Sweet Potato Cultivation Research Articles

American sweet potato and Asia-Pacific crop experimentation during early colonisation of temperate-climate Aotearoa/New Zealand

The American sweet potato (Ipomoea batatas) is a globally important comestible crop that features prominently in Polynesian lore; however, the timing and mode of its Oceanic transplantation remain obscure. New research from the Māori cultivation site M24/11 in Aotearoa/New Zealand, presented here, offers a re-evaluation of evidence for the early use and distribution of the sweet potato in southern Polynesia. Consideration of plant microparticles from fourteenth-century archaeological contexts at the site indicates local cultivation of sweet potato, taro and yam. Of these, only sweet potato persisted through a post-1650 climatic downturn it seems, underscoring the enduring southern-Polynesian appeal of this hardy crop.

Next Generation Sequencing and Genetic Analyses Reveal Factors Driving Evolution of Sweetpotato Viruses in Uganda.

Sweetpotato (Ipomoea batatas L.) is an essential food crop globally, especially for farmers facing resource limitations. Like other crops, sweetpotato cultivation faces significant production challenges due to viral infections. This study aimed to identify and characterize viruses affecting sweetpotato crops in Uganda, mostly those associated with sweetpotato virus disease (SPVD). Infected leaf samples were collected from farmers' fields in multiple districts spanning three regions in Uganda. MiSeq, a next-generation sequencing platform, was used to generate reads from the viral nucleic acid. The results revealed nine viruses infecting sweetpotato crops in Uganda, with most plants infected by multiple viral species. Sweet potato pakakuy and sweet potato symptomless virus_1 are reported in Uganda for the first time. Phylogenetic analyses demonstrated that some viruses have evolved to form new phylogroups, likely due to high mutations and recombination, particularly in the coat protein, P1 protein, cylindrical inclusion, and helper component proteinase regions of the potyvirus. The sweet potato virus C carried more codons under positive diversifying selection than the closely related sweet potato feathery mottle virus, particularly in the P1 gene. This study provides valuable insights into the viral species infecting sweetpotato crops, infection severity, and the evolution of sweet potato viruses in Uganda.

Virus-Free Sweet Potato Industry: Development Status and Production Suggestions

Sweet potato (Ipomoea batatas L.) is an important food, feed, and industrial raw material and new energy crop. Its rich nutritional value and health effects are increasingly being recognized by consumers, and the demand is increasing. However, due to the continuous cultivation of sweet potato over many years, the degeneration of seedlings and the accumulation of viral diseases are important factors affecting the yield and quality of sweet potatoes. This article provides an overview and analysis of the types and hazards of sweet potato virus diseases, the advantages of virus-free sweet potatoes, the scale of virus-free sweet potato cultivation, sweet potato stem tip virus-free production technology, its development status, and the existing problems. Combined with the development of the sweet potato industry across China, relevant development suggestions are proposed to provide a reference for promoting the healthy, stable, sustainable, high-quality, and efficient development of the sweet potato industry.

Metarhizium caribense sp. nov., a Novel Species of Entomopathogenic Metarhizium Fungi Associated with Weevils Impairing Coffee, Sugar Cane and Sweet Potato Cultivation.

(1) Background: Insect pathogenic fungi of the genus Metarhizium are under study and in application as highly solicited, more eco-system friendly substitutes for chemical insecticides in many countries and in different agricultural contexts. In Cuba and Florida, Metarhizium strains have previously been isolated from economically important coffee and sugar cane pests. (2) Methods: Unambiguous species delineation within the Metarhizium anisopliae species complex is methodologically challenging. Recently, a species-discriminating PCR approach has been developed based on ribosomal intergenic spacer (rIGS) sequences that covered the prominent four "PARB" species within the complex. This approach is combined here with further genetic markers and is extended to a further species. (3) Results: Metarhizium isolates from Cuba, found to be more naturally associated with the coffee berry borer, Hypothenemus hampei, were morphologically, microscopically and molecular taxonomically characterized. Multilocus sequence analysis based on 5TEF, MzIGS3 and rIGS markers delineated these weevil-associated strains from all previously established Metarhizium species. (4) Conclusions: The isolates under study represent a new fungal taxon proposed to be designated Metarhizium caribense. The rIGS-based species-discriminating diagnostic PCR is a suitable tool for the identification of new Metarhizium species and can be productively combined to approaches using further genetic markers.

