Changes in Metabolites and Allelopathic Effects of Non-Pigmented and Black-Pigmented Lowland Indica Rice Varieties in Phosphorus Deficiency

Phosphorus(P) levels alter the allelopathic activity of rice seedlings against lettuce seeds. In this study, we investigated the effect of P deficiency on the allelopathic potential of non-pigmented and pigmented rice varieties. Rice seedlings of the white variety Khao Dawk Mali(KDML105, non-pigmented) and the black varieties Jao Hom Nin(JHN, pigmented) and Riceberry(RB, pigmented) were cultivated under high P(HP) and low P(LP) conditions. Morphological and metabolic responses to P deficiency were investigated. P deficiency inhibited shoot growth but promoted root growth of rice seedlings in all three varieties. Moreover, P deficiency led to decreased cytosolic phosphate(Pi) and total P concentrations in both shoot and root tissues. The subsequent reduction in internal P concentration enhanced the accumulation of phenolic compounds in both shoot and root tissues of the seedlings. Subsequently, allelopathy-based inter-and intra-specific interactions were assessed using water extracts from seedlings of the three varieties grown under HP and LP conditions. These extracts were tested on seeds of lettuce, the weed Dactyloctenium aegyptium, and the same rice variety. The shoot and root extracts from P-deficient seedlings reduced the germination of all recipient plants. Specifically, the shoot extract from P-deficient KDML105 seedlings reduced the germination index(GI) of lettuce seeds to 1%, while those from P-deficient RB and JHN seedlings produced GIs of 32% and 42%, respectively. However, when rice seeds were exposed to their own LP shoot and root extracts, their GIs increased up to 4-fold, compared with the HP extracts. Additionally, the shoot extracts from P-deficient plants also stimulated the germination of D. aegyptium by about 2–3-fold, whereas the root extracts did not have this effect. Therefore, P starvation led to the accumulation and exudation of phenolics in the shoots and roots of rice seedlings, altering their allelopathic activities. To adapt to P deficiency, rice seedlings potentially release signaling chemicals to suppress nearby competing species while simultaneously promoting their own germination and growth.

Phenology of desert plants from an arid gravel plain in eastern United Arab Emirates

Phenological events for desert plants were recorded and rainfall and temperature data were gathered over a three-year time scale at a gravel plain in the eastern region of the United Arab Emirates. Variations of phenological periods were analyzed and correlations between phenological periods and climate factors were discussed. The study showed that the growth and flowering of therophytes were significantly correlated with air tem- perature. The timing and abundance of rainfall came to be another factor significantly correlated with the onset and duration of chamaephyte flowering as well as the duration of therophyte growth and flowering. The variation in rainfall did not affect the onset of flowering in phanerophytes. Peak growing seasons were from November to March and flowering from November to December （also February to March depending on the availability of rainfall）. Flowering in phanerophytes and chamaephytes occurs 4-6 weeks and in therophytes 4-8 weeks after rain, The results showed that variations in growth and phenology between species were correlated with environmental factors, such as temperature and rainfall or, maybe, differences in life form and photosynthetic pathways, each being adapted for utilizing a particular phase of the seasonally and yearly variable rainfall. The sequence of flowering for the species under study was more or less constant despite the difference in the amount of rainfall. The fruiting patterns of most of the species were also found parallel to their flowering patterns. Our results emphasized the need to study multiple species at many sites for the understanding and forecast of regional changes in phenology.

An Adaptive Sequential Replacement Method for Variable Selection in Linear Regression Analysis

With the rapid development of DNA technologies, high throughput genomic data have become a powerful leverage to locate desirable genetic loci associated with traits of importance in various crop species. However, current genetic association mapping analyses are focused on identifying individual QTLs. This study aimed to identify a set of QTLs or genetic markers, which can capture genetic variability for marker-assisted selection. Selecting a set with k loci that can maximize genetic variation out of high throughput genomic data is a challenging issue. In this study, we proposed an adaptive sequential replacement (ASR) method, which is considered a variant of the sequential replacement (SR) method. Through Monte Carlo simulation and comparing with four other selection methods: exhaustive, SR method, forward, and backward methods we found that the ASR method sustains consistent and repeatable results comparable to the exhaustive method with much reduced computational intensity.

