Yield gap and resource utilization efficiency of three major food crops in the world——A review

Yield gap analysis could provide management suggestions to increase crop yields,while the understandings of resource utilization efficiency could help judge the rationality of the management.Based on more than 110 published papers and data from Food and Agriculture Organization (FAO,www.fao.org/faostat) and the Global Yield Gap and Water Productivity Atlas (www.yieldgap.org),this study summarized the concept,quantitative method of yield gap,yield-limiting factors,and resource utilization efficiency of the three major food crops (wheat,maize and rice).Currently,global potential yields of wheat,maize and rice were 7.7,10.4 and 8.5 t ha^(–1),respectively.However,actual yields of wheat,maize and rice were just 4.1,5.5 and 4.0 t ha^(–1),respectively.Climate,nutrients,moisture,crop varieties,planting dates,and socioeconomic conditions are the most mentioned yield-limiting factors.In terms of resource utilization,nitrogen utilization,water utilization,and radiation utilization efficiencies are still not optimal,and this review has summarized the main improvement measures.The current research focuses on quantitative potential yield and yield gap,with a rough explanation of yield-limiting factors.Subsequent research should use remote sensing data to improve the accuracy of the regional scale and use machine learning to quantify the role of yield-limiting factors in yield gaps and the impact of change crop management on resource utilization efficiency,so as to propose reasonable and effective measures to close yield gaps.

Rules of Pesticide Use for Food Crop Diseases and Pests: A Concise Diagram Based on Correspondence Analysis

In order to ensure food security, the selection of pesticide must take into account the controlling effect and economy in the chemical control of food crop diseases and pests. Although China has registered a large number of pesticides and fungicides on food crops, traditional statistical methods cannot treat the complex relationships between crops, pests and diseases, as well as pesticides. To this end, the correspondence analysis was used to mine the data of pesticides being registered after January 1, 2010 for the prevention and control of pests and diseases on wheat, corn, and rice in China, in order to reveal the general rules of pesticide use for the prevention and control of grain crop pests and diseases and to provide scientifically recommended pesticide regimens.(1) Recommended pesticides for wheat diseases and pests: For underground pest control, phoxim, diazinon or clothianidin is recommended;imidacloprid is recommended for aphid control;avermectin is recommended for mite control;chlorpyrifos is recommended for midge control;the pesticides for rust control could be selected according to the order of epoxiconazole>flutriafol>kresoxim-methyl>cyproconazole≈hexaconazole;tebuconazole is recommended for the prevention and control of smut;difenoconazole is recommended for the simultaneous occurrence of take-all, smut and sheath blight;it is recommended to use carbendazim or thiophanate-methyl for the control of scab;and triazolone or pyraclostrobin is recommended for the control of powdery mildew.(2) Recommended pesticides for corn diseases and pests: For the control of underground pests, fipronil, carbosulfan or chlorpyrifos are recommended;thiamethoxam is recommended for control of planthoppers and corn aphids;Bacillus thuringiensis or phoxim is recommended for control of corn borers;pyraclostrobin is recommended for the control of northern leaf blight;tebuconazole is recommended for the control of head smut;and fludioxonil+metalaxyl-M is recommended for the control of corn stalk rot.(3) Recommended pesticides for rice diseases and pests: It is recommended to use triazophos, avermectin analogs or methoxyfenozide for the control of borers;for rice planthoppers, the pesticides could be selected in order of pymetrozine>imidacloprid>thiamethoxam>thiazide>nitenpyram;avermectin analogs are recommended for the control of rice leaf rollers;tebuconazole is recommended for the control of rice false smut;prochloraz and its manganese salts are recommended for the control of bakanae disease;hymexazol is recommended for the control of wilt disease;thifluzamide or hexaconazole is recommended for the control of sheath blight;and the pesticides for the control of rice blast are in order of tricyclazole>kasugamycin>fenoxanil>isoprothiolane>Bacillus subtilis. In addition, potential applications of correspondence analysis in other fields of plant protection are discussed.

