Showing papers in "The Journal of Agricultural Science in 2020"

Prediction of Bhutan's ecological distribution of rice (Oryza sativa L.) under the impact of climate change through maximum entropy modelling

Abstract: The current research investigated the present and future projected distribution of rice (Oryza sativa L.) based on climatic suitability under three representative concentration pathways (RCPs) of the Intergovernmental Panel on Climate Change using maximum entropy (MaxEnt) modelling. The MaxEnt models predict that rice distribution in Bhutan will undergo major changes in terms of spatial range shift of varying magnitudes by 2060. Under the anthropogenic radiative forcing of RCP2.6, RCP4.5 and RCP8.5, ecological space of rice is predicted to change between 1 and 43%. Major changes are likely to take place in major rice-growing ecological zones of the country. This is likely to have a negative impact on the livelihood and food security of the people as crop production might start declining due to unfavourable climatic factors. Therefore, the findings of this study could prove beneficial for forecasting focus sites requiring interventions, including future climate research, planning, policy formulation and conservation of natural resources.

Grand challenges for the 21st century: what crop models can and can't (yet) do

Abstract: Crop production is at the core of a 'perfect storm' encompassing the grand challenges of achieving food and nutrition security for all, in the face of climate change, while avoiding further conversion of natural habitats for agriculture and loss of biodiversity. Here, we explore current trends in crop modelling related to these grand challenges by reflecting on research presented at the Second International Crop Modelling Symposium (iCropM2020). A keyword search in the book of abstracts of the symposium revealed a strong focus on 'climate change', 'adaptation' and 'impact assessment' and much less on 'food security' or 'policy'. Most research focused on field-level investigations and far fewer on farm(ing) systems levels - the levels at which management decisions are made by farmers. Experimentation is key to development and testing of crop models, yet the term 'simulation' outweighed by far the terms 'experiments' and 'trials', and few contributions dealt with model improvement. Cereals are intensively researched, whereas roots, tubers and tropical perennials are under-researched. Little attention is paid to nutrient limitations apart from nitrogen or to pests and diseases. The aforementioned aspects represent opportunities for future research where crop models can help in devising hypotheses and driving new experimentation. We must also ensure that crop models are fit for their intended purposes, especially if they are to provide advice to policymakers. The latter, together with cross-scale and interdisciplinary efforts with direct engagement of stakeholders are needed to address the grand challenges faced by food and agricultural systems in the next century.

The role of homofermentative and heterofermentative lactic acid bacteria for alfalfa silage: a meta-analysis

Abstract: Lactic acid bacteria (LAB) are usually employed as alfalfa silage inoculants to obtain high-quality feed for animal husbandry. However, the effects of these inoculants are still unclear and need to be studied extensively. Therefore, the objective of this meta-analysis was to quantitatively summarize published research studies that assess the effects of homofermentative (HoLAB) and heterofermentative lactic acid bacteria (HeLAB) on fermentation parameters, nutritive value, microbiological composition and aerobic stability of alfalfa silage. PubMed, ScienceDirect and Scopus have been screened for articles published from 1980 to 2018. The criteria for inclusion were: randomized and controlled trials using alfalfa silage and published in peer-reviewed journals. It was found that inoculation with LAB decreased silage pH, neutral detergent fibre, acid detergent fibre and ammoniacal nitrogen, while it increased dry matter and crude protein compared to control in the pooled raw mean difference random-effect model. Additionally, LAB inoculation decreased acetate, propionate, ethanol and butyrate concentrations, whereas it increased lactate. In addition, inoculants reduced the counts of yeasts and moulds. Lastly, LAB inoculation improved aerobic stability. To the best of our knowledge, this is the first meta-analysis that aims at comparing the application of HoLAB and HeLAB for alfalfa silage. In the pool estimate, positive effects attributable to the application of microbial silage inoculants were found in most of the evaluated parameters; supporting the importance of applying both types of inoculants to improve forage preservation for the livestock industry.

The effects of cropping sequence, fertilization, and straw management on the yield stability of winter wheat (1986–2017) in the Broadbalk Wheat Experiment, Rothamsted, UK.

Abstract: The development of resilient cropping systems with high yield stability is becoming increasingly important due to future climatic and agronomic challenges. Consequently, it is essential to compare the effects of different agronomic management practices, such as cropping sequences and nutrient supply, on the stability of crop yields. Long-term experiments are a valuable resource for investigating these effects, as they provide enough time to accurately estimate stability parameters. The objective of the current study was to compare the effects of different cropping sequencing (#1: continuous v. rotational), fertilization (#2: mineral v. organic) and straw management techniques (in the case of continuous wheat; #3: removal v. incorporation) on the yield stability of winter wheat; yield risk (the probability of yield falling below a threshold yield level) and inter-annual yield variability were used as stability indicators of the effects. Long-term yield data from the Broadbalk Wheat Experiment (Rothamsted, UK) were analysed using a mixed model. Overall, the results showed that rotational cropping combined with sufficient mineral N fertilizer, with or without organic manure, ensured stable wheat yields while reducing yield risk. In contrast, higher yield risks and inter-annual yield variabilities were found in continuous wheat sections with less mineral N fertilizer or with organic manure only.

