Showing papers in "The Journal of Agricultural Science in 2021"

Hypothetical Soil Thresholds for Biological Effects of Rare Earth Elements

Abstract: Objectives: Anthropogenic exposures to rare earth elements are poorly known and there is limited information on their toxicity and ecotoxicity. At the same time, world production of rare earth elements has doubled every 15 years over the last half-century, and high environmental concentrations of gadolinium and lanthanum have already been found. The current review aims to give some estimates of overall exposures and an initial in-depth appraisal of thresholds for effects on agricultural soil. The results are envisaged to be used in initial assessments of agricultural soil where the natural concentrations have been anthropogenically enhanced. Methods: An extensive review has been made of available scientific literature. Criteria have been established for the selection and analysis of eligible research. For instance, only effects on soils with vegetation have been included in the assessment of biological effects. A species sensitivity distribution based on 25% inhibition of organism functions has been used to establish thresholds for effects on soil organisms. Results: Around the year 2000, mean anthropogenic contributions of lanthanides in European soil regions were at most a few per cent of the total soil content. Since then, they should have increased considerably. The proposed hypothetical threshold for agricultural soils is 1125 mg total rare earth element per kg of soil. This threshold is about 8 times the natural soil concentration. Conclusions: If this result holds up to scrutiny, it implies that general anthropogenic pollution by rare earth elements will not be a threat to agricultural sustainability for the coming generation. A preliminary assessment suggests that this threshold would also protect humans from adverse effects due to secondary exposure.

Performance of 13 crop simulation models and their ensemble for simulating four field crops in Central Europe

Abstract: The main aim of the current study was to present the abilities of widely used crop models to simulate four different field crops (winter wheat, spring barley, silage maize and winter oilseed rape). The 13 models were tested under Central European conditions represented by three locations in the Czech Republic, selected using temperature and precipitation gradients for the target crops in this region. Based on observed crop phenology and yield from 1991 to 2010, performances of individual models and their ensemble were analyzed. Modelling of anthesis and maturity was generally best simulated by the ensemble median (EnsMED) compared to the ensemble mean and individual models. The yield was better simulated by the best models than estimated by an ensemble. Higher accuracy was achieved for spring crops, with the best results for silage maize, while the lowest accuracy was for winter oilseed rape according to the index of agreement (IA). Based on EnsMED, the root mean square errors (RMSEs) for yield was 1365 kg/ha for winter wheat, 1105 kg/ha for spring barley, 1861 kg/ha for silage maize and 969 kg/ha for winter oilseed rape. The AQUACROP and EPIC models performed best in terms of spread around the line of best fit (RMSE, IA). In some cases, the individual models failed. For crop rotation simulations, only models with reasonable accuracy (i.e. without failures) across all included crops within the target environment should be selected. Application crop models ensemble is one way to increase the accuracy of predictions, but lower variability of ensemble outputs was confirmed.

Impact of Recapitalisation and Development Programme on Performance of Land Reform Beneficiary Farmers in KwaZulu-Natal, South Africa

Abstract: Providing appropriate post-settlement support to farmers is crucial for sustainable development of smallholder agriculture in South Africa. In unravelling this, the South Africa’s Recapitalization and Development Programme (RADP) was initiated. Hence, this study analysed the impact of RADP on performance of land reform beneficiary farmers in KwaZulu-Natal, South Africa. A multistage sampling procedure was used to select (n = 264) respondents for the study. Accounting for endogeneity issues in RADP assessments and its impact on the performance of land reform farmers, an endogenous switching regression model (ESRM) was employed. In the same vein, a doubly-robust inverse probability weighted regression adjustment was used as credible remedy for potentially biased estimates of ATT and POM of endogenous treatment model. The main findings revealed that tax compliance, secondary organization, legal entity, farm potential income at acquisition, farmers receiving third party assistance and strategic partnership were statistically significant in influencing the participation of farmers in RADP. Mentorship remains an extremely challenging element in post-settlement. However, through the strategic partnership of RADP farmers had likelihood to improve the farm and increase farm income. The results of the suggest that the RADP can contribute to a deep process of change and empowerment of farmers. In the same vein, strategic partnership of RADP is likely to improve the farmers’ performance. Therefore, there is a need to strongly improve mentorship and strategic partnership programme to encourage participation of land reform farmers in the support programmes.

