Synergy of remotely sensed data in spatiotemporal dynamic modeling of the crop and cover management factor

Soil erosion is a threat to the water quality constituents of sediments and nutrients and can cause long-term environmental damages. One important parameter to quantify the risk of soil loss from erosion is the crop and cover management factor (C-factor), which represents how cropping and management practices affect the rates and potential risk of soil erosion. We developed remotely sensed data-driven models for dynamic predictions of C-factor by implementing dynamic land cover modeling using the SWAT (Soil and Water Assessment Tool) model on a watershed scale. The remotely sensed processed variables included the enhanced vegetation index (EVI), the fraction of photosynthetically active radiation absorbed by green vegetation (FPAR), leaf area index (LAI), soil available water content (AWC), slope gradient (SG), and ratio of area (AR) of every hydrologic response unit (HRU) to that of the total watershed, comprising unique land cover, soil type, and slope gradient characteristics within the Fish River catchment in Alabama, USA between 2001 and 2014. Linear regressions, spatial trend analysis, correlation matrices, forward stepwise multivariable regression (FSMR), and 2-fold cross-validation were conducted to evaluate whether there were possible associations between the C-factor and EVI with the successive addition of remotely sensed environmental factors. Based on the data analysis and modeling, we found a significant association between the C-factor and EVI with the synergy of the environmental factors FPAR, LAI, AWC, AR, and SG (predicted R² (R_pred²) = 0.51; R² = 0.68, n = 3 220, P < 0.15). The results showed that the developed FSMR model constituting the non-conventional factors AWC (R_pred² = 0.32; R² = 0.48, n = 3 220, P < 0.05) and FPAR (R_pred²= 0.13; R² = 0.28, n = 3 220, P = 0.31) was an improved fit for the watershed C-factor. In conclusion, the union of dynamic variables related to vegetation (EVI, FPAR, and LAI), soil (AWC), and topography (AR and SG) can be utilized for spatiotemporal C-factor estimation and to monitor watershed erosion.     

MODULATION OF PHYSIOLOGICAL AND BIOCHEMICAL METABOLITES IN SALT STRESSED RICE BY FOLIAR APPLICATION OF ZINC

An experiment was conducted to evaluate the effect of zinc (Zn) application on five rice cultivars grown under salt stress conditions. Two salinity levels of 0 and 10 dS m^?1 were created with sodium chloride (NaCl) and foliar spray of Zn (0.05%; Chelated-Zn) was applied. A decrease in growth and yield related parameters were observed under salt stress, which was ameliorated in plants that received Zn foliar spray. Similar effects of salinity and Zn foliar spray were noted on photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency, and water relations of plants. Salt induced increase in sodium (Na) content and decrease in other macro- and micronutrients contents were also reversed by Zn. Other salt tolerance indicating parameters likSe total free amino acids and total soluble sugars increased under Zn spray, clearing its role in improving salt tolerance.     

Responses of Some Local/Exotic Accessions of Lentil (Lens culinaris Medic.) to Salt Stress

Assessment of salt tolerance at all growth stages is crucial to determine the overall tolerance of a crop. Salt tolerance of five tolerantILL 5845, ILL 6451, ILL 6788, ILL 6793 andILL 6796, three moderately tolerant ILL 6431. ILL 6770 andILL 6784, and three sensitiveILL 6210, ILL 6439 andILL 6778 accessions selected at the germination and seedling stages was assessed at the adult stage using sand culture sahnized with 0, 30, or 60 mol m^?3 NaCl. A positive correlation was observed between degrees of salt tolerance at different growth stages in three tolerant accessionsILL 6451, ILL 6788 andILL 6793 which produced significantly higher seed yield than the other accessions. This was also affirmed in three sensitive and two moderately tolerant accessions (ILL 6770 andILL 6784) whose salt sensitivity was conferred consistently at all growth stages. In contrastILL 5845, andILL 6796 which were highly salt tolerant andILL 6431 which was moderately tolerant at the early growth stages had relatively low seed yield, hence showing a negative correlation between tolerances at different growth stages. High yielding accessionsILL 6451, ILL 6788 andILL 6793 in general, accumulated higher Na⁺ and higher or moderate Cl^? in their shoots compared with the other accessions, thus showing a typical halophytic mechanism of salt inclusion. K/Na ratios of all the tolerant, moderately tolerant and sensitive accessions exceptILL 6784 andILL 6778 were less than 1, a suggested minimum level for normal functioning of many metabolic processes in plants. The present study shows that salt tolerance observed previously at the early growth stages is conferred at the adult stage in most of the accessions of lentil examined here; but for others in which no positive correlation was observed between different growth stages suggests that a combination of certain characters can be used as selection criterion for improving salinity tolerance in lentil through exploitation of inter- and intra-cultivar/line variation.     