Impact of ICT based extension services on dairy production and household welfare: The case of iCow service in Kenya

Abstract: Smallholder dairy farmers have the challenges of accessing timely and reliable agricultural information, and this limits them from realizing maximum farm output. The use of information and communication technologies (ICT) as a farming extension tool by smallholder farmers has the potential to reverse the scenario and improve farmers’ outputs and incomes leading to increased welfare. This study employed the Propensity score Matching approach to evaluate the impacts of ICT-based extension services, in this case, iCow services on milk production, milk income, and household income using cross-sectional data from a survey of dairy farmers in Uasin Gishu, Nyandarua and Bomet counties of Kenya. The use of ICT-based iCow services is shown to increase Annual milk production per cow, milk income, and household income by 13%, 29%, and 22%, respectively. Partnerships between network providers and research institutes should be encouraged as part of bridging the extension gap occasioned by reduced public expenditure on extension services.

Quantification of Bioactive Molecules, Minerals and Bromatological Analysis in Carao (Cassia grandis)

Abstract: Medicinal plants have various beneficial conditions for humanity, one of them is its medicinal contribution due to the presence of phytochemicals and antioxidants, characterized by these bioactive compounds as the main source of nutraceuticals. The fruit of Cassia grandis, traditionally known as carao, is a plant that is attributed antimicrobial and medicinal properties. The objective of this work was to determine the bromatological, mineralogical composition and bioactive molecules of carao in the department of Choluteca (Honduras). Total phenolic compounds determined by the Folin-Ciocateau method resulted in higher concentrations in the seeds 11.1±0.3 mg EAG 100 g-1. The antioxidant activity was also found to be higher in carao seeds, with concentrations of 7.31±0.11 μg g-1 of DPPH and total carotenoids showed higher concentration in the pulp with a concentration of 4.12±0.11 μg mL-1. Among the macro minerals, high concentrations of magnesium and calcium stand out in the seed with a concentration of 18.27±0.14 mg 100 g-1 and 7.31±0.23 mg 100 g-1 respectively. Among the microminerals, iron stands out in higher concentrations than in the rest of the microminerals being higher in the shell with concentrations of 1.71±0.23 mg 100 g-1 followed by manganese in concentrations of 0.51±0.12 mg 100 g-1.

Carbon stocks and the use of shade trees in different coffee growing systems in the Peruvian Amazon

Abstract: Agroforestry systems can play an important role in mitigating the effects of climate change given their capacity to increase tree diversity and to store more carbon than conventional farming. This study aims at assessing carbon stocks and the use of shade trees in different coffee growing systems in the Northeast Peruvian Amazon. Carbon stocks in trees were estimated by field-based measurements and allometric equations. Carbon stocks in dead wood, litter and soil (upper 60 cm) were determined using field sampling and laboratory analysis. The diversity analysis drew on the Shannon–Weiner diversity index, and focus groups were used to obtain information about the local use of shade trees. The total carbon stock in the polyculture-shaded coffee system was 189 t C/ha, while the Inga-shaded and unshaded systems totalled 146 and 113 t C/ha, respectively. The soil compartment contributed the largest carbon stock in the coffee growing systems and contained 67, 82 and 96% of the total carbon stock in the polyculture-shaded, Inga-shaded and unshaded coffee systems, respectively. The Shannon–Weiner index and tree species richness values were highest for the polyculture-shaded coffee system, with a total of 18 tree species identified as important sources of fodder, food, wood, firewood and medicine. Therefore, coffee agroforestry systems play a significant role in carbon storage, while promoting conservation of useful trees in agricultural landscapes in the Peruvian Amazon.

Substituting chemical fertilizer nitrogen with organic manure and comparing their nitrogen use efficiency and winter wheat yield

Abstract: A 2-year fertilization experiment was conducted to study the effect of different ratios of organic (pig) manure on wheat yield and nitrogen use efficiency (NUE). The four treatments were no nitrogen (N) (CK); 100% chemical fertilizer N (urea; T1); 70% chemical fertilizer N + 30% organic manure N (T2) and 50% chemical fertilizer N + 50% organic manure N (T3), with the same amount of applied nitrogen (120 kg/ha). The results showed the maximum grain yield (3049 kg/ha), crop nitrogen uptake (216 kg/ha), NUE (65.4%) and accumulated nitrate nitrogen (NO3−-N in 0–200 cm, 142 kg/ha) were observed in the T1 among all treatments in the first year. However, the largest grain yield (5074 kg/ha), crop nitrogen uptake (244 kg/ha) and NUE (82.5%) were under T2 treatment in the second year. Furthermore, T2 had the maximum NO3−-N content in 0–100 cm layer (116 kg/ha), especially 0–40 cm layer, and the lowest NO3−-N content in 100–200 cm (58.8 kg/ha). However, 50% organic manure N in T3 increased apparent nitrogen loss by 39.0% compared to that in T2. Therefore, 30% organic manure N application was more conducive for enhancing wheat yield and NUE and promoting environmental safety after 1-year fertilization time.

