Pattern Change and Regional Disparity Tendency of Cultivated Land Use in Jiangsu Province

The study has examined the tempo-spatial patterns of cultivated land use change in Jiangsu province. A principal component analysis （PCA） of 18 selected indicators of cultivated land use during the period 1970-2010 identified 2 main pat- terns of change in planting productivity and economic efficiency. A major shift from production-centered pattern to profit-oriented one occurred in 1984, the time of grain yield surplus and the mitigation of population pressure. In response to the impending Opened Market System, there was a notable tendency of higher efficiency and less productivity since 1997, as well as remarkable regional disparity of cultivated land use change spatially. It revealed a relative decrease in grain cropping share, crop- ping scale and cultivation intensity in South Jiangsu, especially in Tai-Lake region, and the reverse in North Jiangsu. Some suggestions for the future were finally dis- cussed from the above findings.     

Spatial and Temporal Variation in Water Productivity and Grain Water Utilization Assessment of Heilongjiang Province,Northeast China

Improving crop water productivity is necessary for ensuring food security. To quantify the water utilization in grain production from multiple perspectives, gross inflow water productivity (WPg), generalized agricultural water productivity (WPa), evapotranspiration water productivity (WPET) and irrigation water productivity (WPI) were examined in this study. This paper calculated and analyzed the temporal and spatial variation in these water productivity (WP)indices in the irrigated land of Heilongjiang Province.The results showed that almost all of the municipal WP indices increased from 2007 to 2015.The four indices showed large differences in scientific connotation and numerical performance, and their degrees of spatial variation were ranked as WPI>WPa>WPg>WPET.The spatial patterns of WP indices in different years were similar;the central and southern regions on the Songnen Plain and the eastern region had high WP values,while those of the northern region were low.Each WP index was used to evaluate the relationship between the input of water resources and the output of grain between different regions. Most cities had the potential to improve WP by reducing the input of irrigation water.Furthermore,the results provided recommendations to decision makers to plan for efficient use of water resources in different cities.     

Monitoring the Sequential Cropping Index of Arable Land in Zhejiang Province of China Using MODIS-NDVI

The sequential cropping index of arable land is important agricultural information. The aim of this article is to monitor and analyze the parameter, and offer reference for agricultural production. The cropping index of arable land in Zhejiang Province, China from 2001 to 2004 was calculated using the second order difference based MODIS （moderate resolution imagine spectroradimeter） vegetation data from NASA （National Aeronautic and Space Administration） in America and the land use map with a scale of 1：25 000. It was found that the peak of the time series of the NDVI curve indicated that the ground biomass of crops reached the maximum, and fluctuated with the crops growing processes such as sowing, seeding, heading, ripeness, and harvesting within one year. Thus, the sequential cropping index was defined as the number of peaks of the time series of the NDVI curve. The sequential cropping index of all cities in Zhejiang Province, China was worked out. It is seen from the spatial distribution that the cropping index in the southwest Zhejiang Province is larger than that in the northeast. As for the temporal distribution, the sequential cropping index decreased from 2001 to 2003, whereas it increased slightly from 2003 to 2004. However, the index of arable land was relatively low, as far as the geographic position and climatic resource were concerned, and the potential of the sequential cropping index was great.     

Spatial Exploration of Multiple Cropping Efficiency in China Based on Time Series Remote Sensing Data and Econometric Model

This study explored spatial explicit multiple cropping efficiency(MCE) of China in 2005 by coupling time series remote sensing data with an econometric model-stochastic frontier analysis(SFA).We firstly extracted multiple cropping index(MCI) on the basis of the close relationship between crop phenologies and moderate-resolution imaging spectroradiometer(MODIS) enhanced vegetation index(EVI) value.Then,SFA model was employed to calculate MCE,by considering several indicators of meteorological conditions as inputs of multiple cropping systems and the extracted MCI was the output.The result showed that 46% of the cultivated land in China in 2005 was multiple cropped,including 39% doublecropped land and 7% triple-cropped land.Most of the multiple cropped land was distributed in the south of Great Wall.The total efficiency of multiple cropping in China was 87.61% in 2005.Southwestern China,Ganxin Region,the middle and lower reaches of Yangtze River and Huanghuaihai Plain were the four agricultural zones with the largest rooms for increasing MCI and improving MCE.Fragmental terrain,soil salinization,deficiency of water resources,and loss of labor force were the obstacles for MCE promotion in different zones.The method proposed in this paper is theoretically reliable for MCE extraction,whereas further studies are need to be done to investigate the most proper indicators of meteorological conditions as the inputs of multiple cropping systems.     

