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- Abstract：Research in use of near-infrared spectroscopy(NIRS)to establish a fast-quantitative analysis model of measuring maize straw phosphorus concentration will benefit the genetic study of plant nutrient utilization efficiency and breeding. A total of 200 maize straw samples were randomly selected. These samples were measured by both NIRS(at a band width of 4 000-10 000 cm-1)and by chemical method(molybdenum antimony colorimetric method). Four modeling methods including partial least squares(PLS), least absolute shrinkage and selection operator(LASSO), support vector machine(SVM), and regression tree(RT)were then used to establish NIRS prediction models for phosphorus concentration in maize straw. The fivefold cross-validation results showed that PLS was the most optimal modeling method among the four approaches. For PLS, the correlation coefficient(rtest)between predicted and measured phosphorus concentration values was 0. 80±0. 05 in the test set; and the correlation coefficient(rtraining)was 0. 97±0. 03 in the training set. Furthermore, the effects of eleven pre-processing methods based on PLS were evaluated. The results showed that the normalization and smoothing performed the best, with rtest of 0. 80±0. 05. However, no significant difference was observed compared with the original data. The results showed that the prediction accuracy was improved with the increase of the training set size. When the ratio of training set to test set was 8∶2, the prediction accuracy was 0. 80, which was equivalent to the prediction accuracy of Leave-One-Out method(0. 81). To sum up, the NIRS quantitative model of maize straw phosphorus concentration by PLS has a high prediction accuracy and can be used for the determination of phosphorus concentration in breeding and genetic studies.Keywords：near-infrared reflectance spectroscopy;phosphorus concentration;partial least square;maize straw3|11|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the impacts of crop diversity changes on crop production, Scale Advantage Index(SDI)was used to systematically analyze the changing characteristics of the global major cereals and grain legumes′ production and agricultural inputs from 1961 to 2017. The results showed that: 1)From 1961 to 2017, the harvested area of maize and rice increased rapidly, the SDI of the main cereals showed an upward trend in Europe, Asia and Africa. Soybean was the world′s largest grain legume crop, and its harvested area increased significantly and the SDI of grain legumes showed an upward trend in South and North America since 1961. The global major cereals' production and yield improved. 2)From 2002 to 2017, the application rates of nitrogen fertilizer, phosphate fertilizer, potash fertilizer and pesticides increased significantly globally, and the total consumption of agricultural production in China and other parts of Asia were the largest. 3)From 2002 to 2017, the increased SDI of the major cereals resulted in significantly increase of fertilizer and pesticides application rates per unit area in the regions where the main cereals had significant scale advantages. However, the increased SDI of grain legumes caused significant decreasing in the consumption of fertilizer and pesticides. Consequently, in regions like China where major cereals have a large crop diversity index, improving the diversity of grain legumes is of great significance to reduce the fertilizer and pesticide inputs and promote the sustainable development of crop production systems.Keywords：main cereals;grain legumes;planting structure;crop diversity;scale advantage index2|11|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To determine the yield advantages, economic benefits and carbon footprints of the intercropping systems, field experiments of oat‖mung bean, oat‖peanut, and oat‖soybean intercropping were conducted in Baicheng City, Jilin Province from 2011 to 2014. The results showed all intercropping patterns displayed significant yield advantages compared with the corresponding monocultures. The land equivalent ratios(LER)of oat‖peanut and oat‖soybean were 1. 41 and 1. 46, respectively, which were 18. 5% and 22. 7% higher than that of oat‖mung bean. Compared with oat‖mung bean and oat‖peanut, oat‖soybean had stronger yield stabilities in the experimental years. The aggressivity indexes of oat intercropped with mung bean, peanut, and soybean were 0. 13, 0. 65, and -0. 96, respectively. The carbon footprints per unit area of oat‖peanut and oat‖soybean intercropping system were 1 703. 2 and 1 661. 2 kg/hm2, which were 18. 6% and 20. 6% lower than that of oat‖mung bean. The carbon footprints per unit equivalent yield of oat‖mung bean, oat‖peanut, and oat‖soybean intercropping systems were 0. 59, 0. 35, and 0. 31 kg/kg, respectively. The economic benefits of oat‖peanut and oat‖soybean were 12 015 and 13 673 yuan/hm2, which were 59. 5% and 81. 