In situ and in vitro techniques for estimating degradation parameters and digestibility of diets based on maize or sorghum

Abstract: An experiment was conducted to evaluate: (1) the effects of ensiling maize or sorghum grains after reconstitution on readily soluble fraction (a), potentially degradable fraction in the rumen (b) and rate constant for degradation of b (c) of dry matter (DM), organic matter (OM) and starch (STA); and (2) an appropriate incubation time for in situ or in vitro procedures to estimate in vivo digestibility. Four rumen-cannulated Nellore bulls (body weight = 262 ± 19.6 kg) distributed in a 4 × 4 Latin square were used. Diets were based on dry ground maize (DGM); or dry ground sorghum (DGS); or reconstituted ground maize silage; or reconstituted ground sorghum silage. In vitro and in situ incubations of the individual grains and diets were simultaneously performed with in vivo digestibility. In general, reconstituted grains and diets based on reconstituted grains presented greater (P 0.05) were observed between DGM- and DGS-based diets for c estimates. The results suggest that the reconstitution process promotes grains protein matrix breakdown increasing STA availability. The incubation times required for in vivo digestibility estimations of DM, OM and STA are 24 h for in situ and 36 h for in vitro procedures.

The effect of heat stress on quinoa (cv. Titicaca) under controlled climatic conditions

Abstract: Quinoa (Chenopodium quinoa Willd.) is capable of adapting to multiple environments and tolerating abiotic stresses including saline, drought and frost stress conditions. However, the introduction of quinoa into new environments has disclosed adaptation challenges. The principle factor affecting crop pollination is heat stress at flowering, which leads to sterile plants. To investigate the effect of high temperatures during the sensitive phenological phases, flowering and seed germination, a Danish-bred cultivar (cv. Titicaca) was grown in climatic chambers. Selection of the cv. Titicaca was based on the fact that it is the most extensively used cultivar in the Sahel and Middle East and North African region. The results of this research demonstrated that temperatures exceeding 38 °C hindered seed germination and pollination, and therefore, seed yield at harvest. At 38 °C, seed yield losses were 30%, whilst seed germination percentage declined below 50%. In addition, the results of the present research were compared with field observations from Burkina Faso in order to determine the spatiotemporal suitability of this crop with respect to temperature stress. Although many other abiotic stresses need to be considered when defining crop calendars (e.g. heavy precipitation in July and August), this research proposes the following growing periods to avoid heat-stress conditions at flowering: Sahel (July–September and November–February), Soudano–Sahel (June–February) and Soudanian zone (all year round).

Insecticide Resistance and Detoxification Enzymes Activity in Nilaparvata lugens Stål Against Neonicotinoids

Abstract: The Nilaparvata lugens (Stal) is one of the most destructive pests of rice crops in Asian. To assess the resistance of imidacloprid, thiamethoxam, clothianidin, and nitenpyram, N. lugens exposed to each pesticide up to 15 generations. Results showed that the resistance of N. lugens increased significantly against imidacloprid, thiamethoxam, clothianidin, and nitenpyram (neonicotinoids) under selection pressure. There was a 118.07-fold increase in resistance against imidacloprid, 90.37-fold against thiamethoxam, 217.81-fold against clothianidin, and 34.09-fold against nitenpyram in 15th generation as compared to F0. Based on fold increase, imidacloprid and clothianidin subjected for enzymatic analysis and results showed that enzyme activity involves resistance development against neonicotinoids. Cytochrome P450, esterase, and GST had significantly higher activity as the generation passes under the selection pressure of imidacloprid and clothianidin. There was a significant correlation existed between GST, and esterase activity, when compared to LC50 of imidacloprid. GST, esterase and P450 showed a significant correlation with LC50 of clothianidin. The results showed that detoxification enzymes play an important role in insecticide detoxification. When the mixture of imidacloprid and clothianidin tested results showed that the mortality exerted was similar to control when imidacloprid and clothianidin resistant populations were exposed.

Evaluating the potential of different carbon sources to promote denitrification

Abstract: Organic carbon (C) plays an essential role in the denitrification process as it supplies energy for N2O, N2 and CO2 producing reactions. The objectives of this study were to: (i) rank the reactivity of different C compounds found in manures based on their availability for denitrification and (ii) explore C-quality in different C sources based on their capacity to promote denitrification. Evaluation of different C-sources in promoting denitrification was conducted based on the molar ratio of CO2 production to NO3− reduction after incubation. Results of the first experiment (a 12-day investigation) showed that glucose and glucosamine were highly reactive C compounds with all applied NO3− being exhausted by day 3, and glucosamine had significantly high amount of NH4+-N present at end of the experiment. The glucose and glucosamine treatments resulted in significantly greater cumulative CO2 production, compared to the other treatments. In the second experiment (a 9-day investigation), all NO3− had been depleted by day 6 and 9 from acetic acid and glucose, respectively, and the greatest cumulative CO2 production was from acetic acid. The CO2 appearance to NO3− molar ratios revealed that glucose and glucosamine were compounds with highly available C in the first experiment. In the second experiment, the pig slurry and acetic acid were found to be C-sources that promoted potential denitrification. The application of slurry to soil results in the promotion of denitrification and this depends on the availability of the C compounds it contains. Understanding the relationship between C availability and denitrification potential is useful for developing denitrification mitigation strategies for organic soil amendments.

