One approach to apply precision agriculture to optimize crop production and environmental quality is identifying management zones. In this paper, the variables of soil electrical conductivity (EC) data, cotton yield data and normalized difference vegetation index (NDVI) data in an about 15 ha field in a coastal saline land were selected as data resources, and their spatial variabilities were firstly analyzed and spatial distribution maps constructed with geostatistics technique. Then fuzzy c-means clustering algorithm was used to define management zones, fuzzy performance index (FPI) and normalized classification entropy (NCE) were used to determine the optimal cluster numbers. Finally one-way variance analysis was performed on 224 georeferenced soil and yield sampling points to assess how well the defined management zones reflected the soil properties and productivity level. The results reveal that the optimal number of management zones for the present study area was 3 and the defined management zones provided a better description of soil properties and yield variation. Statistical analyses indicate significant differences between the chemical properties of soil samples and crop yield in each management zone, and management zone 3 presented the highest nutrient level and potential crop productivity, whereas management zone 1 the lowest. Based on these findings, we conclude that fuzzy c-means clustering approach can be used to delineate management zones by using the given three variables in the coastal saline soils, and the defined management zones form an objective basis for targeting soil samples for nutrient analysis and development of site-specific application strategies.
Cluster Analysis ; Crops, Agricultural ; Electric Conductivity ; Soil

This paper summarizes the studies on improving crop nutritional quality including protein, saccharide and lipid through gene engineering in recent 10 years. Special emphasis is laid upon the improvement of protein contains and amino acid components. The food safety caused probably by gene engineering and some ways to solve the problem are introduced briefly.
Crops, Agricultural ; Genetic Engineering ; Nutritional Physiological Phenomena

This paper is aimed to study the differences of allelopathic effects of Panax notoginseng under different allelopathic chemicals resources and selection of appropriate rotation crops. The additive main effects and multiplicative interaction ( AMMI) model had been used to evaluate the stability of allelopathic effects of P. notoginseng on the varieties of corn, wheat and rice properly. The model could use not only to evaluate the stability of non-regional trial data but also explore the interaction between the rotation crop genotypes and donor substances more efficiently. Meanwhile, correspondence analysis can be used in the AMMI to evaluate genotype stability and donor substances. Ejingza No. 1 (g6) had stronger allelopathic effects with high stability, but Yunrui No. 1 (g9) which was appropriate rotation crop genotype, had weaker allelopathic effects with high stability. These findings will aid in choosing appropriate rotation crops and establishing proper rotation system.
Allelopathy ; Crops, Agricultural ; Panax notoginseng ; chemistry

Apomixis has been widely concerned because of its great potential in heterosis fixation. Artificial apomixis is an important direction of current apomixis research. Mitosis instead of Meiosis (MIME) produces diploid gametes that is identical with the maternal genetic composition and is a key step in the artificial creation of apomixes. This paper reviews the occurrence of MIME and its application in crop apomixis and the problems encountered, in an aim to provide reference for expanding the application of MIME in crop apomixis.
Apomixis ; Crops, Agricultural ; genetics ; Diploidy ; Germ Cells ; Meiosis ; Mitosis

OBJECTIVETo investigate the effects of top pruning on fruiting characters of Platycodon grandiflorum, and find the suitable stage, in which seed growth and development furtherly.

METHODOne-year old seedlings were chosen and planted in field. Plant height, branching number, fruit number per plant, 1000 grains weight were measured during growth and development period, respectively.

RESULTThe treatment of top pruning postponed in turn the flowering date, lowered the plant heights and the fruit number per plant, increased the branching number and influenced significantly on 1000 grains weights.

CONCLUSIONThe suitable stage of top pruning for producing seeds was from June 20th to July 5th.

OBJECTIVETo study optimum planting density and sowing depth of Tulipa edulis.

METHODThe effects of different planting densities, sowing depth and thin plastic film cover were studied on yield, rate of increase, bulb weight increased multiples, and proliferation rate of bulb.

RESULT AND CONCLUSIONUnder 30-200 bulbs per squremeter density range, the yield increased with the density increasing, and reached significance level. In 5-20 centimeter depth range, the yield and the number of harvested bulbs enhanced along with the sowing depth increasing, and the best sowing depth was 20 cm. Thin plastic film cover showed no effect on the growth.

Field experiments were conducted in farmers' rice fields in 2001 and 2002 to study the effects of nitrogen (N) management strategies on N use efficiency in recovery (RE), agronomy (AE) and physiology (PE) and redistribution of dry matter accumulation (DMA) and nitrogen accumulation (NA) in two typical rice cultivars in Jinhua, Zhejiang Province. This study aimed mainly at identifying the possible causes of poor fertilizer N use efficiency (NUE) of rice in Zhejiang by comparing farmers' fertilizer practice (FFP) with advanced site-specific nutrient management (SSNM) and real-time N management (RTNM). The results showed that compared to FFP, SSNM and RTNM reduced DMA and NA before panicle initiation and increased DMA and NA at post-flowering. There is no significant difference between SSNM and FFP in post-flowering dry matter redistribution (post-DMR) and post-flowering nitrogen redistribution (post-NR). These results suggest that high input rate of fertilizer N and improper fertilizer N timing are the main factors causing low NUE of irrigated rice in the farmer's routine practice of Zhejiang. With SSNM, about 15% of the current total N input in direct-seeding early rice and 45% in single rice could be reduced without yield loss in Zhejiang, China.
Crops, Agricultural ; metabolism ; Fertilizers ; Nitrogen ; metabolism ; Oryza ; metabolism

OBJECTIVETo explore effects on allelopathic autotoxicity of Rehmannia glutinosa of different abatement measures.