Effectiveness of Combined Biochar and Lignite with Poultry Litter on Soil Carbon Sequestration and Soil Health

Healthy soils are important to ensure satisfactory crop growth and yield. Poultry litter (PL), as an organic fertilizer, has proven to supply the soil with essential macro and micronutrients, enhance soil fertility, and improve crop productivity. Integrating this treatment has the potential to improve soil physical and biological properties by increasing soil carbon, C. However, rapid decomposition and mineralization of PL, particularly in the hot and humid southeastern U.S., resulted in losing C and reduced its effect on soil health. Biochar and lignite have been proposed to stabilize and mitigate C loss through application of fresh manure. However, their combined effects with PL on C sequestration and soil health components are limited. A field experiment was conducted on Leeper silty clay loam soil from 2017 to 2020 to evaluate the combined effect on soil properties when applying biochar and lignite with PL to cotton (Gossypium hirsutum L.). The experimental design was a randomized complete block involving nine treatments replicated three times. Treatments included PL and inorganic nitrogen, N, fertilizer with or without biochar and lignite, and an unfertilized control. Application rates were 6.7 Mgkg⋅ha−1 for PL, 6.7 Mgkg⋅ha−1 for biochar and lignite and 134 kg⋅ha−1 for inorganic N fertilizer. Integration of PL and inorganic fertilizer with biochar and lignite, resulted in greater soil infiltration, aggregate stability, plant available water, reduced bulk density and penetration resistance as compared to the sole applications of PL and inorganic fertilizer.

Influence of two different dietary zinc sources in freshwater prawn Macrobrachium rosenbergii post larvae

A feeding experiment was conducted to evaluate the ef fects of bulk zinc(B-Zn) and zinc nanoparticles(Zn-NPs) on survival, growth, compositions of amino acid and fatty acid, and nonspeci?c immune responses of the freshwater prawn, Macrobrachium rosenbergii post larvae. The B-Zn(size 10 μm)and Zn-NPs(size 50 nm) were supplemented separately with the basal feeds of M. rosenbergii at 60 mg/kg and feed without supplementation of any Zn source was served as a control. M. rosenbergii were fed these feeds for 90 days and the results showed that signi?cant( P <0.05) improvements in survival, growth, feed intake,speci?c growth rate, essential amino acids, unsaturated fatty acids, nonspeci?c immune responses(total haemocytes and dif ferential haemocytes count) of M. rosenbergii fed with B-Zn and Zn-NPs supplemented feeds when compared to control. Among these Zn sources, Zn-NPs supplemented feeds fed prawns showed signi?cantly( P <0.05) better performance than that of B-Zn and control. Hence, present study suggests that the 60 mg/kg Zn-NPs can be supplemented with basal feeds of M. rosenbergii for regulating better survival and growth.

Techniques in Utilizing Remote Sensor Technology for Precision Crop Production by Farmers as Climate Change Adaptation Strategy in Nigeria

This paper focuses on techniques in utilizing remote sensor technology for precision crop production by farmers as climate change adaptation strategy in Nigeria. Descriptive survey research design was adopted for the study and was carried out between August 2013 and May 2014. The findings of the study revealed that 32 items were needed by farmers in utilizing sensory technology for precision crop production. The study recommended that the 32 items identified by the study should be utilized by extension agent in teaching the farmers the use of sensor technology for precision crop production while the farmers should make themselves available for the training.

