soil microbial biomass carbon/nitrogen and activity in main winter wheat cropping areas in China

ZHANG Ming-Qian, HAN Zheng-Fang, CHEN Jin, GUO Jia, TIAN Yun-Lu, ZHANG Bin, YANG Bing, ZHANG Wei-Jian

2012, 20(11): 1464-1470. doi: 10.3724/SP.J.1011.2012.01464

Abstract(1196) PDF(1038)

Abstract:
It has been predicted that global climate could warm further with greater increase in daily minimum temperature than in daily maximum temperature. However, little has remained known about the impact of nighttime warming on soil microbial growth and activity. Using the passive nighttime warming (PNW) technique, a 4-year field nighttime warming experiment was conducted during crop-growth periods at the Shijiazhuang, Xuzhou, Xuchang and Zhenjiang sites; covering the main winter wheat cropping regions in China. Soil moisture, soil temperature (0~5 cm), soil microbial biomass and activity were determined under field conditions in 2008-2010. The results showed that nighttime warming significantly decreased soil microbial biomass carbon (C) and nitrogen (N) as well as microbial activity. Compared with the ambient treatment, nighttime warming reduced soil microbial biomass C on average by 11.4%, 7.8%, 10.9% and 8.5%, soil microbial biomass N by 15.2%, 16.7%, 13.8% and 8.4%, and microbial respiration rate by 6.6%, 9.6%, 7.0% and 11.1% at Shijiazhuang, Xuzhou, Xuchang and Zhenjiang sites, respectively. The corresponding soil moisture was 8.8%, 3.7%, 3.8% and 2.9% lower in the warmed plots than in the ambient plots, but all the effects were insignificant. The corresponding temperatures in the 0~5 cm soil layer were higher by 1.2 ℃, 0.7 ℃, 0.7 ℃ and 0.7 ℃ in the warmed plots than in the ambient plots. These results suggest that nighttime warming altered soil C/N cycle and winter wheat growth by influencing soil microbial biomass and microbial activity with certain latitude differences.

Analysis of nutrient and microbial Biolog function diversity in teasoils with different planting years in Fujian Anxi

LIN Sheng, ZHUANG Jia-Qiang, CHEN Ting, ZHANG Ai-Jia, ZHOU Ming-Ming, LIN Wen-Xiong

2012, 20(11): 1471-1477. doi: 10.3724/SP.J.1011.2012.01471

Abstract(1262) PDF(1493)

Abstract:
Premature aging and degradation of tea gardens have been critical issues limiting the economic development of tea industry. Nutrient and microbial diversity in tea garden soils with different planting years were studied. The study was based on pH and fertility indexes of tea producing environmental conditions (NY/T8 53-2004). Soil pH of 1-year-old tea was 4.73, which was at grade Ⅱ level. Also soil pH of 6-year-old tea was 4.41, close to grade Ⅱ. Both these grades conformed to acid-base indicators for high quality tea garden soils. The soil pH of 20-year-old tea was 4.15 (less than 4.5 but close to 4.0) and therefore identified as acidic. Organic matter, available N (nitrogen) and available P (phosphorus) in the 6-year-old tea soil were respectively at fertility gradeⅠlevel. That of available K (potassium) was at grade Ⅲ level. Available P was abundant in the 1-year-old tea soil, which was at gradeⅠlevel. While available N was at grade Ⅱ, organic matter and available K were at grade Ⅲ level. In the 20-year-old tea soil, organic matter reached grade Ⅱ and available N, P and K reached grade Ⅲ. While the 6-year-old tea soil fertility was the best, 1-year-old tea soil fertility was medium and then the 20-year-old tea soil fertility was the worst. Biolog analysis showed that the ability of microbial flora to use six kinds of carbon sources was highest in the 6-year-old tea soil. It was lowest in the 20-year-old tea soil. Microbial utilization of six kinds of carbon sources in the 1-year-old tea soil was moderate. Community diversity indexes analysis showed that the Shannon index, Brillouin index, homogeneity index and richness index of the 6-year-old tea soil were the highest. These indexes were worst in the 20-year-old tea soil. Compared with the 6- and 1-year-old tea soils, the 20-year-old tea soil presented the strongest acidification. Organic matter in the 20-year-old tea soil was 47.81% less than that in the 6-year-old tea soil. Physiological activity of the 20-year-old tea soil microbes was the lowest, which limited physical diversity functions.