5% higher than that of oat‖mung bean, respectively. In summary, the oat‖soybean has a higher yield and economic benefit, simultaneously a lower carbon footprint than oat‖peanut and oat‖mung bean. Therefore, oat‖soybean is the most profitable alternative intercropping pattern in the semi-arid regions of Western of Jilin Province.Keywords：oat;legumes;intercropping;economic benefits;carbon footprint6|13|15<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to reveal the impact of climate change on the production of major crops in Nyingchi region, Nyingchi region of Tibet was taken as a case study, and the regional major crops including winter wheat, corn, spring barley, and spring rapeseed were selected. Thermophilic and chimonophilous crops were distinguished by growing seasons, and the impacts of climate change on the regional crop phenology, planting structure, and crop production from 1981 to 2018 were analyzed. The results indicated that: 1)The Nyingchi region showed a notable warming trend during the growing season, and the annual average temperature in the growing season increased significantly at the rate of 0. 35 ℃/10 year. The temperature increase in the growing season of chimonophilous crops was more obvious. The annual average temperature during the growing seasons of autumn-sown crops, early spring-sown crops, and late spring-sown crops increased at the rates of 0. 34, 0. 30 and 0. 26 ℃/10 year, respectively. The annual precipitation in the crop growth season showed a big variation. 2)Affected by climate warming, the phenological periods of chimonophilous and thermophilic crops in Nyingchi region were prolonged, and the growing seasons of chimonophilous crops were longer than that of thermophilic crops, at the rate of 5. 43 to 11. 7 d/10 year. 3)The planted areas of thermophilic crops increased, while the planted areas of some traditional chimonophilous crops showed a significant decrease trend. There was a large variation in different crop yield, with an increase in corn yield and a decrease in spring barley yield. Under the warming climate, temperature during the crop growing season increased significantly, and the phenological periods were prolonged. With the increases in the area and yield of thermophilic crops, the planted area of chimonophilous crops has decreased. In the future, we should actively adjust and optimize regional cropping system to make the full use of local climatic and land resources and prevent natural disaster risks caused by climatic fluctuations.Keywords：climate warming;crop production;phenological period;planting structure;Nyingchi region of Tibet6|11|9<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to study the effects of different planting densities and nitrogen rates in main season on the yield of ratoon sorghum, the sorghum hybrid ‘Jinyunuo 3' was taken as study material under 3 planting densities, 82 500(LD), 105 000(MD), 127 500 plant/hm2(HD), and 3 nitrogen rates, 120(LN), 150(MN), 225 kg/hm2(HN). The ratooning ability, dry matter accumulation characteristics, yield and yield components of ratoon sorghum were investigated. The results showed that the number and length of regeneration buds decreased with the increase of planting density, while increased with the increase of nitrogen rate. The dry matter accumulation of ratoon sorghum decreased with the increase of planting density and increased with the increase of nitrogen rate at both anthesis and mature stages. The higher planting density reduced dry matter transportation and dry matter transportation efficiency of leaf before anthesis and its contribution to grain, but improved the contribution of dry matter accumulation after anthesis to grain. The higher nitrogen rate reduced dry matter transportation efficiency of leaf and stem+sheath before anthesis, as well as their contribution to grain, but boosted the contribution of dry matter accumulation after anthesis to grain. The yield of ratoon sorghum increased with the lifting of planting density and nitrogen rate. The average yield of ratoon sorghum under HD was respectively 17. 82% and 1. 49% higher than those under LD and MD for two years. The average yield of ratoon sorghum under HN was respectively 24. 23% and 14. 72% higher than those under LN and MN. The ear weight decreased with the increase of planting density, but increased with the increase of nitrogen rate. The 1 000-grain weight showed no significant difference among planting densities, while it increased with the increase of nitrogen rate. In conclusion, under the experimental field condition in this study, the planting density of 127 500 plant/hm2 and nitrogen rate of 225 kg/hm2 could obtain higher yield of ratoon sorghum.Keywords：sorghum;planting density;nitrogen rate;ratooning ability;ratooning yield1|9|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Virus infection directly affects the growth and fruit quality of strawberry. Rapid detection and identification of virus is the premise of virus control. In order to identify the viruses in cultivated strawberry varieties, the viruses in two strawberry cultivars were studied by small RNA deep sequencing and RT-PCR. ‘Toyonoka' and ‘Honeoye' cultivars were taken as test materials. The small RNA sequencing results were assembled and annotated. It was found that, in the mixture samples, a total of 242 contigs were mapped to five strawberry viruses, namely strawberry vein banding virus(SVBV), strawberry mottle virus(SMoV), strawberry pallidosis associated virus(SPaV), strawberry crinivirus 3(SCrV 3)and strawberry crinivirus 4(SCrV 4). RT-PCR results indicated that SMoV, SVBV and SCrV 3 were detected in ‘Toyonoka' and ‘Honeoye' cultivars, while SPaV and SCrV 4 were only detected in ‘Honeoye'. In this study, the viruses in two strawberry varieties were identified by small RNA deep sequencing. The presence of five viruses in strawberry cultivar was first detected, which provided a new idea for the detection and control of strawberry viruses.Keywords：strawberry;sRNA sequencing;strawberry pallidosis associated virus;strawberry crinivirus;RT-PCR2|11|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