Farming Families and Climate Change Issues in Niger Delta Region of Nigeria: Extent of Impact and Adaptation Strategies

The study focused on the impacts of climate change on the farmer and the farming families in Niger Delta Region of Nigeria. The study specifically evaluated the perceived resultant situations attributed to climate change to determine the extent of impacts of climate change on the farmer and the farming families and also explored adoptable strategies for coping with the situations. The study adopted descriptive survey research design. Two research questions and two hypotheses guided the study. The population for the study was 246,909 respondents made up of farmers and extension workers who are registered with the State Ministries of Agriculture. Out of the nine Niger Delta states, Bayelsa and Delta states were randomly chosen for the study. Proportionate stratified random sampling technique was used to select a sample size of 5,038 respondents. Structured questionnaire and interview were used to collect data. The instruments were validated by three experts. Cronbach Alpha method was used to determine the internal consistency of the questionnaire items which yielded a coefficient of 0.81. The Statistical Product and Service Solutions (SPSS v 20.0) was employed for data analysis. The statistical tools used for data analysis were weighted mean to answer research questions and standard deviation to validate the closeness of the respondents from the mean and from each other in their responses while t-test was used to test the null hypotheses. The findings of the study revealed that the extent of impacts of climate change on farmers and the farming families in Niger Delta region of Nigeria are moderate. Findings further revealed that climate change has led to increased poverty level and raised cost of production (input and labour cost) as indicated by the farmers. The study recommends that farmers in the region should be encouraged by providing incentives and subsidizing inputs for them by Federal and State governments as well as other non-governmental organizations, as this will go a long way in improving production especially as most farmers agree to continue cultivation even with the observed impacts.

Isolation and identification of desert habituated arbuscular mycorrhizal fungi newly reported from the Arabian Peninsula

Arbuscular mycorrhizal fungi（AMF） are known to facilitate the growth and vigour of many plants, particularly in arid ecosystems. In a survey of AMF in a date palm plantation and two natural sites of a desert in Oman, we generated many single spore-derived cultures of AMF. We identified a number of these isolates based on spore morphotyping and molecular phylogenetic analysis using the sequence of the LSU-rDNA. Here, we presented the characteristics of four species of AMF recovered, namely Claroideoglomus drummondii, Diversispora aurantia, Diversispora spurca and Funneliformis africanum. The four species have been described previously, but for the Arabian Peninsula they are reported here for the first time. Our endeavor of isolation and characterization of some AMF habituated to arid sites of Arabia represents a first step towards application for environmental conservation and sustainable agriculture in this region.

Determinants of Farmers’ Perception of Climate Change: A Case Study from the Coastal Region of Bangladesh

Socio-economic conditions of farmers, especially in the coastal region in Bangladesh, have been severely affected because of climate change. This study was focused on analyzing the farmers’ perception of climate change by examining three vital issues: (1) description of the socioeconomic characteristics of farmers;(2) reporting on the perception of farmers experiences with climatic change;and (3) identification of the socio-economic factors associated with farmers’ perception of climate change. The study area encompasses three villages within the coastal region (Sathkhira district) of Bangladesh, a geographic region where climate change literature has highlighted as prone to accelerated degradation. A logit model, along with weighted indexes for ranking and descriptive statistics, was used to analyze the result of 100 farmers surveyed by questionnaire. We found that the majority of the farmers (88%) perceived changes in climatic conditions. Almost all farmers indicated increases in temperature, droughts, floods, cyclones, salinity level and decreasing rainfall over the last 20 years. The logit model explained that out of the nine factors surveyed;education, family size, farm size, family income, farming experiences and training received were significantly related and influential factors to perception of climate change. Therefore, government and non-governmental organizations are recommended to push forward with interventions, especially focusing on identified factors, in order to strengthen the farmers’ capacity to battle against climate change effects.

Competency Improvement Needs of Farmers in Soil Erosion Prevention and Control for Enhancing Crop Production: Case Study of Kogi State, Nigeria

This study investigated the competency improvement needs of farmers in soil erosion prevention and control for enhancing crop production in Kogi state of Nigeria and was carried out between January and June, 2014. The study adopted descriptive survey research design and was guided by two research questions. The study found out that farmers needed improvement on 37 cultural practices as follows: 10 competencies in mulching, 12 in cover cropping, 8 in strip cropping, 7 in contour farming and 45 mechanical field practice as follows: 10 competencies in contour bonding, 11 in terracing, 12 in channeling and 11 in tunneling for success in soil erosion prevention and control. The study recommended the organization of rural based programmes for the training of farmers in the practice identified to enhance their competencies in soil erosion prevention and control for increased crop production.