Effect of dietary protein and lipid levels and protein–energy ratio on growth indices, feed utilization and body composition of freshwater prawn, Macrobrachium rosenbergii (de Man 1879) post larvae

A grow‐out experiment was designed to determine the effect of different dietary protein, lipid levels and protein–energy (P:E) ratio on growth performance and feed utilization of the freshwater prawn, Macrobrachium rosenbergii post larvae (PL) culture in pond net enclosures (hapa, 3.75 m^?3 each) for 12 weeks (84 days). The experimental treatments were assigned in triplicate. Six test diets were formulated to contain three different protein levels (300, 350 and 400 g kg^?1 diet) and two lipid levels (100 and 140 g kg^?1 diet) in a factorial manner (3 × 2) to provided six different dietary P:E ratio: 16, 17, 18, 19, 20 and 21 mg CP kJ^?1 g^?1). The result showed that the highest significant (P≤0.05) survival rate, growth indices and feed utilization were observed for M. rosenbergii PL fed a diet with a P:E ratio of 17 mg CP kJ^?1 g¹, whereas, the lowest value was recorded for prawns fed a diet with a P:E ratio of 20 mg CP kJ^?1 g^?1. Whole body contents of protein and lipid were highest (P≤0.05) when fed diets with 21 and 17 mg CP kJ^?1 g^?1 respectively. Concerning dietary protein levels, the highest (P≤0.05) values for survival and growth indices were observed for PL fed a diet containing 300 g kg^?1 diet protein. The same trend was observed for PL fed a diet with 100 g kg^?1 diet lipid level, irrespective of dietary protein levels. A diet containing 300 g kg^?1 protein and 100 g kg^?1 lipid with a dietary P:E ratio of 17 mg CP kJ g^?1 is recommended to stimulate growth performance and nutrients utilization efficiency of M. rosenbergii PL.     

春茶采摘末期遮荫对其生长和品质的影响

为延长春茶采摘期,提高其产量,进行了遮阳网遮荫栽培试验研究。根据不同遮光率和不同遮荫高度,在茶园中设置4个处理:60%遮光率+2.0 m遮荫高度(T1)、40%遮光率+2.0 m遮荫高度(T2)、40%遮光率+2.5 m遮荫高度(T3)和无遮荫的对照处理(CK);试验全程分为前、中、后期。试验研究以上各处理遮阳网内外温、湿度环境的差异,茶树新稍、叶片生长状况和茶芽叶品质指标。结果表明:遮荫后,茶树冠层处的日最高气温显著降低,遮光率越高降幅越大,最大降幅为3.9℃;08:00—17:00的最低相对湿度均增大,遮光率越高增幅越大,最大增幅为9.01%;新稍长度、粗度均增加,以T1处理的增幅最大,分别为22.3%和13.5%;新稍叶片的叶绿素相对含量和芽叶含水率,随着遮光率增大而增高;与CK处理相比,T1处理的新稍叶片日平均净光合速率变大,而T2和T3显著变小;T3处理增加了茶叶水浸出物、茶多酚和酚氨比,降低了氨基酸含量,导致茶汤浓厚、苦涩味加重;而T1处理在试验前期增加了咖啡碱含量,降低了水浸出物含量和酚氨比。综上所述,在春茶采摘末期采用60%遮光率的遮阳网进行遮荫栽培,对于保持春茶品质、延长采摘期具有重要的生产指导意义。     

Dry Matter and Nitrogen Distribution at Maturity of Three Rice (Oryza sativa L.) Cultivars Exposed to Ammonia at Two Growth Stages

A substantial proportion of ammonical fertilizers applied to lowland rice is lost as gaseous N from the soil–plant system. Besides various environmental factors, the low N use efficiency of flooded rice is also attributed to this factor. As atmospheric ammonia found in the leaf environment of the plants could also be responsible for differences in N use efficiency and fertilizer N losses from lowland rice, a greenhouse study was conducted on three rice cultivars varying in physio-morphological characteristics for their dry matter and nitrogen distribution to grains at maturity in response to ammonia (NH₃) exposure at tillering and anthesis growth stages. The results revealed that ammonia exposure of plants at two growth stages did not affect the total dry matter and total N yield of the rice cultivars at maturity; however, the grain yield and grain N yield were negatively effected by NH₃ exposure of the plants at anthesis. The variation observed in dry matter and N partitioning at maturity to grains/roots of the plants exposed to NH₃ at anthesis indicated that the growth stage of the plants at which they are exposed to NH₃ has an influence on N use efficiency of crop plants and subsequent vegetative as well as total N losses from the soil–plant system.     