Mapping and Environmental Diagnosis in Native Acai Areas in the Amazon

Abstract: For several decades, the Acai orchards (acaizais) have directly influenced the survival of the families in the Amazonian floodplains. In this period, the production of the Acai fruit for local consumption was ceased and became an export item produced in intensive management, resulting in an increase in orchards in the floodplains and the emergence of dryland plantations, no longer representing a typical extractive activity in the Amazon. The objective of this study was to map the classes of use and coverage, and the occurrences of the Acai orchards massifs, as well as to analyze the physical and chemical parameters of five islands in the municipality of Igarape-Miri, State of Para, Brazil, where there is a great occurrence of productive Acai orchards. This work evaluated the following islands: Jarimbu, Mamangal, Itaboca, Mutirao, and Bucu, where geolocalized collections were carried out in the areas with the highest occurrence of Acai orchards, both to assist in the classification of images and for soil sampling. August 2019 Planet images were processed using the unsupervised method, where seven classes of cover use were obtained: hydrography, exposed soil, urban, alluvial, lowland, arboreal, and agriculture areas. Therefore, occurrences of productive orchards were identified and correlated to the good attributes of soil fertility in the floodplains under continuous flooding and sedimentation. The correlation confirmed the higher productivity of Acai in the Alluvial and Lowland classes, which predominate in the evaluated area, presenting soils considered fertile with a loam-clay-silty and loam -silty texture, high base saturation (greater than 50%), high organic matter content, and significant presence of potassium and phosphorus.

Physico-chemical and sensory interactions of arabica coffee genotypes in different water regimes

Abstract: The production of specialty coffee has several factors and parameters that are added up in the course of production, so that the quality is expressed in the act of consumption Based on this scenario, this study included the analysis of ten genotypes of arabica coffee, the materials being subjected to irrigated and rainfed water regimes, in a low altitude region, to identify responses for sensory and physical–chemical quality The genotypes were evaluated in a split-plot scheme with a randomized block design, with three replications Arabica coffee fruits were harvested with 80% cherry seeds and processed by the wet method Subsequently, the characteristics related to physical–chemical and sensory analyses were evaluated The genotypes of the Paraiso group showed great variability for the physical–chemical and sensory variables for rainfed and irrigated regimes The genotypes of the Catuai group, however, showed less variability for sensory characteristics in both cultivation environments and for physical–chemical characteristics in the irrigated regime In the sensorial data set, the genotypes Catuai 144 CCF and Catuai 144 SFC (when irrigated) and Paraiso H 419-3-3-7-16-2, Paraiso H 419-3-3-7-16-11 and Catucai 24-137 (rainfed cultivation), are more favourable to the production of specialty coffee at low altitude

Soybean yield in integrated crop–livestock system in comparison to soybean–maize succession system

Abstract: Abstract Among integrated crop–livestock systems, forage succession is an advantageous strategy for the use of pasture to feed cattle in periods of low rainfall, as well as for the generation of biomass for the no-till system for the next crop. Different species have different abilities to accumulate nutrients in their biomass, which are then released into the soil through the decomposition of crop residues. This study aimed to evaluate soybean yield in an integrated crop–livestock system in comparison to soybean–maize succession system through the production, decomposition and nutrient accumulation in the biomass. The experiment had a randomized block design with four replicates. The treatments were three cropping systems: integrated crop–livestock with Paiaguas palisadegrass (Brachiaria brizantha cv. BRS Paiaguas), integrated crop–livestock with Tamani guinea grass (Panicum maximum cv. BRS Tamani) and maize grown in succession to soybean. The results showed that the use of the integrated crop–livestock system in the form of forage succession provided greater soil cover and nutrient cycling as a result of the better utilization of the animal's excreta, than the cropping of maize in succession and resulted in higher soybean productivity, thus contributing to agricultural sustainability. Paiaguas palisadegrass and Tamani guinea grass showed a C:N ratio greater than 30:1, indicating slow decomposition of plant residues. The forages accumulated amounts of nutrients in their biomass that met the soybean demand, resulting in higher grain yield.

The influence of lime application on the chemical and physical characteristics of acidic grassland soils with impeded drainage

Abstract: Soil acidity and poor nutrient use efficiency are major limiting factors as regards output potential on heavy soils, soils which are dominated by high proportions of clay and organic matter, with impeded drainage, high buffering capacity and located in high rainfall areas. Lime is applied in order to counteract these limiting factors and in turn improve agricultural output and productivity. The current study investigates the effects of two commonly used lime products at three comparable treatment rates, ground lime (7.5, 5 and 2.5 tonne/ha) and granulated lime (7.5, 2.5 and 1.5 tonne/ha), applied across three distinct sites. The ability of each lime product and treatment rate to counteract soil acidity, increase nutrient availability and influence soil physical structure was assessed over time. On average across sites, 1 tonne/ha of each lime product increased soil pH by 0.15 and 0.21 pH units between ground and granulated lime, respectively. Site 3 experienced the greatest increase change in soil pH in comparison to the other two sites, largely due to lower clay content and cation exchange capacity. Granulated lime was 5.7 times more expensive than ground lime in its ability to reduce soil acidity. The high treatment rate showed the greatest reduction in soil acidity, aluminium and iron concentration as a mean across all sites. Morgan's soil test phosphorus concentration increased across all sites, with treatment rates having no effect on the rate of increase. There was evidence of reduced soil compaction and lime application showed no negative implication on soil physical structure.