Effects of Plant Density on Boll Retention and Yield of Cotton in the Mid-South

The number of cotton (Gossypium hirsutum L.) plants being grown per unit of land area has gained attention due to the technology fees associated with seed containing value added traits. We investigated boll retention, yield, and yield components of cotton grown with reduced stands of 20% to 40% from the uniform planting pattern of four seeds per 30.5 cm of row. Five field experiments were conducted from 2012-2014 using eight treatments arranged in a randomized complete design with six replications. Yield and yield component data were collected. The plant one-row skip one-row treatment resulted in significant yield losses across all five experiments compared to the uniform planting pattern. Treatments with 20% stand reductions did not result in lower total yields;however, each plant in these treatments had to produce two additional bolls to maintain yield. Treatments which had at least 61 cm skips, 40% stand reduction, resulted in lower yields. Treatments had minor affects on boll weight, and lint percentage. The uniform planting pattern produced 67% of its yield from position one bolls compared to about 50% for treatments with reduced stands. Reduced stand treatments produced about 20% of their yield on monopodial branches compared to 10% for the uniform treatment. With modern precision planting equipments, opportunities exist to reduce seed rate and maintain yield;however, many production risk factors must also be considered before a reduced seeding rate is adopted.

Potential reduction in water consumption of greenhouse evaporative coolers in arid areas via earth-tube heat exchangers

This study aimed to explore the potential of developing a novel cooling system combining a greenhouse and an earth-tube heat exchanger(ETHE).In this system,greenhouse air is circulated through the underneath soil mass to use the deep-soil cooling effect.This was achieved through the following steps.First,soil temperature profile inside and outside the cultivated greenhouse was monitored for almost one year to study the possibility of using deep-soil coldness for cooling the greenhouse air.Second,a prototype ETHE was built to practically investigate the potential reduction in air temperature as the air flows inside the deep earth pipes.Third,a prototype greenhouse was erected to study the ETHE concept.Results from the first experiment revealed that soil temperature at a soil depth of 2.5 m inside the greenhouse offers good conditions to bury the ETHE.The soil temperature at this soil depth was below the maximum temperature(32℃)that most greenhouse crops can withstand.Results from the prototype ETHE showed a slight reduction in air temperature as it passed through the pipes.From the prototype of the integrated greenhouse and ETHE system,reduction in air temperature was observed as the air passed through the ETHE pipes.At night,the air was heated up across the ETHE pipes,indicating that the ETHE was working as a heater.We concluded from this study that greenhouses in arid climates can be cooled using the ETHE concept which would save a large amount of water that would otherwise be consumed in the evaporative coolers.Further investigations are highly encouraged.

Nutritional, Phytochemicals and Antioxidant Properties of Some Popular Pulse Varieties of Bangladesh

In this study, we estimate the proximate compositions, phytochemicals (polyphenol, flavonoids, flavonol, tannin, protein, carbohydrate, reducing sugar, and β carotene), antioxidant activities, vitamins, minerals, and heavy metals of the four pulses (mung, anchor, chickpea, lentils) and compare among them to find out more nutritious pulse samples. Mung was found to contain the highest amount of polyphenol (98.02 ± 1.74 mg GAE/100 g) and tannin (447.98 ± 9.96 mg TE/100 g) and anchor (771.35 ± 3.76 mg CE/100 g) was rich in flavonoids as compared to other two pulse samples. Mung was also rich in ash, carbohydrate, vitamin B1, copper and anchor was rich in crude fiber, protein, reducing sugar, and vitamin B2 content. The highest amount of phytochemicals contained in mung and anchor corresponded to its highest antioxidant activity in analyzed antioxidant assays respectively. Other two pulses included in this study were found to contain good source of vitamins, minerals and other nutrients.