Macro-nutrients in edible parts of food crops in the region of Moanda,Gabon

The assessment of nutritive foodstuffs quality is an important step in the estimation of dietary intake of metals. This study aimed to assess accumulation and the daily intake of macro-elements magnesium, calcium, potassium and sodium in edible parts of plants grown in Moanda area. The ranges of concentrations were 246 - 5645 mg/kg, 1167 - 35105 mg/kg, 158 - 12563 mg/kg and 88 - 795 mg/kg for Mg, Ca, K and Na, respectively. Mg and K levels were significantly higher in fruits than in tubers. The trend of accumulation in the edible parts of plants was generally: Ca > K > Mg > Na. The daily intakes of Mg and Ca were the highest and indicated food crops in Moanda had a good nutritive quality.

Risk Assessment of Heavy Metals in Food Crops at Abandoned Lead-Zinc Mining Site at Tse-Faga, Logo, Lga, Benue State, Nigeria

Hundreds of children died in 2010 due to suspected lead poisoning from mining sources in Zamfara State among epidemiological concerns. Evaluating ecological and human health risks of heavy metals levels in sampled food crops harvested near two abandoned Lead-Zinc mining sites at Logo Benue State is crucial. Abelmoschus esculentus, Carica papaya, Manihot esculenta, and Zea mays were sampled, prepared, and analyzed for four heavy metals using the Atomic Absorption Spectrophotometric method. The mean data from the analysis of variance was subjected to ecological and health risk models. Pb means value ranged from Carica papaya Peel 0.46 ± 0.011 mg/kg to 1.30 ± 0.01 mg/kg in Zea mays seed. Zn was highest in Carica papaya flesh 0.50 ± 0.01 mg/kg, and lowest in Manihot esculenta peels and its flesh 0.12 ± 0.000 mg/kg. Hg and Cd were below detectable levels. Zea mays seeds (1.001) had the highest Pd bioaccumulation factor. BAF of zinc and ecological indices were <1. Daily Intake of Metals were all <1, however, Hazard Quotient (HQ) of Pb was ≥1 in Manihot esculenta flesh 1.143 and Zea mays at 1714. Cancer Risks were within permissible range (10-4 - 10-6). Health Risk result indicates communities around the mining area may be at risk of lead poisoning therefore due to high contamination of samples, routine checks on heavy metals especially lead is recommended to prevent excessive bioaccumulation in the body.

Adaptation Strategies to Mitigate Impact of Climate Change on Food Crops Farming in Oyo State,Nigeria

The research investigated the adaptation strategies to mitigate consequence of climate change on food crops farming in Oyo State.120 respondents were selected for this study using multi-stage sampling procedures.Primary data was collected through interview schedule and analyzed using both descriptive and inferential statistics.Available results indicated that 84.2% of the respondents were male,93.3% of them were married and maize(45.8%),cassava(37.5%)are the mainly crops cultivated.Results also revealed that 70.0% of the respondents have knowledge of climate change with majority(84.17%)of them regularly accessed information on climate change through radio and 88.3%of them claimed to adopt planting crops favorable for the present weather condition as an adaptation techniques to mitigate the consequences of climate change more frequently.Chi-square and Correlation results revealed a significant relationship existed between farmers educational levels(X2=4.861;p=0.003);household size(r=-0.089;p=0.002);knowledge(r=-0.157;p=0.002),and adaptation strategies to reduce the consequences of climate change on the food crops farming.It was recommended that food crop farmers should be provided with better education and sensitized in order for them to be acquainted with adaptation techniques and coping mechanisms that are currently been offered by research.