Effects of Mg on C and N Metabolism of Soybean at Different Nitrogen Supplying Levels

A pot experiment was conducted to study the effects of magnesium on carbon and nitrogen metabolism of soybean at different nitrogen supplying levels. The results showed that the effects of magnesium at low nitrogen rate on N content, soluble protein, soluble sugar contents were not alike at different growth stage, although nodule dry weights raised, the yield and protein content of seeds decreased, however, the oil content was improved. The application of magnesium at medium and high nitrogen supplying levels promoted the uptake of N effectively, increased the soluble protein and soluble sugar contents, but the nodule dry weights of application magnesium at medium nitrogen supplying level decreased and the yield increased only a little despite the improved quality. Application of magnesium at high nitrogen supplying level raised nodule dry weights and soybean yield significantly, the quality of seeds was also improved.     

Effects of Quercetin on Performance and Lipid Metabolism in Laying Hens

Quercetin has a variety of biological activities. However, its application as a feed additive in poultry production is limited. In this study, the effects of quercetin on performance and lipid metabolism in Hessian laying hens were investigated and the possibility of quercetin to decrease cholesterol in eggs and Low Density Lipoprotein cholesterol(LDL-cholesterol) in laying hens were explored. A total of 240 laying hens at 29-week-old were randomly assigned to four treatments, with six replicates of 10 birds per replicate. The treatments were fed with basal diet supplemented with 0, 0.2, 0.4 and 0.6 g · kg~(-1) quercetin for 8 weeks. Layer performance, lipid concentration in livers, yolks and serum were measured at the end of the experiment. The results showed that laying rate had a quadratic correlation with the level of quercetin(p=0.056) and was maximized by the supplement level of 0.2 g · kg~(-1) diet. When the level of dietary quercetin increased, feed-egg ratio decreased. Crude fat and the total cholesterol of livers decreased by supplementation of quercetin. The total cholesterols of yolks also decreased and had a quadratic correlation with the levels of quercetin(p=0.019). Insulin increased by supplement of quercetin. In conclusion, quercetin improved the performance and reduced egg yolk cholesterol by affecting serum hormone levels.     

Growth and physiological responses of four kiwifruit genotypes to salt stress and resistance evaluation

In this study,four genotypes(Acva-1,Acva-2,Acva-3 and ZM-2) of Actinidia germplasm resources were grown in different NaCl concentrations(0,0.4,0.8 and 1.2 g L–1).The growth,physiological and biochemical indicators were measured,and a graded scale was developed as the salt damage index(SDI) according to different damage symptoms in leaves.The results showed SDI increased gradually,and average number and length of new shoot decreased significantly.Three antioxidant enzymes(superoxide dismutase,peroxidase and catalase) and two osmotic adjustment substances(soluble sugar and proline) showed different changes in old and new leaves of four genotypes.SPAD values exhibited a decreased trend in the whole except in the new leaves of Acva-2.Malonaldehyde contents increased and root activity decreased with the increasing salt concentrations.Principal component analysis was used to assess the salt tolerance,and the results showed Acva-3,from Actinidia valvata Dunn.,had the strongest tolerance to salt,and could be a potential resistant resource to the salt-tolerance dedicated rootstock breeding of kiwifruit.     