Relational analysis of soil enzyme activities, nutrients and microbes inRobinia pseudoacacia plantations in the Yellow River Dalta withdifferent degradation degrees

BAI Shi-Hong, MA Feng-Yun, LI Shu-Sheng, YAO Xiu-Fen

2012, 20(11): 1478-1483. doi: 10.3724/SP.J.1011.2012.01478

Abstract(1433) PDF(1112)

Abstract:
A great deal of degradation of plantations across the globe are caused by natural and artificial factors. The Yellow River Delta (YRD) is one of China's three estuarine deltas where plenty protection forests were established in the 1980s to improve local ecological environment. Among the forest plants is Robinia pseudoacacia, covering the largest area as main sand/windbreaker in this region. In recent years, however, much of the R. pseudoacacia plantation has dry-tops and some even wither to death. This has caused significant loss to shelter forest construction and management of salinization in the region. In this paper, R. pseudoacacia plantations with different degradation degrees in the YRD were selected for relational analysis of soil enzymes, nutrients, microbes as a means of exploring the causes of degradation of the plants. The results showed soil urease, polyphenol oxidase and peroxidase activities decreased with the aggravation of R. pseudoacacia plantations degradation. However, hydrogen peroxidase activity presented first increasing and then decreasing tendency. Urease was significantly positively correlated with polyphenol oxidase and peroxidase. Peroxidase was also significantly positively correlated with polyphenol oxidase, but not with the other enzymes. Soil nutrients such as organic matter, total nitrogen, available nitrogen and available phosphorus decreased with increasing degradation degree of R. pseudoacacia plantations. The reverse was the case for soil pH and soil salts. Soil enzymes, especially urease, were significantly positively correlated with soil nutrients and negatively correlated with soil pH and soil salts. Bacteria count was highest in R. pseudoacacia plantation soils with different degradation degrees. With increasing degradation degree of R. pseudoacacia plantation, average soil bacteria count was in the following order: no degradation > slight degradation > moderate degradation > severe degradation. The order for average fungi count was as follows: slight degradation > no degradation > moderate degradation > severe degradation. Then that for actinomycetes was: moderate degradation > slight degradation > no degradation > severe degradation. Urease was highly positively correlated with bacteria and actinomycetes. Bacteria count was highly positively correlated with enzymes, except hydrogen peroxidase. The other enzymes showed no significant correlations with microbial count.

Effect of perennial drought environments on Citrus tangerina Hort. cv. "Chuanju" growth, nutrient absorption and physiology

FAN Wei-Guo, LI Qing-Hong, WU Su-Fang

2012, 20(11): 1484-1493. doi: 10.3724/SP.J.1011.2012.01484

Abstract(1262) PDF(1323)

