A genetic linkage map with 89 SSR marker loci was constructed based on a maize (Zea mays L.) population consisting of 184 F-2 individuals from the cross, Huangzao 4 X Ye 107. The 184 F-3 families were evaluated in the...A genetic linkage map with 89 SSR marker loci was constructed based on a maize (Zea mays L.) population consisting of 184 F-2 individuals from the cross, Huangzao 4 X Ye 107. The 184 F-3 families were evaluated in the field under well-watered and drought-stressed regimes in Shanxi Province of China. The objectives of the study were to identify genetic segments responsible for the expression of anthesis-silking interval (ASI), ear setting and grain yield, and to examine if the quantitative trait loci (QTLs) for ASI or yield components can be used in marker-assisted selection (MAS) to improve grain yield under drought conditions. Results showed that under well-watered and drought-stressed regimes, three and two QTLs involved in the expression of ASI were detected on chromosomes 1, 2 and 3, and 2 and 5, respectively. Under well-watered regime, two QTLs for ear setting were detected on chromosomes 3 and 6, explaining about 19.9% of the phenotypic variance, and displayed additive and partial dominant effects, respectively. Under drought-stressed condition, four QTLs for ear setting were detected on chromosomes 3, 7 and 10, which were responsible for interpreting 60.4% of the phenotypic variance, and showed dominant or partial dominant effects. Under well-watered condition, four QTLs controlling grain yield were identified on chromosomes 3, 6 and 7, while five QTLs were identified under drought stress on chromosomes 1, 2, 4 and 8. The gene action was of additive or partial dominant effects, and each QTL could explain 7.3% to 22.0% of the phenotypic variance, respectively. Under drought conditions, ASI and ear setting percentage were highly correlated with grain yield, which can be used as secondary traits for grain yield selection. Based on linked markers detected and gene action analyzed, an MAS strategy for yield improvement under drought condition could be established, which consists of QTLs contributing to decreased ASI and to increased ear setting and grain yield, respectively.展开更多
[Objective] The objective of this paper was to screen out suitable high- yielding cultivars and to understand the current yield performance of wheat in Anhui Province. In addition, the influencing factors on wheat yie...[Objective] The objective of this paper was to screen out suitable high- yielding cultivars and to understand the current yield performance of wheat in Anhui Province. In addition, the influencing factors on wheat yield were discussed to es- tablish suitable cultural practice. [Method] Main popularized cultivars and some new strains of wheat were selected as matedals and planted in the Funan Farm and Longkang Farm in 2009-2011. The yield stability and influencing factors on yield of wheat were discussed. [Resalt] In Anhui Province, the weather had a great influence on wheat yield, resulting in significant differences in wheat yield among different years. Drought was the main factor restricting the yield. [Conclusion] (1) It was easy to achieve high yield when the three influencing factors on wheat yield were coordi- nated. (2) The occurred drought disaster in 20tl was the main factor limiting the 1 000- grain weight and final yield of wheat. (3) Different cultivars showed different yield stabilities. Among the test wheat cultivars, two cultivars (Wanke 06290 and Yannong 19) showed good yield stability, while Xinfumai No.1 showed higher yield. (4) The three influencing factors played different roles in different cultivars. In the promotion process, the characteristics of wheat cultivars should be fully understood. To achieve high yield, integrating cultural practices is a necessity.展开更多
We aimed to investigate the effects of phosphate treatment on growth dynamics of wheat in wheat/corn intercropping system in southwest hil y area. [Method] Five phosphate fertilization levels were designed for wheat a...We aimed to investigate the effects of phosphate treatment on growth dynamics of wheat in wheat/corn intercropping system in southwest hil y area. [Method] Five phosphate fertilization levels were designed for wheat and corn respectively to investigate the effects of phosphate fertilization level on wheat/corn intercropping system by field block experiment. [Result] The number of til ers, plant height and yield component of wheat trended to increase with the increase of phos-phate fertilization amount and al reached the peak for phosphate fertilization amount of 135 kg/hm2. However, the number of til ers, plant height and yield component of wheat al decreased significantly with the further increase of phosphate fertilization amount. [Conclusion] Phosphate fertilization contributed to the wheat growth in a certain degree. However, excessive phosphate fertilization would affect final yield.展开更多
A population of 180 recombinant inbred lines (RILs) was developed by single seed descended from the cross of high yield Upland cotton (Gossypium hirsutum L.) varieties Zhongmiansuo12 (ZMSI2) and 8891, the two pa...A population of 180 recombinant inbred lines (RILs) was developed by single seed descended from the cross of high yield Upland cotton (Gossypium hirsutum L.) varieties Zhongmiansuo12 (ZMSI2) and 8891, the two parents of Xiangzamian2 (XZM2). A genetic linkage map consisting of 132 loci and covering 865.20 cM was constructed using the RIL population chiefly with SSR markers. Yield and yield components were investigated for RILs in three environments in China. The purpose of the present research was to analyze the relationship between yield and its components and to map QTL for yield and yield components in cotton. QTL were tagged with data sets from single environment (separate analysis) and a set of data from means of the three environments (joint analysis). A total of 34 QTL for yield and yield components were independently detected in three environments, whereas fifteen QTL were found in joint analysis. Notably, a stable lint percentage QTL qLP-A10-1 was detected both in joint analysis and in two environments of separate analysis, which might be of special value for marker-assisted selection. The QTL detected in the present study provide new information on improving yield and yield components. Results of path analysis showed that bolls/plant had the largest contribution to lint yield, which is consistent with the mid-parent heterosis value in F1. Accordingly, in cotton breeding, bolls/plant can be considered first and other yield components measured as a whole to implement variety enhancement and hybrid selection of cotton.展开更多
To make clear the emission characteristics of soil N20 from typical green- house vegetable fields in North China, an experiment was conducted in greenhouse tomato field in Shouguang city, Shandong province, China's ...To make clear the emission characteristics of soil N20 from typical green- house vegetable fields in North China, an experiment was conducted in greenhouse tomato field in Shouguang city, Shandong province, China's "Home of Vegetables". The N2O fluxes were observed in four experimental treatments, as follows: none N fertilizer (CK), single organic fertilizer (OM), conventional fertilization (FP) and opti- mized and reduced nitrogen fertilization (OPT), by a close chamber-gas chromato- graph method. The effects of different fertilization treatments on N2O emission and tomato yield were analyzed. The results showed that following the fertilization and ir- rigation, the pulsed emissions of N2O were measured. The N2O emission peak ap- peared after basal fertilizer application and irrigation and could be maintained for about 20 days. While the N2O emission peak caused by topdressing was smaller and last only 3-5 days. The statistical analysis showed that the N2O fluxes were affected by air temperature, soil temperature and WFPS at soil depth of 3 cm. The total contents of soil N2O fluxes had significant differences among experimental groups. The total content orderly was FP of 14. 77 kg/hm^2, OPT of 9. 73 kg/hm^2, OM of 6.84 kg/hm^2 and CK of 2.37 kg/hm^2. The N~:~ emission coefficient ranged from 0.83%-1.10%,which was close to or more than the recommended value (1.0%) by IPCC. Compared with the FP treatment, the tomato yield in OPT treatment, whose application rate of chemical N fertilizer decreased by about 60%, increased by 2.2%. Under the current management measures, the reasonable reduction on ap- plicaUon rate of organic manure and chemical nitrogen fertilizer could effectively re- duce the N=O emissions in greenhouse vegetable fields.展开更多