Elaboration of Blends of Pitaya Pulps With Acerola

Abstract: Pitaya and acerola are fruits rich in nutrients and can be used in blends formulation in order to improve the sensory characteristics of both pulps in isolation and complement each other in terms of nutritional aspects. Thus, the aim of this research was to develop different blends of pitaya pulp with acerola and choose the best formulation based on physical-chemical and colorimetric characteristics. Three blends formulations were prepared: F1-90% pitaya and 10% acerola; F2-70% pitaya and 30% acerola; and F3-50% pitaya and 50% acerola. The formulations were evaluated for physical-chemical parameters of water activity, water content, ash, total soluble solids (SST), pH, total titratable acidity (ATT), SST/ATT ratio, ascorbic acid, proteins, lipids, sugars totals, reducers and non-reducers and colorimetric analysis. The obtained data were subjected to variance analysis (ANOVA) and to comparison between means by the Tukey test at 5% probability. The formulation F1 stood out when compared to the others. The parameters pH, soluble solids, ratio SS/ATT, ash, water content, water activity, proteins, sugars, luminosity and hue angle were the ones that gave the formulation F1 the best results. However, it is noteworthy that the formulation F3 presented a greater amount of ascorbic acid and higher values of a, b and chroma in the colorimetric analysis. The use of these fruits allows to obtain an innovative product with excellent nutritional and functional characteristics. The blend is a viable alternative for the use of perishable and seasonal fruits, adding greater economic value to the very promising product to the market.

Marker-assisted stacking of null Kunitz trypsin inhibitor and off-flavour generating lipoxygenase-2 in soybean

Abstract: Soybean varieties genetically free from Kunitz trypsin inhibitor (KTI) and lipoxygenase-2 (Lox2) are desirable to increase human consumption, as the former is an antinutritional factor that affects protein digestibility while the latter is a principal contributor to off-flavour. In the present investigation, soybean genotypes free from both these undesirable components were developed by introgression of null allele of Lox2 from NRC109 (lox2lox2) into two KTI-free soybean genotypes derived from genotypes JS97-52 and NRC7. Foreground selection of plants in F1, F2, BC1F1, BC1F2, BC2F1 and BC2F2 generations developed from two cross combinations i.e. NRC7-derived KTI-free genotype (N7KTIF)×NRC109 (parental combination 1) and JS97-52 derived KTI free genotype (JKTIF)×NRC109 (parental combination 2) was performed using null allele specific markers and tightly linked simple sequence repeat (SSR) markers for both KTI and Lox2 genes for the identification of homozygous recessive (titilox2lox2) plants. Background selection was performed using 239 and 241 polymorphic SSR markers across the genome. This resulted in the development of 9 and 13 soybean lines stacked for null alleles of both KTI and Lox2 (titilox2lox2) exhibiting recurrent parent genome content more than 97 and 96%, respectively. Days-to-flowering, days-to-maturity, 100-seed weight and yield per plant of the stacked lines developed from both the parental combinations were at par with the respective recurrent parents.

Effect of Inoculum Concentration and Pretreatment on Biomethane Recovery From Cotton Gin Trash

Abstract: The potential of cotton gin waste, a considerable challenge to the gin owners, has not been fully investigated as a renewable energy source via anaerobic digestion. The weathered cotton gin trash and inoculum for triplicate biomethane potential assays were obtained from a local cotton gin mill and a municipal wastewater treatment plant, respectively. The moisture, total solids, volatile solids, and C, H, N, S, hemicellulose + cellulose, and lignin contents of gin waste were determined in triplicates. The biomethane potential of untreated and pretreated (hot water and 6% NaOH (wet CGT weight basis) gin waste was determined at different inoculum to substrate ratios. The highest cumulative biomethane yield of 111.8 mL gvs-1 was observed in inoculum to substrate ratio of 2.3, and it was statistically similar to the values; 101.8, 104.7, 100.5, and 108.9 gvs-1, observed in 0.8, 1.2, 1.5, and 1.9, respectively. The biomethane yield at the inoculum to substrate ratio of 0.4 was significantly lower than all higher ratios. The T80-90 for biomethane production was 26-30 for the ISRs of 1.2, 1.5, and 2.3. The T80-90 for inoculum to substrate ratios of 0.4, 0.8, and 1.9 were 26-31, 27-32, and 27-31 d, respectively. The modified Gompertz equation fitted very well (R2 = 0.98-0.99) to the anaerobic digestion at all inoculum to substrate ratios and pretreatments as the observed and predicted biomethane values were similar. The model predicted a lag phase of 8-10 days for control and treatments compared to the observed of 10-15 days. The highest biodegradability of 24.8±2.6% was observed at inoculum to substrate ratio of 2.3, which was statistically similar to the values observed in ratios of 0.8, 1.2, 1.5, and 1.9, respectively. Among pretreatments, the highest biodegradability of 33.0±2.4 was observed in 6% NaOH pretreatment, and it was statistically similar to hot water treatment and non-pretreated or control. These research findings advance the knowledge in the anaerobic degradation of cotton gin trash, thus helping to maximize biomethane recovery from this agro-industrial waste.