Abstract:
The objective of this paper was to study the specifics of Citrus tangerina Hort. cv. "Chuanju" in terms of growth, nutrient absorption and related physiological responses to perennial drought environments using annual irrigations as the control. The main aim of the study was to reveal any adverse impacts of perennial drought on citrus. The phenological phases, new shoot/fruit growth conditions, leaf life spans, and N, P, K, Ca, Mg, Fe, Cu, Zn and B contents of spring-shoot leaves/fruits were measured in four successive years. The relationships among physiological diseases, droughts and nutrient uptakes were researched into along with morphological characteristics, organizational structures and drought-resistance physiology. Also the relationships between physiological response and the adaptability to perennial drought were discussed. The results showed that under perennial drought environments, growth, flowering and fruit-dropping periods clearly delayed while fruit maturity period advanced. Leaf life span shortened; shoots became shorter, thinner and the amounts of shoots and leaves dropped while leaf withering worsened. The degree of leaf leathery increased and so leaves became smaller and thicker. Deficiency symptoms caused by elements such as N, Zn, Fe, B, etc became very distinct. Fresh weight, dry-matter weight, water content, seed amount, juice content and N, P, K, Ca, Mg, Fe, Cu, Zn and B contents in spring shoot leaves obviously dropped along with those of N, P, Ca, Fe and B in fruits. The degrees of fruit gummosis and juice sac granulation worsened such that fruit quality fell drastically. Leaf palisade tissues thickened while spongy tissues thinned out. CTR (tissue tense ration) and stomata density increased as stomata and SR (tissue soothing ratio) got smaller. The contents of proline, soluble sugar and water saturation deficiency in leaves increased. Dehydration rate, relative water content and leaf water potential dwindled. Then while Pn and Tr clearly dropped, WUE drastically improved in summer. The study showed that C. tangerina Hort. cv. "Chuanju" had strong ability to adapt to perennial droughts. Under perennial drought environments, C. tangerina Hort. cv. "Chuanju" adopted specific adjustments to resist adverse environments. Such adjustments involved in growth regularities, plant/leaf shapes and life spans, leaf thicknesses and structures, stomata densities and sizes, leaf water saturation deficiencies, dehydration rates and relative water contents, leaf water potentials, proline/soluble sugar contents, Pn/Tr. Perennial droughts were the main causes of canopy shoot deaths, slow fruit developments, seed abortions, seedcase gummoses, juice sac granulations and decreased element contents of fruits/spring shoot leaves.

Correlation between tobacco leaf chemical compositionsand latitude in Sichuan Tobacco Region

LI Jia-Ying, YU Jian-Jun, YE Xie-Feng, SHI Shuang-Shuang, WANG Long, MA Jun-Hong, WANG Wei-Ning

2012, 20(11): 1494-1499. doi: 10.3724/SP.J.1011.2012.01494

Abstract(1325) PDF(1220)

Abstract:
The growth, development and quality of flue-cured tobacco are influenced by main geographic factor of latitude. The correlations of tobacco leaf chemical content and latitude in the Sichuan Tobacco Region (STR) were analyzed in this study. The aim of the study was to determine the best latitude range for tobacco cultivation, provide a reference for tobacco production layout and allocation in the region. Partial least squares (PLS) regression, for dealing with 7 chemical indicators with internal linear correlation, and grey relational analysis were used to determine the relationships between leaf chemical compositions of flue-cured tobacco and latitude in the STR. The study analyzed 243 cured leaf samples collected respectively from the upper (14~16 leaf-position), middle (8~12 leaf-position) and lower (4~6 leaf-position) tobacco leaf positions at 153 monitoring points in four latitude regions (Panzhihua, Liangshan, Luzhou and Dazhou) of the STR in 2010. The results showed that Sichuan tobacco performed best in the latitude range of N26°02′~N31°20′. The overall chemical compositions of STR tobacco leaf showed that total sugar and reducing sugar were marginally in the highest amount, followed by starch and chlorine. The contents of nicotine, total nitrogen and potassium were in suitable range with higher variation coefficient of nicotine, chlorine and starch. PLS regression model of chemical composition in relation to upper tobacco leaf and latitude was latitude=28.762 0.146x1 0.214x2 0.005 23x3 0.172x4+0.316x5 0.232x6 0.046 4x7; that for middle tobacco leaf was latitude=28.762 0.117x1 0.088x2+0.009 9x3 0.127x4+0.288x5 0.328x6 0.041 3x7; and that for lower tobacco leaf was latitude = 28.762 0.026x1 0.123x2+0.25x3+0.010 3x4+0.271x5 0.237x6 0.136x7. x1~x7 respectively denoted total sugar, reducing sugar, nicotine, total nitrogen, potassium, chlorine and starch contents. Correlation analysis showed that for the same position leaves, latitude was positively correlated with potassium, but negatively correlated with total sugar, reducing sugar and chlorine contents. It meant that increment of latitude across Sichuan form south to north increased tobacco leaf potassium content and decreased total sugar, reducing sugar and chlorine contents. For different position leaves, however, correlations between latitude and nicotine, total nitrogen and starch were inconsistent. The correlation sequence for chemical compositions and latitude was as follows: reducing sugar > total sugar > total nitrogen > potassium > starch > nicotine > chlorine.

