Evapotranspiration and its components over a rainfed spring maize cropland under plastic film on the Loess Plateau, China

Aim of study: To determine seasonal variations in evapotranspiration (ET) and its components; and ascertain the key factors controlling ET and its components in a rainfed spring maize field under plastic film.Area of study: Shouyang County in Shanxi Province on the eastern Loess Plateau, ChinaMaterial and methods: Eddy covariance system combined with micro-lysimeters and meteorological observing instruments were used in the field. The manual method was used to measure the green leaf area index (GLAI) during the growing season.Main results: In 2015 and 2016, the growing season ET accounted for 80% and 79% of annual ET, respectively. Soil evaporation (E) accounted for 36% and 33% of the growing season ET in 2015 and 2016, respectively. The daily crop coefficient increased with increasing GLAI until a threshold of ~3 m2 m−2 in the canopy-increasing stage, and decreased linearly with decreasing GLAI in the canopy-decreasing stage. At equivalent GLAI, daily basal crop coefficient and soil water evaporation coefficient were generally higher in the canopy-increasing and -decreasing stages, respectively. During the growing season, the most important factor controlling daily ET, T, and E was net radiation (Rn), followed by GLAI for daily ET and T, and soil water content at 10-cm depth for daily E; during the non-growing season, daily ET was mainly controlled by Rn.Research highlights: The daily crop coefficient and its components reacted differently to GLAI in the canopy-increasing and -decreasing stages

Sampling redesign of soil penetration resistance in spatial t-Student models

 Aim of study: To reduce the sample size in an agricultural area of 167.35 hectares, cultivated with soybean, to analyze the spatial dependence of soil penetration resistance (SPR) with outliers.Area of study: Cascavel, BrazilMaterial and methods: The reduction of sample size was made by the univariate effective sample size ( ) methodology, assuming that the t-Student model represents the probability distribution of SPR.Main results: The radius and the intensity of spatial dependence have an inverse relationship with the estimated value of the . For the depths of SPR with spatial dependence, the highest estimated value of the  reduced the sample size by 40%. From the new sample size, the sampling redesign was performed. The accuracy indexes showed differences between the thematic maps with the original and reduced sampling designs. However, the lowest values of the standard error in the parameters of the spatial dependence structure evidenced that the new sampling design was appropriate. Besides, models of semivariance function were efficiently estimated, which allowed identifying the existence of spatial dependence in all depth of SPR.Research highlights: The sample size was reduced by 40%, allowing for lesser financial investments with data collection and laboratory analysis of soil samples in the next mappings in the agricultural area. The spatial t-Student model was able to reduce the influence of outliers in the spatial dependence structure

Phylogenetics of the genus Sechium P. Brown: A review

The Sechium P. Br. genus composed of 11 species, which originated from the mountainous regions of Mesoamerica, have been domesticated and diversified. These species are clustered in two large groups: the Mexican clade and the Central American clade. Morphological and molecular studies have shown that species of the Mexican clade are formed through interspecific hybridizations and genetic flow, with the exception of S. mexicanum, which is strongly linked to the genus Sicyos. The objective of this review was to analyze the phylogenetics of Sechium based on morphological and molecular studies, which contributed to taxonomic knowledge and utilization, thereby favoring its conservation and improvement. The Central American clade is well supported with molecular data, but not so with morphological data. The species in this clade were geographically isolated and endemic. S. edule and S. tacaco are exploited species in the agricultural and industrial sectors, and both have an extensive genetic and phenotypic diversity that has allowed them to diversify and expand into different ecological niches. Finally, the Central American species of Sechium thrive in adverse environments of temperatures of mesophyll forest and high relative humidity, with characteristics that can give resistance to frosts and phytopathogenic agents, as well as cultivated species of this genus

Effect of Asiatic mangrove plant (Rhizophora mucronata) extract on the growth and virulence of Vibrio harveyi causing bioluminescence disease in Penaeus monodon larviculture