Public Health Significance of <i>Campylobacter jejuni</i>

Campylobacter jejuni is a prominent bacterial cause of human gastroenteritis. Campylobacteriosis outbreaks reported were related to the ingestion of the contaminated food. Meat are reported to be frequently infected with C. jejuni. It is well recognized that C. jejuni is one of the main causes of gastroenteritis in humans, and poultry meat is reported to be the main source. A number of studies in several countries have shown the occurrence of C. jejuni in animal farms, slaughterhouses, and meat. This review simply describes the occurrence, spreading, and public health significance of C. jejuni.

Catalytic upgrading of bio-oil from halophyte seeds into transportation fuels

Because of socioeconomic considerations,wide-scale production of biofuel necessitates the utilization of nonedible biomass feedstock that does not compete for land and fresh water resources.In this regard,Salicornia bigelovii(SB)is the most investigated halophyte species.The high oil content in SB seeds has sparked mounting research that aims to utilize SB as an industrial crop in the production of bio-oil,particularly in coastal areas where these plants thrive.However,the oil extracted from the pyrolysis of raw SB seeds is largely dominated by oxygenated fatty acids,most notably 9,12-octadecadienoic acid and 9,17-octadecadienal,typical to that of other crops.The pyrolysate bio-oil of the raw SB seeds exhibited a relative yield of oxygenated compounds that decreased from 57.05%at 200℃to 9.81%at 500℃,and the relative yield of nitrogenated compounds increased from 4.86%at 200℃to 21.97%at 500℃.To improve the quality of the produced bio-oil,herein we investigated the catalytic hydrodeoxygenation(HDO)of the fragments that were produced from the thermal degradation of SB seeds.A 5%Ni–CeO_(2)catalyst was prepared and characterized by a wide array of methods X-ray diffraction,X-ray photoelectron spectroscopy,temperature programmed reduction,scanning electron microscope,BrunauerEmmett-Teller analysis,and thermogravimetric analyzer.The catalytic run was executed between 200 and 500℃in a flow reactor.The deployed catalytic methodology displayed a profound HDO capacity.At 400℃,for instance,the gas chromatography mass spectroscopy(GC–MS)detected loads of paraffin and aromatic compounds exists at appreciable values of 48.0%and 28.5%,respectively.With a total relative yield of 43.2%(at 400℃),C8–C15 species(i.e.,jet fuel fractions)were the most abundant species in the upgraded SB bio-oil.The release of H_(2),CO,CO_(2),and CH_(4)was analyzed qualitatively and quantitatively using gas chromatography thermal conductivity detector and Fourier infrared spectroscopic analysis.When the Ni–CeO_(2)catalyst was utilized,a complete deoxygenated bio-oil was obtained from SB seeds using the surface-assisted HDO reaction.On the basis of the elemental analysis,the biochar’s hydrogen and oxygen contents were found to decrease significantly.Density functional theory computations showed mechanisms for reactions that underpinned the experimentally observed hydrodeoxygenation process.Outcomes presented herein shall be instrumental toward the effective utilization of halophyte in the production of commercial transportation fuels.

Dietary sources and their effects on animal production and environmental sustainability