寒地早粳花培培养基中铁的效应(英文)

In this study, through vitro culturing anthers of 7 F1 progenies of early Japonica rice in cold region on medium with different Fe2+ contents, it was found that Fe2+ content generated greater impacts on the induction rate and green plantlet differentiation. The result demonstrated that if Fe2+ increased from 32 to 40 mg/kg, the induction rate of early Japonica rice anther culture in N6 culture media was more then 1.4 times higher than that in N6 culture media containing 5.6 mg/kg Fe2+. In this concentration range, the induction rate increased with the increase of Fe2+ content, while if the concentration was over this concentration range, the induction rate decreased with the increase of Fe2+, showing single peak distribution. When the Fe2+ was 40 mg/kg in differentiation medium, the differentiation rate decreased dramatically. The green plantlet differentiations of callus which were induced on culture media containing 32-40 mg/kg Fe2+ were different, when they were cultured on MS culture media, and 85.7% materials could increase green plantlet productivity to about 7.8%. Therefore, increasing Fe2+in induction media properly could increase anther culture efficiency of early Japonica rice in cold region.     

Delineating the rice crop activities in Northeast China through regional parametric synthesis using satellite remote sensing time-series data from 2000 to 2015

Accurate rice area extraction and yield simulations are important for understanding how national agricultural policies and environmental issues affect regional spatial changes in rice farming. In this study, an improved regional parametric syntheses approach, that is, the rice zoning adaptability criteria and dynamic harvest index(RZAC-DHI), was established, which can effectively simulate the rice cultivation area and yield at the municipal level. The RZAC was used to extract the rice area using Moderate Resolution Imaging Spectroradiometer time-series data and phenological information. The DHI was calculated independently, and then yield was obtained based on the DHI and net primary productivity(NPP). Based on the above results, we analyzed the spatial–temporal patterns of the rice cultivation area and yield in Northeast China(NEC) during 2000–2015. The results revealed that the methods established in this study can effectively support the yearly mapping of the rice area and yield in NEC, the average precisions of which exceed 90 and 80%, respectively. The rice planting areas are mainly located on the Sanjiang, Songnen and Liaohe plains, China, which are distributed along the Songhua and Liaohe rivers. The rice cultivation area and yield in this region increased significantly from 2000 to 2015, with increases of nearly 58 and 90%, respectively. The rice crop area and yield increased the fastest in Heilongjiang Province, China, whereas small changes occurred in Jilin and Liaoning provinces, China. Their gravity centers exhibited evident northward and eastward shifts, with offset distances of 107 and 358 km, respectively. Moreover, Heilongjiang Province has gradually become the new main rice production region. The methodologies used in this study provide a valuable reference for other related studies, and the spatial-temporal variation characteristics of the rice activities have raised new attention as to how these shifts affect national food security and resource allocation.     

Phosphorus Status and Risk of Phosphate Leaching Loss From Vegetable Soils of Different Planting Years in Suburbs of Changsha,China

The aim of the study was to develop an index to assess the environmental risk of P loss potential in vegetable soils with chronic difference of plantation in the suburbs of Changsha, Hunan Province, China. Chemical methodology was used to study soil phosphorus status and the relationships between available P in soil and potential soil leaching P. The results showed that there was a significant linear relationship between Olsen P and CaC12-P or P concentration in soil solution. Olsen P increased sharply when either CaCI2-P or P concentration in soil solution reached a certain level. It was confirmed that 80 mg kg-t of Olsen P was the critical value of soil P leaching in the vegetable soils. P leaching probability over the critical was assessed by GIS and indicator Kriging and four secondary risks of phosphorus leaching loss were defined. In the area with vegetable cropping for over 30 yr （Chenjiadu） and 10-15 planting years （Huangxingzhen）, the indices of phosphorus leaching loss risk were 3 and 2.93, respectively. These two areas belonged to strong secondary of risk of phosphate leaching loss. In the new vegetable planting field less than 2 yr （Ningxiang）, the index was 0.06, which had almost no risk of phosphorus leaching. In vegetable soils in the suburban region of Changsha, the phosphorus leaching peotential is high and the phosphorus leaching loss is related to chronic length of vegetable cropping.     