Aim of the study: Vibrio harveyi bacteria are affecting shrimps during grow-out practices. The application of chemicals to control V. harveyi has resulted in antibiotic‐resistance among bacteria. An extract of the leaves of Rhizophora mucronata was tested to control the growth and virulences of V. harveyi. Area of study: This study was conducted in the Crustacean Culture Division of ICAR-CIBA, Chennai city, Tamil Nadu State, India. Material and methods: R. mucronata plants were collected from the Pitchavaram area, and the leaves contents extracted. The resultant extract was prepared and tested against the growth of V. harveyi and its virulence factors. The various functional compounds of R. mucronata were screened and volatile compounds were analyzed. Main results: When R. mucronata extract was treated against V. harveyi (350 µg/mL) an inhibitory zone of 14 ± 0.1 mm was observed. At 300 µg/mL, the extract was found to be active in decreasing the luciferase to a maximum of 76 counts per second in 30 days and a similar level of bioluminescence was reduced in 15 days. During, shrimp larviculture a reduction in the cumulative percent of mortality 15.70% (p<0.033) was observed when treated with the extract of R. mucronata. Research highlights: When extract (200 μg/mL) of R. mucronata was tested against V. harveyi during Penaeus monodon larviculture, the V. harveyi counts decreased (p<0.049). Volatile compounds viz, tetramethyl-6,7,8,8a-tetrahydro-5H-naphthalene-1-one (38.63%), squalene (31.19%), α-amyrin, (7.07%) and β-amyrin (8.75%) were detected. It would be desirable to use crude extracts of R. mucronata during shrimp culture to control V. harveyi

A two-step feeding of calcium salts of fish oil improves reproductive performance in Holstein cows

Aim of study: To examine the effects of a biphasic schedule of feeding n-3 fatty acids on dairy cows.Area of the study: Isfahan, Iran.Materials and methods: 140 lactating Holstein cows were allotted at calving into two groups of 70 animals and received one of two dietary treatments: 1) saturated fatty acids (SFA, containing 80% palmitic acid) or 2) calcium salt of fish oil (CSFO, containing 16% eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA)), with an n-6/n-3 FA ratio of approximately 7 for SFA and 5 for CSFO treatments. The dietary supplements were fed to the respective groups at 240 g/head.day from 0 to 21 days in milk, and 120 g/head.day from 22 to 150 days in milk. Milk yield was recorded biweekly and milk composition was evaluated monthly. The concentration of FA in the milk and blood was determined on d-90 of the experiment in 10 cows randomly selected from each group. Reproductive indices were recorded until d-150.Main results: The CSFO supplementation did not affect average milk yield, milk composition or milk somatic cell count (SCC); however, in some weeks it decreased milk SCC (p<0.05). Plasma concentrations of palmitic acid and n-3 FA as well as milk fat concentration of EPA and DHA increased in the CSFO-fed cows (p<0.05). Feeding the CSFO decreased open days (100 vs 119 days, p<0.05), service per conception and all service conception rates (p<0.05).Research highlights: The implementation of a two-stage feeding program of n-3 FA improved reproductive variables and reduced milk SCC in dairy cows

Effect of mulching and subsurface drip irrigation on soil water status under arid environment

Aim of study: We investigated water evaporation of the soil surface and the soil water distribution under different mulching techniques using subsurface drip irrigation (SDI) system.Area of study: The experiment was conducted at the Agricultural Research and Experimental Farm in Dirab, Riyadh, Saudi Arabia, locating 24.4195° N, 46.65° E, and 552 m altitude.Material and methods: The two types of soil surface mulching were black plastic film (BPF) and palm tree waste (PTW), with no mulching (NM) as control. The two drip line depths from the soil surface (DL) were 15 cm and 25 cm, and surface drip irrigation (DI) was the control.Main results: In SDI, the use of BPF or PTW mulching resulted in enhanced water retention capacity of the soil and an approximately 6% water saving, compared with NM. The amounts of water saved at DL of 15 cm (19-24 mm) were greater than those at DL of 25 cm (15-20 mm), whereas the DI used the highest amount of applied water. The distribution of soil water content for BPF and PTW were found to be more uniform than NM.Research highlights: It is advised to mulch the soil with PTW due to lower costs and through a DL of 15 cm

Determining the radiation use efficiency of potato using sunshine hour data: a simple and costless approach

Aim of study: Radiation parameters and photoperiod influence potato biomass and tuber yield significantly. Lack of instrument facilities in developing countries is the main hindrance to estimate global solar radiation (GSR) and radiation use efficiency (RUE). Considering these facts, an experiment was conducted to estimate light extinction coefficient (K) and RUE using a simple but indirect approach that can be implied in any location lacking sophisticated instruments.Area of study: Field experiments were conducted in Kalyani, West Bengal, representing the Indo-Gangetic Plains.Material and methods: Angstrom-Prescott (A-P) equation was used to calculate GSR. The experiment was laid out in a split-plot design with three dates of planting (DOP), 15th Nov, 29th Nov and 13th Dec, as main plot treatment and three potato cultivars (ˈKufri Suryaˈ, ˈKufri Chandramukhiˈ and ˈKufri Jyotiˈ) as sub-plot treatment. Leaf area indices and K values were used to determine intercepted PAR (IPAR) as well as RUE.Main results: The cumulative IPAR from emergence to harvest ranged 246-429 MJ m-2 depending on planting time and varieties. Irrespective of DOPs, the highest mean RUE (4.19 g MJ-1) was calculated in ˈKufri Chandramukhiˈ, showing that it used the radiation more efficiently that the other two cultivars (ˈKufri Suryaˈ= 3.75 g MJ-1 and ˈKufri Jyotiˈ= 3.14 g MJ-1).Research highlights: Statistical indices confirmed that the A-P model can be reliably used in the study region for estimation of GSR. This simple way to estimating RUE using bright sunshine hours data can be used in developing countries, where costly radiation instruments are not available