Review:Assessing potential dietary toxicity of heavy metals in selected vegetables and food crops

Heavy metals, such as cadmium, copper, lead, chromium and mercury, are important environmental pollutants, particularly in areas with high anthropogenic pressure. Their presence in the atmosphere, soil and water, even in traces can cause serious problems to all organisms, and heavy metal bioaccumulation in the food chain especially can be highly dangerous to human health. Heavy metals enter the human body mainly through two routes namely: inhalation and ingestion, ingestion being the main route of exposure to these elements in human population. Heavy metals intake by human populations through food chain has been reported in many countries. Soil threshold for heavy metal toxicity is an important factor affecting soil environmental capacity of heavy metal and determines heavy metal cumulative loading limits. For soil-plant system, heavy metal toxicity threshold is the highest permissible content in the soil (total or bioavailable concentration) that does not pose any phytotoxic effects or heavy metals in the edible parts of the crops does not exceed food hygiene standards. Factors affecting the thresholds of dietary toxicity of heavy metal in soil-crop system include: soil type which includes soil pH, organic matter content, clay mineral and other soil chemical and biochemical properties; and crop species or cultivars regulated by genetic basis for heavy metal transport and accumulation in plants. In addition, the interactions of soil-plant root-microbes play important roles in regulating heavy metal movement from soil to the edible parts of crops. Agronomic practices such as fertilizer and water managements as well as crop rotation system can affect bioavailability and crop accumulation of heavy metals, thus influencing the thresholds for assessing dietary toxicity of heavy metals in the food chain. This paper reviews the phytotoxic effects and bioaccumulation of heavy metals in vegetables and food crops and assesses soil heavy metal thresholds for potential dietary toxicity.

Heavy Metal Contaminated Food Crops Irrigated with Wastewater in Peri Urban Areas, Zambia

Studies on peri urban farming in Zambia have not adequately tackled the issues pertaining to heavy metal contaminated wastewater irrigation farming. The study investigated heavy metal contamination of water, soils and crops at two peri urban areas in Zambia. Two study sites were New Farm Extension in Mufulira Town in the Copperbelt Province and Chilumba Gardens in Kafue Town in Lusaka Province. The heavy metals investigated were lead, copper, cobalt, nickel and chromium. These heavy metals were found to be higher than acceptable limits in wastewater used to irrigate crops and there are potential human health risks associated with consumption of heavy metal contaminated food crops which have implications on the livelihoods of people. Samples of water, soil and crops were collected and analysed for lead (Pb), copper (Cu), chromium (Cr), cobalt (Co) and nickel (Ni) using the Atomic Absorption Spectrometer (AAS). The data on heavy metals was analysed using mean, standard error and T-test. The results indicated that the levels of heavy metals in wastewater, soil and food crops were above acceptable limits at two study sites. It can be concluded that there was heavy metal contamination of wastewater, soil and food crops at the two peri-urban areas in Zambia. The study highlighted the actual levels of heavy metal contaminant uptake in food crops consumed by the peri urban population. The information from this study can be used by the relevant authorities to develop appropriate measures for monitoring and control of heavy metal contamination in wastewater irrigation farming systems in peri urban areas inZambia.

Elevated CO₂Levels Affect Phytochemicals and Nutritional Quality of Food Crops

Rising atmospheric CO2 levels pose many challenges to global climate, thus to all forms of life including plants. The impact of elevated CO2 on plant growth and development and the nutritional quality in relation to major nutrients in many crops has been explored extensively. However, information on the elevated CO2 effects on the health-promoting phytochemicals in food crops is rather limited. Major nutrients in food crops including protein, phosphorus, potassium, calcium, iron, zinc and other micronutrients in many food crops are known to be suppressed at elevated CO2 levels. Elevated CO2 increases carbohydrate accumulation but decreases nitrogen accumulation in plants thus affecting their C-N ratio. A number of studies show that high C-N ratio and nitrogen limiting conditions in plants can result in the accumulation of carbon-based secondary metabolites, many of which are health-promoting phytochemicals and allelochemicals involved in plants’ defense against pathogens and herbivory. Although the results from these studies are variable, it can be concluded that while elevated CO2 is known to suppress the content of major nutrients, it may actually have a favorable impact on the accumulation of carbon-based phytochemicals in food crops.