Effects of land use change on the spatiotemporal variability of soil organic carbon in an urban-rural ecotone of Beijing,China

Understanding the effects of land use changes on the spatiotemporal variation of soil organic carbon（SOC）can provide guidance for low carbon and sustainable agriculture.In this paper,based on the large-scale datasets of soil surveys in 1982 and 2009 for Pinggu District—an urban-rural ecotone of Beijing,China,the effects of land use and land use changes on both temporal variation and spatial variation of SOC were analyzed.Results showed that from 1982 to 2009in Pinggu District,the following land use change mainly occurred:Grain cropland converted to orchard or vegetable land,and grassland converted to forestland.The SOC content decreased in region where the land use type changed to grain cropland(e.g.,vegetable land to grain cropland decreased by 0.7 g kg^-1;orchard to grain cropland decreased by 0.2 g kg^-1).In contrast,the SOC content increased in region where the land use type changed to either orchard（excluding forestland）or forestland(e.g.,grain cropland to orchard and forestland increased by 2.7 and 2.4 g kg^-1,respectively;grassland to orchard and forestland increased by 4.8 and 4.9 g kg^-1,respectively).The organic carbon accumulation capacity per unit mass of the soil increased in the following order:grain cropland soikvegetable land/grassland soikorchard soikforestland soil.Therefore,to both secure supply of agricultural products and develop low carbon agriculture in a modern city,orchard has proven to be a good choice for land using.     

Preliminary Research on Regional Material Flow Analysis： A Case Study of Chengyang District in Qingdao

The method ＂Material Flow Analysis （MFA）＂ is one of the effective tools to study law and quantification of material flow between economic system and ecological system. On the national level, economy-wide material flow analysis has been published for a number of countries. However, published studies on the regional or local level are still very limited and a standardized method does not exist yet. On the basis of framework of Material Flow Analysis proposed by Eurostat, the paper collected related data and analyzed material input and output for the Chengyang district in Qingdao. The results showed that DMI （Direct Material Input） and TMR （Total Material Requirement） in absolute number increased about 3.6 and 3.9 times, respectively from 1995 to 2004. Fossil fuel and mineral contributed to about 50.3%-76.3% of DMI. Imports of material increased about 5.0 times and became the most important Contributor to DMI, which showed that local economic growth was highly dependent on resources from other regions and countries. DPO （Domestic Processed Output） and TDO （Total Domestic Output） represent slow increasing trend, and DPO contributed to 22.2%-58.1% of TDO, suggesting local hidden flows were of obvious effect on TDO. The biggest component of DPO is CO2, approximately accounting for 90% of DPO. The material productivity increased 57.7% in last decade, reflecting improvement of efficiency of resources utilization in some extent. However, compared to developed countries and regions, material productivity of Chengyang district was relatively low. Therefore, in order to promote the sustainability, it is essential to develop circular economy and enhance materials productivity.     

Effects of land use change on the spatiotemporal variability of soil organic carbon in an urban-rural ecotone of Beijing,China

Understanding the effects of land use changes on the spatiotemporal variation of soil organic carbon(SOC)can provide guidance for low carbon and sustainable agriculture.In this paper,based on the large-scale datasets of soil surveys in 1982 and 2009 for Pinggu District—an urban-rural ecotone of Beijing,China,the effects of land use and land use changes on both temporal variation and spatial variation of SOC were analyzed.Results showed that from 1982 to 2009in Pinggu District,the following land use change mainly occurred:Grain cropland converted to orchard or vegetable land,and grassland converted to forestland.The SOC content decreased in region where the land use type changed to grain cropland(e.g.,vegetable land to grain cropland decreased by 0.7 g kg~(-1);orchard to grain cropland decreased by 0.2 g kg~(-1)).In contrast,the SOC content increased in region where the land use type changed to either orchard(excluding forestland)or forestland(e.g.,grain cropland to orchard and forestland increased by 2.7 and 2.4 g kg~(-1),respectively;grassland to orchard and forestland increased by 4.8 and 4.9 g kg~(-1),respectively).The organic carbon accumulation capacity per unit mass of the soil increased in the following order:grain cropland soikvegetable land/grassland soikorchard soikforestland soil.Therefore,to both secure supply of agricultural products and develop low carbon agriculture in a modern city,orchard has proven to be a good choice for land using.     

