中国生态农业学报(中英文)

Response of rice-rice ecosystem productivity and yield stabilityto long-term fertilization

CHEN Chun-Lan, CHEN An-Lei, WEI Wen-Xue, PENG Zhong, YIN Chun-Mei, XIE Xiao-Li

2012, 20(10): 1263-1267. doi: 10.3724/SP.J.1011.2012.01263

Abstract(1155) PDF(1125)

Abstract:
The productivity and yield stability of rice-rice ecosystem in Huazhong with different fertilizers were investigated using experimental data from the Chinese Ecosystem Research Network at Taoyuan Station of Agro-ecology Research, Chinese Academy of Sciences. The field trials included no fertilizer (CK), chemical fertilizer (NPK), rice straw with low N, K and high P (optimal fertilization, OF) and rice straw with some amount of NPK (general fertilization, GF). The results showed that fertilization was the basic mode of maintaining or increasing productivity of rice in paddy ecosystem. Productivity and stability were different in paddy ecosystems with different fertilizers. The total rice biomass was significantly higher in fertilizer treatments than in no fertilizer treatments; 0.33~1.23 times higher for the period of 2005 to 2010. The order of stability from high to low was OF > GF > NPK > CK. OF treatment improved total biomass stability in the study area. Yield under fertilizer treatments was 0.35~1.02 times higher than under no fertilizer treatment for the period of 2005 to 2010. It was 0.35 times higher in GF than CK in 2005, 0.82 times higher in NPK than CK in 2007 and 1.02 times higher in OF than CK in 2010. The stability of rice yield was high in OF treatment and significantly low in CK treatment. Yearly variation coefficient under CK, NPK, OF and GF treatments was 22.4%, 15.8%, 10.3% and 15.7%, respectively. Productivity of underground biomass was significantly higher in fertilizer treatments than in no fertilizer treatment. Also ecological stability was significantly higher under GF treatment than the other treatments. In conclusion, rice productivity and production stability were highest under OF treatment and lowest under CK treatment. While fertilizers influenced rice yield stability and total or over-ground rice biomass, they little affected the stability of below-ground biomass productivity.

Effect of optimized application of nitrogen on nitrogen volatilization in Nicotiana tobacum shoots at rapid growth and maturity stages

WANG Jun, CHEN Neng-Chang, DING Xiao-Dong, CHEN Ze-Peng, XIE Yu-Hua, WANG Hang, FU Xian-Zhong, WANG Xiao-Bin, HE Guang-Sheng

2012, 20(10): 1268-1275. doi: 10.3724/SP.J.1011.2012.01268

Abstract(1189) PDF(1176)

Abstract:
A pot experiment equipped with volatilization devices was used to study the effects of applied nitrogen (N) amounts and basal/top-dressing fertilizer ratios on N volatilization of "Yueyan 97" flue-cured tobacco shoot at rapid growth and maturity stages. The treatments used in the study included T1 (zero N fertilization), T2 [0.30 g(N)·kg^-1(soil) and 7∶3 basal/top-dressing fertilizer ratio, conventional fertilization mode] and T3 [0.15 g(N)·kg^-1(soil) and 3∶7 basal/top-dressing fertilizer, optimized fertilization mode]. The results showed that compared with T1 and T2, T3 significantly improved flue-cured tobacco shoot NO volatilization at maturity stage. However, for NO₂ at maturity stage, it was net absorption for all the three treatments, there was not significant difference among three treatments at maturity stage. Among the three treatments, average shoot N₂O volatilization of T2 at both rapid growth and maturity stages was largest. This was followed by T3 and then T1. Shoot N₂O volatilization losses in T2 and T3 at maturity were 3.06 and 6.12 times of that at rapid growth stage, respectively. There was no significant difference in tobacco shoot NH₃ volatilization among three nitrogen treatments at rapid growth stage. While at maturity stage, T3, compared with T2, obviously increased shoot NH₃ volatilization. While reduced N application and optimized basal/top-dressing fertilizer ratio decreased aerial plant organ N₂O volatilization at rapid growth and maturity stages, it increased NH₃ volatilization at maturity stage. The above results suggested that although optimized N application (by postponement) enhanced N absorption at middle and late growth periods of flue-cured tobacco, it facilitated endogenous N₂O formation and volatilization. There was no definitive effect of optimized N application (by postponement) on flue-cured tobacco N volatilization inhibition.

Effect of planting density on nitrogen uptake, utilization anddistribution in winter wheat

WANG Shu-Li, HE Ming-Rong, DAI Xing-Long, ZHOU Xiao-Hu

2012, 20(10): 1276-1281. doi: 10.3724/SP.J.1011.2012.01276

Abstract(1419) PDF(1459)