Effects of nitrogen and red and blue light on NiR enzyme activity and gene expression inL. seedlings
Abstract：To study the response of amaranth NiR gene to nitrogen metabolism regulated by different ammonium and nitrate ratio and red and blue composite light ratio, a NiR gene named AtrNiR(GenBank Accession no. MT374155)was cloned from Amaranth by RT-PCR combined with qRT-PCR, its relative expression was analyzed and the activity of NiR enzyme was measured. The results showed that 1)The AtrNiR gene contained an open reading frame of 1 785 bp in length, which encoded 595 amino acids; 2)Bioinformatics analysis indicated that the protein molecular formula of AtrNiR is C2937H4692N828O873S28, with a relative molecular mass of 66. 47 ku. It is a hydrophilic protein; 3)Phylogenetic tree analysis showed that the AtrNiR protein sequence has the highest homology with that of Beta vulgaris L. , Chenopodium quinoa Willd. and Spinacia oleracea L. and has similar function; 4)The analysis of nitrite reductase content in Amaranth seedlings showed that the nitrite reductase activity is the highest when the molar ratio of NH4+-N to NO3--N was 10∶0 at different ammonium nitrate ratios for 3 days. When the molar ratio of NH4+-N to NO3--N was 3∶7, the nitrite reductase activity is the highest for 6 days. The nitrite reductase activity was the highest under the treatment of R∶B=2∶8 with different red and blue light ratios for 3 days. It can be seen that NO3 - N and blue light can improve the NiR enzyme activity of amaranth seedlings; 5)qRT-PCR analysis showed that AtrNiR expression was highest when the molar ratio of NH4+-n to NO3--N is 5∶5 at different ammonium nitrate ratios for 3 days. The AtrNiR expression was the highest under the treatment of R∶B=2∶8 with different red and blue light ratios for 3 days. The results suggested that the nitrogen absorption and nitrogen metabolism of Amaranth, seedlings were improved by the appropriate ratio of nitrogen and red and blue combined light energy. The study provides theoretical support for the factory production of quality amaranth.2|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27- Abstract：To investigate the effect of Bacillus treatment on Huanglongbing-infected citrus nusery-growth plants, a single colony of Bacillus was isolated and purified from the compound bacterial agent. Bacterial pure culture identification tests and sequencing were performed to determine the classification status of strain No. 4, then, No. 4 bacterial agent was prepared by solid-state fermentation. The plants of three citrus varieties were irrigated with it. The results showed that No. 4 strain was gram positive stain and it belongs to the genus Bacillus, and it shared 93% homologous with Bacillus velezensis via the sequence alignment of 16S rDNA and recA genes; Irrigation the citrus plants with B. velezensis No. 4 bacterial agent for 21 times, the positive rate of HLB decreased from 100% to 50% and 75% in Citrus reticulata Blanco ‘orah' and C. reticulata cv. ‘shiyue ju' separately, the positive rate of the control samples remained unchanged. No. 4 bacterial agent could promote the root system developed well and the browning root system decreased in ‘orah', ‘shiyue ju', and ‘nanfengmiju' obviously; Microstructural observation in C. reticulata cv. Kinokuni indicated that the root system browning caused by Candidatus Liberobacter was serious, the epidermal cells of browning root showed corkization, turn upward and structural damaged by scanning electron microscopy and paraffin section; The analysis of relative expression levels of resistance-related genes indicated that the relative expression levels of mRNA of pathogen-induced promoter GST1 and transcription factors WRKY22 and WRKY24 genes were higher than those of the control group. Therefore, No. 4 Bacillus agent had inhibition effect to a certain extent on citrus Huanglongbing disease, and it had obvious relieving effect on browning root.2|12|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to promote the research process of circular RNAs(CircRNAs)in plants, the literature related to circular RNAs published from 2018 to 2020 were searched and the research process of functions, research methods, and application prospects of animal and plant circRNAs were discussed. The results showed that circRNAs can be used as competitive endogenous RNAs to bind to microRNAs(MiRNAs)and indirectly regulate protein expressions. They regulate the transcription of source genes, rolling translate polypeptides and combine with other proteins. Up to now, the research on circRNAs in clinical field is the most in-depth. After the estimations of the potential diagnosis, prognosis and evaluation of treatment methods, they are expected