Response of the Yam Variety Krengle (Dioscorea rotundata) to Organo-mineral Fertilisation at Bouaké in Central of Côte d’Ivoire

Abstract: The decline in yam productivity due to the lack of arable land and impoverished soils forces farmers to use fertiliser. The fertilisers used are mineral, organic or organo-mineral. A study of these fertilisers has been carried out to propose to the farmers a dose or combination that can improve their yield. Thirteen (13) fertilisers obtained from the combination of mineral fertiliser (NPK 15-15-15) and composted cow or poultry manure were tested on the yam variety Krengle in a 3 replicate randomized complete block design. The experiment was conducted over two (2) campaigns at Bouake in Central of Cote d’Ivoire. The results show that high dose mineral fertilisation (NPK 15-15-15, 300 kg/ha) negatively influenced the growth and yield parameters of the yam variety Krengle. High doses of organic fertilisers (Cow manure (CM) 20 t/ha and poultry manure (PM) 20 t/ha) have a positive effect on vegetative growth. While the medium-high doses of organic fertiliser (CM 15 t/ha and PM 15 t/ha) gave better tuber yield (13.5 t/ha) and allowed an increase in tuber yield from 17 to 18%. Organo-mineral fertilisation combining a small dose of organic fertiliser (5 t/ha) with a medium dose of mineral fertiliser (200 kg/ha) gave also fairly good yield (13.3 and 14.42 t/ha) with an increase of 15 to 25%. Thus, 200 kg/ha of NPK 15-15-15 associated with 5 t/ha of poultry or cow manure can be recommended for the cultivation of the yam variety Krengle at Bouake.

Yield and Yield Components of Potato (Solanum tuberosum) as Affected by Rock Phosphate in Standoff Soil, Southern Alberta Canada

Abstract: An experiment was conducted in Standoff, Southern Alberta in April, 2020. The object of the experiment was to investigate effect of rock phosphate organic fertilizer on growth and yield of potato crop grown in Standoff. The varying levels of rock phosphate were broadcasted into the soil at control (0 P Kg ha-1), Low P level (50 P Kg ha-1) and High P level (100 P Kg ha-1). The basal application of urea inform of nitrogen fertilizer was applied at 280 N Kg ha-1. Potato seeds were planted at a distance of 30 by 90 cm. The three treatments were replicated three times, resulting into nine plants. One plant was taken out of uniformly grown tallest plant in each of the treatment to measure yield parameters. The yield parameters collected were subjected to analysis of variance (ANOVA) using Duncan’s Multiple Range Test (DMRT) for separation of means. Results of the experiment indicated that High P and Low P rock phosphate fertilizer levels positively influenced weight of potatoes at 76 and 112 Days after sowing (DAS), respectively while High P rock phosphate fertilizer level got highest number of potatoes than Low P and control at 76 DAS. Furthermore, High P rock phosphate fertilizer level and control plots supported marketable number of potatoes at 76 DAS while High P rock phosphate fertilizer level favoured unmarketable number of potatoes at 112 DAS. It was quite obvious from the results that marketable weight of potatoes was positively influenced by High P rock phosphate level and Low P rock phosphate level at 76 and 112 DAS, respectively whereas unmarketable weight of potatoes was affected by High P rock phosphate fertilizer level at 112 DAS. These results revealed the beneficial use of rock phosphate for potato crop production

Inoculant, nitrogen and phosphorus improves photosynthesis and water-use efficiency in soybean production

Abstract: Abstract Soybean yield within the Southern Africa falls below its potential despite similar climatic conditions across some agroecologies, replicable agronomic management practices and introduced improved varieties. Understanding physiological processes and water-use efficiency (WUE) of soybean offer information on bridging this yield gap. A field study was conducted in 2017 and 2018 seasons in two agroecologies (Angonia and Ruace) in Mozambique to evaluate the effects of Bradyrhizobium diazoefficiens strain USDA110 formerly known as Bradyrhizobium japonicum inoculant, nitrogen and phosphorus on nodulation, physiology and yield of non-promiscuous (Safari) and promiscuous (TGx 1740-2F) soybean varieties. Data on transpiration, photosynthesis, leaf area index, radiation interception and WUE from the beginning of flowering to maturity were collected. Transpiration rate varied considerably with interaction between locations, growth stages, varieties and treatments. At podding, phosphorus-treated soybean at Angonia transpired less (6.3 mmol/m2/s) than check plants (6.6 mmol/m2/s). Photosynthesis rate and WUE were distinct with variety, growth stages and inputs within agroecologies. For instance, in Angonia 2018 season, phosphorus fertilized TGx 1740-2F photosynthesized more at flowering (25.3 μmol/m2/s) while the lowest was phosphorus-treated Safari at podding with 17.2 μmol/m2/s. At the same site in 2017, inoculated soybean photosynthesized more at 22.8 μmol/m2/s leading to better WUE of 3.6 that corresponded to 2894 kg/ha yield. Overall, soybean WUE was higher when inoculated than N-treated, while P application yielded better. Results from this study will complement breeders’ effort in developing phosphorus efficient varieties suited for a wide range of changing climatical conditions.