Abstract:
Intensive wheat cultivation requires large inputs of nitrogen (N) fertilizer. However, only a limited proportion of the applied N is taken up by winter wheat, meaning that large amounts of N are lost to the environment. This loss of N fertilizer represents not only a considerable cost to the grower, but may also to the environment. Therefore, there has been increasing global emphasis on optimized management strategies for high nitrogen use efficiency (NUE; i.e., grain yield/available N) to help reduce excessive N fertilizer inputs while maintaining acceptable grain yields. The amount and spatial distribution of plant roots in soil profile reflect potential nutrient up-take. Also plant density can influence root distribution in soil profile, increasing seminal roots per unit area and reducing nodal roots per culm. Various planting densities were therefore considered in relation to high NUE. The aim of the study was to find suitable wheat planting density that simultaneously produced high grain yields and NUE. To that end, two winter wheat cultivars (large-spike "Tainong 18" and medium-spike "Shannong 15") were selected and experimented under field conditions at various planting densities. The planting densities were 1.35 million·hm^-2, 2.70 million·hm^-2, 4.05 million·hm^-2 and 5.40 million·hm^-2 for "Tainong 18"; and 1.725 million·hm^-2, 3.45 million·hm^-2, 5.175 million·hm^-2 and 6.90 million·hm^-2 for "Shannong 15". The tow wheat cultivars were analyzed for the uptake, distribution and utilization of N, and for grain yield and inorganic N accumulation in soil profile. The results showed that N accumulation at maturity, grain yield, N uptake efficiency and N partial factor productivity were highest under the planting densities of 2.70 million·hm^-2 for "Tainong 18" and 3.45 million·hm^-2 for "Shannong 15". Grain N accumulation at maturity, gain N after anthesis and N translocation to grain after anthesis reduced with increasing planting density. Translocated N amount, proportion and contribution to grain from stored N in vegetative organs before anthesis increased with increasing planting density. N harvest index, grain N concentration, and NO₃^-N, NH4₊^-N and inorganic N accumulation at different depths of the soil profile decreased at wheat maturity with increasing planting density. In conclusion, grain yield and NUE were highest under planting densities of 2.70 million·hm^-2 for "Tainong 18" and 3.45 million·hm^-2 for "Shannong 15". The recommended planting densities were therefore 2.70 million·hm^-2 for "Tainong 18" and 3.45 million·hm^-2 for "Shannong 15".

Effects of different cultivation management modes on dry matteraccumulation, nitrogen uptake and yield of winter wheat

MA Ying-Hui, WANG Ling-Min, YE You-Liang, ZHU Yun-Ji

2012, 20(10): 1282-1288. doi: 10.3724/SP.J.1011.2012.01282

Abstract(1295) PDF(1480)

Abstract:
The effects of different cultivation management modes on dry matter accumulation, distribution, nitrogen (N) uptake, N use efficiency (NUE) and yield of winter wheat in Henan Province were investigated in a field experiment in Wenxian County in 2009-2011. The experiments aimed to provide theoretical basis for cultivation management mode of winter wheat in the Wenxian region of Henan Province. The four different cultivation management modes used were conventional management (T1, conventional management mode in the region), optimized management mode 1(T2), high-yield management (T3), optimized management mode one the base of T3 (T4). Compared with T1, T2 with fertilizer applications at basal and jointing stages enhanced time and rate of rapid dry matter accumulation, grain dry matter accumulation, stem and leaf N transport to grain and per-ear grain and kernel weight. This resulted in higher output and efficiency. Also compared with T3, T4 reduced fertilizer dose, increased grain weight by improving N translocation amount and contribution rate to grain of leaves after anthesis and maintained grain yield while improving nutrient efficiency. Compared with treatments T1 and T2, T3 and T4 improved rapid dry matter accumulation and N translocation from stem and leaf storage to grain after anthesis. Based on the results, T2 was worthy cultivation mode under the present production management conditions. Treatment T4 was both the high-yield and high-efficiency cultivation management mode under high-yield conditions.

Transport and redistribution of nitrogen at late growth stagesin different oilseed rape cultivars

YANG Ming, SONG Hai-Xing, XU Hao-Ran, LIU Qiang, RONG Xiang-Min, ZHU Zhao-Kun, WANG Xiao-Juan, YANG Lan

2012, 20(10): 1289-1294. doi: 10.3724/SP.J.1011.2012.01289

Abstract(1415) PDF(1153)

Abstract:
This paper used ¹⁵N tracer method in sand culture conditions to determine the physiological factors of N redistribution and its relationship with N utilization efficiency. The paper also studied the differences in N distribution, transshipment and loss under different N levels in different N-efficient oilseed rape cultivars. The results showed that different N levels had different outputs in terms of biomass, grain yield, grain N content, plant N content, plant total N, grain total N, harvest index, accumulated N and N harvest index of selected oilseed rapes. Under normal N level, oilseed rape cultivar "742" had higher biomass, grain yield, grain total N, harvest index and N harvest index than cultivar "814". However, rape cultivar "742" had lower grain N content, plant N content and plant total N than "814" at low N level. Oilseed rape cultivar "742" had higher plant N content, grain N content, harvest index and N harvest index at peduncle growth stage than "814". At harvest stage, however, "742" had lower biomass, grain yield, plant total N and grain total N than "814". ¹⁵N tracer method results showed decreasing N amount in vegetable organs and the proportions and redistributions of N in propagative organs were significantly different. Under different N levels, N decline in root and stem in cultivar "742" was higher than in "814". This difference was especially evident in the stems of the oilseed rape cultivars. Under normal N level, the proportions of N decline in roots and leaves were lower in cultivar "742" than in "814". However, the proportion of N decline in stems was much higher in cultivar "742" than in "814". Under low N level, the proportion of N decline in all vegetable organs was highest in cultivar "742". Under normal or low N levels, less N was redistributed to silique husk of cultivar "742" than in cultivar "814". However, more N was redistributed to grain of "742" than "814". T-test showed that the amounts of redistributed N were significantly different, except for silique husk under normal N level. This implied that N redistribution from vegetative organs benefited N use efficiency. Furthermore, with normal N level, N loss and proportion in oilseed rape cultivar "742" were higher than in "814", and the reverse was the case for low N level.