Fermentation profile and nutritional quality of silages composed of cactus pear and maniçoba for goat feeding

Abstract: This study aimed to evaluate the fermentation profile and nutritional quality of silages composed of cactus pear and manicoba. Two experiments were performed: the first evaluated the fermentation characteristics, chemical composition and determined the organic acids in cactus pear silages with the inclusion of five levels of manicoba (0, 25, 50, 75 and 100%) in six opening times (1, 7, 15, 30, 60 and 90 days). The second experiment determined the nutrient intake, digestibility, water balance and nitrogen balance in Caninde goats fed diets based on cactus pear silage with the inclusion of four levels of manicoba (25, 50, 75 and 100%), with six animals per treatment. The increase in manicoba levels in cactus pear silage provided a linear increase in the butyric acid, dry matter (DM), ether extract, crude protein, neutral detergent fibre, acid detergent fibre, lignin, cellulose, hemicellulose, water intake via drinking fountain and metabolic water, and reduced the pH, lactic acid, acetic acid, mineral matter, total carbohydrates, non-fibrous carbohydrates, water intake via food, total water intake, water excreted in the faeces, water excreted in the urine, total water excretion and water balance. Quadratic behaviour was observed for N-NH3, DM recovery and propionic acid, with an increase in manicoba levels in cactus pear silages. Regarding the different opening times, there was a significant effect in pH, N-NH3, acetic acid, lactic acid and butyric acid (P < 0.050). The inclusion of manicoba in cactus pear silage improved the fermentation characteristics and nutritional quality to be used in diets for goats.

Eco-efficiency Assessment in Agriculture: A Literature Review Focused on Methods and Indicators

Abstract: Combining economic performance with environmental and social concern has been a developing topic in recent decades Eco-efficiency analysis is a widely applied tool to assess the efficiency of agricultural systems, while increasingly considering their environmental and social impact The main objective of this article is to accomplish a literature review on the application of eco-efficiency analysis in agricultural systems, focusing on methods and indicators that are most regarded for the quantitative assessment of agricultural eco-efficiency The literature review found two main methods most widely applied to assess eco-efficiency: Life Cycle Assessment (LCA) and Data Envelopment Analysis (DEA), which are often combined LCA is generally focused on the assessment of the environmental impacts of products and practices DEA is mostly used to measure the eco-efficiency of decision-making units, such as farms, regions, or countries, and has no subjective focus on neither technical nor environmental performance Both methods share a wide range of economic and environmental indicators but fail to incorporate the social dimension of sustainability into the eco-efficiency analysis A simple framework, based on Data Envelopment Analysis, is offered to assess the eco-efficiency of the Brazilian agriculture, aiming at identifying the benefits and limitations of the analysis

Marine and fungal biostimulants improve grain yield, nitrogen absorption and allocation in durum wheat plants

Abstract: Durum wheat culture requires a high fertilization rate to achieve sufficient protein concentration for semolina and pasta quality, contributing to losses through atmosphere and water. Optimizing plant capacity to use N could help improve its agroenvironmental balance Our objective was to study the impact of the marine extract DPI4913 and the fungal extract AF086 on growth, N absorption and fluxes in durum wheat.Three experiments were conducted in France: under standard N 25 fertilization in a first field (Carbonne, 43.333328 N, 1.33333 E), under varying N supply in a second field (Mervilla, 43.503451 N, 1.472316 E) and under varying water conditions in greenhouse (Toulouse, 43.527272 N, 1.501492 E). Various 15N labelling experiments were performed at flag leaf fully emerged stage to follow N fluxes until maturity. In Carbonne, 15NO3- and 15NH4+ were injected in the soil to investigate the effect of biostimulants on allocation to grains of soil mineral N. In greenhouse, some plants were 15NH4+ labelled on the flag-leaf to follow N remobilization. For other plants, flag-leaf was removed at flag-leaf fully emerged stage to characterize flag-leaf implication in N translocation to grains. Flag leaf senescence was studied estimating leaf chlorophyll concentration with the SPAD-502 meter. Under standard N conditions, biostimulants increased mean grain yield in the field (+1.8 % for DPI4913 and 4.0 % for AF086 in Carbonne; +5.5 % for DPI4913 and +3.9 % for AF086 in Mervilla; not significant). In greenhouse, under water standard conditions, biostimulants increased grain yield (+19.7% for DPI4913, +19.3 % for AF086), total N in plant and in ear (respectively +28.9 % and +44.6 % for DPI4913, +23.3 % and +32.7 % for AF086) and proportion of N in the ear (68.7 % for CONTROL, 77.1 % for DPI4913, 74.2 % for AF086). Biostimulants had no effect under N and water stress conditions. In the field, DPI4913 increased soil mineral N accumulated in grains at maturity (15N labelling). In greenhouse, flag leaf N was very mobile (15N resorption of 98.2 %). Biostimulants increased the proportion of 15N applied to the flag leaf recovered in grains (40.9 % for Control, 52.5 % for DPI4913, 47.2 % for AF086, p-value=0.09) and accelerated leaf senescence (SPAD-measurements). Flag leaf key-role in grain filling processes was revealed by the fact that flag leaf ablation decreased N amount in grains more than flag leaf N content at the time of ablation (respectively - 5.9 mg and - 2.7 mg). The increase in N remobilization from flag leaf represented 4.3 % of the supplementary amount of N found in grains for plants treated with DPI4913 and 0.6 % with AF086. Biostimulants mainly increased mineral N root uptake rather than remobilization. In conclusion, it is suggested that DPI4913 and to a lesser extent AF086 – which promote plant growth, N uptake and remobilization – could be used in standard N and water conditions to optimize durum wheat N fertilization.