Phalaris arundinacea L. is fine perennial herbage of Gramineae. Eight treatments including N, P, K, NP, NK, NPK, PK and controls were done for studying its absorbing efficiency of soil nutrition. At tillering stage, t...Phalaris arundinacea L. is fine perennial herbage of Gramineae. Eight treatments including N, P, K, NP, NK, NPK, PK and controls were done for studying its absorbing efficiency of soil nutrition. At tillering stage, the coefficient of absorbing and utilizing of N, P, and K from soil and fertilizer were analyzed according to M.K. Kaeomobk抯 formula and the contents of crude protein and fat were also measured. The yields of fresh crop, hay and seed were measured at ripening stage. For N absorbing coefficient of Ph. arundinacea from soil (Kn%), the composition PK treatment is best (12.36%) and K treatment is worse, while for N absorbing coefficient from fertilizer (Ky%), all the treatments are higher than control but the composition NPK treatment presented the highest (14.78%). For the absorbing coefficient of P from soil (Kn%), composition NK treatment is highest (19.30%), but K treatment was lower than control, while for that of P from fertilizer (Ky%), all the treatment were higher than control but the composition NP treatment showed the highest (19.52%). As to K absorbing coefficient from soil (Kn%), NP treatment is the best (19.2%) and single P treatment is worst, while for that (Ky%) of K from fertilizer the composition NPK treatment was best (28.44%). As concerns treatments for the outputs of fresh and dry crop, the composition NP treatment was best and all the treatment were higher than control. The composition NK treatment produced highest yield of seed and highest content of crude protein as compared to other treatments. For content of crude fat, the compositions NK and N treatments are best. The experiment indicates that application of fertilizer at proper proportions could increase the yield of Ph. Arundinacea and raise the utilizing efficiency of nourishment element from soil and fertilizer.展开更多
To provide "more reasonable, more saving and more efficient" water and fertilizer application proposals, taking ‘Yujiao 5' as the experimental material, the effects of different irrigation times and nitrogen appli...To provide "more reasonable, more saving and more efficient" water and fertilizer application proposals, taking ‘Yujiao 5' as the experimental material, the effects of different irrigation times and nitrogen application treatments on the leaf area index and yield of wheat were studied using three-factor split plot method. The results showed that irrigation times, nitrogen application rate and the ratio of basa to topdressed nitrogen respectively had significant effects on the leaf area index, the yield and component factors of wheat. Under the treatment of W1(irrigation before sowing), the leaf area index showed a positive linear correlation with nitrogen application rate; under the treatments of W2(irrigation before sowing and at jointing stage) and W3(irrigation before sowing, at jointing stage and at grain filling stages),the leaf area index showed a positive linear correlation with nitrogen application rate at the jointing stage, booting stage and heading stage; 20 d after heading, the leaf area index showed a quadric curve relationship with nitrogen application rate at these stages, and the LAI of N3R2 was the highest. Under different irrigation times,the yield, ear number and kernels per ear showed quadric curve relationship with nitrogen application rate, 1 000-seed weight showed the trend of linear decrease with the increase of nitrogen application rate. Under the treatment combination of irrigation before sowing, at jointing stage and at grain filling stage, nitrogen application rate at 240 kg/hm^2 and the ratio of basal to topdressed nitrogen of 5:5, the grain yield(8 609.60 kg/hm^2), ear number(688.2×104/hm^2) and kernel number per ear(37.9 grains) reached the highest value at W3N3R2, and the grain yield of W3N3R2 increased by 144.8% compared to the W1N0. In conclusion, in Eastern Henan where the rainfall is insufficient at the late growth stage of wheat, the irrigation-saving space in wheat production is relatively small, but the nitrogen-saving space is relatively large.展开更多
This study aimed to investigate the effects of reducing application amount of base fertilizer and increasing application time of leaf fertilizer on corn yield so as to find out the most economical fertilization way fo...This study aimed to investigate the effects of reducing application amount of base fertilizer and increasing application time of leaf fertilizer on corn yield so as to find out the most economical fertilization way for corn. On the basis of protecting environment, the economic benefits will be also increased. The results showed that the corn yield was increased with the increase of application amount of base fertilizer, and was also increased with the increase of application time of leaf fertilizer.For each time of spaying of leaf fertilizer, the corn yield was increased 258-592.5kg/hm^2 with increase amplitude ranging from 2.3%-5.6%.展开更多
We investigated the quantity and quality 0f fallen l0gs in different Tsuga l0ngibracteata f0rest c0mmunities in the Tianba0yan Nati0nal Nature Reserve. We used redundancy analysis t0 determine the spatial distributi0n...We investigated the quantity and quality 0f fallen l0gs in different Tsuga l0ngibracteata f0rest c0mmunities in the Tianba0yan Nati0nal Nature Reserve. We used redundancy analysis t0 determine the spatial distributi0n 0f fallen l0gs in the different f0rest c0mmunities and t0 analyze the relati0nships am0ng stand structure, t0p0graphic fact0rs and human disturbance. The v0lume, c0vered area, mean l0g length and number 0f fallen l0gs differed significantly am0ng f0rest types (P 〈 0.05), but mean diameter at breast height sh0wed n0 significant difference (P 〉 0.05). The l0g v0lume and c0vered area in different f0rest types sh0wed the f0ll0wing trend: T. l0ngibracteata pure f0rest 〈 T. l0ngibracteata + Olig0staehyum scabrifl0rur 〈 T. l0ngibraeteata + hardw00d 〈 Rh0d0dendr0n simiarum + T. l0ngibraeteata 〈 T. l0ngibraeteata + Phyll0stachys heter0cycla pubescens. The spatial distributi0n patterns 0f l0gs quantity and quality indicated that l0g v0lume and c0vered area were str0ngly affected by envir0nmental fact0rs in the f0ll0wing 0rder: human disturbance 〉 elevati0n 〉 sl0pe p0siti0n 〉 b0le height 〉 tree height 〉 sl0pe aspect 〉 density 〉 basal area 〉 sl0pe gradient. The relative c0ntributi0n 0f envir0nmental variables 0n the t0tal variance was t0p0graphy (76%) 〉 disturbance (42%) 〉 stand structure (35%). T0p0graphy and disturbance c0mbined explained 8.2% 0f the variance. Fallen l0~s auantitv and aualitvwere negatively related t0 elevati0n and sl0pe p0siti0n, and p0sitively ass0ciated t0 human disturbance. The l0g v0lume decreased fr0m n0rthern t0 s0uthern sl0pes. Envir0nmental fact0rs had the highest impact 0n class I (slightly decayed), and l0west impact 0n class V (highly decayed).展开更多