Effects of long-term fertilization on As (arsenate) accumulation intypical fluvo-aquic soils and crops

WANG Qing-Yun, ZHANG Jia-Bao, XIN Xiu-Li, ZHAO Bing-Zi, DENG Xi-Hai, QIN Sheng-Wu

2012, 20(10): 1295-1302. doi: 10.3724/SP.J.1011.2012.01295

Abstract(1458) PDF(1606)

Abstract:
Huang-Huai-Hai Plain is a strategic grain production base in China with a wild distribution of fertile fluvo-aquic soils. During the past 20 years, high-input intensive agriculture with excess chemical fertilizer application has sustained high grain yields. However, unreasonable field management has resulted in potential pollution issues in the plain. In this study, the effects of long-term differential fertilization practices on the accumulation of arsenate (As) in typical fluvo-aquic soils and crops were investigated. Field experiments were launched in 1989, in which 7 treatments were established. The treatments included OM (organic manure), OM+NPK (50% organic manure + 50% chemical fertilizer), NPK, NP, PK, NK and CK (the control experiment with no fertilizer). With over 20 years (1989-2009) of cultivation, As in the surface (0~20 cm) and subsurface (20~40 cm) soil layers markedly accumulated. The soil As content was, however, too low for loading negative effects on eco-agricultural safety. As accumulation in the plain was mainly affected by irrigation and deposition, and relatively less affected by different fertilizer applications. The content of As in phosphorus (P) fertilizers was higher than in nitrogen (N) and potassium (K) fertilizers or in organic manure (OM). Hence P fertilization was the main drive of soil As accumulation in the plain. Nevertheless, long-term P fertilization did not significantly increase soil As content since it was largely used up by crops. Also As accumulation trend slowed with OM fertilization. Crop tissue content of As was in the order of root > stalk > grain. Grain As content was not only significantly lower than that of root or stalk, but also than that of China's national standard. For different fertilization treatments, wheat tissue As content was in the order of PK > OM > OM+NPK > NPK > NP > NK > CK. This was somehow similar to that of soil available P, which was indirectly affected by soil organic matter content. Under OM, OM+NPK, NPK and NP treatments, there was high soil organic matter accumulation, which led to high crop yields. Although soil organic matter promoted high As adsorption by wheat, it had no significant effect on maize root As content. Since maize cultivation period was relatively short, low soil available As content inhabited maize root As content. More As was adsorbed by maize stalk due to strengthened transferability.

Effects of nitrogen on sweet sorghum seed germination, seedling growth and physiological traits under NaCl stress

MU Jing, LIU Xiao-Jing, XU Jin, MAO Ren-Zhao, WEI Wei, YANG Li-Lin

2012, 20(10): 1303-1309. doi: 10.3724/SP.J.1011.2012.01303

Abstract(1307) PDF(1398)

Abstract:
The effects of nitrogen application on germination, seedling growth and physiological traits of sweet sorghum [Sorghum bicolor (L.) Moench] were investigated under NaCl stress. The aim of the study was to enhance salt-tolerance of sweet sorghum through laboratory germination experiments at different salt and nitrogen (N) concentrations using two N sources. The results showed that either salt or N significantly influenced seed germination and seedling growth of sweet sorghum. Under NaCl stress, sweet sorghum salt uptake increased via improved enzyme activities and osmoregulation during seed germination and bud seedling growth stages. Under NaCl stress, there was a little ability for sweet sorghum to resist salt by improving enzyme activity and osmoregulation substance during seed germination and seedling growth stage. Lowest root POD activity, highest leaf MDA accumulation, leaf soluble sugar and leaf POD under 100 mmol·L^-1 NaCl stress indicated the greatest salt damage to sweet sorghum. N treatments without NaCl markedly affected seed germination and seedling growth of sweet sorghum. Sweet sorghum seedling grew best under 20 mmol(N)·L^-1 due to lessening cell damage by NaCl. NH₄Cl improved more than KNO₃ in seed germination and seedling growth of sweet sorghum. Under 100 mmol·L^-1 NaCl stress, supplementation with either form of the two N sources (NH₄⁺ and NO₃^- ) ameliorated adverse salt stress effects on seedling growth and examined physiological traits. This was possible by improving POD activity and reducing MDA accumulation. It was evident that an appropriate nitrogen fertilizer application improved the salt tolerability of sweet sorghum.

Effect of frozen saline water irrigation in winter on soil salt and water dynamics,germination and yield of cotton in coastal soils

ZHANG Xiu-Mei, GUO Kai, XIE Zhi-Xia, FENG Xiao-Hui, LIU Xiao-Jing

2012, 20(10): 1310-1314. doi: 10.3724/SP.J.1011.2012.01310

Abstract(1203) PDF(1154)

Abstract:
A three-year field experiment was conducted to investigate soil water and salt dynamics, cotton emergence, seedling salt content and cotton seed yield in coastal soils (Xiaoshan, Haixing County of Hebei Province) under frozen saline water irrigation in winter. The irrigation water salinity and volume were 8.15~14.27 g·L^-1, and 180 mm, respectively. After saline ice melt-water infiltration in spring, the soil was mulched with plastic film to prevent further soil salinization via evaporation. The results showed that soil salt and water contents at sowing in 2009, 2010 and 2011 were respectively 0.32%, 0.29% and 0.17% and 26.2%, 25.0% and 24.2% under saline ice water irrigation. This implied that longer saline ice water irrigation had better soil desalination effect, providing suitable soil water and salt conditions for cotton growth. While cotton germination rate was above 85% under saline ice water irrigation treatment, few cotton seeds emerged under the control treatment (no irrigation and no mulching) due to high soil salinity. Seedling sodium content decreased by 57.6%~64.5% under saline ice water irrigation but potassium and calcium contents remained higher than the control. This prevented mono-ion problems in cotton plants, which further enhanced normal metabolism in cotton plant tissues. Salt content of the topsoil decreased further with the arrival of rainfall, which further ensured normal cotton growth. Overall, cotton seed yield reached 2 643.8~3 607.7 kg·hm^-2 with that of the succeeding year higher than preceding year. The above findings showed that frozen saline water irrigation in winter improved cotton growth in coastal soils in north China.