Analysis of the Impact of the Growing Area of Food Crops on Farmers' Income in Yunnan Province

As a major agricultural province,Yunnan has always attached great importance to food production,and the proportion of the growing area of food crops to the growing area of total crops is more than one half in Yunnan Province,but the grain production efficiency has been low in recent years.Therefore,under the guidance of stabilizing food production and adjusting structure proposed by Yunnan provincial government,we analyze the impact of the growing area of food crops on farmers' income,based on the recent trends of the growing area of food crops.Finally we put forth the following recommendations:developing the food production based on market; rationally making overall arrangement of planting structure; paying attention to the agricultural science and technology progress.

Use of Random Amplified Polymorphic DNA Analysis for Economically Important Food Crops

The objective of this review is to summarize numerous studies on the use of the random amplified polymorphic DNA （RAPD） technique on rice, corn, wheat, sorghum, barley, rye, and oats to examine its feasibility and validity for assessment of genetic variation, population genetics, mapping, linkage and marker assisted selection, phylogenetic analysis, and the detection of somaclonal variation. Also we discuss the advantages and limitations of RAPD. Molecular markers have entered the scene of genetic improvement in different fields of agricultural research. The simplicity of the RAPD technique made it ideal for genetic mapping, plant and animal breeding programs, and DNA fingerprinting, with particular utility in the field of population genetics.

Aflatoxin contamination in food crops:causes,detection,and management:a review

Mycotoxins are secondary metabolites produced by several fungal species and molds.Under favorable conditions like high temperature and moisture,they contaminate a large number of food commodities and regional crops during pre and post-harvesting.Aflatoxin is the main mycotoxin that harm animal and human health due to its carcinogenic nature.Aflatoxins are mainly released by Aspergillus flavus and Aspergillus parasiticus.AFB1 constitutes the most harmful type of aflatoxins and is a potent hepato-carcinogenic,mutagenic,teratogenic and it suppresses the immune system.To maintain food safety and to prevent aflatoxin contamination in food crops,combined approaches of using resistant varieties along with recommended farming practices should be followed.This review concentrates on various aspects of mycotoxin contamination in crops and recent methods to prevent or minimize the contamination.

An Integrated Framework for Regional Assessment of Water, Energy, and Nutrients from Food Loss of Selected Crops in the Lower Fraser Valley, Canada

Although there is no global shortage of food or water, food security has not been achieved, as human activity has turned these vital resources into “waste”. Wasted food not only loses valuable water resources but embedded calories of human energy and nutrients for healthy human populations. The Food and Agricultural Organization of the United Nations, in addressing these concerns, focuses on a global scale largely on an economic estimate of individual components of energy or water or nutrient loss. It is suggested that more information is required through local or regional assessments to provide better estimates, incorporating regional factors of the losses along the food supply chain. To address this suggestion, this study focused on an intensive agricultural and rapidly urbanizing region of Canada, the Lower Fraser Valley of British Columbia. Seven selected crops, including annual crops such as green peas, sweet corn and potato, and perennial crops that included three berry crops were assessed for their water, both constituent and virtual, as well as embedded energy, protein, and Vitamin C. Annual virtual water losses were higher for sprinkler than drip irrigation, ranging from 82 × 106 kg of water for strawberry to 7570 × 106 kg for blueberry. These high virtual water losses estimated along the food chain confirm the significance of food loss impacts on local water resources. Estimates of losses of food in kg were highest at the consumer level along the food chain and it was estimated that wasted food from the seven crops selected would have supplied the protein and caloric energy of over 33,000 men per year and Vitamin C of about 240,000 men per year. This assessment increases the awareness of food loss impacts from a regional perspective and provides a framework for future research on both environmental and nutritional implications of wasted food.