The goal of this study was to apply artificial neural networks to predict rain-fed wheat yield using meteorological data a few days to few months before harvesting. The climatic observation data used; were mean of dai...The goal of this study was to apply artificial neural networks to predict rain-fed wheat yield using meteorological data a few days to few months before harvesting. The climatic observation data used; were mean of daily minimum and maximum temperature, extreme of daily minimum and maximum temperature, sum of daily rainfall, number of rainy days, sum of daily sun hours, mean of daily wind speed, extreme of daily wind speed, mean of daily relative humidity, and sum of daily water requirements that were collected during 1990-1999 in Sararood Station for wheat phenological stages consisting; sowing, germination, emergence, 3rd leaves, tillering, stem formation, heading, flowering, milk maturity, wax maturity, full maturity, separately for each growing season. Then, they arranged in a matrix whose rows form each of the statistical years and the columns are meteorological factors at each phenological stage. Finally, the obtained model had the following capabilities: Prediction of wheat yield with maximum errors of 45-60 kg/ha at least two months before full maturity stage, determination of the sensitivity of each phenological stage with respect to meteorological factors, and determination of the priority order and importance of each meteorological factor effective in plant growth and crop yield.展开更多
Remote sensing data from the Terra Moderate-Resolution Imaging Spectroradiometer (MODIS) and geospatial data were used to estimate grass yield and livestock carrying capacity in the Tibetan Autonomous Prefecture of Go...Remote sensing data from the Terra Moderate-Resolution Imaging Spectroradiometer (MODIS) and geospatial data were used to estimate grass yield and livestock carrying capacity in the Tibetan Autonomous Prefecture of Golog, Qing-hai, China. The MODIS-derived normalized difference vegetation index (MODIS-NDVI) data were correlated with the aboveground green biomass (AGGB) data from the aboveground harvest method. Regional regression model between the MODIS-NDVI and the common logarithm (LOG10) of the AGGB was significant (r2 = 0.51, P < 0.001), it was, there-fore, used to calculate the maximum carrying capacity in sheep-unit year per hectare. The maximum livestock carrying capacity was then adjusted to the theoretical livestock carrying capacity by the reduction factors (slope, distance to water, and soil erosion). Results indicated that the grassland conditions became worse, with lower aboveground palatable grass yield, plant height, and cover compared with the results obtained in 1981. At the same time, although the actual livestock numbers decreased, they still exceeded the proper theoretical livestock carrying capacity, and overgrazing rates ranged from 27.27% in Darlag County to 293.99% in Baima County. Integrating remote sensing and geographical information system technologies, the spatial and temporal conditions of the alpine grassland, trend, and projected stocking rates could be forecasted for decision making.展开更多
28 oilseed rape Pol CMS three-line hybrid combinations diallel-crossed were compared in the yield and harvest index and analyzed on the correlation between the experimental yields and harvest indexes in this study. Th...28 oilseed rape Pol CMS three-line hybrid combinations diallel-crossed were compared in the yield and harvest index and analyzed on the correlation between the experimental yields and harvest indexes in this study. The correlation coeffcient was only 0.365 4, lower than a signifcant level, which indicated that there was no signifcant positive (or negative) correlation between the economic yields and the harvest indexes in oilseed rape. Among them, 8 hybrid combinations including 7 with a harvest index〉0.30 and one with a harvest index〈0.27 increased signifcantly in the yields compared with the control, and then were screened for production experiment. Under different cultivation methods, all the 8 combinations had a stable harvest index, and the combinations with higher harvest indexes also had a stable performance in yields. An oilseed rape variety Fengyou 737 with higher yield and harvest index selected through a further screening was grown with the harvest indexhigher than 0.33 whether transplanted or directly seeded in Yangtze River Basin Demonstration Area, demonstrating stable high yields as well as good ecological adaptability. The combination of yield and harvest index in the study is conducive to breeding a new oilseed rape variety with stable yields and good tolerance to close planting.展开更多
A wet impact crusher was used to breakdown waste printed circuit boards (PCB's) in a water medium. The relationship between the yield of crushed product and the operating parameters was established. The crushing me...A wet impact crusher was used to breakdown waste printed circuit boards (PCB's) in a water medium. The relationship between the yield of crushed product and the operating parameters was established. The crushing mechanism was analyzed and the effects of hammerhead style, rotation speed, and inlet water volume on particle size distribution were investigated. The results show that the highest yield of -1 + 0.75 mm sized product was obtained with an inlet water volume flow rate of 5.97 m3/h and a smooth hammerhead turning at 1246.15 r/rain. Cumulative undersize-product yield curves were fitted to a nonlinear function: the fitting correlation coefficient was greater than 0.998. These research results provide a theoretical basis for the highly effective wet crushing of PCB's.展开更多
Field experiments were conducted during 2008-2010 to investigate the ef- fects of NPK fertilization on seed yield and economic benefit of a new hybrid cultivar of winter oilseed rape (Brassica napus L.) - Xiangzayou...Field experiments were conducted during 2008-2010 to investigate the ef- fects of NPK fertilization on seed yield and economic benefit of a new hybrid cultivar of winter oilseed rape (Brassica napus L.) - Xiangzayou763, and to determine the optimum NPK ratio and dose in Hunan, China. The results showed that NPK ratio (1:0.50:0.50) with 180 kg/hm2 N, 90 kg/hm2 P2O5 and 90 kg/hm2 K20 was the optimum combination for the highest seed yield (2 231.13 kg/hm2) and economic benefit (9 816.97 Yuan/hm2), of which 1 641.23 Yuan/hm2 being set for fertilizer in- vestment (VCR=4.11). Besides, the effects of N, P and K fertilizers on seed yield and oil production of winter oilseed rape were not identical. N had the greatest ef- fect on plant growth of winter oilseed rape, followed by P and K. Total leaf number, green leaf number, leaf length and width, rhizome diameter, branch number, dry weight per plant and other agronomic characters in high N treatments were higher than those in low N treatments. By correlation and path analysis of yield components, the contribution rate to seed yield was found: effective silique number per plant〉seed number per silique〉l 000-seed weight.展开更多
Breeding and mass scale larval rearing of clownfish Amphiprion percula is very limited in brackishwater. We designed an indoor program of A. percula culture in brackishwater with a salinity of 24±1, during which ...Breeding and mass scale larval rearing of clownfish Amphiprion percula is very limited in brackishwater. We designed an indoor program of A. percula culture in brackishwater with a salinity of 24±1, during which the impacts of feed type, water temperature, and light intensity, on the efficiency of its reproduction, were revealed. The fish were accommodated along with sea anemones in fibre glass tanks to determine the influence of brooder diet on breeding efficiency. Higher reproductive efficiency [number of eggs laid (276±22.3 eggs)] was observed when fish were fed live Acetes sp. rather than clam (204±16.4 eggs), trash fish (155±12 eggs) and formulated feed (110±10 eggs). The spawning rate was increased during September and October (water temperature, 28.74±0.55℃) on average of 2.4 spawning per month; and low spawning rate was in January (water temperature, 24.55±0.45℃) on average of I spawning per month. Among three light intensities (100, 500, and 900 1x) set to evaluate larval survival rate, larvae showed the highest survival rate (65.5%) at 900 lx. The breeding method specifically in brackishwater developed in the present study is a new approach, will help the people from the regions of estuary and backwater to enhance their livelihood and it will lead to reduce the exploitation from the wild habitat.展开更多