Brachiaria and Panicum maximum in an integrated crop–livestock system and a second-crop maize system in succession with soybean

Abstract: Owing to its contribution to the maintenance of carbon stocks, soil nitrogen and nutrient cycling for subsequent crops, the integrated systems become increasingly important for agricultural conservation. Thus, the objective of this study was to evaluate the biomass production of and total nutrient in Brachiaria spp. and Panicum maximum forage grasses used as mulch and soybean yields in an integrated crop–livestock system and second-crop maize succession system. The treatments consisted of the following cropping systems: Xaraes palisadegrass intercropped with soybean, Congo grass intercropped with soybean, Mombaca guinea grass intercropped with soybean, Tamani guinea grass intercropped with soybean and a soybean/maize succession system. The forage grasses were established during the soybean R6–R7 stage. Compared with Congo grass, Xaraes palisadegrass, Mombaca guinea grass and Tamani guinea grass produced more biomass and equivalent amounts of fertilizer returned to the soil and resulted in greater nutrient cycling, indicating the benefits of these grasses for use as mulch in integrated production systems. Maize had a greater C/N ratio, but the forage grasses also exhibited high potential by protecting the soil until the end of the soybean development cycle. The use of an integrated crop–livestock system combined with a forage cropping system provided greater soil nutrient cycling than the maize cropping system did, which resulted in increased soybean yields, thus contributing to the sustainability of agricultural systems.

Genome introgression of Híbrido de Timor and its potential to develop high cup quality C. arabica cultivars.

Abstract: Hibrido de Timor is the principal source for disease and pest resistance genes in C. arabica breeding program worldwide. The part of the chromosome responsible for resistance introgressed from C. canephora to Hibrido de Timor are claimed to affect the cup quality of the C. arabica cultivars derived from the crossing program of Hibrido de Timor. Therefore, this work was done to study the genome introgression of Hibrido de Timor and its impact on the cup quality on the C. arabica cultivars. For genome introgression and genetic relationship analysis, seventy-six accessions from C. arabica, C. canephora and Hibrido de Timor were analyzed using AFLP and SSR molecular markers. To understand the effect of genome introgressed from Hibrido de Timor on cup quality, three C. arabica, seven Hibrido de Timor and six cultivars derived from Hibrido de Timor × C. arabica were genotyped using SSR molecular markers and sensorial analysis was performed. The genetic diversity analysis among the tested genotypes showed high genetic similarity between Hibrido de Timor with C. arabica and clear differentiation among coffee species. The analysis of genome introgression of C. arabica and C. canephora var Robusta into Hibrido de Timor not reach 30% of C. canephora genome. The sensorial analysis of coffee genotypes demonstrated non-significant difference on cup quality parameters among C. arabica cv Bourbon and cultivars derived from Hibrido de Timor that showed the possibility of developing C. arabica cultivars without affecting the cup quality. Similarly, the SSR marker diversity showed high genetic similarity between the Bourbon and the C. arabica cultivars derived from Hibrido de Timor.

The characterization of the cow-calf, stocker and feedlot cattle industry water footprint to assess the impact of livestock water use sustainability

Abstract: Perception of freshwater use varies between nations and has led to concerns of how to evaluate water use for sustainable food production. The water footprint of beef cattle (WFB) is an important metric to determine current levels of freshwater use and to set sustainability goals. However, current WFB publications provide broad WF values with inconsistent units preventing direct comparison of WFB models. The water footprint assessment (WFA) methodologies use static physio-enviro-managerial equations, rather than dynamic, which limits their ability to estimate cattle water use. This study aimed to advance current WFA methods for WFB estimation by formulating the WFA into a system dynamics methodology to adequately characterize the major phases of the beef cattle industry and provide a tool to identify high-leverage solutions for complex water use systems. Texas is one of the largest cattle producing areas in the United States, a significant water user. This geolocation is an ideal template for WFB estimation in other regions due to its diverse geography, management-cultures, climate and natural resources. The Texas Beef Water Footprint model comprised seven submodels (cattle population, growth, nutrition, forage, WFB, supply chain and regional water use; 1432 state variables). Calibration of our model replicated initial WFB values from an independent study by Chapagain and Hoekstra in 2003 (CH2003). This CH2003 v. Texas production scenarios evaluated model parameters and assumptions and estimated a 41–66% WFB variability. The current model provides an insightful tool to improve complex, unsustainable and inefficient water use systems.