Animal agriculture has been an important component in the integrated farming systems in developing countries. It serves in a paramount diversified role in producing animal protein food, draft power, farm manure as well as ensuring social status-quo and enriching livelihood. Ruminants are importantly contributable to the well-being and the livelihood of the global population. Ruminant production systems can vary from subsistence to intensive type of farming depending on locality, resource availability,infrastructure accessibility, food demand and market potentials. The growing demand for sustainable animal production is compelling to researchers exploring the potential approaches to reduce greenhouse gases(GHG) emissions from livestock. Global warming has been an issue of concern and importance for all especially those engaged in animal agriculture. Methane(CH_4) is one of the major GHG accounted for at least 14% of the total GHG with a global warming potential 25-fold of carbon dioxide and a 12-year atmospheric lifetime. Agricultural sector has a contribution of 50 to 60% methane emission and ruminants are the major source of methane contribution(15 to 33%). Methane emission by enteric fermentation of ruminants represents a loss of energy intake(5 to 15% of total) and is produced by methanogens(archae) as a result of fermentation end-products. Ruminants' digestive fermentation results in fermentation end-products of volatile fatty acids(VFA), microbial protein and methane production in the rumen. Rumen microorganisms including bacteria, protozoa and fungal zoospores are closely associated with the rumen fermentation efficiency. Besides using feed formulation and feeding management, local feed resources have been used as alternative feed additives for manipulation of rumen ecology with promising results for replacement in ruminant feeding. Those potential feed additive practices are as follows: 1) the use of plant extracts or plants containing secondary compounds(e.g., condensed tannins and saponins) such as mangosteen peel powder, rain tree pod; 2) plants rich in minerals, e.g., banana flower powder; and 3) plant essential oils, e.g., garlic, eucalyptus leaf powder, etc. Implementation of the-feed-system using cash crop and leguminous shrubs or fodder trees are of promising results.

基于KINEROS2对坡面径流侵蚀及总氮流失的模拟分析

坡面土壤侵蚀及养分流失是造成土地生产力下降、地表水体富营养化等环境问题的主要原因.采用物理模型对次降雨条件下坡面径流量、侵蚀量及养分流失量进行准确估算具有重要意义.本文通过不同降雨强度(20、50、75mm/h)、不同坡长(1、5、10、15、20m)下径流小区内人工模拟降雨试验,分析了坡面径流侵蚀特征及总氮(TN)流失特征,构建了估算坡面总氮流失量的经验模型,并将其嵌入基于次降雨的KINEROS2(A Kinematic Runoff and Erosion Model)模型中进行模拟验证.结果表明:降雨强度是影响坡面径流率、侵蚀率及总氮流失率的主要因素;降雨强度、坡长及其交互作用与径流量、侵蚀量之间呈多项式关系(决定系数R^2>0.95);坡面总氮主要以结合态的形式流失,且坡面TN流失量与径流量、侵蚀量之间呈一元线性关系(R^2>0.92);KINEROS2对次降雨条件下坡面径流量、侵蚀量的模拟精度较高(相对误差RE,0.03%~11.31%);嵌入坡面TN流失模型的KINEROS2对径流中TN流失量、泥沙中TN流失量及坡面TN流失量模拟效果较好(R^2>0.91,纳什系数NSE>0.76).

Characteristics of Nutrient Salt Uptake Associated with Water Use of Corn as a Catch Crop at Different Plant Densities in a Greenhouse

Dent corn, as a catch crop used for salt removal, was cultivated at different densities, i.e., 7.3(low density), 59.7(normal density), and 119.5 plants m-2(high density), during a 50 d fallow period after cultivation of a commercial crop in a greenhouse, to analyze the characteristics of nutrient salt(N, K, Mg, and Ca) uptake by roots and to study the effect of plant density on the characteristics associated with crop water use. Leaf area index for the high and normal density treatments reached extremely high values of 24.3 and 14.9, respectively. These values induced higher transpiration rates that were estimated using the Penman-Monteith model with the incorporation of specific parameters for crop and greenhouse conditions. The total N, K, Mg, and Ca contents in the crop canopy at harvest were 26.8, 13.0, 1.0, and 1.7 g m-2, respectively, under the high density treatment. The dynamics of salt uptake rates for high, normal, and low density treatments were evaluated by assessing weekly changes in salt content, and were subsequently compared against the transpiration rate. A positive linear relationship was obtained between these 2 parameters for all 3 density treatments and all tested salts. Hence, higher transpiration rates caused higher salt uptake rates through water absorption. On the other hand, salt uptake efficiency per unit water use by cultivation was lower in the low density treatment. Therefore, management procedures with dense planting that induce higher transpiration rates and lower evaporation rate are extremely important for the effective cultivation of corn catch crops.