Empoasca fabalis DeLong (Hemiptera: Cicadellidae) in European sweet potatoes: records, leaf damage, and Auchenorrhyncha insights

The recent surge in sweet potato (Ipomoea batatas) cultivation in Europe prompted an investigation into associated entomofauna within Portugal's southwestern region, known for its longstanding sweet potato production. This study aimed to assess entomofauna associated with this culture.Insect sampling was conducted by leaf and sweep net across three regional sites during 2018 and 2019 revealing the presence of Empoasca fabalis. Histological examination of sweet potato leaves affected by E. fabalis feeding unveiled significant damage, including the emergence of whitish spots (termed “stipples”) and subsequent necrotic spots. Comparative analysis between infested and undamaged control leaves revealed significant damage, involving mesophyll cell content deprivation and cellular disruption. This study describes, for the first time, the histological nature of the necrotic damage and suggests that E. fabalis primarily acts as a stippler on sweet potatoes, mainly targeting mesophyll cells with limited consumption of vascular tissue. The invasive behaviour and wide host range of E. fabalis pose a threat to sweet potato cultivation. These findings emphasize the need for monitoring to address the potential impact of E. fabalis on Europe’s agricultural ecosystem and native vegetation.In addition, six other Auchenorrhyncha species were identified during this study, including four crucial vectors of plant diseases: Laodelphax striatellus, Psammotettix alienus, Anaceratagallia glabra, Austroagallia sinuata, together with Empoasca solani and E. alsiosa. These results emphasise the importance of managing these insects in sweet potato cultivation.

Application of Digestate from a Methane Fermentation Process for Supplying Water and Nutrients in Sweet Potato Cultivation in Sandy Soil

Application of Digestate from a Methane Fermentation Process for Supplying Water and Nutrients in Sweet Potato Cultivation in Sandy Soil

The effect of giving sweet potato leaf-based functional drink to increase HB levels

BeckgroundMenstruating young women experience twice as much iron loss as young men. One alternative effort that can be made is to provide functional drinks that are useful for overcoming anemia. Functional beverages must provide nutritional intake and sensory satisfaction, such as good taste and good texture, using sweet potato leaves (Ipomoea Batatas L). Sweet potato leaves are chosen as raw material because, besides being abundantly available and accessible to cultivate, they are also very cheap, so that they can reduce production costs. Pancalang Health Center is one of the Health Centers in the Kuningan Regency Area with reasonably high sweet potato cultivation. AimsThis study aims to determine the level of compliance with functional drink consumption, determine hemoglobin levels before and after functional drink intervention, describe anemia status before and after functional drink intervention, describe the effects of functional drink consumption, and nutritional status picture before and after consuming functional drink products. Research methodeThe study was conducted by quasi-experiment in one group (nonrandomized pre-test and post-test without control group design). Purposive sampling was carried out by Purposive Sampling on adolescents at the Pancalang Health Center, Kuningan Regency. Data collection was done by checking HB levels before the intervention and after the intervention. The intervention is carried out for 52 days. Resultsand Conclussion: The majority of respondents were compliant in consuming functional drinks, and only 7.5 % were non-compliant. The median before the intervention is 11 and after the intervention is 12 and a p value of <0,001 is obtained, meaning that statistically there is a significant difference between HB before the intervention and after the intervention. ContributionThere was a significant difference between Hb levels before the intervention and after the intervention, obtaining a p-value of <0.001.

Design and control of a side dense transplanting machine for sweet potato seedlings on mulch film

At present, China is the leading country in sweet potato cultivation worldwide. However, there are still several problems such as high labor intensity, low efficiency of manual transplanting, and lack of machinery for side transplanting for sweet potato seedlings on mulch film. Therefore, a side dense transplanting machine for sweet potato seedlings on mulch film is designed, using a multi-row side transplanting method. It is mainly composed of a transplanting device, a seedling conveying device, a traveling device, and a control system. Based on the agronomic requirements for sweet potato transplanting, the study focuses on the structure and working principle of the complete machine. It involves the detailed structural design and motion analysis of the crank-rocker and cam of the transplanting device. Based on the sweet potato seedlings transportation plan, parameters such as the vertical height of the seedling conveying device, the size of the support frame, and the relative relationship between position of the transplanting device are determined. To ensure the smooth transplantation of sweet potato seedlings, the motor parameters required for each device are calculated and determined. An Arduino control system is developed to manage the coordinated movement of each device. Positioning components are integrated to ensure accurate coordination between the transplanting device and the seedling conveying device. This setup enables the seedling claws to pick sweet potato seedlings and perform the side transplanting on the mulch film. Field test results show the missed rate of seedlings, the qualified rate of transplanting and the qualified rate of transplanting depth are 4.13 %, 91.62 % and 93.86 % respectively. The transplant spacing coefficient of variation and the average spacing between seedlings are 1.90 and 177.06 mm respectively. All indicators of the transplanting machine meet the agronomic requirements for side dense transplanting for sweet potato seedlings on mulch film. The transplanting machine is integrated with sweet potato seedling transplanting agronomy, achieving mechanized transplanting of sweet potato seedlings, reducing labor intensity, and promoting the quality and efficiency of sweet potato production. This research provides a reference for the development of sweet potato seedlings transplanting equipment.