Investigation of cotton mega-environment based on fiberstrength selection and GGE biplot

XU Nai-Yin, ZHANG Guo-Wei, LI Jian, ZHOU Zhi-Guo

2012, 20(11): 1500-1507. doi: 10.3724/SP.J.1011.2012.01500

Abstract(1316) PDF(1089)

Abstract:
Environmental interactions with genotype have heightened among plant breeders and/or extension agronomists the exploration and application of useful traits in the discrimination of genetic differences among candidate genotypes and similarities to average performances in target regions. GGE biplot with "which-wins-where" view has been a useful technique in graphical display and visualization of interrelation between environments and genotypes, and of mega-environment investigations. However, first two principal component restrictions in GGE biplots have led to uncertainties in terms of fitting degree optimizations of GGE models. Therefore a GGE biplot analysis was adopted in exploring and investigating possible mega-environments in a target cotton planting region. The region included fifteen test sites (Anqing, Nanyang, Huanggang, Jingzhou, Wuhan, Xiangfan, Changde, Yueyang, Nanjing, Nantong, Yancheng, Jiujiang, Jianyang, Shehong and Cixi) for cotton fiber strength selection in 27 independent test sets of cotton variety trials in the Yangtze River Valley for the period 2000-2010. The information ratio (IR) adjustment method was used as a validation tool to ensure that sufficient and necessary principal component scores were selected in the GGE biplot analysis. The study showed that the average effective fitting degree of the GGE biplot analysis of cotton fiber strength selection was 68.4%, with 13 exception records of over-fit or lost-fit. The counterpart fitting degreet of the IR-adjusted GGE model was 73.7%, with 6.0% improvement. This showed that optimization and adjustments to the GGE biplot using IR obviously enhanced the reliability of mega-environment investigations. Based on the GGE biplot analysis, the cotton planting region in the Yangtze River Valley was subdivided into four mega-environments for fiber strength selection ― the first mega-environment included Anqing, Xiangfan, Nantong and Yueyang; the second comprised of Changde, Jiujiang and Wuhan; the third included Cixi, Nanjing, Huanggang, Jingzhou and Yancheng; and the forth also included Nanyang, Jianyang and Shehong. Based on the IR-adjusted GGE model, however, the cotton planting region more distinctively consisted of three mega-environments ― the main mega-environment contained eleven out of fifteen test sites (Anqing, Wuhan, Jiujiang, Xiangfan, Nanyang, Yueyang, Changde, Huanggang, Jingzhou, Nanjing and Cixi), the minor mega-environment consisted of two test sites (Nantong and Jianyang), and the other minor mega-environment also consisted of two test sites (Yancheng and Shehong). Compared with the results of GGE biplot mega-environment analysis, IR-adjusted results were more reliable with distinct geographical characteristics for cotton fiber strength selection. Cotton plants in the Sichuan Basin and Jiangsu Coastal Regions were not suitable for fiber strength selection. It was therefore recommended to target the whole cotton planting region in the Yangtze River Valley. On the basis of the mega-environment investigation and above divisions, scientific decision-makings on cotton fiber strength selection, new cultivar breeding and policy registration for the Yangtze River Valley were recommended.