to become biomarkers for diagnosis and treatment of diseases. Meanwhile, plant circRNAs have also shown abundant differential expression patterns under different growth conditions and development stages, hormonal stimulation, and adversity stresses, which initially reflect the diversity of their functions. However, compared with the research depth of animal circRNAs, the research of plant circRNAs is still in the emerging stage, and the database and analysis tools related to plant circular RNA still need to be developed. In conclusion, the review focuses on the specificity and homology of circRNAs of different types of circular RNAs in animals and plants in terms of generation mechanisms, splicing recognition sites, function development and application potential, discusses the main problems in the research of circular of circRNAs in animals and plants, and prospects the future research of circRNAs in plants.Keywords：circRNAs;biosynthesis;function development;research methods;application potential3|11|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To analyze the feasibility and economic efficiency of shortening and canceling the dry period in the production of high-yield dairy cows, this study summarized and analyzed the research progress on the effects of dry period length on milking, healthy, fertility and economic benefit of dairy cows based on the literature published from 2003 to 2020. The results showed that: 1)Shortening the dry period to 30 days or canceling the dry milk period can lead to the decrease of milk yield in the subsequent lactation, whereas the milk yield precalving in cows with a 30 d or 0 d dry period can partly compensate the milk yield loss post calving. 2)Shortening or canceling the dry period can significantly improve the negative energy balance in early lactation, alleviate the metabolic disorder caused by negative energy balance and improve the fertility of dairy cows. The benefits obtained from the improvement of health and fertility of dairy cows can partly make up for the economic losses caused by the reduction of milk yield. 3)Shortening or canceling the dry period had no effect on the health of calves. However, further researches are needed for the application and promotion of the strategy in practice. In the future, the researches could focus on the improvement of management strategies to match 30 or 0 d dry milk period, the prediction mode of the proper dry period length for individual cow, and the molecular mechanism of the mammary gland involution and regeneration in order to provide a reference for the future research on the suitable dry period length of dairy cows, and also provide scientific basis for the selection of the suitable dry period length of dairy cows in practice.Keywords：dry period;milk yield;energy balance;reproductive performance;mammary gland0|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to obtain the weight data of fattening pigs quickly, accurately and without stress, deep convolutional networks were applied to estimate the weight of fattening pigs. The results showed that: 1)Among the transformed Xception, MobileNetV2, DenseNet201 and ResNet152V2, the pre-trained DenseNet201 model had the best weight estimation effect. On the validation set, the estimated correlation coefficient of the model was 0. 9939, the root mean square error was 1. 85 kg, the mean absolute error was 1. 10 kg, and the mean relative error was 1. 57%. The Densenet201 model was then selected as the fattening pig weight estimation model in this study; 2)The generalization effect of the model was investigated based on the test data. The estimated correlation coefficient of 0. 976 7, the root mean square error of 2. 75 kg, the mean absolute error of 2. 10 kg, and the mean relative error of 3. 03% showed that the performance of the model was good. 3)The mean estimated time of pre-trained DenseNet201 was 0. 16 s, which was much faster than that of the traditional methods. Therefore, the Densenet201 model was more suitable for sorting systems, sow feeding stations and other occasions where the speed of pig weight acquisition was strict. In conclusion, the deep convolution network can be used to quickly estimate the weight of fattening pigs and provides basis for automated, intelligent and unmanned management of pig farms.Keywords：fattening pigs;weight estimation;deep learning;convolutional neural network3|11|8<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the feasibility of wheat straw as roughage, the effects of wheat straw on rumen fermentation metabolism and intestinal morphology of Hu sheep were analyzed by feeding experiment with alfalfa as control. The contents of digestive tract pH and weight, blood and rumen fluid lipopolysaccharide content, rumen fluid enzyme activity, volatile fatty acid content and organ index of Hu sheep were determined, and the intestinal morphology were observed. The results showed that: 1)Compared with the alfalfa hay group, the rumen pH of the wheat straw group was significantly lower(P<0. 05), but there was no significant difference in reticulum, omasum, abomasum and intestinal pH; 2)Compared with the alfalfa hay group, the weight of rumen content and the proportion of pre-slaughter live weight in the wheat straw group increased significantly(P<0. 