Agronomic and Molecular Characterization of Sweet Potato (Ipomoea batatas [L.] Lam) Varieties in Nigeria

Study’s Excerpt/Novelty This study addresses the breeding challenges of sweet potato (Ipomoea batatas) by utilizing agronomic, morphological, and molecular data to identify optimal parental combinations for enhanced cross-breeding. The research demonstrated significant variations and strong correlations among agronomic traits, with principal component analysis revealing complete variability at the fifth principal component. Key findings include the identification of TIS 8164 and TIS 0087/087 as closely related varieties, while molecular characterization highlighted Nwaoyinma and Umuspo 1 as promising parental combinations, providing a foundation for improved breeding strategies in sweet potato cultivation. Full Abstract Sweet potato (Ipomoea batatas [L.] Lam.); 2n = 6x = 90) is a significant root crop globally. However, breeding and cross-breeding of the crop are difficult due to its enormous, complex genome and highly heterozygous hexaploid genetic makeup. This study used data on agronomic traits and morphological and molecular characterization to determine the best parental combinations for improved breeding and cross-breeding of the crop. Agronomic traits analysis and morphological characterization were carried out in the research farm while molecular analysis was done in the molecular biology laboratory. Results of the study show significant variations (p-value = 0.000) and a strong positive correlation among the majority of the agronomic traits and morphological characters, principal component analysis shows 100% variability at the 5th principal component, a dendrogram of agronomic traits analysis shows that TIS 8164 and TIS 0087/087 varieties are about 76% similar and Dixon variety is approximately 66.67% similar to the Umuspo 1 and the Butter Milk varieties, morphological characterization shows 37% similarity between the Umuspo 1 variety and the TIS 8164 variety, polymorphic information content shows polymorphism of 42.86% for IBS166 primer, 28.5% for IB02 primer and 14.29% for IBS199 and Ibu4 primers respectively, a dendrogram of molecular characterization shows no similarity between the Umuspo 1 variety and the other variety and 100% similarity between the TIS 8164 and the TIS 0087/087 varieties. The study concluded that the Nwaoyinma and the Umuspo 1 varieties are good parental combinations

On farm diversity and genetic erosion of sweet potato [Ipomoea batatas (L.) Lam.]

ABSTRACT Sweet potato [Ipomoea batatas (L.) Lam.] varieties can be distinguished by their flesh and skin colors (white, yellow, orange, and purple). The present study was undertaken to assess on-farm diversity and the status of genetic erosion of sweet potatoes in Haramaya district, Ethiopia. Data were collected for similarity/dissimilarity index, preference index, and genetic erosion. The result of the preference index indicated the highest preference index (25.60) with preference rank 1 recorded for the BeelaBochol genotype as the lowest preference index (12.10) was recorded for the BeelaBaleyso genotype. About 66% of the respondents use the intercropping system for sweet potato cultivation. The majority of respondents 97% observed loss of sweet potato varieties. Eighty-two percent of the respondent farmers suggested the use of their seed source for planting. About 73% of the respondents suggested the cultivation of sweet potato as a subsistence crop. The major constraints of sweet potato cultivation, as suggested by the respondents, were tiresome land preparation 37%, lack of improved variety 26%, land scarcity 23%, and market demand 15%. It can be concluded from the result of the present study that farmers can identify and prefer sweet potato genotypes frequently using storage root yield and boiled quality.

Characterisation of the Endophytic and Rhizospheric Bacillus licheniformis Strains Isolated from Sweet Potato with Plant Growth-Promoting and Yield Enhancing Potential