The Impact of Better Management Practices (BMPs) Among Cotton Farmers in Punjab, Pakistan

Abstract: Better management practices (BMPs) as a sustainable approach made it attractive for growers to control the provision of pollutants from agricultural activities as well as enhance the financial return. The experiments of cotton production were conducted in four different regions of Punjab in cotton-growing years 2017-2019. The objective of the study was to evaluate the potential impact of BMPs among cotton farmers by rationalizing the use of input resources (viz., seed, fertilizers, pesticides and water). The data were collected from randomly selected adopters of BMPs (n = 400) and non-adopters of BMPs (n = 100) through a well-structured pretested questionnaire using a multistage sampling procedure from four different regions of Punjab province. Descriptive analysis was employing an independent two-sample t-test to evaluate the significant effect of BMPs on the utilization of input resources and profitability of cotton production between adopters and non-adopters of BMPs. The results indicated that adopters of BMPs were efficiently used input resources (at p ≤ 0.001 & p ≤ 0.01) and significantly enhanced the average cotton yield (855.09 kg acre-1) in Punjab, while non-adopters of BMPs had a significantly high cost of production by 11% (35,655 PKR acre-1) and output was lower by 15% (751.70 kg acre-1) under conventional farming for cotton cultivation. The economic analysis revealed that the average gross income gained by adopters of BMPs was significantly high by 11% (72,648 PKR acre-1 at p ≤ 0.001) with the maximum net return of 36% (40,785 PKR acre-1 at p ≤ 0.001) as well as a good B:C (1.28) as compared to non-adopters of BMPs. This study provides useful information about the potential impact of BMPs among cotton farmers even without the extra use of inputs. It is concluded that precision in inputs and management practices with lower input costs can significantly improve cotton productivity leading to uplift the farmers’ profit.

The effects of compound treatment of Aspergillus oryzae and fibrolytic enzyme on in vitro degradation, gas production and fermentative profile of maize silage and sugarcane silage

Abstract: The present study was conducted to evaluate the effect of a live culture of Aspergillus oryzae (A; CCT4359) and fibrolytic enzyme (E; Fibrozyme Alltech Inc.) on fibre digestibility by a gas production bioassay and in vitro degradation of maize silage and sugarcane silage. A completely randomized design trial was performed to evaluate: A doses (0, 20, 60 and 100 mg/l), E doses (0, 160, 320 and 480 mg/l) and roughage source (R; maize and sugarcane silage) in a 4 × 4 × 2 factorial arrangement. The inclusion of increasing doses of A and E increased dry matter and neutral detergent fibre in vitro digestibility linearly, but for E this effect occurred only in maize silage. There was a linear increase in the potential for gas production at the highest dose of A only in sugarcane silage, with no effect on lag time (L). Increasing doses of E increased the volume of gases produced linearly, and a trend of linear reduction of L, regardless of the roughage. There was a linear reduction in ammonia-nitrogen concentration in response to increasing doses of A and E, and an increase in acetic acid concentration at the highest dose of A, regardless of roughage. The additives had no synergistic effect on gas production and digestibility, but were efficient in altering the fermentative pattern, demonstrating the potential to increase fibre degradation.

On-farm assessment of cover cropping effects on soil C and N pools, enzyme activities, and microbial community structure

Abstract: Abstract Introducing cover crops (CC) in annual cropping systems can promote nutrient cycling and improve soil health. However, impacts of CC on soil health indicators vary and depend on the duration of CC, cropping systems, and other environmental conditions. We performed an on-farm assessment of cover cropping impacts on soil health indicators including C and N pools, enzyme activities, and microbial community structure under different no-till maize-based cropping systems (maize (Zea mays L.)–soybean (Glycine max L.) [CS], CS-winter wheat (Triticum aestivum L.) [CSWw], and maize-oats (Avena sativa L.) [CO]). At five farms, fields with different durations of CC were compared to adjacent no CC (NCC) fields. In general, long-term CC enhanced the soil health parameters compared to NCC. Long-term (20-year) winter rye CC had higher water-extractable C and N content, enzyme activities (β-glucosidase (1.2 times greater), urease (5.5 times greater), acid (1.5 times greater) and alkaline (4 times greater) phosphatase, arylsulfatase (0.8 times greater) and fluorescein diacetate (FDA) (0.7 times greater)) and soil bacterial community abundance (1.2 times greater). Short-term (3–6 years) legume and grass CC mixtures increased β-glucosidase (0.9 times), acid (0.7 times) and alkaline (1.5 times) phosphatase, arylsulfatase (3 times), FDA (0.8 times) activities and total phospholipid fatty acid (1.6 times) concentration. However, short-term (3–6 years) winter rye, legume and brassica mixtures did not significantly alter soil microbial community structure. This study showed that implementation of CC for >6 years promoted C, N, S, and P cycling that are beneficial to soil health in maize-based cropping systems.