Phenology and plant functional type dominance drive CO2 exchange in seminatural grasslands in the Pyrenees

Abstract: Understanding the mechanisms underlying net ecosystem CO2 exchange (NEE) in mountain grasslands is important to quantify their relevance in the global carbon budget. However, complex interactions between environmental variables and vegetation on NEE remain unclear; and there is a lack of empirical data, especially from the high elevations and the Mediterranean region. A chamber-based survey of CO2 exchange measurements was carried out in two climatically contrasted grasslands (montane v. subalpine) of the Pyrenees; assessing the relative contribution of phenology and environmental variables on CO2 exchange at the seasonal scale, and the influence of plant functional type dominance (grasses, forbs and legumes) on the NEE light response. Results show that phenology plays a crucial role as a CO2 exchange driver, suggesting a differential behaviour of the vegetation community depending on the environment. The subalpine grassland had a more delayed phenology compared to the montane, being more temperature than water constrained. However, temperature increased net CO2 uptake at a higher rate in the subalpine than in the montane grassland. During the peak biomass, productivity (+74%) and net CO2 uptake (NEE +48%) were higher in the subalpine grassland than in the montane grassland. The delayed phenology at the subalpine grassland reduced vegetation's sensitivity to summer dryness, and CO2 exchange fluxes were less constrained by low soil water content. The NEE light response suggested that legume dominated plots had higher net CO2 uptake per unit of biomass than grasses. Detailed information on phenology and vegetation composition is essential to understand elevation and climatic differences in CO2 exchange.

Tannin Supplementation in Animal Feeding; Mitigation Strategies to Overcome the Toxic Effects of Tannins on Animal Health: A Review

Abstract: Optimum animal production depends on the type of feedstuffs available for the whole year. Plants such as trees and shrubs have significance in the animal production due to high nutritious values of tannins which reduce the rumen protein degradability and improve the feed digestibility as well as amino acid absorption in the small intestine. But, some of these plant materials are usually rich in anti-nutritional factors, known as tannins. Tannins are a complex group of plant secondary compounds widely distributed in the plant kingdom. Tannins have both deleterious and advantageous effects depending on the types, doses, composition and concentration of tannins. Rural farmers face fodder scarcity during the winter season. Therefore, tannins containing browse species may help farmers to use tannins as supplementary feed for livestock. But higher concentrations of tannins cause metabolic disorder which in results reduces the animal productivity. Therefore, it is need to investigate the effects of tannin supplementation in animal feeding; mitigation strategies to overcome the toxic effects of tannins on animal health. In this review paper, we have discussed safety and hazard associated with tannins in animal feeding.

Model-based yield gap analysis and constraints of rainfed sorghum production in Southwest Ethiopia

Abstract: For ensuring food demand of the fast growing population in developing countries, quantification of crop yield gaps and exploring production constraints are very crucial. Sorghum is one of the most important climate change resilient crops in the rainfed farming systems of semi-arid tropics. However, there is little information about yield gaps and production constraints. This study aimed at analysing existing yield gaps and exploring major constraints of sorghum production in Southwest Ethiopia. A crop simulation model approach using AquaCrop and DSSAT was used to estimate potential yield and analyse the yield gaps. Model calibration and evaluation was performed using data from field experiments conducted in 2018 and 2019. Sorghum production constraints were assessed using a survey. The actual and water-limited yield of sorghum ranged from 0.58 to 2.51 and 3.6 to 6.47 t/ha, respectively for the period 2003–17. The regional yield gaps of sorghum for the targeted period were 3.02–3.95 t/ha with a mean value of 3.51 t/ha. Majority of respondent farmers considered seasonal rainfall risk (98%), poor soil fertility (86%), lack of improved varieties (78%) and inadequate weed management (56%) as major factors responsible for the existing yield gaps. The mean exploitable yield gap (2.5 t/ha) between water-limited and actual yield showed the level of existing opportunity for improvement in the actual productivity of sorghum. The gaps also call for introduction of proper interventions such as adoption of improved varieties, planting date adjustment, conservation tillage, fertilizer application and on time weed management.

Rural Public Expenditure and Poverty Alleviation in China: A Spatial Econometric Analysis

Abstract: In China, one of the most important reducing poverty means is continuous and large-scale public financial investment. This paper investigated the structural differences between rural public expenditure (namely, education, health, social security, infrastructure, living environment) and poverty in 27 provinces of China in 2010-2016 from the spatial econometric perspective. The results showed the structural differences in poverty reduction effects of government spending are very obvious, indicating that expenditures on education, health care, social security and infrastructure have all shown good poverty alleviation effects, while living environment spending has no significant effect on poverty reduction. We further find that government spending not only promote poverty reduction in the region, but also reduce poverty in economically and geographically similar areas, which suggests that future work should look more closely at whether and how the effect of government spending on poverty varies by structure. Thus, the findings established in this paper have significant implications for targeted poverty alleviation measures in China through government spending policies.

Influence on tail-biting in weaning pigs of crude fibre content and different crude fibre components in pigs' rations

Abstract: The aim of the study was to analyse the influence on tail-biting in undocked pigs during the rearing period of crude fibre in piglets' rations. All pigs were fed the same pre-starter until weaning. The study comprised two trials with four experimental groups each. The first trial contained: a control group (CG1) with conventional feed (up to 40 g/kg crude fibre), two groups with an increased crude fibre content of up to 50 g/kg (G5) and 60 g/kg (G6), respectively, and one group with conventional feed and crude fibre provision ad libitum (AL). The second trial consisted of a control group (CG2) which received the same conventional feed as CG1 and three treatment groups with either soya hulls (SS), dried sugar beet pulp (DP) or oat fibre (OF) admixed to their ration, to achieve a crude fibre content of 60 g/kg in all three groups. The rearing week, the batch, the treatment group (only in trial one) and the interaction between batch and treatment group had a significant influence on tail-lesions (P < 0.05). The tail-biting process started in rearing week 3 (trial one) and 5 (trial two), respectively. Due to the low frequency of tail-biting during the present study, crude fibre seems to have no major influence on tail-biting during the rearing period. This unexpected result may be caused by the optimized conditions in which the piglets were kept and the intensive animal observation carried out by the employees. However, the batch effect was most influential.