01); 3)There was no significant difference in rumen contents and blood lipopolysaccharide concentrations between the two groups; 4)The xylanase activity in the rumen content of the wheat straw group was significantly higher than that of the alfalfa hay group(P<0. 01); 5)There was no significant difference in the content of volatile fatty acids between the two groups; 6)There was no significant difference in the organ index between the two groups of Hu sheep; 7)There were no pathological changes in the morphology of the duodenum, jejunum and cecum of the two groups of Hu sheep. In summary, compared with alfalfa, feeding wheat straw slowed down the rumen emptying rate of Hu sheep and significantly improved the activity of rumen xylanase and promoted fiber hydrolysis of Hu sheep in a certain extent. Feeding alfalfa or wheat straw will not change the type of rumen fermentation, rumen metabolism and intestinal tissue morphology of Hu sheep, which provides basic data for the rational utilization of wheat straw in ruminants.Keywords：Hu sheep;wheat straw;rumen fermentation;intestinal tissue morphology5|11|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To explore the antifreezing effect of different cryoprotectants on chicken semen, and explain the antifreeze mechanism of different cryoprotectants by comparing the differentially expressed genes, Hy-line Breeder Cocks were taken as study objects to invesitgate the activity of sperm preserved in different cryoprotectants(cryoprotectant Ⅰ and cryoprotectant Ⅱ), and the differentially expressed genes were screened by Affymetrix microarray. The results showed that: 1)The sperm viability of group Ⅰ(27. 05±1. 22 vs 47. 65±5. 89)was significantly higher than that of group Ⅱ(20. 65±1. 50 vs 35. 15±5. 15)(P<0. 05); 2)A total of 1 604 differentially expressed genes were found in the two treatment groups. In group Ⅰ, 1 380 genes were significantly up-regulated and 224 genes were significantly down-regulated; 3)Gene ontology analysis showed that the processes including ribosomal subunits, mitochondrial respiratory chain, ubiquitin protein ligase binding, and tubulin binding, translation initiation and RNA catabolism were related to semen antifreeze; 4)KEGG pathway enrichment analysis found that it was mainly enriched in endoplasmic reticulum stress pathway, oxidative phosphorylation, protein ubiquitination, ribosome regulation and mitochondrial respiratory regulation and other related signal pathways. 5)Four differentially expressed genes of CCND1, HSP70, HSP90 and CIRBP were selected and verified by fluorescence quantitative PCR. To sum up, the preliminary study compared the freezing effects of two cryoprotectants and screened out differentially expressed genes, and found that the cryoprotectant I was more suitable for the preservation of frozen semen of Hy-line Breeder Cocks, which provided references for chicken semen freezing technology and direction for the molecular mechanism analysis of chicken sperm antifreeze.Keywords：chicken sperm;cryoprotectants;differentially expressed gene;expression profiling chip2|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Due to the problems of low operating speed and insufficient precision of traditional cotton seeding mechanism, the cotton air suction seed metering mechanism is optimized. Based on the FLUENT software, the fluid simulation method of simple cylindrical holes, conical holes, cylindrical and cone combined holes, and arc-shaped holes on the seeding disk is used to analyze the influence of the four types of holes on the wind pressure. The test indicators for seeding quality are the overlapping index and missing index, which are verified by single factor test and two factor full level test. The results show that different holes have different influence on wind pressure: Simple cylindrical holes have the largest wind pressure loss and the worst filling effect; cylindrical and cone-combined holes have medium wind pressure and relatively stable inlet pressure; The conical holes have the smallest wind pressure loss, but have a larger inlet pressure gradient. The filling effect is better; The wind pressure at the entrance of the arc-shaped hole is relatively large and relatively uniform, and the filling effect is the best. The results of two-factor full-level test shows that when the seeding speed is 10. 01 km/h and the air pressure chamber pressure is -5. 23 kPa, the arc-shaped hole corresponds to the overlapping index of 9. 95% and the missing index of 3. 62%, and all indicators meet the design requirements.Keywords：cotton;driven by motor;air suction;seeding agency;fluid simulation1|10|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Aiming at the problems of poor stability and uniformity in screw-type feeding device of air-assisted centralized fertilizer application device, this study proposed a method of“concentrated fertilizer discharge from the fertilizer discharge device + pneumatic conveying fertilizer”. The impacts of model-hole section, model-hole depth and number of model-holes on the rate and of uniformity fertilizer application were investigated, and the variation coefficient of the application consistency of each row were adopted with the EDEM simulation. The results showed that: When the rotation speed is 30 r/min, the optimal structural parameters of the fertilizer wheel were the model-hole section II, the model-hole depth of 15 mm, and the model-hole number of 8. eWhen the rotation speed is 10-50 r/min, under the optimal parameters, the rate of fertilizer application increased linearly with the increase of the rotational speed, and the c variation coefficient of the application consistency of each row, and the variation coefficient of application uniformity were lower than 3. 