Crop succession and split-application of nitrogen effects on common bean yield in short no-tillage system

Abstract: Evaluating the effects of crop successions in no-tillage system (NTS) is essential for the correct recommendation of agronomic practices, such as top-dressing nitrogen fertilization. The aim was to evaluate the effect of the crop succession and the splitting of top-dressing N fertilization on the agronomic performance and economic viability of common bean crop. The experiment was conducted in southeastern Brazil for two agricultural seasons in an area under NTS, using a split-plot in randomized complete block design. The plots represented three cropping successions (maize in sole crop, maize intercropped with Urochloa ruziziensis and U. ruziziensis in sole crop) and the subplots composed of ten combinations of splitting of top-dressing N, at the stages V3, V4 and R5 of the common bean crop. In relation to the single application of the N dose of 90 kg ha−1, the common bean had higher response as a function of the N splitting schemes adopted, regardless of the previous cropping succession. The cropping successions evaluated did not interfere with the seed yield of common bean as subsequent crop, even at the beginning of the establishment of NTS. To obtain higher seed yield and economic viability, the N dose of 90 kg ha−1 indicated for the crop must be split and applied among the phenological stages V3, V4 and R5.

Nitrogen use and agronomic efficiency of rainfed wheat in permanent beds as affected by N fertilizer, precipitation and soil nitrate

Abstract: Nitrogen (N) fertilizer is an input that has played an important role in grain yield, N use efficiency (NUE), and agronomic efficiency (AE) that needs to be studied on rainfed wheat grown in permanent beds as a planting system. The objective of this study was to test the effect of N treatments on yield, NUE and AE from 2005 to 2009. The experimental design consisted of three N rates (25, 50 and 75 kg/ha) and four N timing treatments (two single basal applications and two splits), plus a control plot (0 N). Results showed that N rate and N timing treatments had no effect on grain yield, but years, meanwhile Year–N rate interaction affected NUE and AE. Precipitation and post-harvest soil N-NO3 were identified as factors to test the years' effect on yield, NUE and AE. Regression procedures showed that the effect was greater for 25 kg N/ha treatment. The relationships between these variables and precipitation were positive, whereas the opposite occurred with soil N-NO3. NUE and AE, however, showed negative values in crop seasons with moisture constraints from precipitation ( 90 kg N-NO3/ha). This result indicated that N removal and yield in these years were larger in control plots (0 N) than fertilizer application. Precipitation and soil N-NO3, rather than N treatments, explained most of the yield, NUE and AE variation over years. Therefore, to enhance that effect of weather and soil, further research on alternate N sources is needed.

Screening of Selected Sorghum Genotypes for Resistance to Covered Kernel Smut Disease in Western Kenya

Abstract: Sorghum is an important food security crop for arid and semi-arid tropics but its production is hampered by many biotic and abiotic factors including covered kernel smut disease (CKSD) caused by fungus Sporosorium sorghi in the Ustilaginaceae family. The disease attacks susceptible sorghum genotypes causing yield losses estimated at 43% in Western Kenya. This study determined the response of selected sorghum genotypes to CKSD under field and greenhouse conditions. A total of 15 elite sorghum genotypes were screened under field conditions in Migori and Homa Bay sites and under greenhouse at the University of Eldoret. Data on disease incidence and severity were collected per genotype and analyzed using R-Studio software and means were separated at 1% using Tukey’s test. Results showed significant differences among genotypes for disease incidence and severity under fields and greenhouse conditions. Disease incidence varied significantly (p < 0.001) among the genotypes ranging from zero (for T53, T30, IS3092, N4 and N68) to 64% (for Nyadundo2) under field conditions but ranged from 0-69% under greenhouse conditions. Similarly, severity followed the same trend with C26 having the worst attack with a score of 5 while T53 recorded the least (score of 1). This study has identified potential sources of resistance for covered kernel smut disease that can be utilized to manage the disease and significantly improve sorghum yields in the target regions.

The Export Competitiveness of Ghana’s Cocoa Industry in West Africa

Abstract: Ghana in the year 1911 became the world’s largest exporter of cocoa. However, cocoa export in Ghana nearly came to standstill in the 1970s as a result of the outbreak of swollen shoot disease of cocoa. Ghana since then has not been able to rejuvenate its cocoa export as expected. The years 1999 to 2018 have witnessed a downward trend in the export of cocoa in Ghana. This raises questions of whether the phrase “Ghana is cocoa, and cocoa is Ghana” is still valid. The study attempts to analyze the competitiveness of Ghana’s cocoa sector vis-a-vis its neighbors. In doing so, the authors calculate the Revealed Comparative Advantage (RCA) and Revealed Symmetric Comparative Advantage (RSCA) for Ghana to compare with other West African exporters of cocoa and assess the determinants of Ghana’s cocoa exports. The authors adopt a regression framework to explore the determinants of cocoa exports. The results revealed that Ghana is highly competitive in the export of cocoa beans. The study attributed this advantage to the quality of the cocoa beans Ghana exports. The results further showed that Ghana’s cocoa production volumes and the World consumer price of cocoa beans were the major determinants of the volume of cocoa beans exported in Ghana. The study concluded that although Ghana enjoys a comparative advantage in the export of cocoa beans, Ghana’s cocoa production volumes fluctuate thus affecting the volume of cocoa exported. Ghana, therefore, needs to invest in new hybrid climate-smart cocoa cultivation to boost production and export.