In the light of an increasing demand for staple food, especially rice, in southeast China, investigations on the specific site potential expressed as the relationship between soil and crop yield parameters gain increa...In the light of an increasing demand for staple food, especially rice, in southeast China, investigations on the specific site potential expressed as the relationship between soil and crop yield parameters gain increasing importance. Soil texture and several soil chemical parameters as well as plant properties such as crop height, biomass and grain yield were investigated along two terraced catenas with contrasting soil textures cropped with wet rice. We were aiming at identifying correlative relationships between soil and crop properties. Data were analyzed both statistically and geostatistically on the basis of semivariograms. Statistical analysis indicated a significant influence of the relief position on the spatial distribution of soil texture, total carbon and total nitrogen contents. Significant correlations were found for the catena located in a sandstone area (Catena A) between rice yield and silt as well as total nitrogen content. Corresponding relationships were not detectable for paddy fields that developed from Quaternary clays (Catena B). As suggested by the nugget to sill ratio, spatial variability of soil texture, total carbon and nitrogen was mainly controlled by intrinsic factors, which might be attributed to the erosional transport of fine soil constituents, indicating the importance of the relief position and slope in soil development even in landscapes that are terraced. The crop parameters exhibited short ranges of influence and about one third of their variability was unexplained. Comparable ranges of selected crop and soil parameters, found only for Catena A, are indicative of close spatial interactions between rice yield and soil features. Our findings show that especially in sandstone-dominated areas, a site-specific management can contribute to an environmentally safe rice production increase.展开更多
Microsatellite markers have become one kind of the most important molecular tools used in various researches. A large number of microsatellite markers are required for the whole genome survey in the fields of molecula...Microsatellite markers have become one kind of the most important molecular tools used in various researches. A large number of microsatellite markers are required for the whole genome survey in the fields of molecular ecology,quantitative genetics and genomics. Therefore,it is extremely necessary to select several versatile,low-cost,efficient and time-and labor-saving methods to develop a large panel of microsatellite markers. In this study,we used Zhikong scallop(Chlamys farreri) as the target species to compare the efficiency of the five methods derived from three strategies for microsatellite marker development. The results showed that the strategy of constructing small insert genomic DNA library resulted in poor efficiency,while the microsatellite-enriched strategy highly improved the isolation efficiency. Although the mining public database strategy is time-and cost-saving,it is difficult to obtain a large number of microsatellite markers,mainly due to the limited sequence data of non-model species deposited in public databases. Based on the results in this study,we recommend two methods,microsatellite-enriched library construction method and FIASCO-colony hybridization method,for large-scale microsatellite marker development. Both methods were derived from the microsatellite-enriched strategy. The experimental results obtained from Zhikong scallop also provide the reference for microsatellite marker development in other species with large genomes.展开更多
Understanding the relationships between topographic indices and crop yield variability is important for soil manage- ment and crop production in rolling landscape. Two agricultural fields at Alvena and Hepburn, Saskat...Understanding the relationships between topographic indices and crop yield variability is important for soil manage- ment and crop production in rolling landscape. Two agricultural fields at Alvena and Hepburn, Saskatchewan, Canada were selected to examine how topographic indices were related to wheat yield under two topographic and weather conditions in the Canadian prairies. The landscapes of the two sites are classified as hummocky and the dominant soil type is an Aridic Ustoll. The relationships among yield, topography, soil, and weather were analyzed using wheat (Triticum aestivum L.) grain yield from Alvena in 2001 (dry year) and 2004 (wet year) and from Hepburn in 1998 (dry year). Topographic/soil indices included relative elevation, wetness index, upslope length, curvature, soil organic matter, and soil moisture storage before seeding. The results indicated that, in the dry years, the correlation coefficients between upslope length and grain yield were 0.79 for the typical rolling landscape (Alvena) in 2001 and 0.73 for shallow gentle rolling landscape (Hepburn) in 1998. In the wet year (2004), the relationships between yield and topographic/soil attributes were not as strong as in dry years. Therefore, upslope length was the best yield indicator for the two landscapes in dry years, whereas no topographic indices were highly correlated to crop yield in wet years. Those topographic indices seemed useful in identifying the yield variability and delineating the proper management zone.展开更多
Straightening machine is widely used for improving the quality of the defective mild steel plates.In general,the capacity of straightening machine is affected by material properties,the initial shape of the incoming p...Straightening machine is widely used for improving the quality of the defective mild steel plates.In general,the capacity of straightening machine is affected by material properties,the initial shape of the incoming plate and the plastic ratio.The mechanics model describing the capacity of the machine was developed.The deviation of the straightening capacity curves was studied.Then,the presented model was evaluated by comparative study to filed production data.Finally,the influences of overstretch,straightening speed,strengthening coefficient,elastic modulus,width of the plate on the straightening capacity were studied.It is convenient to determine whether the plate can be straightened or not by a series of straightening capacity curves.The straightening speed,width of the plate and elastic modulus of the material are more sensitive to the straightening capacity than the strengthening coefficient.展开更多