Transcriptome profiling of lentil in response to Ascochyta lentis infection

Aim of study: The purpose was to identify some general and genotypic-specific defense responses, in order to obtain a set of candidate genes presumably involved in the resistance.Area of study: The experiment was carried out in León, Spain.Material and methods: We have analyzed the response of three lentil genotypes to Ascochyta lentis (isolate AL 84) at transcriptomic level using the Massive Analysis of cDNA Ends (MACE) technique: the susceptible cultivar 'Lupa', the moderately resistant 'ILL5588' and the resistant wild accession 'BG 16880' (L. culinaris subsp. orientalis).Main results: MACE results yielded a total of 50,935 contigs. The average number of detected contigs in each of the six samples was approximately of 40,000. In response to Ascochyta infection, the jasmonic acid pathway and the lignin biosynthesis were up-regulated in resistant genotypes, while they were down-regulated in the susceptible one. The response to chitin, the salicylic pathway and the auxin response were activated only in the resistant L. c. culinaris genotype, while the giberellin synthesis was only induced in the susceptible L. c. culinaris cv. 'Lupa'. A set of 18 lentil gene sequences putatively involved in the response to the pathogen were validated by RT-qPCR.Research highlights: It can be concluded that in response to the infection by Ascochyta, the lignin biosynthesis and the JA pathway were critical for the resistance, while the giberellin synthesis seems to be related with susceptibility to the pathogen

Spain’s national network of silos and granaries: architectural and technological change over time

Aim of study: To analyse the 670 silos in Spain’s NNSG (National Network of Silos and Granaries), along with the changes in typologies and degree of mechanisation taking place over time.Area of study: Spain.Material and methods: Research began in 2014, collecting NNSG grain storage data across Spain further to the methodology developed by the authors. In a first stage the information was gathered from the FEGA’s general archives in Madrid and the archives of the departments of agriculture in the 13 regions where silos were built. In the second stage of the study, 665 silos were explored in situ. Photographs were taken and information was gathered on their characteristics (general features; architectural features; technological facilities).Main results: This paper discusses the architectural and typological changes taking place over time, from the earliest small, local, richly adorned brick silos to larger, more modern and austere reinforced concrete structures. The machinery with which they are fitted is also addressed, with the progression from basic grain storage to more sophisticated equipment designed to clean, refrigerate or disinfect the grain. Some facilities were used exclusively to select and condition seed for subsequent sowing. The most modern structures, known as macrosilos, are highly mechanised affairs.Research highlights: Spain’s national network of silos and granaries was 41 years in the building. The inventory of the 665 existing silos identified 20 types or subtypes. Early richly adorned units gradually gave way to more austere, functional structures. The machinery in place in silos varied with type/purpose and period of construction

Nitrogen mineralization of legume residues: interactions between species, temperature and placement in soil

Aim of study: To assess the interactive effects of legume species, residue placement and temperature on the net nitrogen (N) mineralization dynamics in a sandy loam soil.Area of study: Northern PortugalMaterial and methods: Cowpea (Vigna unguiculata L. Walp), faba bean (Vicia faba L.) and pea (Pisum sativum L.) residues were incorporated or applied to the soil surface at typical field yields in Europe and incubated in aerobic conditions for up to 240 days, either at 10ºC or 20ºC. Initial chemical characteristics of the soil and residues were determined. Net N mineralization was estimated at eight time intervals.Main results: Cowpea residues caused no negative changes in soil mineral N contents and were able to release the equivalent of 21-45 kg N ha-1 in 240 days. Net N immobilization (up to 17 kg N ha-1) was observed throughout most of the trial in soil with faba bean and pea residues. Differences in mineralization patterns could be attributed to the higher quality (lower carbon to nitrogen (C:N) ratios) of cowpea. Surface placement increased net N mineralized by as much as 18 kg N ha-1. The sensitivity of N mineralization to changes in temperature and residue placement varied with legume species, likely due to effects associated with differences in C:N ratios.Research highlights: Adding cowpea residues to soil is suitable when high N availability is immediately required. Faba bean or pea residues are better suited for conservation of soil N for later release