Nitrogen metabolites in cucumber leaves treated with parsley root extracts

BAO Yan-Yan, YUN Xing-Fu, ZHANG Dong-Dong, QIAN Cheng, GAO Xiao-Min, FU Chong-Yi

2012, 20(11): 1508-1513. doi: 10.3724/SP.J.1011.2012.01508

Abstract(1175) PDF(1223)

Abstract:
Previous studies have noted that parsley extracts had allelopathic effect on Fusarium oxysporium f. sp. Cucumerinum with an inhibitory rate of 12.89%~84.83%. It has also been noted that different fresh parsley root and root soil extracts had different prohibitive allelopathic strengths against cucumber wilt. With steep decline in morbidity, however, the prohibitive allelopathic strengths were within 5.45%~46.95%. Concerns have been reported on the mechanism of parsley extract allelopathy, including protective enzyme systems, soluble substances and active oxygen metabolism of cucumber leaf. However, no concerns have been reported in relation to nitrogen metabolites in cucumber leaf. To study the mechanisms of fresh parsley root and root soil extract allelopathy on F. oxysporium f. sp. Cucumerinum, changes in nitrogen metabolites were analyzed in cucumber seedlings treated with extracts once its first leaf was 5 cm wide. In contrast to earlier studies, this study showed that nitrogen metabolites in "Jinchun 4" cucumber leaves treated with fresh parsley root and root soil extracts were significantly changed. The contents of soluble protein, ammonia, Ser, Arg, Pro and amino acids were increased compared to the control, with the highest increases over the acetone control by 10.58%, 18.31%, 6.54%, 3.10%, 9.64% and 3.16%, respectively. However, nitrate, Gly and Met contents dropped, with the greatest declines of 7.52%, 3.41% and 15.55%, respectively. For the different treatments, the most significant effects on nitrogen metabolites were noted by acetone extracts, followed by ethanol extracts and distilled water extracts. Fresh root extracts caused more distinct changes in nitrogen metabolite contents than root soil extracts.

Gene expression profiling in response to allelopathic autotoxicityin melon by cDNA-AFLP

ZHANG Zhi-Zhong, SUN Zhi-Hao, CHEN Wen-Hui, LIN Wen-Xiong

2012, 20(11): 1514-1520. doi: 10.3724/SP.J.1011.2012.01514

Abstract(1345) PDF(1405)

Abstract:
As an important horticultural crop worldwide, melon cultivation has been significantly affected by increasingly serious cultivations problems in recent years due to changes in cultivation systems and environment. Critical for continuous melon cultivation was allelopathy. However, little has been done in terms of the molecular biology of melon allelopathy. In this research, allelopathic autotoxicity genes of melon germplasm 'New Silverlit' were analyzed using the cDNA-AFLP technique. Seedlings were treated with 0.03 g·mL 1 concentrations of aqueous extracts from melon roots and stems for cDNA-AFLP analysis. A total of 3 600 transcript-derived fragments (TDFs) were obtained via cDNA-AFLP with 82 primer pairs. Each primer pair was amplified to 30~50 bands with fragment size of 50~800 bp. The TDF expression patterns were divided into four ― up-regulation, down-regulation, transient-expression and continuous-expression. From 103 selected TDFs, 75 had reliable sequences. Also 55 (73%) of the reliable TDF sequences functions were determined through BLAST search in GenBank database. Most of the 55 TDF genes involved in energy and metabolism (17.31%), signal transduction and regulation (15.38%), protein synthesis and ion transport (34.62%) and disease defense (32.69%) were predictable. Of the 75 reliable TDFs, 10 homologous genes were critical for disease defense conditions and signal transductions. Uncharacterized genes were validated in cDNA-AFLP expression patterns using semi-quantitative reverse-transcription polymerase chain reaction (PCR) analyses. This analysis used melon actin as the internal reference gene. The cDNA-AFLP technique confirmed altered expression patterns of 9 (90%) genes. The results show that cDNA-AFLP was a reliable technique for analyzing expression patterns of genes involved in melon allelopathy. Genes involved in melon allelopathy were identified and their expression patterns determined. This study was helpful in shedding more light on molecular mechanisms of melon allelopathy. It was also useful in identifying genes that could alleviate allelopathic autotoxicity in melon.