文摘A genetic linkage map with 89 SSR marker loci was constructed based on a maize (Zea mays L.) population consisting of 184 F-2 individuals from the cross, Huangzao 4 X Ye 107. The 184 F-3 families were evaluated in the field under well-watered and drought-stressed regimes in Shanxi Province of China. The objectives of the study were to identify genetic segments responsible for the expression of anthesis-silking interval (ASI), ear setting and grain yield, and to examine if the quantitative trait loci (QTLs) for ASI or yield components can be used in marker-assisted selection (MAS) to improve grain yield under drought conditions. Results showed that under well-watered and drought-stressed regimes, three and two QTLs involved in the expression of ASI were detected on chromosomes 1, 2 and 3, and 2 and 5, respectively. Under well-watered regime, two QTLs for ear setting were detected on chromosomes 3 and 6, explaining about 19.9% of the phenotypic variance, and displayed additive and partial dominant effects, respectively. Under drought-stressed condition, four QTLs for ear setting were detected on chromosomes 3, 7 and 10, which were responsible for interpreting 60.4% of the phenotypic variance, and showed dominant or partial dominant effects. Under well-watered condition, four QTLs controlling grain yield were identified on chromosomes 3, 6 and 7, while five QTLs were identified under drought stress on chromosomes 1, 2, 4 and 8. The gene action was of additive or partial dominant effects, and each QTL could explain 7.3% to 22.0% of the phenotypic variance, respectively. Under drought conditions, ASI and ear setting percentage were highly correlated with grain yield, which can be used as secondary traits for grain yield selection. Based on linked markers detected and gene action analyzed, an MAS strategy for yield improvement under drought condition could be established, which consists of QTLs contributing to decreased ASI and to increased ear setting and grain yield, respectively.
基金Supported by Anhui Provincial Wheat Industrial Technology System R&D Center~~
文摘[Objective] The objective of this paper was to screen out suitable high- yielding cultivars and to understand the current yield performance of wheat in Anhui Province. In addition, the influencing factors on wheat yield were discussed to es- tablish suitable cultural practice. [Method] Main popularized cultivars and some new strains of wheat were selected as matedals and planted in the Funan Farm and Longkang Farm in 2009-2011. The yield stability and influencing factors on yield of wheat were discussed. [Resalt] In Anhui Province, the weather had a great influence on wheat yield, resulting in significant differences in wheat yield among different years. Drought was the main factor restricting the yield. [Conclusion] (1) It was easy to achieve high yield when the three influencing factors on wheat yield were coordi- nated. (2) The occurred drought disaster in 20tl was the main factor limiting the 1 000- grain weight and final yield of wheat. (3) Different cultivars showed different yield stabilities. Among the test wheat cultivars, two cultivars (Wanke 06290 and Yannong 19) showed good yield stability, while Xinfumai No.1 showed higher yield. (4) The three influencing factors played different roles in different cultivars. In the promotion process, the characteristics of wheat cultivars should be fully understood. To achieve high yield, integrating cultural practices is a necessity.
文摘We aimed to investigate the effects of phosphate treatment on growth dynamics of wheat in wheat/corn intercropping system in southwest hil y area. [Method] Five phosphate fertilization levels were designed for wheat and corn respectively to investigate the effects of phosphate fertilization level on wheat/corn intercropping system by field block experiment. [Result] The number of til ers, plant height and yield component of wheat trended to increase with the increase of phos-phate fertilization amount and al reached the peak for phosphate fertilization amount of 135 kg/hm2. However, the number of til ers, plant height and yield component of wheat al decreased significantly with the further increase of phosphate fertilization amount. [Conclusion] Phosphate fertilization contributed to the wheat growth in a certain degree. However, excessive phosphate fertilization would affect final yield.
基金This work was supported by the National Science Foundation for Outstanding Youth Scholars (No. 30025029), Chinese National Programs for High Technology Research and Development (No. 2002AA207006), the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions, and Program for Changjiang Scholars and Innovative Research Team in University of MOE, China.
文摘A population of 180 recombinant inbred lines (RILs) was developed by single seed descended from the cross of high yield Upland cotton (Gossypium hirsutum L.) varieties Zhongmiansuo12 (ZMSI2) and 8891, the two parents of Xiangzamian2 (XZM2). A genetic linkage map consisting of 132 loci and covering 865.20 cM was constructed using the RIL population chiefly with SSR markers. Yield and yield components were investigated for RILs in three environments in China. The purpose of the present research was to analyze the relationship between yield and its components and to map QTL for yield and yield components in cotton. QTL were tagged with data sets from single environment (separate analysis) and a set of data from means of the three environments (joint analysis). A total of 34 QTL for yield and yield components were independently detected in three environments, whereas fifteen QTL were found in joint analysis. Notably, a stable lint percentage QTL qLP-A10-1 was detected both in joint analysis and in two environments of separate analysis, which might be of special value for marker-assisted selection. The QTL detected in the present study provide new information on improving yield and yield components. Results of path analysis showed that bolls/plant had the largest contribution to lint yield, which is consistent with the mid-parent heterosis value in F1. Accordingly, in cotton breeding, bolls/plant can be considered first and other yield components measured as a whole to implement variety enhancement and hybrid selection of cotton.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(201103039)Shandong Provincial Natural Science Foundation,China(ZR2013DQ023)+1 种基金Science and Technology Development Plan Project of Shandong Province(2013GNC11204)Major Agricultural Application Technology Innovation Project of Shandong Province(Study on Environmental Regulation and Fertilizer Application Techniques for High Yield and High Efficiency Utilization of Greenhouse Tomato)~~
文摘To make clear the emission characteristics of soil N20 from typical green- house vegetable fields in North China, an experiment was conducted in greenhouse tomato field in Shouguang city, Shandong province, China's "Home of Vegetables". The N2O fluxes were observed in four experimental treatments, as follows: none N fertilizer (CK), single organic fertilizer (OM), conventional fertilization (FP) and opti- mized and reduced nitrogen fertilization (OPT), by a close chamber-gas chromato- graph method. The effects of different fertilization treatments on N2O emission and tomato yield were analyzed. The results showed that following the fertilization and ir- rigation, the pulsed emissions of N2O were measured. The N2O emission peak ap- peared after basal fertilizer application and irrigation and could be maintained for about 20 days. While the N2O emission peak caused by topdressing was smaller and last only 3-5 days. The statistical analysis showed that the N2O fluxes were affected by air temperature, soil temperature and WFPS at soil depth of 3 cm. The total contents of soil N2O fluxes had significant differences among experimental groups. The total content orderly was FP of 14. 77 kg/hm^2, OPT of 9. 73 kg/hm^2, OM of 6.84 kg/hm^2 and CK of 2.37 kg/hm^2. The N~:~ emission coefficient ranged from 0.83%-1.10%,which was close to or more than the recommended value (1.0%) by IPCC. Compared with the FP treatment, the tomato yield in OPT treatment, whose application rate of chemical N fertilizer decreased by about 60%, increased by 2.2%. Under the current management measures, the reasonable reduction on ap- plicaUon rate of organic manure and chemical nitrogen fertilizer could effectively re- duce the N=O emissions in greenhouse vegetable fields.