METHODThe experiments for abating allelopathic effects of R. glutinosa were designed with the reducing rate as a indication, three measures of the treating soil with lime nitrogen, and water washing were employed, R. glutinosa- Achyranthes bidentata rotation system and using Achyranthes bidentata as green manure, and seedling transplant were also studied for the abatement effect.

RESULTEffect of seedling transplant was the best, reducing rate of transplant and bare root transplant on the 20th day after emergence was 76.80%, 71.70%, respectively. The reducing rate of the treating soil with microorganism reached 54.25%. The effects of water washing and R. glutinosa-A. bidentata rotation system and using A. bidentata as green manure were not satisfied. Especially only using A. bidentata as green manure without rotation system worsened the allelopathic effects of R. glutinosa.

CONCLUSIONAll measures can abate allelopathic effects of R. glutinosa to some extent except only using A. bidentata as green manure.

OBJECTIVES: This study was conducted to assess the concentration of urine cadmium and health risks of residents in the vicinity of abandoned metal mines in Gyeongsangbuk-do. METHODS: The concentration of cadmium in the soil, water, and agricultural crops was measured in Gyeongsangbuk-do, Butdeun and Suksan, which have abandoned metal mines. We measured the concentration of cadmium in the urine of residents from the following areas: 78 from village A, 99 from village C and 147 from control areas. Other health-risk assessments were performed on each resident, such as measuring the concentration of beta2-MG and a bone density test. RESULTS: In abandoned mine areas, the mean concentration of cadmium was higher in agricultural soil and in the crops than in that of control areas. The concentration of cadmium in the stream exceeded the guideline level. In regard to provisional tolerable daily intake (PTDI) of cadmium, the actual intake rate through crops was 33.81%, 72.74% in abandoned mine areas and 5.03%, 6.16% in control areas. Residents in abandoned mine areas, A village and C village had a geometric mean of urine Cd of 1.90 microgram/g cr and 1.45 microgram/g cr. These measurements were significantly higher than those of residents in control areas, B village and D village, 0.59 microgram/g cr and 0.65 microgram/g cr (p<0.01). Following adjustments for age, sex, smoking habit, and occupational history, the concentration of urine cadmium of residents in the Butdeun abandoned meta mine was higher by 1.62 microgram/g cr as compared with the control group (p<0.01). Residents from the Suksan abandoned metal mine also had a higher concentration by 1.07 microgram/g cr (p<0.01). A multiple linear regression analysis was performed for the factors associated with T-score, and this showed that the concentration of urine cadmium was not an influential factor. CONCLUSIONS: Based on these measurements, areas with abandoned metal mines contaminated streams, agricultural soil, and crops of the adjacent areas, with cadmium. Because residents in the adjacent areas intake contaminated crops, their urine cadmium was increased. Despite a lack of evidence demonstrating the detrimental effect of increased urine cadmium in residents, an additional study is needed to assess the health risks of residents in the vicinity of abandoned metal mines.
Bone Density ; Cadmium ; Crops, Agricultural ; Korea ; Linear Models ; Rivers ; Smoke ; Smoking ; Soil ; Water

The availability of crop residues in China is reviewed in this article. The definition of crop residues is clarified as the total byproducts of field production and processing industry thereafter, and methodology for evaluating crop residues is discussed. Based on literature, the progress on the crop residue assessment is addressed. The annual field crops residues in China from 1991 to 1999 were estimated between 6.0-6.8 hundred million tons, while the data for the process residues were not available. From 2000 to 2007, the annual crop residues were estimated between 5.9-7.3 hundred million tons, while the processing residues at the range of 0.9-1.1 hundred million tons. The reasons for the significant variations are due to the disagreement on crop residue definition, different, even inaccurate residue to grain ratio data used in the estimations, and the lacking of clear understanding on the statistical analysis and grain outputs related to the crop residue evaluation. With the complete statistic analysis method, the author's group evaluated the residues in 2006 and 2007 to be 7.4 hundred million tones in total, including 6.5 hundred million tons for field crop residues and 0.9 hundred million tons for process residues. Moreover, the geographic distribution of the field crop residues was analyzed based on the harvest indices (HI) tested within the near five years.
Biofuels ; China ; Conservation of Natural Resources ; methods ; Crops, Agricultural ; economics ; Plant Stems ; chemistry ; Refuse Disposal ; methods