Soil faunal community structure in winter season under variousland use types in Guangzhou

LI Qing-Fang, ZHANG Jia-En, QIN Zhong

2012, 20(11): 1521-1526. doi: 10.3724/SP.J.1011.2012.01521

Abstract(1305) PDF(1262)

Abstract:
Rapid urbanization process changes the spatial pattern of land utilization, soil physical and chemical properties. As an important part of urban ecosystem, soil animals have been used in monitoring researches of many environmental problems from urbanization, in which some of them may be used as indicator species to monitor and evaluate soil quality and health as well as one of the main influential factors on material cycles. To better know the impacts of urbanization on soil animals community and soil ecosystem, we took Tianhe and Yuexiu Districts of Guangzhou City as a case study area, 6 sites from three different land use systems including the two woodlands, two grasslands and two farmlands were selected as the investigation sites in January 2008. Soil meso- and micro- faunal communities in six sites located in three different land use types were investigated. The total number and groups of soil meso- and micro- fauna genera sampled were 1 365 and 25 respectively, belonging to 7 phyla. Dominant genera were Nematoda, Acarina and Turbellaria, comprising 83.44% of total samples collected. The community complexity index (C), a measure of the complexity and diversity of the communities was highest (2.822) in forestland of the South China Botanical Garden plot and lowest in grassland of the Ren Min Park plot. The vertical distribution of soil meso- and micro-faunal communities in the six sampling plots showed clear surface assembly, with the total number of soil fauna and genera declining with soil depth. Detrended correspondence analysis indicated that soil animal communities responded differently to varying intensities of human activities. Rare genera within the Orders of Diplopoda and Archaeognatha could be only found in the two forestland plots and very sensitive to human disturbance, indicating that soil fauna within these two orders might be used to detect land use changes resulting from urbanization. The results of this study provided scientific and fundamental data for the indicative function of the soil quality change by giving a survey of variations of soil meso- and micro-faunal community's composition and distribution under the influences of rapid urbanization. Moreover, the study pointed out that future studies should integrate the studies of the soil animals and changes in land use type for the enhancement or improvement of soil quality.

Chiral selective effect of quizalofop-ethyl enantiomer toxics on Brachydanio rerio

XU Yang-Guang

2012, 20(11): 1527-1531. doi: 10.3724/SP.J.1011.2012.01527

Abstract(1360) PDF(1165)

Abstract:
This paper studied chiral selective effect of quizalofop-ethyl enantiomer toxics on aquatic species. To that end, acute toxicity tests of quizalofop-ethyl enantiomers to B. rerio were conducted and variant ATPase activities of B. rerio under sublethal concentrations investigated. The study showed that although quizalofop-ethyl belonged to low-toxic pesticides, it was highly toxic to B. rerio. For Na⁺,K⁺-ATPase and Ca²⁺-ATP, the modes of quizalofop-ethyl enantiomers at both induction time and intensity were different. At 24 h and 48 h, the effects of quizalofop-ethyl on Ca²⁺-ATPase activity of B. rerio were not significantly different in all exposure and control groups. At 72 h, the exposure groups of 250 μg·L^-1 and 1 000 μg·L^-1 showed significant induction (P < 0.05). At 96 h, each exposure group showed an overall induction. Quizalofop-p-ethy1 showed significant induction of Ca2⁺-ATPase of B. rerio in each exposure group, except for 5 μg·L^-1 and 10 μg·L^-1 exposure groups at 24 h. While enzyme activity showed a declining tendency in 25 μg·L^-1 and 100 μg·L^-1 exposure groups after 72 h, it continued to rise in the other two exposure groups. The 250 μg·L^-1 and 1 000 μg·L^-1 exposure groups showed significant induction of Na⁺,K⁺-ATPase activity for B. rerio (P < 0.05) at 48 h. At 72 h, however, only the 1 000 μg·L^-1 exposure group showed significant induction. Quizalofop-p-ethy1 showed significant induction in 25 μg·L^-1 and 100 μg·L^-1 exposure groups at 24 h. After 48 h, enzyme activity began to increase significantly in each exposure group. At 72 h, enzyme activity showed a downward tendency in each exposure group. At 96 h, there was no significant difference between each set of the exposure and control groups. It was concluded that quizalofop-ethyl enantiomers had chiral selective effect on B. rerio.