Effects of riparian vegetation on soil organic carbon andtotal nitrogen distribution - a case study of Wenyu River, Beijing

GUO Er-Hui, SUN Ran-Hao, CHEN Li-Ding, WANG Zhao-Ming, XIAO Jun, SHI Peng

2012, 20(10): 1315-1321. doi: 10.3724/SP.J.1011.2012.01315

Abstract(1278) PDF(1604)

Abstract:
Riparian ecosystem is an ecological ecotone that occurs between river and terrestrial ecosystems. Riparian ecosystems are normally sensitive and vulnerable ecological niches. There are vast changes in riparian vegetation systems due to human disturbances of river systems. Thus this study analyzed the effects of 7 riparian vegetation systems on the contents and spatial distributions of soil organic carbon and total nitrogen in Wenyu River in Beijing. The results showed that riparian vegetation mainly affected soil organic carbon and total nitrogen in the surface soil layer, especially in the 0~5 cm soil layer, with relatively minimal effect on below the 5 cm soil layer. The impact of vegetation on the content and distribution of soil total nitrogen and organic carbon was significant. While soil total nitrogen and organic carbon decreased with increasing soil depth, vertical variations among the 7 vegetation systems were different. The rate of decrease in soil organic carbon and total nitrogen with soil depth was significantly higher under natural grasslands, abandoned farmlands and forests than under farmland ecosystems. In the 0~30 cm soil profile, the average content of soil organic carbon was highest under Populus simonii forestland (9.54 g·kg^-1), followed by natural grassland (9.33 g·kg^-1), pear orchard (9.18 g·kg^-1), Rhus typhina forestland (8.89 g·kg^-1), abandoned farmlands (7.91 g·kg^-1), corn field (7.22 g·kg^-1) and then soybean field (7.17 g·kg^-1). Also the average soil total nitrogen was highest under natural grassland (1.30 g·kg^-1), followed by P. simonii for-estland (0.91 g·kg^-1), pear orchard (0.90 g·kg^-1), R. typhina forestland (0.83 g·kg^-1), abandoned farmlands (0.80 g·kg^-1), corn field (0.72 g·kg^-1) and then soybean field (0.70 g·kg^-1).

Biomass allocation and estimation model at different planting ages ofwine grape forest in east Helan Mountain

WU Xu-Dong, XIE Ying-Zhong, XU Kun, WANG Shi-Ping, ZHANG Xiao-Juan

2012, 20(10): 1322-1328. doi: 10.3724/SP.J.1011.2012.01322

Abstract(1202) PDF(1095)

Abstract:
The biomass and morphological indexes of different planting ages of wine grape forest (1~12 years) were investigated by analyzing biomass distributions in different organs of varying-age stands and the relationships of biomass with component factors in east Helan Mountain. The study then established biomass prediction models for wine grape forests in the region. The results showed that plant height (H), stem height (SH), young shoot height (YSH), branch number (BN) and stem diameter (D) gradually increased with increasing planting age. Also different aboveground organs biomass increased with increasing forest age. The distribution of aboveground biomass showed an order of leaf > young shoot > stem for forest of ages 1~4 years. Although leaf formed a principal component of aboveground biomass, stem biomass was greater than young shoot biomass which was in turn greater than leaf biomass for forest of ages 4~12 years. Aboveground biomass gradually transformed into stem and young shoot. Belowground and aboveground biomasses significantly increased for ages 1~12 years. Biomass allocation was in the order as follows: aboveground biomass > belowground biomass for forest ages of 2~12 years. The pattern of relationship between biomasses of different plant organs and D²H was uniform with age structures. The optimal biomass models were the power function models of the form W=a×(D²H)^b. The relationship between leaf biomass and D²H fitted the form W=12.909×(D²H)^{0.825 9} (R²=0.849 9, P=0.000); that between shoot biomass and D²H fitted the form W=3.963 4×(D²H)^{1.344 9} (R²=0.938 1, P=0.000); also that between young shoot biomass and D²H fitted the form W=6.190 6×(D²H)^{1.051 7} (R²=0.804 7, P=0.000); next that between aboveground biomass and D²H fitted the form W=23.017×(D²H)^{1.076 6} (R²=0.938 5, P=0.000); and the relationship between belowground biomass and D²H fitted the form W=27.126×(D²H)^0.689 (R²=0.892 4, P=0.000). The optimal wine grape biomass models at different planting ages showed a certain degree of generality of high accuracy.

Artificial biological soil crust property and potential for rainwater harvest

ZHOU Gui-Lian, ZHANG Wan-Jun

2012, 20(10): 1329-1333. doi: 10.3724/SP.J.1011.2012.01329

Abstract(1012) PDF(1185)

Abstract:
It is important to collect limited rainwater for agricultural and domestic use in arid and semiarid areas. Rainwater harvesting systems used for collection, storage and purification of rainwater are critical for rainwater utilization. Materials used in building the surfaces of rainwater harvesting plots determine the efficiency of rainwater harvesting system as they affect the hydrological characteristics of the plot surfaces. This paper discussed the potential and feasibility of artificially cultivated biological soil crusts (BSCs) as surface materials of rainwater harvesting plots. It investigated the effects of artificial BSCs on soil physical properties and infiltration and also on the efficiency of rainwater harvest. The results showed that the surface soil (0~1 cm) with artificial BSCs contained more tiny particles and less coarse particles than natural soil. However, no significant difference was noted in bulk density of 0~5 cm soil between artificial BSCs and natural soil. Infiltration rate decreased under artificial BSCs. Initial and stable infiltration rates as well as stable infiltration water volume of BSCs decreased by 59.1%, 44.4% and 50.0%, respectively. The investigation based on rainwater harvesting plots established on 30° slope loamy soil mountain showed that BSCs rainwater runoff efficiency increased. The average runoff efficiency of BSCs rainwater harvesting plot was 60.86% during six runoff events in May to August 2005. BSCs rainwater harvesting plot increased runoff efficiency over that of natural soil by 23.0%. Benefit analysis showed that BSCs not only increased runoff efficiency, but also longer-lasting with significantly less runoff sediment. BSCs were therefore recommended as potential green materials for rainwater harvest.