基金This paper is supported by Educational Committee of Inner Mongolia autonomous Region (No. 950023)
文摘Phalaris arundinacea L. is fine perennial herbage of Gramineae. Eight treatments including N, P, K, NP, NK, NPK, PK and controls were done for studying its absorbing efficiency of soil nutrition. At tillering stage, the coefficient of absorbing and utilizing of N, P, and K from soil and fertilizer were analyzed according to M.K. Kaeomobk抯 formula and the contents of crude protein and fat were also measured. The yields of fresh crop, hay and seed were measured at ripening stage. For N absorbing coefficient of Ph. arundinacea from soil (Kn%), the composition PK treatment is best (12.36%) and K treatment is worse, while for N absorbing coefficient from fertilizer (Ky%), all the treatments are higher than control but the composition NPK treatment presented the highest (14.78%). For the absorbing coefficient of P from soil (Kn%), composition NK treatment is highest (19.30%), but K treatment was lower than control, while for that of P from fertilizer (Ky%), all the treatment were higher than control but the composition NP treatment showed the highest (19.52%). As to K absorbing coefficient from soil (Kn%), NP treatment is the best (19.2%) and single P treatment is worst, while for that (Ky%) of K from fertilizer the composition NPK treatment was best (28.44%). As concerns treatments for the outputs of fresh and dry crop, the composition NP treatment was best and all the treatment were higher than control. The composition NK treatment produced highest yield of seed and highest content of crude protein as compared to other treatments. For content of crude fat, the compositions NK and N treatments are best. The experiment indicates that application of fertilizer at proper proportions could increase the yield of Ph. Arundinacea and raise the utilizing efficiency of nourishment element from soil and fertilizer.
基金Supported by the National Project of Transformation Fund for Agricultural Science and Technology Achievements:Pilot Production and Demonstration of New Wheat Variety and the Propagation of Breeder Seed(2013GB2D000300)The Special Fund of National Modern Agricultural Industry Technology System(CARS-03)~~
文摘To provide "more reasonable, more saving and more efficient" water and fertilizer application proposals, taking ‘Yujiao 5' as the experimental material, the effects of different irrigation times and nitrogen application treatments on the leaf area index and yield of wheat were studied using three-factor split plot method. The results showed that irrigation times, nitrogen application rate and the ratio of basa to topdressed nitrogen respectively had significant effects on the leaf area index, the yield and component factors of wheat. Under the treatment of W1(irrigation before sowing), the leaf area index showed a positive linear correlation with nitrogen application rate; under the treatments of W2(irrigation before sowing and at jointing stage) and W3(irrigation before sowing, at jointing stage and at grain filling stages),the leaf area index showed a positive linear correlation with nitrogen application rate at the jointing stage, booting stage and heading stage; 20 d after heading, the leaf area index showed a quadric curve relationship with nitrogen application rate at these stages, and the LAI of N3R2 was the highest. Under different irrigation times,the yield, ear number and kernels per ear showed quadric curve relationship with nitrogen application rate, 1 000-seed weight showed the trend of linear decrease with the increase of nitrogen application rate. Under the treatment combination of irrigation before sowing, at jointing stage and at grain filling stage, nitrogen application rate at 240 kg/hm^2 and the ratio of basal to topdressed nitrogen of 5:5, the grain yield(8 609.60 kg/hm^2), ear number(688.2×104/hm^2) and kernel number per ear(37.9 grains) reached the highest value at W3N3R2, and the grain yield of W3N3R2 increased by 144.8% compared to the W1N0. In conclusion, in Eastern Henan where the rainfall is insufficient at the late growth stage of wheat, the irrigation-saving space in wheat production is relatively small, but the nitrogen-saving space is relatively large.
文摘This study aimed to investigate the effects of reducing application amount of base fertilizer and increasing application time of leaf fertilizer on corn yield so as to find out the most economical fertilization way for corn. On the basis of protecting environment, the economic benefits will be also increased. The results showed that the corn yield was increased with the increase of application amount of base fertilizer, and was also increased with the increase of application time of leaf fertilizer.For each time of spaying of leaf fertilizer, the corn yield was increased 258-592.5kg/hm^2 with increase amplitude ranging from 2.3%-5.6%.
基金supported by the National Natural Science Foundation of China (Grant No.31370624)the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20103515110005)the Natural Science Foundation of Fujian, China (Grant No. 2011J01071)
文摘We investigated the quantity and quality 0f fallen l0gs in different Tsuga l0ngibracteata f0rest c0mmunities in the Tianba0yan Nati0nal Nature Reserve. We used redundancy analysis t0 determine the spatial distributi0n 0f fallen l0gs in the different f0rest c0mmunities and t0 analyze the relati0nships am0ng stand structure, t0p0graphic fact0rs and human disturbance. The v0lume, c0vered area, mean l0g length and number 0f fallen l0gs differed significantly am0ng f0rest types (P 〈 0.05), but mean diameter at breast height sh0wed n0 significant difference (P 〉 0.05). The l0g v0lume and c0vered area in different f0rest types sh0wed the f0ll0wing trend: T. l0ngibracteata pure f0rest 〈 T. l0ngibracteata + Olig0staehyum scabrifl0rur 〈 T. l0ngibraeteata + hardw00d 〈 Rh0d0dendr0n simiarum + T. l0ngibraeteata 〈 T. l0ngibraeteata + Phyll0stachys heter0cycla pubescens. The spatial distributi0n patterns 0f l0gs quantity and quality indicated that l0g v0lume and c0vered area were str0ngly affected by envir0nmental fact0rs in the f0ll0wing 0rder: human disturbance 〉 elevati0n 〉 sl0pe p0siti0n 〉 b0le height 〉 tree height 〉 sl0pe aspect 〉 density 〉 basal area 〉 sl0pe gradient. The relative c0ntributi0n 0f envir0nmental variables 0n the t0tal variance was t0p0graphy (76%) 〉 disturbance (42%) 〉 stand structure (35%). T0p0graphy and disturbance c0mbined explained 8.2% 0f the variance. Fallen l0~s auantitv and aualitvwere negatively related t0 elevati0n and sl0pe p0siti0n, and p0sitively ass0ciated t0 human disturbance. The l0g v0lume decreased fr0m n0rthern t0 s0uthern sl0pes. Envir0nmental fact0rs had the highest impact 0n class I (slightly decayed), and l0west impact 0n class V (highly decayed).