Identification and evaluation of the main risk periods of Botrytis cinerea infection on grapevine based on phenology, weather conditions and airborne conidia

Abstract: In the present study, a new method for a decision-support system for fungicide administration against the pathogen Botrytis cinerea in vineyards was developed based on Integrated Pest Management principles which identified an infection risk before the appearance of disease symptoms. The proposed method is based on the combination of (i) the phenological observations of the main susceptible stages to infection, (ii) the airborne spores monitoring, (iii) the forecasting of the suitable meteorological conditions for B. cinerea spore germination during the subsequent 4–6 days after the spore detection. Aerobiological, phenological and meteorological analyses were carried out using data from 2008 to 2015 in a vineyard of Northwestern Spain. Aerobiological spore data were obtained using a Lanzoni VPPS-2000 pollen-spore trap. Phenological observations were conducted on 22 plants of Treixadura cultivar following the BBCH (Biologische Bundesanstalt fur Land und Forstwirtschaft, Bundessortenamt und CHemische Industrie) scale. The Magarey generic fungal model was applied for the identification of the main meteorological suitable periods for infection within the susceptible phenological stages of flowering and ripening of berries. Our results showed that climatic conditions favoured fungal development during flowering, although a higher incidence of B. cinerea infection risk-periods occurred during the prior-to-harvest stage of ripening of berries, the most susceptible phenological stage to B. cinerea infection obtained by the proposed methodology. This approach enables more precise targeting in pesticide spraying and reduction in pesticide application from 4–5 to 2–3 times per year at our commercial study. It also illustrates the real-world benefits of integrated disease risk modelling.

A probit Analysis of Determinants of Adoption of Improved Sorghum Technologies Among Farmers in Tanzania

Abstract: The adoption of improved sorghum technologies by smallholder farmers is still low in Tanzania. Many farmers fail to acquire quality inputs due to different underlying reasons. This article analyzes factors underlining the adoption of improved technologies among sorghum farmers in Tanzania and evaluates profitability of grain production. A total of 212 individual farmers were interviewed through structured questionnaires from nine districts. Data were analyzed using descriptive statistics, probit regression model and gross margin analysis. Results show that 39.2%, 26.5%, 16.9%, 8.4% and 7.2% of sorghum farmers adopted seeds of improved varieties, insecticides, inorganic fertilizers, threshing machine and optimum seed rate, respectively. Probit estimates indicated that age, sex, number of years in school, group membership, farm size, availability of free seeds, seed accessibility, grain market accessibility and grain market price were the significant factors influencing adoption of these technologies. Adopters obtained higher profitability (822,288 Tshs/ha) than non-adopters (374,363 Tshs/ha) of improved varieties. Further policy actions are needed to improve determinants of adoption, breeding technologies and accessibility of agricultural inputs to ensure benefits to farmers and the sorghum sub-sector.

Performance of Spodoptera frugiperda (Lepidoptera: Noctuidae) Fed on Six Host Plants: Potential Risks to Mid-high Latitude Crops in China

Abstract: The fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a polyphggous and widespread insect pest. In the study, the biological characteristics and nutritional indices of S. frugiperda fed on six crops, namely corn, sorghum, wheat, soybean, peanut, and cotton, were investigated under laboratory conditions. These crops are cultivated mainly in the mid-high latitude of China. Results showed that S. frugiperda was able to develop and reproduce on all six tested plants. Larvae reared on corn exhibited a significant shorter larval and pupal duration, higher pupal weight, and higher fecundity, which were 16.2 d, 8.9 d, 0.248 g, and 979.4 eggs per female, respectively. The host plant significantly affected relative growth, consumption, and metabolic rates, as well as other nutritional indices. Biology and nutritional indexes suggested that corn was the most suitable host. Besides, peanut, sorghum, and wheat have also been shown to be the suitable hosts for S. frugiperda. Although cotton and soybean were found to be less adequate, high larval and pupal survivors recorded on cotton and soybean leaves have indicated that damage may occur in these plants. This work reveals the damage risk of potential hosts of S. frugiperda, lays the foundation for the design of pest management strategies.

Enhanced-Efficiency Phosphorous Fertilizer Impacts on Corn and Common Bean Crops and Soil Phosphorus Diffusion

Abstract: Phosphorus (P) supply to crops is a major constraint on the quantity and quality of food production in tropical soils, which are often characterized by highly weathered soils having low phosphorus use efficiency Increasing P fertilizer use efficiency is a good tool for increasing food production to feed an increasing world population Enhanced efficiency P fertilizer is used to achieve this goal The lack of information about soil P diffusive flux and corn and common bean yield response with increased efficiency P fertilizers justify studies to evaluate the performance of this type of fertilizer The aims of this study were to evaluate P diffusive flux and corn and common bean crop response to P sources and rates A laboratory trial was carried out to evaluate soil P diffusive flux in response to P sources (MAP and Policote coated MAP) Field trials were carried out to evaluate corn and common bean yields in response to P sources (MAP and Policote coated MAP) and rates Policote, an additive based on water-soluble polymers, is an anionic copolymer with iron an aluminum affinity Increasing contact time between P-fertilizers and soil reduced phosphorus diffusive flux Policote coated P-fertilizer resulted in higher phosphorus diffusion than conventional phosphorus fertilizer Phosphorus fertilization increased corn and common bean yields Policote coated phosphorus fertilizer resulted in higher agronomic P efficiency use, corn, and common bean yields than conventional phosphorus fertilizer Policote coated P fertilizer can be used as an enhanced efficiency fertilizer and is a more efficient way to deliver required phosphorous to plants Reducing farm investment, increasing agricultural profits, preserve phosphatic rocks reserves, and avoid the overuse of phosphate fertilizer could be realized through the rational use of enhanced efficiency fertilizers and fertilizer rate use reduction