Balanced nitrogen economy as a flexible strategy on yield stabilizing and quality of aquatic food crops in wetland ecosystem

In wetland ecosystem, nitrogen along with other elements and its management is most imperative for the production of so many aquatic food, non-food and beneficial medicinal plants and for the improvement of soil and water characteristics. With great significant importance of INM (integrated nutrient management) as sources, emphasizing on management on nitrogen as a key element and its divergence, a case study was undertaken on such aquatic food crops (starch and protein-rich, most popular and remunerative) in the farmers' field of low-lying randomized block design, where, three important aquatic food crops (water chestnut (Trapa bispinosa Roxb.), makhana (Eurya/e ferox Salisb.) and water lily (Nymphaea spp.) as major factor and eleven combinations of organic and inorganic sources of nutrients as sub-factor was considered in the experiment. It revealed from the results that the production of fresh kernels or nuts of water chestnut (8.57 t ha-1), matured nut yield of makhana (3.06 t ha-1) and flower stalks of water-lily as vegetables (6.38 t ha-1) including its nutritional quality (starch, protein, sugar and minerals) was remarkably influenced with the application of both organic (neem oilcake @ 0.2 t ha-1) and inorganic sources (NPK @ 30:20:20 kg ha-1 along with spraying of NPK @ 0.5% each over crop canopy at 20 days interval after transplanting) than the other INM combinations applied to the crops. Among the crops, highest WCYE (water chestnut yield equivalence) exhibited in makhana due to its high price of popped-form in the country, which is being exported to other countries at now. Sole application of both (organic and inorganic sources) with lower range did not produce any significant outcome from the study and exhibited lower value for all the crops.Besides production of food crops, INM also greatly influenced the soil and water characterization and it was favourably reflected in this study. The physico-chemical characteristics of soil (textural class, pH, organic carbon, organic matter, ammoniacal nitrogen, nitrate nitrogen, available nitrogen, phosphorus and potassium) are most important and contributed a significant improvement due to cultivation of these aquatic crops. Analysis of such wet bodies represented the water characteristics (pH, BOD, COD, CO3-, HCO3-, NO3-N, SO4-S and Cl-) were most responsive,adaptable and quite favourable for the cultivation of these crops in this vast waste unused wetlands for the mankind without any environmental degradation.

Banana as a Cash Crop and Its Food Security and Socioeconomic Contribution: The Case of Southern Ethiopia, Arba Minch

Food security is a challenge in many developing countries. Nations are still struggling to make use of available resources so as to combat hunger. Drought, land degradation, marketing constraints, improper post-harvest handling and anthropogenic factors are minimizing the production and productivity of agricultural land resources. Making use of improved technologies, adaptable crops and high yielding cash crops, however, are also helping many to cope up with food insecurity. Banana production is significantly contributing for food security as well as livelihood opportunities in Southern Ethiopia. But, technical works on the value chain of the crop are still minimal;it would have resulted a tangible impact on the national income in terms of export earnings and food security too. The Southern Ethiopia, Gamo Gofa Zone is the leading banana producer in the country. This article assesses the potential contribution of banana production to food and income security in the area. The paper also explored the major banana production maximization bottlenecks. 63 farmers of Arba Minch Zuriya District were interviewed to extract primary information. Discussions were held with Government officials. Different reports and related literatures were also reviewed. The result showed that, banana production was having a significant role for the wellbeing of the community explained in terms of food security, income source and serving as source of feed for livestock. Problems associated with marketing and post-harvest handling are also identified being production problems. The fact that, the production of banana is mainly dominated by men has also let the men to sell the crop and have an independent control over the cash. Therefore, community awareness development, improving production systems and developing the culture of saving could help to have a sustained impact of banana production in the region.