0% and 26. 0%, respectively. Using Sanning, Zhushang, and Zhonghua compound fertilizers commonly used in rice planting for bench tests, the bench test results showed that the variation coefficient of the total application stability and the coefficient of variation of the discharge consistency of each row of the three types of compound fertilizers were lower than 2. 0% and 4. 0%, respectively. The deviation between the experimental value of the fertilizer rate and the theoretical value predicted by the model was within 2%. The field experiment results showed that when the fertilization application amount was 490. 05 and 588. 00 kg/hm2, the relative error between the actual fertilization rate and application quantity of agronomic requirements was less than 2%.Keywords：centralized fertilizer application device;screw-type feeding device;fertilizer application uniformity;granular fertilizer3|10|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to overcome low usage of the traditional spraying system, a precise intermittent spraying system using double valve control was proposed in this study. In view of the coupled multi-energy domains in the spraying system, the spraying dynamics under different pressures was simulated using 20-sim bond graph simulation platform. The spraying system was constructed to test the spraying pressure dynamic characteristics of the nozzle under three different pressures(0. 2, 0. 3 and 0. 4 MPa), and profile analysis was applied to evaluate the accuracy of simulation results. The test results showed that the spraying system had an accuracy over 89% when the vehicle speed was 0. 8 m/s, the crop spacing was 20 cm and diameter of the crop coverage was 10 cm. The maximum confidence level of the simulation calculation for the test results was 0. 088. Therefore, the numerical model based on the bond graph theory can achieve a good performance of predicting the spraying pressure dynamic characteristics.Keywords：bond graph;equation of state;precision spraying;numerical calculation1|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Aiming at the problem of frequent occurrence of lettuce tipburn caused by calcium deficiency in the plant factory under artificial light, a lettuce variety, which is relatively sensitive to tipburn, was chosen as the experimental material. An electric field generation system in the root area with the electric voltage of -15 kV was employed in this experiment. The system was operated for 24 h per day to make the lettuce plant negatively charged and form a positive electric field with the shoot growth space. The rhizosphere electrified treatment was used as the experimental group, and the non electrified treatment was used as control. The effects of rhizosphere electrified cultivation on the growth, Ca2+ absorption and tipburn of lettuce were explored. The results showed that: 1)Tipburn occurrence of lettuce plant was observed in the control on day 13, whileit was observed on day 15 in the experimental group. Compared with the control, the ratio of the number of leaves with tipburn to total leaves was reduced by 46. 9% under the experimental group on day 20; 2)Compared with the control, the fresh weight of shoot and root of the experimental group increased by 6. 3% and 30. 9%, and the dry weight increased by 17. 2% and 22. 4% on the 20th day of transplanting; 3)On the 10th day of transplanting, the root activity and Ca2+ absorption capacity of the experimental group were increased by 133. 3% and 108. 9% respectively compared with the control; 4)On the 20th day of transplanting, the stomatal conductance, transpiration rate and intercellular carbon dioxide concentration of the experimental group were increased by 46. 2%, 49. 0% and 5. 2%, respectively, and the accumulation of photosynthetic products was also improved. In conclusion, under the comprehensive environmental control conditions of plant factory, the rhizosphere electrified cultivation can significantly improve lettuce plant development and alleviate tipburn occurrence.Keywords：lettuce;rhizosphere electrified cultivation;plant factory;tipburn;calcium absorption;photosynthesis2|11|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the existing problems and development rules of water resources in Inner Mongolia, and to achieve rational use of regional water resources, based on the water footprint theory, this study analyzed the water consumption structure of Inner Mongolia from 1998 to 2018 and evaluated the regional water resources situation. The results showed that: The water footprint of the whole region was on the rise, and the total water footprint reached 77. 86 billion m3 in 2018; The agricultural blue and green water footprint occupied the leading position in the total water footprint, among which the largest proportion of the agricultural blue water footprint was 72. 