Effects of Fe supplementation on Solanum nigrum seedlinggrowth under Zn toxicity

LI Yu-Long, GAO Feng, SUN Jian-Hang, YU Qiong, HOU Xiao-Yu, LIU Xiao-Jing, XU Jin

2012, 20(10): 1334-1339. doi: 10.3724/SP.J.1011.2012.01334

Abstract(1077) PDF(1443)

Abstract:
The alleviating effects of iron (Fe) supplementation on zinc (Zn) toxicity were investigated in hydroponic Solanum nigrum seedlings. Hydroponic method was used to raise S. nigrum seedlings with three combined Zn and Fe concentrations - of 400 μmol·L^-1 Zn, 0 μmol·L^-1 Fe, 400 μmol·L^-1 Zn + 200 μmol·L^-1 Fe and standard 0.5 Hoagland nutrient solution as the control. The results showed that seedling height, root length and chlorophyll content reduced while H₂O₂ accumulation significantly increased in Zn-treated S. nigrum seedlings. Supplementation with Fe did not only improve Zn tolerance, but also increased gene expression and enzyme activities of SOD, CAT and APX in S. nigrum seedlings. RT-PCR results showed that supplementary Fe significantly increased FeSOD2 and CAT1 genes expressions. These results indicated that Zn toxicity-induced oxidation damage and growth inhibition were largely due to Zn-induced Fe deficiency in plants. Supplemental Fe in Zn-poisoned conditions improved FeSOD2 and CAT1 genes expressions. This enhanced antioxidant enzyme activity and reduced reactive oxygen species (ROS) level and oxidative damage of plants. The study provided the theoretical basis for further studies on molecular mechanisms of plant response to Zn toxicity and the practical applications for phytoremediation technology.

Dynamic changes in fungal community structure in rhizosphere soils of transgenic rice with antifungal genes

LV Xin, CHEN Li-Hua, LIU Lan-Ying, LI Wei, LI Yue-Ren

2012, 20(10): 1340-1346. doi: 10.3724/SP.J.1011.2012.01340

Abstract(1070) PDF(1116)

Abstract:
The effects of transgenic rice with antifungal genes on fungal community structure and the amounts of cultivable fungi in rhizosphere soils were investigated using classical plate counting and denaturing gradient gel electrophoresis (DGGE). Two varieties of transgenic rice ("ZP-1" and "ZP-8") were tested and compared with their controls "QS" of non-transgenic variety. The results showed that no significant differences existed between the amounts of cultivable fungi in rhizosphere soils of transgenic rice and non-transgenic rice at the same growth stages. This suggested that transformation of antifungal genes into rice had no significant effect on the amounts of cultivable fungi in rhizosphere soils. Fungal 18S rRNA DGGE profile showed that the number and relative positions of DGGE bands in rhizosphere soils were similar for transgenic and non-transgenic rice at the same growth stages. This also implied that the transformation of antifungal genes into rice had no significant effect on fungi community structure in rhizosphere soils. Dynamic changes in Shannon diversity and evenness indexes of fungal communities in rhizosphere soils showed no notable differences between transgenic and non-transgenic rice at the same growth stages. It implied that transformation of antifungal genes into rice also had no significant effect on the amounts and community structure of fungi in rhizosphere soils. The study also excised, cloned and sequenced different DGGE bands denoting varying phylotypes. Phylogenetic analysis of cloned bands showed that fungal phylotypes were made up of five phyla- Ascomycota, Basidiomycota, Chytridiomycota, Zygomycota and an unknown fungi.

Toxicity difference of different acetamiprid formulations againstBemisia tabaci and reasons

XU De-Jin, GU Zhong-Yan, XU Guang-Chun, XU Xiao-Long, DONG Yu-Xuan

2012, 20(10): 1347-1352. doi: 10.3724/SP.J.1011.2012.01347

Abstract(1151) PDF(1405)

Abstract:
The fate of pesticide droplets on plant leaves is significantly influenced by the fine structures of leaf surfaces and the characteristics of pesticide solutions. Deposition quantity is the main factor that influences pesticide toxicity. Using appropriate pesticide formulations greatly increases pesticide utilization and efficiency while it at the same time reduces environmental pollution. Cabbage and cucumber leaves were used as bioassay carriers in order to explore the differences in toxicity among different acetamiprid formulations to Bemisia tabaci Gennadius. The toxicities of five different acetamiprid formulations - emulsifiable concentrate (EC), microemulsion (ME), soluble liquid (SL), soluble powder (SP) and wettable power (WP) - were examined in a laboratory study. The mechanisms of the different toxicities were analyzed through detections of leaf critical surface tension, acetamiprid solution surface tension, dynamic contact angle and leaf retention volume of liquid. The results showed that differences among the pesticide formulations were more obvious when cabbage leaf was used as bioassay carrier. However, differences among the formulations were not so notable when cucumber leaf was used as bioassay carrier. Toxicities differences of SL, SP and WP between two bioassay carries were larger than those of EC and ME. Critical surface tension of cabbage and cucumber leaves were 30.73 mN·m^-1 and 57.91~63.30 mN·m ^-1, respectively. The solution surface tensions of EC and ME were less than critical surface tensions of cabbage and cucumber leaves, if acetamiprid active ingredient concentration reached 7.81 mg·L^-1. For SL, SP and WP, however, solution surface tensions were only less than critical surface tensions of cabbage when acetamiprid active ingredient concentration exceeded 500 mg·L^-1. Contact angle was significantly lower than 90° when ME droplets instantly dripped on plant leaf surface of two plants. Cabbage leaf retention volumes of low concentration ME and EC solutions were higher than the other three formulations. There was no obvious difference in retention volumes of cucumber leaf for the 5 acetamiprid formulations. Differences in leaf surface characteristics and solution surface tensions were the main reasons for the variations in toxicities of different formulations.