Phytotoxic Potential of Benzyl Salicylate and Benzyl Benzoate on Bioindicator and Invasive Species

Abstract: The growing number of invasive species in agricultural areas reduces productivity and results in production losses. The need to discover new compounds with herbicidal activity increases as cases of resistance of invasive plants to herbicides rise. The aim of this study was to evaluate the phytotoxic potential of benzyl salicylate and benzyl benzoate upon the growth of Triticum aestivum coleoptiles and on the initial growth of Lactuca sativa, Lycopersicon esculentum, Allium cepa, T. aestivum, Euphorbia heterophylla, and Megathyrsus maximus. For the T. aestivum coleoptile bioassays, the treatments used the concentrations of 10-3 M, 3 × 10-4 M, 10-4 M, 3 × 10-5 M, and 10-5 M; while for the initial growth bioassays the concentrations of 10-3 M, 10-4 M, and 10-5 M were used. Both compounds presented a minimum of 89% growth inhibition on T. aestivum coleoptiles in all concentrations. Both compounds inhibited the growth of the root system and shoot of A. cepa and E. heterophylla at all concentrations. The species most affected by both compounds in all evaluated parameters was E. heterophylla. For the benzyl benzoate, the inhibition of the roots of E. heterophylla were statistically equivalent to those obtained with the herbicide. Regarding benzyl salicylate, the root inhibition in this species in the 10-4 M and 10-5 M treatments did not differ statistically from the herbicide in the same concentrations. Benzyl salicylate and benzyl benzoate are compounds that presented phytotoxic activity on E. heterophylla and for the first time the phytotoxic effect of these compounds on invasive species is reported.

Direct Estimation of Maize Leaf Area Index as Influenced by Organic and Inorganic Fertilizer Rates in Guinea Savanna

Abstract: Leaf area index (LAI) plays an important role in radiation capture, crop growth and yield formation. However, there is limited quantitative data on the influence of poultry manure (PM) and NPK fertilizer rate (NPK) on LAI, as estimated directly. Using a split-plot design with three replications, a field experiment was conducted to determine the effects of three PM rate (0, 2 and 4 t/ha) as main plot and three NPK rate (0:0:0, 60:30:30 and 120:60:60 kg N P2O5 K2O/ha) as sub plot, on LAI and maize grain yield. The maize was planted at a density of 106,666 plants/ha; two rows on a ridge, one plant per stand at 75 × 25 cm. Linear regression was used to establish predictive equations among correlated variables and to describe the degree of associations. The application of PM in maize increased (p < 0.05) number of leaves/plant (NL) at 8 and 10 weeks after sowing maize (WASM). NL, leaf area constant at 6 and 10 WASM, leaf area (LA) and LAI were significantly affected by NPK. LAI correlated positively with NL, LA and grain yield. The coefficient of determination between actual and estimated LA was in the range of 0.85-0.97. The PM × NPK interaction was significant on maize grain yield. The results suggest that small-scale maize farmers faced with challenges in obtaining and transporting large quantities of poultry manure can use 2 t PM/ha with either 60:30:30 kg N P2O5 K2O/ha or 120:60:60 kg N P2O5 K2O/ha to increase grain yield of maize.

Typology and Prospects for the Improvement of Market Gardening Systems in South-Kivu, Eastern DR Congo

Abstract: Vegetables play a very important role in rural and urban communities as both food and a business opportunity. They are fast-growing species, with high nutritional values and able to generate income in a relatively short period compared to other crops. A characterization of market gardening systems was carried out with 368 producers from major market gardening sites in South-Kivu, in Easten of the RD Congo.The aim pursued was to assess existing systems and perspectives to enable steady transition to integrated, sustainable and resilient crop systems. The results showed that very few producers in the region practice plant integration. The typology carried out made it possible to identify three classes of market gardening farms based on adopted agronomic practices, production factors and possible outcomes derived from different systems. Most of the surveyed farms practice crop rotation and are market-oriented. However, they majorly differ in terms of farm size, practices of intercropping, permanent agriculture, mulching, production constraints and producer’s perception on the level of production. For instance, producers who are much more into intercropping also cultivate small areas (less than 0.25 ha). Results also showed that variables such as type of labour, cropping system, type of fertilizer used, mulching practice, adoption of permanent agriculture, producer’s perception of the level of soil fertility, and the water source used affect producer’s appreciation of the level of production obtained (p < 0.05). These variables can be mobilized for improvement of the market gardening system towards more sustainable, diversified and resilient systems.