Regulation of some biochemical attributes in drought-stressed cauliflower (Brassica oleracea L.) by seed pre-treatment with ascorbic acid

Cauliflower (Brassica oleracea L. var. botrytis) is widely used as a vegetable in many countries; however, productivity is adversely affected in areas affected by drought. To investigate the role of exogenously applied ascorbic acid (AsA) in mitigating the negative effects of drought on cauliflower, a pot experiment was performed using two cultivars of cauliflower ‘Local’ and ‘S-78’. Seeds of both cultivars were soaked in 75 mg l^–1, or in 150 mg l^–1 AsA, or in water (control) for 16 h. Water-deficit stress suppressed plant growth, reduced leaf chlorophyll concentrations, relative water contents (RWC), shoot and root P and K⁺ ion concentrations, and total soluble protein concentrations, significantly. However, significant drought-induced increases were observed in relative membrane permeability (RMP), the accumulation of total phenolic compounds, leaf free proline, glycinebetaine (GB), endogenous AsA, and hydrogen peroxide concentrations, and in the activity of superoxide dismutase (SOD). Seed treatment with 75 or 150 mg l^–1 AsA resulted in lower accumulations of H₂O₂, while increasing shoot and root fresh weights and dry weights, RWC, total phenolic compound, free proline, GB, and endogenous AsA concentrations, and the activities of SOD and catalase (CAT). No changes were observed in leaf chlorophyll concentrations or in peroxidase (POD) activities, RMP, shoot and root P and K⁺ ion accumulation, or in total soluble protein concentrations under water stress or non-stress conditions following seed treatment with AsA. ‘Local’ had higher proline concentrations and SOD activities; however, ‘S-78’ had higher RWC values, GB, and AsA concentrations. Overall, a pre-sowing treatment of cauliflower seed with 75 or 150 mg l^–1 AsA improved seedling tolerance to drought stress in both cultivars, which could be attributed to AsA-induced decreases in RMP and H₂O₂ concentrations, increases in the activities of CAT and SOD, increased RWC, and higher total phenolic compound, proline, GB, and AsA concentrations. The exogenous application of AsA therefore offers an effective strategy to minimise the adverse effects of drought stress on vegetable crops, including cauliflower.     

Improving Drought Tolerance by Exogenous Application of Glycinebetaine and Salicylic Acid in Sunflower

Water shortage is a severe threat to the sustainability of crop production. Exogenous application of glycinebetaine (GB) and salicylic acid (SA) has been found very effective in reducing the adverse affects of drought stress. This study was conducted to examine the possible role of exogenous GB and SA application in improving the yield of hybrid sunflower (Helianthus annuus L.) under different irrigation regimes. There were three levels of irrigation, viz. control (normal irrigations), water stress at vegetative stage (irrigation missing at vegetative stage) and water stress at flowering stage (irrigation missing at flowering stage). GB and SA were applied exogenously at 100 and 0.724 mm , respectively, each at the vegetative and at the flowering stage. Control plants did not receive application of GB and SA. Water stress reduced the head diameter, number of achene, 1000‐achene weight, achene yield and oil yield. Nevertheless, exogenous GB and SA application significantly improved these attributes under water stress. However, drought stress increased the free leaf proline and GB, and were further increased by exogenous application of GB and SA. However, exogenous GB application at the flowering stage was more effective than other treatments. Oil contents were also reduced under water stress; however, GB and SA application could not ameliorate the negative effect of water stress on achene oil contents. The effects of water stress and foliar application of GB were more pronounced when applied at the flowering stage than at the vegetative stage. Moreover, exogenous GB application was only beneficial under stress conditions.     

Diagnosis of bovine mastitis: from laboratory to farm

Accurate diagnosis of disease is the major step between the cause and cure of disease. An economical, reliable, and rapid diagnostic tool is fundamental for the management of udder health. The earlier the disease is identified, the less will be the damage; keeping this in mind, many efforts are being made to develop reliable diagnostic tools for use on farm. However, traditional gold standard methods including somatic cell count and microbial culturing are still in use. They are partially being replaced with polymerase chain reaction and sequencing-based tests. Nanotechnology and protein-based tests have also gained lot of attention and some of them are potential candidate of future diagnostic tests for bovine mastitis. Research laboratories are struggling to develop simple, economical, and user-friendly biosensor-based methods that can be performed on farm for rapid diagnosis. The combination of both genomic and proteomic approaches, together with further involvement of nanotheranostic technologies and other sensors, will assist in the quest of better mastitis diagnostic tools.