Diversity of opportunistic fungi colonizing egg and femaleroot-knot nematodes of tobacco

LIN Sen, WU Xia, WANG Feng-Long, YANG Jin-Guang

2012, 20(10): 1353-1358. doi: 10.3724/SP.J.1011.2012.01353

Abstract(1129) PDF(1379)

Abstract:
Suppression of plant parasitic nematodes with nematode predators, parasites or antagonists is a more eco-friendly approach than using nematicides. Opportunistic fungi have been investigated as potential biological control agents for root-knot nematodes. In this study, sequence data for the 18S rDNA-ITS region were used in conjunction with morphological observations to resolve opportunistic fungi taxonomy associated with eggs and female root-knot nematodes of tobacco. Fungal colonization was determined for eggs, egg masses and females of 156 specimens of tobacco root-knot nematodes from 7 provinces in China during 2010-2011. A total of 9 839 eggs, 408 egg masses and 284 females of Meloidogyne incognita and M. hapla were examined. Also 13 species, belonging to 9 genera of fungi, were isolated and identified. The common fungi associated with eggs, egg masses and females were Purpureocillium lilacinum, Fusarium oxysporum, F. solani, Penicillium purpurogenum, Alternaria alternata, Aspergillus unguis, A. niger and Acremonium strictum. The new strains of root-knot nematodes were Isaria farinose, Trichoderma longibrachiatum, Lecanicillium attenuatum, F. redolens and A. implicatum. P. lilacinum was the dominant species, which predominated in egg, egg masses and female root-knot nematodes with average frequencies of 0.49%, 24.00% and 16.90%, respectively. It occupied a wide range of niches in the study area, isolated from Yunnan, Anhui, Hubei, Guizhou, Shandong Provinces. Significant differences existed among fungal species communities isolated from eggs and females from various locations. As there hardly existed any information on the potential importance of I. farinose and L. attenuatum as nematode pathogens, pathogenicity tests were recommended in future studies.

Potential impacts of organic contaminant on δ¹⁸O and δD in leaf and xylem water detected by isotope ratio infrared spectroscopy

MENG Xian-Jing, WEN Xue-Fa, ZHANG Xin-Yu, HAN Jia-Yin, SUN Xiao-Min, LI Xiao-Bo

2012, 20(10): 1359-1365. doi: 10.3724/SP.J.1011.2012.01359

Abstract(1148) PDF(1141)

Abstract:
There is considerable interest in the use of δ¹⁸O and δD of leaf (δL), xylem (δX) and soil water (δS) as important tracers in analyzing the role of terrestrial biosphere in eco-hydrological cycle. Isotope ratio infrared spectroscopy (IRIS) has emerged as a faster, more cost-effective and field-deployable method for water stable isotope analysis. However, previous studies have also demonstrated the potential for large errors in IRIS. These errors included considerable deviation from isotope ratio mass spectrometry (IRMS) values in the range of (2.64±0.43)‰ for δ¹⁸O and (3.6±0.8)‰ for δD when water stable isotopes were cryogenically extracted from plants/soils with methanol/ethanol-based organic contaminants. As this study focused mainly on establishing correction methods, deionized water spiked with varying amounts of methanol (MeOH, 10~800 μL·L^-1) and ethanol (EtOH, 2~40 mL·L^-1) was used to create correction curves for δ¹⁸O and δD associated with metrics of narrow-band (MeOH, NB) contamination and broad-band (EtOH, BB) determined using Spectral Contamination Identifier (of Los Gatos Research Inc. software, United States). The results showed that while no significant time drift (P > 0.01) existed in correction curves of liquid water δ¹⁸O and δD analyzer (Los Gatos Research Inc.), it varied significantly from other analyzers (P < 0.01). The lightly contaminated (NB < 4 000 and BB < 1.2) δL and δX of winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) were accurately corrected. The mean differences in isotope ratios between corrected IRIS and measured IRMS were ( 0.11±0.12)‰ for δ¹⁸O and ( 0.7±0.4)‰ for δD. The study discussed the necessity for further validation of the established correction methods for highly contaminated samples (NB > 4 000 or BB > 1.2). It recommended cross-validation between corrected IRIS and measured IRMS using random investigation of small amounts of each unknown species of plants or soils.

GIS-fuzzy neural network-based evaluation of tobacco ecologicalsuitability in southwest mountains of China

WANG Xuan, XU Xiao-Hong, LV Jia-Ke, WEI Chao-Fu, XIE De-Ti

2012, 20(10): 1366-1374. doi: 10.3724/SP.J.1011.2012.01366

Abstract(1202) PDF(1425)

Abstract:
Evaluation of tobacco ecological suitability is important for the scientific tobacco planting and mountain agro-resources utilization in the southwest mountains of China. In this study, Qianjiang County tobacco plantation in southeast Chongqing was used as a case to evaluate tobacco ecological suitability. After analysis of tobacco biological characteristics, thirteen ecological factors with strong influence on local tobacco growth were selected to construct a tobacco planting ecological suitability evaluation indexes system. The spatial distributions of the factors of temperature, precipitation, sunshine and soil were modeled by gridded interpolation, multi-factor sunshine simulation and co-Kriging on GIS platform. This was followed by evaluation of Qianjiang tobacco planting suitability using the fuzzy neural network approach. The results showed that the average acreage of the most suitable regions was 648.63 km². This accounted for 27.03% of the total study area and mainly covered the moderate hillslope and middle mountain areas within altitude 800~1 100 m. The combined acreage of suitable and sub-suitable regions was 964.13 km², which covered 40.18% of the total area and mainly distributed in the hilly, low mountains within altitude 600~800 m. Unsuitable region with an acreage coverage of 775.16 km² mainly covered the mountain areas above 1 600 m of altitude or 25 degree of slope. The study not only provided guidance for adjustments of local tobacco planting but also offered a new evaluation mode of crop planting ecological suitability in mountain terrains.