Changes in Soil Properties Under the Influences of Cropping and Drip Irrigation During the Reclamation of Severe Salt-Affected Soils

Reclamation of salt-affected land plays an important role in mitigating the pressure of agricultural land due to competition with industry and construction in China. Drip irrigation was found to be an effective method to reclaim salt-affected land. In order to improve the effect of reclamation and sustainability of salt-affected land production, a field experiment （with reclaimed 1-3 yr fields） was carried out to investigate changes in soil physical, chemical, and biological properties during the process of reclamation with cropping maize and drip irrigation. Results showed that soil bulk density in 0-20 cm soil layer decreased from 1.71 g·cm-3 in unreclaimed land to 1.44 g ·cm^-3 in reclaimed 3 yr fields, and saturated soil water content of 0-10 cm layer increased correspondingly from 20.3 to 30.2%. Both soil salinity and pH value in 0-40 cm soil layer dropped markedly after reclaiming 3 yr. Soil organic matter content reduced, while total nitrogen, total phosphorus, and total potassium all tended to increase after cropping and drip irrigation. The quantities of bacteria, actinomycete, and fungi in 0-40 cm soil layer all greatly increased with increase of reclaimed years, and they tended to distribute homogeneously in 0-40 cm soil profile. The urease activity and alkaline phosphatase activity in 0-40 cm soil layers were also enhanced, but the sucrase activity was not greatly changed. These results indicated that after crop cultivation and drip irrigation, soil physical environment and nutrients status were both improved. This was benefit for microorganism＇s activity and plant＇s growth.     

The Ecological Effects of Young Elm Trees Belt-Pumpkin Strip Intercropping System at the Agro-Pastoral Ecotone in Northern China

Young elm trees belt-pumpkin strip intercropping was studied to solve the actual problem of resource losses in the large barren area resulted from reconverting cultivated land into forest in the agro-pastoral ecotone in northern China. The final objective was to realize effective utilization of the barren land with both ecological improvement and economic development. Field experiments were conducted together with laboratory analysis. The results indicated that the soil moisture level was remarkably increased in young elm trees belt-pumpkin strip intereropping because the pumpkin vines covered the gap between pumpkin planting-furrow and elm trees belt. The water use efficiency of the intercropping system was increased by 23.7-163.3% as compared with the single cropping. Elm trees belt-pumpkin strip intercropping changed the sequential succession trend of the grasses growing in the gap of the pumpkin planting-furrow. The annual grasses become the dominant vegetation. The nutritive value as fodder and yield of the annual grasses were also increased remarkably. The biomass of pumpkin, elm trees and grasses under intercropping increased by 24.4, 28.4 and 144.4%, respectively, as compared with those under single cropping. The land use efficiency was increased by 132%. It was also indicated that the soil erosion from the intercropping land was not increased due to pumpkin plantation. The differences in the soil erosion among intercropped area, elm trees belt and pumpkin strip with single cropping were not remarkable. Therefore, it was concluded that young elm trees belt-pumpkin strip intercropping is an effective way to utilize the barren land between the young elm trees belt and realize synergistic enhancement of ecological benefit and economic profit.     

Analysis on Technical Efficiency of Rice Farms and Its Influencing Factors in South-western of Niger

The present study focused on analyzing the technical efficiency of rice farms in southwest of Niger. The data from January to March 2015 survey of 148 ms in three districts of south-western of Niger were analyzed by using DEA-Tobit two-step method. In the first step, data envelopment analysis (DEA) was applied to estimate technical, pure technical and scale efficiency. In the second step, Tobit regression was used to identify factors affecting technical efficiency. The results showed that rice producers in southwest of Niger could reduce their inputs by 52% and still produce the same level of rice output. The Tobit regression showed that factors, such as farm size, experience in rice farming, membership of cooperative, main occupation and land ownership had a direct impact on technical efficiency.     