Tropical Viticulture Diagnosis in the North and Northwest Fluminense

Abstract: Viticulture has proved to be an alternative for farmers in the northen and northwestern Rio de Janeiro State; however, the activity is still very recent and requires the development of agronomic and managerial techniques. Therefore, the objective of this work was to diagnose the production areas and the characteristics inherent to the inner and outer environment of this farming enterprise. It was observed that the grape-growing farms predominate in an average area of 1 hectare, with productivity between 20 and 25 t/ha, with offer in the harvest and in the off-season. The inner points are stronger than the weak ones, and can be adjusted with the joint execution of the viticulturists allied to the opportunities, such as agrotourism and the diversification of available cultivars that allow a greater offer of the product and minimize the inherent threats observed, such as climatic variations and the shortage of skilled labor. These identified points may indicate competitiveness strategies for the wine market in the studied regions.

Is There a Benefit of Adding Atrazine to HPPD-Inhibiting Herbicides for Control of Multiple-Herbicide-Resistant, Including Group 5-Resistant, Waterhemp in Corn?

Abstract: The evolution of multiple-herbicide-resistant (MHR) waterhemp (resistant to Groups 2, 5, 9, and 14) in Ontario, Canada is challenging for growers. The complementary activity of the co-application of hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides with atrazine has been well documented. The objective of this research was to determine if the addition of atrazine to 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides applied postemergence improves their consistency of MHR waterhemp (including Group 5 resistance) in corn. Five field trials were conducted over a two-year period (2018, 2019) in Ontario, Canada. Five HPPD-inhibiting herbicides [isoxaflutole (105 g ha-1), mesotrione (100 g ha-1), topramezone (12.5 g ha-1), tembotrione (90 g ha-1), and tolpyralate (30 g ha-1)] were applied postemergence with and without atrazine to 10-cm-tall waterhemp. Corn injury (≤ 10%) was observed at specific sites where the application of tembotrione, isoxaflutole and isoxaflutole + atrazine resulted in characteristic white bleaching of corn foliage; however, yield was not affected. Averaged across field sites, the addition of atrazine to isoxaflutole, mesotrione, topramezone, or tembotrione improved MHR waterhemp control 15%, 11%, 7%, and 7%, respectively at 4 weeks after application (WAA). Averaged across herbicide treatments and sites, the addition of atrazine reduced the standard error of MHR waterhemp control by 13% to 100%. This study concludes that the co-application of atrazine with HPPD-inhibitors applied postemergence reduced the risk of herbicide failure and resulted in greater and more consistent control of MHR waterhemp.

Production of Natural Insecticide on Management of Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae) in Family Farming

Abstract: Collard greens are commonly grown in family farming systems; however, damage caused by the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) reduces yields, leading to successive applications of insecticides and consequently, environmental and toxicological problems. Therefore, it is essential to search for alternatives that reduce the use of pesticides and are economically viable and accessible to small farmers. This study was aimed at evaluating the insecticidal activity of aqueous extracts of neem and tobacco on P. xylostella. First instar caterpillars were offered collard leaf discs treated with different concentrations (30 caterpillars per treatment) and after the third day, mortality was evaluated. To evaluate ovicidal properties, collard leaves with 30 eggs were immersed in extracts and after 48 h, viability was measured. Oviposition deterrent activity was assessed with 23 couples of P. xylostella released in cages (repetitions) containing treated collard plants and after 48 h, the number of eggs per plant was recorded. Neem and tobacco extracts exhibited larvicidal, ovicidal, and oviposition deterrent properties against P. xylostella, indicating that the use of these extracts may be promising alternatives in family farming systems.

Callogenesis and in vitro Regeneration of Baru (Dipteryx alata Vog.) Esprouts

Abstract: The aim of this study was to evaluate the effect of different concentrations of 6-benzylaminopurine (BAP) and naphthalene acetic acid (ANA) on calogenesis and regeneration from baru leaf and apex segments. The explants were obtained from baru plants previously established in vitro from almonds and cauline apices. The leaf segments were placed in Petri dishes containing MS medium (Murashige & Skoog, 1962) with concentrations (0.0, 2.0, 3.0, 4.0 and 5.0 mg L-1) BAP combined with ANA (0.0 and 2.0 mg L-1). The shoot apices were inoculated in test tubes with the same medium using the concentrations (0.0, 0.5, 1.0 and 1.5 mg L-1) BAP combined (0.0 and 0.1 mg L-1) ANA. After 25 days of inoculation, the percentages of callus and texture in leaf explants and apices were evaluated. The number of shoots was also evaluated by the Scott-Knott test at 5% of probability. The most efficient concentration in the formation of callus in leaves was 3.0 mg L-1 BAP + 2.0 mg L-1 ANA (68.88%), at apexes the most efficient concentration was 1.0 mg L-1 BAP without ANA with 100% calogenesis. The most effective concentration was 1.0 mg L-1 BAP without ANA with an average of 1.90 of shoots in relation to the concentrations evaluated.