Growth kinetic model of Fusarium oxysporum under different pH

LAN Jiang-Lin, XIAO Rong-Feng, LIU Bo, ZHU Yu-Jing, CHE Jian-Mei, LIN Kang-Mei

2012, 20(11): 1532-1538. doi: 10.3724/SP.J.1011.2012.01532

Abstract(1166) PDF(1532)

Abstract:
Fusarium wilt disease in agricultural crops caused by Fusarium oxysporum facultative fungi has always been difficult to control. In this paper, the effects of different pH on the growth characteristics of six F. oxysporum strains isolated from different host plants were studied by constructing a kinetic model with growth characteristics of F. oxysporum inoculated on potato sucrose (PS) agar mediums with different pH levels. The tested six F. oxysporum strains could grow in PS liquid medium with pH 3~9. pH changes of PS liquid medium with different stains was similar, closing to 6~7 after 14 days cultivation. This colony was divided into 4 categories (hyhae, stick-slip, hyhae and stick-slip, and hyhae with powdery types) in the range of pH 3~9. The hyhae and culture medium colors of the strains were different. F. oxysporum growth rate in different pH media was determined at 25 ℃, which was later used to build the kinetic growth model. Growth rate was affected by medium pH. The optimal growth (with maximum average colony diameter of 45~49 mm) was attained in the range of pH 6~8, followed by pH 4, 5 and 9, with colony diameter significantly smaller (17~21 mm) at pH 3, 10 and 11. Colony morphology and color were affected by media pH after 14 days cultivation. Differences existed among stain sporification at different pH, with the highest average sporification (223.8~273.3)×104 cfu·mL^-1 in the range of pH 4~8. Sporification was highest at pH 6.38 (natural pH) and was lowest at pH 11. Strain colony growth and sporification at different pH were best depicted by quadratic equation.

Impact of climate change in 1981-2009 on winter wheatphenology in the North China Plain

XIAO Deng-Pan, TAO Fu-Lu

2012, 20(11): 1539-1545. doi: 10.3724/SP.J.1011.2012.01539

Abstract(1399) PDF(2595)

Abstract:
A warming climate trend in the last three decades has been well documented around the global and this trend have had a considerable impact on agricultural productivity. Phenology is a plant growth progress that is largely driven by meteorological conditions. Phenological changes are vital indicators for changes in climate and other environmental conditions. In this study, the trends in winter wheat phenology for 1981-2009 were investigated based on phenological dates from 16 agro-experimental stations in the North China Plain (NCP). The study showed that the dates of sowing, emergence and dormancy delayed. On the other hand, the dates of green-up, anthesis and maturity advanced in most of the stations. The advance or delay of winter wheat phenology resulted in corresponding changes in the durations of the different growth stages. In most of the investigated stations, the durations from emergence to dormancy, dormancy to green-up, green-up to anthesis and in the entire period from emergence to maturity of winter wheat shortened during 1981-2009. However, the duration of anthesis to maturity slightly prolonged on the average by 0.9 days per decade. Observed changes in winter wheat phenology were functions of both climate and management practices, especially that of cultivated cultivar shift. The effect of crop cultivar shift was isolated from that of climate change on winter wheat phonological changes by comparing field observed phonological events in four stations with those simulated by the CERES (Crop Environment Resource Synthesis)-Wheat model. The results suggested that climate warming played a dominant role in phenological changes in winter wheat in the NCP. However, the effect of cultivar shift on winter wheat phenological changes was not entirely negligible. Moreover, correlation analysis on the durations of green-up to anthesis and anthesis to maturity against mean temperatures for the growth periods showed that temperature increase by 1 ℃ shortened the durations of green-up to anthesis and anthesis to maturity by 3.8 and 1.2 days, respectively. Understanding the response of crop development and phenology to climate change was critical for not only building in-depth insights into the impacts of climate change on crop development and productivity, but also on food security for the millions of people in the region and beyond.