43%-82. 97%; Comparing the characteristics of water use, the higher ecological blue water footprint made Alxa the highest blue water footprint per capita area, and Xingan was the region with the highest green wate footprint per capita due to higher precipitation and lower crop yields; The pressure of water resources was always in a high state, and Wuhai ranked first in water pressure, but the water quality problem didn't exist during the study in Inner Mongolia. In conclusion, it is urgent for Inner Mongolia to improve the current situation of local water resources utilization by adjusting the water structure, so as to promote sustainable development of the region.Keywords：evaluation of water resources;blue water footprint;green water footprint;grey water footprint;Inner Mongolia1|9|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aim of this study was to evaluate the cultivated land use efficiency in different areas quantitatively and identify their obstacle factors. Qingpu District of Shanghai, Changsha Country of Changsha and Pengyang Country of Guyuan, which are respectively located in the east, middle and west of China, are taken as three study areas. The evaluation index system of cultivated land use efficiency was constructed from 3 dimensions of ecological efficiency, economic efficiency and social efficiency. The entropy TOPSIS method and the obstacle degree model were applied to estimate the cultivated land use efficiency and identify obstacle factors in the three study areas. The results showed that: 1)The ecological and economic benefits in Qingpu District were generally high. The ecological benefits in Changsha County were high, while the economic benefits were lower than that of Qingpu District. Both the ecological and economic benefits in Pengyang County were at a lower level. And the social benefits of three regions increased as a whole. 2)Qingpu, with higher economic level and better natural conditions, had the highest level of cultivated land use efficiency, while Pengyang, with lower economic level and poor natural conditions, had the lowest level. And Changsha was in the middle level. 3)The social efficiency was the major factor restraining the cultivated land use efficiency from improving in Qingpu. Changsha and Pengyang were similar, namely, the economic efficiency was the main obstacle factors. The top three obstacle factors during 2016-2018 in Qingpu were the per capita gross agricultural output value, the per capita grain yield and the land productivity. The obstacale fators in Changsha were the agricultural mechanization efficiency, the labour productivity and the per capita grain yield, while in Pengyang were the agricultural mechanization efficiency, the irrigation rate and the net income per farmer. Therefore, in order to promote the rational utilization of cultivated land resources and the sustainable development of agriculture, three regions should take targeted measures to overcome the impact of their main obstacle factors on the cultivated land use efficiency.Keywords：land use;rural areas;efficiency evaluation;models;obstacle factor1|9|10<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to understand the research status and development trend of rural residential land consolidation in China, “homestead reclamation”, “homestead consolidation”, “homestead reconstruction”, “optimization of spatial layout of homestead”, “rural residential land reclamation”, “rural residential land consolidation”, “rural residential land reconstruction”, “optimization of spatial layout of rural residential land” were taken as keywords to search the relevant literature published from 1998 to 2020 in CNKI core database. Visual analysis and literature review from five aspects were conducted by using Citespace software, such as the number of articles published, cooperative characteristics, keywords, path evolution analysis and salient words. The results showed that: 1)In China, the research field of rural residential land remediation was highly concerned and valued at the national level, and a few of cooperative groups were formed initially; 2)Current research focused on the potential measurement and planning of rural residential land consolidation, the exploration of rural residential land consolidation models in different regions, and the related policy research of rural residential land consolidation; 3)There are three development stages in the rural residential land consolidation research, namely, the initial stage(1998-2005), the development stage(2006-2013), and the stable stage(2014-2020). In conclusion, It was found that there is more in-depth research in the early stage of the planning of current land consolidation area. Future research can be implemented to the later period of consolidation measures and arrangement mode of exploring, at the same time the research on policy and law needs to be further implemented.Keywords：research progress;rural residential land consolidation;CiteSpace;knowledge map4|9|8<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to clarify whether the results of the empirical literature on “the factors influencing the farmers' willingness to abdicate the land contract right” are affected by the characteristics of specific studies, major empirical literature were selected for meta-regression analysis. The results show that: 1)Differences in perspectives of “the research object” “the research area”, “effective samples”, “number of independent variable” and “regression method” are the most important factors affecting the divergence of research conclusions. 