文摘The goal of this study was to apply artificial neural networks to predict rain-fed wheat yield using meteorological data a few days to few months before harvesting. The climatic observation data used; were mean of daily minimum and maximum temperature, extreme of daily minimum and maximum temperature, sum of daily rainfall, number of rainy days, sum of daily sun hours, mean of daily wind speed, extreme of daily wind speed, mean of daily relative humidity, and sum of daily water requirements that were collected during 1990-1999 in Sararood Station for wheat phenological stages consisting; sowing, germination, emergence, 3rd leaves, tillering, stem formation, heading, flowering, milk maturity, wax maturity, full maturity, separately for each growing season. Then, they arranged in a matrix whose rows form each of the statistical years and the columns are meteorological factors at each phenological stage. Finally, the obtained model had the following capabilities: Prediction of wheat yield with maximum errors of 45-60 kg/ha at least two months before full maturity stage, determination of the sensitivity of each phenological stage with respect to meteorological factors, and determination of the priority order and importance of each meteorological factor effective in plant growth and crop yield.
基金Supported by the National Basic Research Program (973 Program) of China (Nos.2009CB421102 and 2005CB422005-01)the Second Scheme of CAS Action Plan for the Development of Western China (No.KZCX2-XB2-06-02)the National Key Technology R&D Program of China (No.2006BAC01A02-01)
文摘Remote sensing data from the Terra Moderate-Resolution Imaging Spectroradiometer (MODIS) and geospatial data were used to estimate grass yield and livestock carrying capacity in the Tibetan Autonomous Prefecture of Golog, Qing-hai, China. The MODIS-derived normalized difference vegetation index (MODIS-NDVI) data were correlated with the aboveground green biomass (AGGB) data from the aboveground harvest method. Regional regression model between the MODIS-NDVI and the common logarithm (LOG10) of the AGGB was significant (r2 = 0.51, P < 0.001), it was, there-fore, used to calculate the maximum carrying capacity in sheep-unit year per hectare. The maximum livestock carrying capacity was then adjusted to the theoretical livestock carrying capacity by the reduction factors (slope, distance to water, and soil erosion). Results indicated that the grassland conditions became worse, with lower aboveground palatable grass yield, plant height, and cover compared with the results obtained in 1981. At the same time, although the actual livestock numbers decreased, they still exceeded the proper theoretical livestock carrying capacity, and overgrazing rates ranged from 27.27% in Darlag County to 293.99% in Baima County. Integrating remote sensing and geographical information system technologies, the spatial and temporal conditions of the alpine grassland, trend, and projected stocking rates could be forecasted for decision making.
文摘28 oilseed rape Pol CMS three-line hybrid combinations diallel-crossed were compared in the yield and harvest index and analyzed on the correlation between the experimental yields and harvest indexes in this study. The correlation coeffcient was only 0.365 4, lower than a signifcant level, which indicated that there was no signifcant positive (or negative) correlation between the economic yields and the harvest indexes in oilseed rape. Among them, 8 hybrid combinations including 7 with a harvest index〉0.30 and one with a harvest index〈0.27 increased signifcantly in the yields compared with the control, and then were screened for production experiment. Under different cultivation methods, all the 8 combinations had a stable harvest index, and the combinations with higher harvest indexes also had a stable performance in yields. An oilseed rape variety Fengyou 737 with higher yield and harvest index selected through a further screening was grown with the harvest indexhigher than 0.33 whether transplanted or directly seeded in Yangtze River Basin Demonstration Area, demonstrating stable high yields as well as good ecological adaptability. The combination of yield and harvest index in the study is conducive to breeding a new oilseed rape variety with stable yields and good tolerance to close planting.
基金financially supported by the National Natural Science Foundation of China for Creative Research Groups Science Foundation (No.50921002)the National Natural Science Foundation of China (Nos.50574094 and 51074156)+2 种基金the China Postdoctoral Science (No.20090461153)the China Postdoctoral Science Foundation funded projects in particular (No.201003607)the Key Laboratory for Solid Waste Management and Environment Safety Open Foundation (No.swmes-2010-08)
文摘A wet impact crusher was used to breakdown waste printed circuit boards (PCB's) in a water medium. The relationship between the yield of crushed product and the operating parameters was established. The crushing mechanism was analyzed and the effects of hammerhead style, rotation speed, and inlet water volume on particle size distribution were investigated. The results show that the highest yield of -1 + 0.75 mm sized product was obtained with an inlet water volume flow rate of 5.97 m3/h and a smooth hammerhead turning at 1246.15 r/rain. Cumulative undersize-product yield curves were fitted to a nonlinear function: the fitting correlation coefficient was greater than 0.998. These research results provide a theoretical basis for the highly effective wet crushing of PCB's.
基金Supported by the Youth Fund of Orient Science and Technology College,Hunan Agricultural University(14QNZ09)Cultivation Physiology Station of National Technical System in Rape Industrial,National Key Technology Support Program(2012BAD15B04,2010BAD01B01)+1 种基金Special Fund of Government in Hunan Province,National Natural Science Foundation of China(31071851,31101596,3132130)Open Fund Project of Innovation Platform in Colleges and Universities of Hunan Province(12K064)
文摘Field experiments were conducted during 2008-2010 to investigate the ef- fects of NPK fertilization on seed yield and economic benefit of a new hybrid cultivar of winter oilseed rape (Brassica napus L.) - Xiangzayou763, and to determine the optimum NPK ratio and dose in Hunan, China. The results showed that NPK ratio (1:0.50:0.50) with 180 kg/hm2 N, 90 kg/hm2 P2O5 and 90 kg/hm2 K20 was the optimum combination for the highest seed yield (2 231.13 kg/hm2) and economic benefit (9 816.97 Yuan/hm2), of which 1 641.23 Yuan/hm2 being set for fertilizer in- vestment (VCR=4.11). Besides, the effects of N, P and K fertilizers on seed yield and oil production of winter oilseed rape were not identical. N had the greatest ef- fect on plant growth of winter oilseed rape, followed by P and K. Total leaf number, green leaf number, leaf length and width, rhizome diameter, branch number, dry weight per plant and other agronomic characters in high N treatments were higher than those in low N treatments. By correlation and path analysis of yield components, the contribution rate to seed yield was found: effective silique number per plant〉seed number per silique〉l 000-seed weight.