Differences in farmer production technical efficiency and irrigation wateruse efficiency from household micro-data analysis in northwest inland arid regions of China

LIU Qi-Jun, LI Zhao-Nan

2012, 20(10): 1375-1381. doi: 10.3724/SP.J.1011.2012.01375

Abstract(1071) PDF(1085)

Abstract:
Water resources shortage is a key factor restricting agricultural production and sustainable socio-economic development in the northwest inland arid regions of China. Also technical production efficiency, agricultural water waste and inefficient water use in inland arid farming regions contribute immensely to water resources shortage. To this end, an empirical research was conducted using a combination of experimental investigation and quantitative analysis in the middle reaches of Heihe River, the northwest inland arid region of China. The results showed that farmer technical production efficiency (TPE) in the region was significantly higher than irrigation water use efficiency (WUE). The farmer average TPEs for Minle County and Linze County were 83.82% and 83.16% with mean irrigation WUEs of only 24.54% and 22.16%, respectively. Assuming no efficiency loss, it implied that the unit outputs of wheat in Minle County and seed corn in Linze County successively increased by 16.18% and 16.84% under present technical production conditions. This also suggested that compared with the minimum feasible water input under the present input-output conditions, about 75.46% of the water resources was wasted in wheat production in Minle County. Similarly, about 77.84% of water was wasted in seed corn production in Linze County. The result further indicated that farmer production inefficiency was mainly driven by TPE. While wheat TPE in Minle County accounted for 73.45%, other factors not controllable by farmers accounted for 26.55% of the production efficiency. Also for seed corn, farmer TPE accounted for 23.42% and other factors beyond farmer control accounted for 76.58% of the production efficiency in Linze County. Moreover, farmer TPE and irrigation WUE were obviously different for different farm/farming family sizes. The plot of management scale versus farmer TPE tracked an inverted U-shaped curve, with a stretched out co-rotation tendency of farmer irrigation WUE and management scale. The study also advanced and discussed several measures concerning enhancement of farmer irrigating WUE and TPE.

Evaluation of water resource carrying capacity of Qitai Oasis inXinjiang by entropy method

XIONG Hei-Gang, FU Jin-Hua, WANG Kai-Long

2012, 20(10): 1382-1387. doi: 10.3724/SP.J.1011.2012.01382

Abstract(1193) PDF(1501)

Abstract:
The reality is that there today exists not only an increasing scarcity of water resources, but also worsening ecology of the Qitai Oasis in Xinjiang. It is thus urgent to build an index system of water resources carrying capacity. So, in this paper, principal component and entropy analyses were used to select and empower the main indexes of water resources carrying capacity in the oasis region. Water resources carrying capacity of Qitai Oasis was analyzed and evaluated to facilitate not only rational use of water resources in the oasis region but also sustainable development of the oasis ecology. The results showed that water resources carrying capacity in the oasis region was 0.83 and 0.75 in 1993 and 1998, respectively. It dropped to the lowest value of 0.66 in 2005. The trend of decline in water resources carrying capacity accelerated with time. The rate of decline in 2003 to 2005 was 47.96 times as much as that in 1993 to 1998 and 8.93 times that in 1999 to 2002. Qitai Oasis water resources carrying capacity was mainly driven by five main factors, including economic and ecological factor, population factor, agricultural water use factor, climatic factor, and other water uses factor. The accumulated contribution rate of the three former factors was 73.58%. This was a solid reflection of the negative effects of rapid economic development, increasing population and agricultural irrigation, and worsening ecological environment on the availability of water resources and the increasing potential for further water saving in the oasis region.

Energy flow analysis of straw-return agricultural modes in theCentral Shaanxi Plain

JIANG Bi, WU Fa-Qi, WU Xi-Hui, LI Ming, TONG Xiao-Gang

2012, 20(10): 1388-1393. doi: 10.3724/SP.J.1011.2012.01388

Abstract(1207) PDF(1036)

Abstract:
Energy is not only the power base, but also a basic function of ecological systems. Analyzing the characteristics of agro-ecosystems via energy flow analysis can ensure comprehensive component objectivity. The energy output level of any agro-ecosystem is an energy flow key index. Using the characteristic indexes of energy flow, different function characteristics of agro-ecosystems were analyzed. The 21st century view emphasized the coordinated development of resources, environment, economy and society. This eventually gave rise to a new mode of sustainable agricultural production, promoted mainly through straw return to farmlands. Although straw return may not make full use of crop straw resources, it reduces environmental pollution. It is therefore the inevitable mode of sustainable economy development in the Central Shaanxi Plain (CSP). To build further understanding into the energy-flow characteristics of wheat/corn straw-return mode in farmland ecosystems, eco-theory and system analysis were used to investigate different straw-return modes in CSP. Then supplemental energy inputs, outputs and transformation efficiencies of different straw-return modes were analyzed and discussed. The results showed that total energy input (7.12×10¹⁰ J·hm^-2), organic energy input (5.44×1010 J·hm^-2), organic/inorganic energy value (3.25) and CREF (0.76) of WH-MC mode (wheat high stubble mulching and straw returning to field plus maize straw chopping and direct returning to field) were highest. While WC-MC mode (both wheat and maize straw chopping and direct returning to field) was the effective in solar energy use (0.669%), WN-MN mode (no turning of both wheat and maize straw) was the most in energy conversion (6.05). In summary, the energy analysis of the functions of the straw-return modes produced better results than the no-straw-return modes. The WH-MC mode had the highest integrated score (0.792). This showed that WH-MC was the optimal mode with the highest eco-efficient plant production, recommended for promotion and wide adoption in CSP.