2)By means of the funnel plot asymmetry analysis, it is discovered that there are some publication bias existed in the sample literature, which mainly concentrated on “gender”, “the percentage of non-agricultural income” and “urban real estate”. It is suggested that the research method and theoretical model should be more carefully selected in the follow-up studies in order to obtain more scientific and practical policy recommendations.Keywords：land contract right abdication;willingness;influence factors;meta-regression analysis1|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to study the relationship between China's financial subsidies for agriculture and grain total factor productivity, this study adopts the traditional DEA-Malmquist index to measure grain total factor productivity, takes structural effects and technological effects as mediation, and uses agricultural technology environment as moderation to explore the influence mechanism of financial subsidies for agriculture on grain total factor productivity. The results show that: The financial subsidies for agriculture can effectively increase the TFP, and the impact on non-major food producing areas is greater than that of major food producing areas. The financial subsidies for agriculture increase the TFP through structural and technological effects. In a better agricultural technology environment, the financial subsidies for agriculture have a significant role in promoting the TFP. In the end, this study puts forward suggestions to promote the TFP, such as improving fiscal subsidy policies for agriculture, making full use of structure and technical effects, and increaseing the optimization of the agricultural technology environment.Keywords：financial subsidies for agriculture;food total factor productivity;agricultural technology environment;structure effect;technical effect3|11|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the impact of labor mobility, service outsourcing and their interactions on grain technical efficiency, a micro survey data of 2 058 farmers in Henan Province is taken as study case. The transcending stochastic frontier production function is used to measure the technical efficiency of wheat growers, the CLAD model is adopted for empirical research. The results show that: 1)The average technical efficiency of the sample farmers is 0. 707, and there is a large heterogeneity and imbalance in technical efficiency among different farmers; 2)Labor mobility has a significant negative impact on technical efficiency. The technical efficiency of food obtained by short-distance labor mobility is greater than that obtained by long-distance labor mobility; 3)Service outsourcing has a significant positive impact on technical efficiency. The technical efficiency obtained by outsourcing all key links of farming and harvesting by farmers is greater than the technical efficiency obtained by outsourcing some key links; 4)Labor mobility and service outsourcing have an interdependent and interactive link relationship and Labor mobility is conducive to promoting the degree of service outsourcing. Service outsourcing can in turn stimulate labor mobility and restrain the loss of food technology efficiency caused by labor mobility. In view of this, policy recommendations such as developing local industries, increasing nearby employment opportunities, increasing the degree of outsourcing of key links, and land transfer are put forward.Keywords：labor mobility;service outsourcing;food technology efficiency;stochastic frontier production function;CLAD2|10|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To study the impact of mechanization on the efficiency of fertilizer input, China's wheat production from 1998 to 2017 was taken as study object. The impact of agricultural mechanization on fertilizer input efficiency and the resulting fertilizer reduction effects are empirically analyzed by using panel data fixed-effect SFA models and counterfactual measurement methods. The results show that mechanization has a significant positive impact on the efficiency of fertilizer input for wheat production. During 1998-2017, China's wheat production and fertilizer input efficiency shows an overall upward trend, with an average level of 0. 73, of which mechanization increased the average fertilizer input efficiency by approximately 0. 03. The average fertilizer reduction effect of wheat production mechanization is about 4. 31 kg/hm2, and there are significant differences between regions, showing the spatial pattern of low in the east and high in the west. Based on the analysis conclusions, three policy recommendations are put forward to further promoting the development of agricultural mechanization.Keywords：agricultural mechanization;chemical fertilizer input efficiency;fixed effect SFA model;counterfactual analysis1|9|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