文摘Breeding and mass scale larval rearing of clownfish Amphiprion percula is very limited in brackishwater. We designed an indoor program of A. percula culture in brackishwater with a salinity of 24±1, during which the impacts of feed type, water temperature, and light intensity, on the efficiency of its reproduction, were revealed. The fish were accommodated along with sea anemones in fibre glass tanks to determine the influence of brooder diet on breeding efficiency. Higher reproductive efficiency [number of eggs laid (276±22.3 eggs)] was observed when fish were fed live Acetes sp. rather than clam (204±16.4 eggs), trash fish (155±12 eggs) and formulated feed (110±10 eggs). The spawning rate was increased during September and October (water temperature, 28.74±0.55℃) on average of 2.4 spawning per month; and low spawning rate was in January (water temperature, 24.55±0.45℃) on average of I spawning per month. Among three light intensities (100, 500, and 900 1x) set to evaluate larval survival rate, larvae showed the highest survival rate (65.5%) at 900 lx. The breeding method specifically in brackishwater developed in the present study is a new approach, will help the people from the regions of estuary and backwater to enhance their livelihood and it will lead to reduce the exploitation from the wild habitat.
基金the German Research Foundation (DFG) (No.LE 945/10-1).
文摘In the light of an increasing demand for staple food, especially rice, in southeast China, investigations on the specific site potential expressed as the relationship between soil and crop yield parameters gain increasing importance. Soil texture and several soil chemical parameters as well as plant properties such as crop height, biomass and grain yield were investigated along two terraced catenas with contrasting soil textures cropped with wet rice. We were aiming at identifying correlative relationships between soil and crop properties. Data were analyzed both statistically and geostatistically on the basis of semivariograms. Statistical analysis indicated a significant influence of the relief position on the spatial distribution of soil texture, total carbon and total nitrogen contents. Significant correlations were found for the catena located in a sandstone area (Catena A) between rice yield and silt as well as total nitrogen content. Corresponding relationships were not detectable for paddy fields that developed from Quaternary clays (Catena B). As suggested by the nugget to sill ratio, spatial variability of soil texture, total carbon and nitrogen was mainly controlled by intrinsic factors, which might be attributed to the erosional transport of fine soil constituents, indicating the importance of the relief position and slope in soil development even in landscapes that are terraced. The crop parameters exhibited short ranges of influence and about one third of their variability was unexplained. Comparable ranges of selected crop and soil parameters, found only for Catena A, are indicative of close spatial interactions between rice yield and soil features. Our findings show that especially in sandstone-dominated areas, a site-specific management can contribute to an environmentally safe rice production increase.
基金supported by ‘863’ Program (2006AA10A408 and 2006AA10A411), NSFC30571417, NYHYZX07-047, 2005DKA30470, 2006BAD09A10 and NCET-06-0594.
文摘Microsatellite markers have become one kind of the most important molecular tools used in various researches. A large number of microsatellite markers are required for the whole genome survey in the fields of molecular ecology,quantitative genetics and genomics. Therefore,it is extremely necessary to select several versatile,low-cost,efficient and time-and labor-saving methods to develop a large panel of microsatellite markers. In this study,we used Zhikong scallop(Chlamys farreri) as the target species to compare the efficiency of the five methods derived from three strategies for microsatellite marker development. The results showed that the strategy of constructing small insert genomic DNA library resulted in poor efficiency,while the microsatellite-enriched strategy highly improved the isolation efficiency. Although the mining public database strategy is time-and cost-saving,it is difficult to obtain a large number of microsatellite markers,mainly due to the limited sequence data of non-model species deposited in public databases. Based on the results in this study,we recommend two methods,microsatellite-enriched library construction method and FIASCO-colony hybridization method,for large-scale microsatellite marker development. Both methods were derived from the microsatellite-enriched strategy. The experimental results obtained from Zhikong scallop also provide the reference for microsatellite marker development in other species with large genomes.
基金Project supported by the National Science and Engineering Research Council (NSERC) of Canada.
文摘Understanding the relationships between topographic indices and crop yield variability is important for soil manage- ment and crop production in rolling landscape. Two agricultural fields at Alvena and Hepburn, Saskatchewan, Canada were selected to examine how topographic indices were related to wheat yield under two topographic and weather conditions in the Canadian prairies. The landscapes of the two sites are classified as hummocky and the dominant soil type is an Aridic Ustoll. The relationships among yield, topography, soil, and weather were analyzed using wheat (Triticum aestivum L.) grain yield from Alvena in 2001 (dry year) and 2004 (wet year) and from Hepburn in 1998 (dry year). Topographic/soil indices included relative elevation, wetness index, upslope length, curvature, soil organic matter, and soil moisture storage before seeding. The results indicated that, in the dry years, the correlation coefficients between upslope length and grain yield were 0.79 for the typical rolling landscape (Alvena) in 2001 and 0.73 for shallow gentle rolling landscape (Hepburn) in 1998. In the wet year (2004), the relationships between yield and topographic/soil attributes were not as strong as in dry years. Therefore, upslope length was the best yield indicator for the two landscapes in dry years, whereas no topographic indices were highly correlated to crop yield in wet years. Those topographic indices seemed useful in identifying the yield variability and delineating the proper management zone.
文摘Straightening machine is widely used for improving the quality of the defective mild steel plates.In general,the capacity of straightening machine is affected by material properties,the initial shape of the incoming plate and the plastic ratio.The mechanics model describing the capacity of the machine was developed.The deviation of the straightening capacity curves was studied.Then,the presented model was evaluated by comparative study to filed production data.Finally,the influences of overstretch,straightening speed,strengthening coefficient,elastic modulus,width of the plate on the straightening capacity were studied.It is convenient to determine whether the plate can be straightened or not by a series of straightening capacity curves.The straightening speed,width of the plate and elastic modulus of the material are more sensitive to the straightening capacity than the strengthening coefficient.