Reduced Asian Soybean Rust Control by Commercial Fungicides Co-formulations in the 2018-2019 Growing Season in Southern Brazil

Abstract: It has been a growers concen the reduction of Asian soybean rust (ASR) control by commercial fungicide co-formulations in the last growing seasons in southern Brazil. The objective of this work was to assess the ASR control efficacy by the most used co-formulations in the 2018/19 season. In a field experiment, 19 fungicides in commercial formulations to control soybean rust caused by Phakopsora pachyrhizi, were evaluated. Chemicals at their recommended doses were sprayed at four soybean growth stages. The first application was performed with 1.82% leaflet incidence and coinciding with R1 phenological stage. The others were performed at 14-18 days intervals. At stage R6, end of the epidemic and coinciding with half of the defoliation in the control plots, the leaf severity was appraised. The experiment was conducted with Ativa soybean cultivar, in 3 × 6 m plots, four replications and randomized block design. The harvest was made with a plot combine and the yield expressed in grains kg/ha. The means were compared by the Scott-Knott test. The disease control efficacy by 17 fungicide co-formulation showed control less than 57%, one with 78% and none with ≥ 80%. The unsprayed treatment severity was 81% and the greatest control of 78% resulted in 3,876 kg/ha yield. Therefore, the hypothesis raised in this work was accepted showing that the site-specific fungicides co-formulations are showing efficacy reduction season after season.

Directional Selection of Phakopsora pachyrhizi Towards Site-Specific Fungicides in Mato Grosso State

Abstract: This review focus on the sensitivity reduction of Phakopsora pachyrhizi to site specific fungicides in the Brazilian state of Mato Grosso.The soybean grown area in this state in the 2018/19 growing season was 9,756,668 hectares. The main crop disease is Asian soybean rust that depending on disease severity may cause 80% yield reduction. The rust chemical control started in the 2002/003 season with site-specific fungicides applied solo and with 3.6 sprayings/ha/season. For these reasons, the fungus had sensitivity reduction to the fungicides DMIs, QoIs and SDHIs resulting in a short effective life. Anti-resistance strategies were not adopted to prevent or delay the development of soybean rust resistant population to site-specific fungicides. Reduced sensitivity to the target site has been observed for all site-specific fungicides involving cross and multiple resistance resulting in ineffective control. So far, eight mutations in Phakopsora pachyrhizi have been identified conferring reduced sensitivity to DMIs, QoIs and SDHIs but so far specific mutations are not considered in chemical control. The directional selection has occurred and has been aggravated season-after-season by the continuous use of site-specific fungicides in a large area, for 18 season and with more than three sprayings/area/season. The presence of soybean weed in one million hectares of cotton crop infected by rust aggravates the directional selection. Anti-resistance strategies should include sowing at the beginning of the recommended season, avoid the December season and replacing it by February, use of scientific criteria to time the first application and the use of multisite fungicides in all applications and in the entire area cultivated with soybean.

Financial Feasibility Assessment of Sweet Potato Cultivation Technology Packages Application in Tidal Swamp Land

Abstract: Sweet potato is consumed as a source of carbohydrate as a substitute for essential food (rice). Due to limited area in Java island, Indonesia, the expansion of sweet potato could be cultivated in tidal swamp land. Therefore, this research was aimed to determine the financial feasibility of sweet potato technology packages in tidal swamp field. This research was carried out in tidal swamp fields: Roham Village, Wanaraya District, Barito Koala Regency, and South Kalimantan Province, Indonesia from March to July 2019. This study compared two innovative and existing technologies. The innovative technology introduced to the farmers emphasized on intensive processing in order to reduce the occurrence of the main pests of sweet potato in tidal fields. Innovative technologyy includes tillage done with plows and rakes. The results of this research showed that application of sweet potato cultivation technology packages with improved tillage, land cover with mulch, pest control using chemical fungicides and shallot extracts has proven to be financially feasible. Existing farmers (local variety) who switch to innovative technology using Sari variety, the profit earned increased by 232.47%. Technically, the application of the tuber yield innovative technology for Sari variety was higher, both controlled using chemical insecticides and innovative technology of 18.25 and 24.15 tons/ha, respectively. The implementation of the introduced cultivation technology package was able to increase local sweet potato production to the superior Sari variety by 96.82% compared to the farmer technology package at the same location. R/C and B/C ratio > 1 for innovative technology shows that innovation technology is feasible to be developed at the researched location.