Analysis of climate resource changes during maize growth period inNingxia under SRES A1B scenario

GOU Shi-Wei, ZHANG Ying-Xian, XU Yin-Long

2012, 20(10): 1394-1403. doi: 10.3724/SP.J.1011.2012.01394

Abstract(1117) PDF(1282)

Abstract:
Maize is one of the three main food crops in Ningxia and is widely cultivated in central arid and south mountain zones; where maize is mainly cultivated under rain-fed conditions and with significant influence of climatic conditions. Climate change has adversely affected local agricultural production in Ningxia and several other studies have reported even further adversities under SRES A2 and B2 scenarios. Also climate change has reportedly led to temperature and precipitation anomalies in Ningxia. This study therefore analyzed the impact of future climate change on maize production under moderate emission scenario. The analysis was based on revised data of the PRECIS regional climate model simulation under SRES A1B scenario. The data included changes in average temperature, maximum temperature, minimum temperature, ≥10 ℃ effective accumulated temperature and precipitation for the periods from April to September of 2011-2040 (for the 2020s), 2041-2070 (for the 2050s), 2071-2100 (for the 2080s) and 1961-1990 (the baseline period of climate). In the first step, the study analyzed the distribution of climatic factors in Ningxia for the baseline period and compared that with observed data for the same period. This was followed by distribution and variation analysis of 5 climatic factors for the 2020s, 2050s and 2080s under A1B scenario. These future values minus those of the baseline period yielded the changes in the climatic factors, where precipitation was specifically expressed in anomaly percent. In the final step, climate change during maize growth period was discussed for the future scenarios. The results showed that simulated average temperature, maximum temperature, minimum temperature and ≥10 ℃ effective accumulated temperature were generally lower than the observation values. However, the simulated distributions were similar to the actual situation; i.e., temperatures were high in the north and low in the south. Also while simulated precipitations for relatively large regions were higher than observation values, the simulated and observed precipitation distributions were similar. Overall, the simulated climatic factors reflected the observed conditions in Ningxia. Average temperature, maximum temperature, minimum temperature, ≥10 ℃ effective accumulated temperature and precipitation for the 2020s, 2050s and 2080s were higher than those of the baseline period and the gaps also widened with time. In south Ningxia, maximum temperature intensely increased while average temperature, minimum temperature and ≥10 ℃ effective accumulated temperature more or less increased in north Ningxia under the scenario simulations. Also precipitation increased in the north and decreased in the south of Ningxia under the scenario simulations. The future scenario analysis showed that maximum temperature and precipitation respectively increased and fluctuated with high likelihoods of extreme hot weathers, droughts and floods. Climate change in the future scenario facilitated maize production in the north irrigation zone of Ningxia, especially increase in ≥10 ℃ effective accumulated temperature provided additional heat for higher maize production. In the south mountain zone of Ningxia, however, limited precipitation negatively affected rain-fed production of maize despite any positive effect of increased temperature on maize production. This paper put forward and discussed appropriate countermeasures for crops production in the rain-fed condition.

Study on ecological compensation model for Major Function Oriented Zones

XU Meng-Yue, CHEN Jiang-Long, GAO Jin-Long, YE Qian

2012, 20(10): 1404-1408. doi: 10.3724/SP.J.1011.2012.01404

Abstract(1260) PDF(1782)

Abstract:
Reasonable scientific ecological compensation mechanisms that balance different interests are critical to a successful implementation of Major Function Oriented Zone (MFOZ) plan. Current studies on ecological compensation standard of MFOZ are relatively deficient. This study divided the four MFOZs in China into two groups and analyzed three classical ecological compensation theories. The two MFOZ groups were development and protection zones and three classical theories were ecological environment value theory, externality theory and public goods theory. On the basis of "protector to profit, beneficiary to compensate", an ecological compensation model was constructed. The model also took into account the willingness of the development zones to pay, and the ecological benefits and ecosystem services of the protection zones to contribute along with its influence scope. Ecological footprint and ecosystem service-driven gravity model were used to establish the compensation model for MFOZ. The four steps that accounted for the eco-compensation mechanism included compensation standard, compensation fund, distribution plan and implementation mode. Development zones paid ecological compensations to protection zones via financial payments by governments to realize the model objectives. The study also suggested funding from multiple sources, implementation of diverse and diverse participants. It was of urgent theoretical and practical importance to establish ecological compensation model that facilitated the realization of the objectives of MFOZ plan. It was also recommended that implementation of a sound ecological compensation model would encourage ecological protection, limit vandalism and provide scientific basis for balanced differential region development.

Effect of saline ice irrigation on the soil salt distribution and vegetationrestoration in the marine reclamation land

WANG Wen-Cheng, GUO Yan-Chao, SUN Chang-Yu, LIU Xiao-Jing, XUE Zhi-Zhong, WANG Yu-Hua, ZHAO Bing-Jun

2012, 20(10): 1409-1411. doi: 10.3724/SP.J.1011.2012.01409

Abstract(1089) PDF(1029)

Abstract:

2012 Vol. 20, No. 10