Difference between the WTP and WTA in cultural service value evaluation of agriculture ecosystems: Shanghai pond aquaculture case study

FAN Xiao-Yun, YANG Zheng-Yong, TANG Ke-Yong, YANG Huai-Yu

2012, 20(11): 1546-1553. doi: 10.3724/SP.J.1011.2012.01546

Abstract(1377) PDF(1939)

Abstract:
Pond aquaculture has existed in China for thousands of years and has been not only a major source of food, but also provided cultural service. The development of service industry in agriculture has further highlighted the value of pond aquaculture. The Contingent Valuation Method (CVM), one of several methods for evaluating non-market values, has been widely used data analysis. However, there has remained much controversy on the effectiveness and stability of CVM. One such hot spot of discussion has been strategic bias, a significant disparity between willingness to pay (WTP) and willingness to accept (WTA), in evaluation of environment products and services values. Current literature has shown that few researches exist on the evaluation of cultural service values of aquaculture ecosystems. This paper used pond aquaculture in Qingpu, Jiading and Fengxian Districts of Shanghai to evaluate the cultural services values and discuss the difference between WTP and WTA as given by Tobit and Mulit-Logit models. The results showed that WTP was affected by the income, education, interest and satisfaction with pond environments of the interviewees. A significant positive relationship existed between WTP and the above factors. WTA was also influenced by income and satisfaction with pond environments. WTA was significantly positively related to income. But satisfaction with pond environment was negatively related to both WTP and WTA. Household income, register, age and interest in pond activities of interviewee were the main influence factors on WTA/WTP asymmetry. The average WTA/WTP ratio was 5︰1. Income, substitution, endowment and prospect effects as well as property right affected the differences between WTP and WTA. Due to deviations in interviewees' understandings of WTA, responses were higher than the real pond value. Based on this fact, WTP was used as the preferred assessment method. The average value of WTP of the investigated area was 163.75 Yuan per person. Then based on the population statistical yearbook, total cultural services values of Qingpu, Jading and Fengxian were 177.161, 241.040 and 177.521 million Yuan per year, respectively. It suggested that in the construction of new rural areas in Shanghai, sufficient attention needed to be paid on the full play of cultural services values of aquaculture pond ecosystems. Functional departments needed to achieve full protection and sustainable utilization of ponds, with focus on increased farmer income.

Cultivated land carrying capacity and population migration in ecological barrier zone of the Three Gorges Reservoir

YANG Xin-Yue, WEI Chao-Fu, NI Jiu-Pai

2012, 20(11): 1554-1562. doi: 10.3724/SP.J.1011.2012.01554

Abstract(1346) PDF(1629)

Abstract:
An ecological barrier zone project in the Three Gorges Reservoir is an important follow-up of the Three Gorges Project for protecting water quality and ecological environment, reducing population pressure on the Three Gorges Reservoir environment. Nonetheless, numerous project building difficulties have been caused by excessive human activity and sharp contradictions between population and available land. It was imperative to transfer congested residential in the region in order to relieve ecological pressure. Relevant consideration was the ecological carrying capacities of current and post-aforestation of cultivated lands. Based on "status-quo" state analysis, this study calculated the existing carrying capacities of cultivated lands (CLCC) in 15 districts in Chongqing. The study area is along the Three Gorges Reservoir and both the area and yield of cultivated lands were analyzed through calculation of per cap. demand for cultivated land and grain. The study also forecasted the CLCC after afforestation construction. The result showed that population carrying capacity of cultivated lands in the study area was severely inadequate. Deficit in the "status-quo" carrying capacity of cultivated lands for area (CLCCa) was 117.01 million people and that in the carrying capacity of cultivated land for production (CLCCp) was 94.93 million people. Moreover, regional deficit in terms of the CLCCa in 2020 was 127.39 million people. It was necessary to enhance an ecological migration of people in the region based on congestion trend in CLCC. Rural population migration was required with the key emigration and immigration areas being the northeast and southeast regions, respectively, according to distributions of CLCC and population in the study area. Added to migration implementation, it was the enhancement of CLCC to maintain dynamic balance of the area, and enhance the quantity of cultivated land. This was good for economic development, social stability and ecological security in the study area.

2012 Vol. 20, No. 11