Application of Chinese milk vetch affects rice yield and soil productivity in a subtropical double-rice cropping system

Green manure can be used as a substitute for chemical fertilizer without reducing rice yield. We studied the responses of soil fertility and rice yield to different combinations of Chinese milk vetch(CMV; Astragalus sinicus L.) and chemical fertilizer in a subtropical double-rice cropping system. Our goal is to reduce chemical fertilizer use and decrease environmental contamination. Compared with the recommended rate of chemical fertilizer(CF), both early-and late-rice yields in the two treatments supplied with 15 and 22.5 Mg CMV ha–1 plus 60% CF(represented as 60 A and 60 B, respectively) showed no significant differences while the two treatments supplied with 30 and 37.5 Mg CMV ha–1 plus 60% CF(represented as 60 C and 60 D, respectively) showed significantly higher values. The sustainable yield index(SYI) values in the 60 C and 60 D treatments with double-rice croppong system were significantly higher than those in other treatments(P0.05). Early-rice yield showed a significant positive relationship with the Chinese milk vetch incorporation rate. The coefficients increased annually from 2009 to 2013 and then decreased in 2014. Soil organic matter increased over time by the end of the experiment in all of the treatment groups. Soil organic matter in 60 A, 60 B and 60 C showed no significant difference compared with that in CF, while soil organic matter in 60 D was significantly higher than that in CF. The slopes of soil organic matter and total nitrogen over six years were the highest in 60 C and 60 D. The soil total nitrogen content in 60 A, 60 B, 60 C and 60 D was higher than that in CF, but the differences were not significant(P0.05). Therefore, a relatively high Chinese milk vetch incorporation rate(≥30 Mg ha–1) was more effective in improving the productivity and sustainability of paddy soil. The decreased coefficients of early-rice yield and the Chinese milk vetch incorporation rate in 2014 implied that the benefits of soil fertility and rice yield created by Chinese milk vetch input may decline after five years under a continuously high rate of Chinese milk vetch incorporation.     

Effects of deep vertical rotary tillage on the grain yield and resource use efficiency of winter wheat in the Huang-Huai-Hai Plain of China

Tillage represents an important practice that is used to dynamically regulate soil properties,and affects the grain production process and resource use efficiency of crops.The objectives of this 3-year field study carried out in the Huang-Huai-Hai(HHH) Plain of China were to compare the effects of a new deep vertical rotary tillage (DVRT) with the conventional shallow rotary tillage (CT) on soil properties,winter wheat (Triticum aestivum L.) grain yield and water and nitrogen use efficiency at different productivity levels,and to identify a comprehensive management that optimizes both grain yield and resource use efficiency in the HHH Plain.A split-plot design was adopted in field experiments in the winter wheat growing seasons of 2016–2017 (S1),2017–2018 (S2) and 2018–2019 (S3),with DVRT (conducted once in June 2016) and CT performed in the main plots.Subplots were treated with one of four targeted productivity level treatments (SH,the super high productivity level;HH,the high productivity and high efficiency productivity level;FP,the farmer productivity level;ISP,the inherent soil productivity level).The results showed that the soil bulk density was reduced and the soil water content at the anthesis stage was increased in all three years,which were due to the significant effects of DVRT.Compared with CT,grain yields,partial factor productivity of nitrogen (PFP_N),and water use efficiency (WUE) under DVRT were increased by 22.0,14.5 and 19.0%.Path analysis and direct correlation decomposition uncovered that grain yield variation of winter wheat was mostly contributed by the spike numbers per area under different tillage modes.General line model analysis revealed that tillage mode played a significant role on grain yield,PFP_N and WUE not only as a single factor,but also along with other factors(year and productivity level) in interaction manners.In addition,PFP_N and WUE were the highest in HH under DVRT in all three growth seasons.These results provided a theoretical basis and technical support for coordinating the high yield with high resource use efficiency of winter wheat in the resource-restricted region in the HHH Plain of China.     