Water, Energy and Nutrient Losses from Food Wastage of Selected Crops in Three Agro-Climatic Zones in British Columbia, Canada

Food waste is a growing global concern. Data on the factors and magnitude are largely global estimates, thus local studies aid in providing information on the impacts of food waste. Three important agro-climatic zones in British Columbia and nine common crops, both annual and perennial, were selected to evaluate the environmental and nutritional implications of local food waste. Using Canadian estimates of total food waste, the constituent water, caloric content, protein, vitamin C, phosphorus and potassium wasted by each crop were estimated. Regionally, the total production and losses were the highest in the Lower Fraser Valley which had high production of potatoes and blueberries, followed by the Okanagan, with grapes and apples, and Vancouver Island, with potatoes. Virtual water was estimated by the BC Agriculture Water Calculator and used to assess the soil and climatic factors impacting the local water demand. Although soil texture seemed to influence water demand, the agro-climatic zone was the main factor controlling the water demand and the corresponding amount of water wasted. Dry agro-climatic zones had annual virtual water up to two times higher for the same crop and soil texture. Lower water demand crops, finer soils and more efficient irrigation systems were more congruent with water stress scenarios. Total losses for each region were based on conservative estimates and would have supplied the caloric energy and protein for over 40,000 adults, and vitamin C for over 300,000 adults for one year. Additionally, the total N, P and K wasted accounted for up to 32, 2 and 13 kg/ha respectively for common fertilizers used in British Columbia. This study confirmed the significance of food waste impacts on local water demand, human nutrition and soil management based on regional data for representative crops.

淮河生态经济带安徽段粮食生产时空演化及其驱动力分析

淮河流域是我国三大商品粮生产基地之一,优化其粮食生产格局对于保障中国粮食安全具有重要意义。基于比较优势理论测度淮河生态经济带安徽段50个区县2006—2020年的粮食生产优势,并采用ESDA模型、地理探测器模型分析其时空分异及其影响因素。研究表明:水稻的优势区域多数为规模主导型,小麦、玉米的生产区域普遍具有综合比较优势且分布逐渐向淮河以北地区聚集,种植面积的减少使豆类部分优势区域变为劣势区域;主要粮食作物的生产比较优势具有较强的空间自相关性,其中水稻、小麦比较优势指数的空间聚集情况较为稳定,玉米的高值聚集区分布由“双核心”变为“带状”,而豆类恰好相反,两种作物呈“竞争”态势。此外,早期区域粮食生产优势与灌溉水平高度相关;年降水量与水资源总量解释力逐年增强且成为决定性因素,表明粮食生产布局与自然资源条件的匹配程度有所提高;农民可支配收入解释力处于低位状态且逐年减弱,反映粮食生产的优势区域农户收入反而较低,粮食生产与农民可支配收入“脱钩”程度加剧。

Vitamin, Protein and Essential Mineral Enhancement of Cereal Crops for Food Security

Recent estimates indicate that more than half of the world's population suffers from diseases caused by dietary defi ciencies and inadequate supplies of essential micronutrients. This situation is exacerbated by the

基于特征优选的GF-6WFV影像主要粮食作物提取

针对高分六号(GF-6)宽幅多光谱影像具有红边波段的特点,构建一种基于特征优选的GF-6 WFV影像主要粮食作物提取方法。首先从预处理后的GF-6影像中提取光谱特征、植被指数、水体指数和红边指数特征,然后利用递归特征消除算法进行特征优选来构建最优特征集,最后基于最优特征集和机器学习算法对影像进行分类从而提取主要粮食作物。以江苏省南通市如东县为研究区,采用6种方案进行粮食作物提取试验,并探讨不同特征、不同分类模型对小麦、水稻和玉米3种粮食作物提取精度的影响,结果表明,利用GF-6 WFV影像可以准确提取主要粮食作物,尤其在红边波段和红边指数上主要粮食作物与其他地物间具有较高的可分性;利用最优特征集和XGBoost算法对影像进行分类的精度最高,在小麦和水稻、玉米提取试验中比未采用红边特征时的分类精度分别提高了3.08、5.58个百分点。