Combined effect of shading time and nitrogen level on grain filling and grain quality in japonica super rice

There is limited information about the combined effect of shading time and nitrogen(N) on grain filling and quality of rice. Therefore, two japonica super rice cultivars, Nanjing 44 and Ningjing 3, were used to study the effect of shading time and N level on the characteristics of rice panicle and grain filling as well as the corresponding yield and quality. At a low N level(150 kg N ha~(–1), 150 N), grain yield decreased(by 21.07–26.07%) under the treatment of 20 days of shading before heading(BH) compared with the no shading(NS) treatment. These decreases occurred because of shortened panicle length, decreased number of primary and secondary branches, as well as the grain number and weight per panicle. At 150 N, in the treatment of 20 days of shading after heading(AH), grain yield also decreased(by 9.46–10.60%) due to the lower grain weight per panicle. The interaction of shading and N level had a significant effect on the number of primary and secondary branches. A high level of N(300 kg N ha~(–1), 300 N) could offset the negative effect of shading on the number of secondary branches and grain weight per panicle, and consequently increased the grain yield in both shading treatments. In superior grains, compared with 150 N NS, the time to reach 99% of the grain weight(T_(99)) was shortened by 1.6 to 1.7 days, and the grain weight was decreased by 4.18–5.91% in 150 N BH. In 150 N AH, the grain weight was 13.39–13.92% lower than that in 150 N NS due to the slow mean and the maximum grain-filling rate(GR_(mean )and GR_(max)). In inferior grains, grain weight and GR_(mean) had a tendency of 150 N NS150 N BH150 N AH. Under shaded conditions, 300 N decreased the grain weight due to lower GR_(mean) both in superior and inferior grains. Compared with 150 N NS, the milling and appearance qualities as well as eating and cooking quality were all decreased in 150 N BH and 150 N AH. Shading with the high level of 300 N improved the milling quality and decreased the number of chalky rice kernels, but the eating and cooking quality was reduced with increased chalky area and overall chalkiness. Therefore, in the case of short term shading, appropriate N fertilizer could be used to improve the yield and milling quality of rice, but limited application of N fertilizer is recommended to achieve good eating and cooking quality of rice.     

Evolution of varieties and development of production technology in Egypt wheat: A review

Wheat was the first crop grown in Egypt, and it remains highly important. Egypt is the largest wheat importer in the world and consumes an extensive amount of bread. It is imperative for wheat scientists to decrease the large gap between production and consumption. Wheat yields in Egypt increased 5.8-fold(6.7 billion kg) between 1961 and 2017 due to variety improvement and the use of better planting methods such as the raised bed method, ideal sowing date, surge flow irrigation and farm irrigation systems, laser levelling, fertilizers, and intercropping with raised beds. In this paper, the development of wheat production techniques and variety evolution over more than five decades in Egypt have been analyzed. In particular, we have focused on the technologies, cultural practices and causes for per unit area yield increase. The main purpose was to study the issues that have arisen during wheat production and to make recommendations for smart agricultural practices. In 1981, the yield was 3 300 kg ha–1 and through the improvement of varieties, expansion of agricultural land and the adoption of modern agricultural techniques yield reached 6 500 kg ha–1 by 2017. The production growth rate was 4.1% annually, and the total grain yield increased 4.3-fold, from 1.9 billion kg in 1981 to about 8.1 billion kg in 2017. The use of new improved varieties, new cultivation techniques, and modern irrigation techniques contributed to 97.0% of the increase in yield per unit area and 1.5% of the increase in yield was due to planting area expansion. Therefore, the increase in total yield mainly depended on the increase in yield per unit area. Wheat production in Egypt has been improved through the development of breeding and cultivation techniques. The use of these new techniques, the popularization of new high-quality seed varieties, and the use of the raised bed method instead of the old method of planting in basins have made the largest contributions to increased yield. In the future, wheat yield could be further increased by using the tridimensional uniform sowing mode and the development of wheat varieties that are resistant to rusts, deficit irrigation, and abiotic stress, that are highly adaptable to mechanized operation and have high yields. Based on our analysis, we propose the main technical requirements and measures to increase wheat yield in Egypt in the near future.