The primary aim of the present study was to identify bacterial isolates with yield-enhancing potential for application as biofertilisers in the cultivation of sweet potato. Therefore, endophytic and rhizospheric strains were isolated from sweet potato plantations in Hungary to identify bacterial strains with plant growth-promoting and antifungal potential. In total, seven Bacillus licheniformis strains were identified and subjected to detailed ecophysiological investigations. Experiments have been conducted to investigate the tolerance of selected strains to different limiting factors such as pH, temperature, and water activity, which affect survivability in various agricultural environments. The majority of tested B. licheniformis strains exhibited plant growth-promoting potential (e.g., production of indole-3-acetic acid up to 40.42 μg mL−1, production of ammonia up to 0.87 mg mL−1, phosphorus solubilising activity, siderophore production), with two strains (SZMC 27713 and SZMC 27715) demonstrating inhibitory activity (ranging between 7% and 38%) against plant pathogenic fungi prevalent in sweet potato cultivation. Furthermore, strain SZMC 27715 induced accelerated germination and a significantly higher germination rate in tomato seeds compared to the control. In a field study, it was observed that strain SZMC 27715 had a potent yield enhancing effect in sweet potato, where a significant yield per plant increase was observed in all treatments (1.13, 1.09 and 1.40 kg) compared to the control plants (0.92 kg). The highest yield per plant was observed when the cuttings were soaked combined with two additional foliar treatments. To the best of our knowledge, this is the first report of the successful utilisation of the B. licheniformis strain as a biofertiliser for yield enhancement in sweet potato cultivation. Based on our results, strain SZMC 27715 has potential for application as a biofertiliser in sweet potato cultivation either as a standalone option or in a microbial consortium.

Risk of climate change to sweet potato cultivation in the American continent

ABSTRACT Sweet potato, Ipomoea potatoes L., is an essential crop for food security in various countries. However, the effects of climate change could reduce or increase the yield and profitability of this crop, especially for small farmers. Thus, we developed species distribution models for the current and six climate change scenarios based on environmental variables, species occurrence, and global climate change model. Also, we identified the most relevant environmental variables for cultivation. Future scenarios showed gradual shifts in suitable areas for cultivation. Losses in suitable areas were more relevant than gains at the low concentration of greenhouse gas emissions (RCP 2.6). This trend is maintained in the worst scenario of a high concentration of greenhouse gas emissions (RCP 8.5) with more significant losses of suitable areas. The temperature and precipitation of warmest and wettest quarters, temperature seasonality, and isothermality are the most critical variables for sweet potato cultivation. The cultivation is expected to expand the suitable areas in some regions and retract in others due to climate change. Knowledge about climate change effects in cultivated areas is essential for developing management plans that could mitigate the adverse effects of climate change.

Phenological growth stages of sweet potato (Ipomoea batatas (L.) Lam.) according to the extended BBCH scale

AbstractSweet potato is grown for its starchy roots in many countries and is widely cultivated in India. This crop is widely acknowledged for its substantial economic and health benefits. However, a comprehensive description of its phenology has not been reported. The phenological growth stages of sweet potato are described here for the first time using the extended Biologische Bundesantalt, Bundessortenamt, and Chemische Industrie (BBCH) scale. Nine primary growth stages have been specifically defined, including germination (0), leaf development (1), main shoot development (2), side shoot development (3), tuber development (4), inflorescence emergence (5), flowering (6), fruit development (7), fruit maturation (8), and senescence (9). The sequential progression of key growth stages has been described according to the phenological development structure and environmental requirements of different phenophases. Because it covers all phenophases related to the vegetative and reproductive stages, the extended BBCH scale is extensively useful for sweet potato cultivation. The extended BBCH scale may also be a useful tool for assessing the potential effects of climate change on crop productivity and fruit quality.

Mulching to improve sweet potato production

Sweet potato ((Ipomoea batatas L.) is a high-yielding nutritious specialty crop. There is a growing need for proactive information on sustainable production of sweet potatoes under short growing seasons. The objective of our study was to evaluate the effects of crop residue and synthetic mulches on the growth, yield, and quality parameters of three varieties of sweet potatoes. Three types of mulch, wheat straw (straw), white polyethylene film (white mulch), and black plastic film (black mulch), and a control (no mulch) were evaluated during the 2021 and 2022 growing seasons in the south-eastern region of Kazakhstan. The vine length, meristem number, tuber per plant, and tuber weight were significantly higher under white mulch and black mulch than under straw, and the results were significantly different from the control. The total yields of sweet potato tubers under white mulch and black mulch also varied significantly among the varieties, ranging from 20.5 t/ha for Rizi 0603 to 54.5 t/ha for Xushu 25. The results of the present study will be used to develop other technological sequences for the cultivation of sweet potatoes in the south-eastern region of Kazakhstan. More research is needed to ascertain the stability of the effects of varieties, mulch treatment, and their interactions on yields and to determine other treatments and varieties with better potential to improve sweet potato yields for cultivation in Kazakhstan.

Alleviating sweetpotato salt tolerance through exogenous glutathione and melatonin: A profound mechanism for active oxygen detoxification and preservation of photosynthetic organs

Salt stress profoundly impacts sweetpotato production. Exogenous glutathione (GSH) and melatonin (MT) promoted plant growth under stress, but their specific roles and mechanisms in sweetpotato salt tolerance need exploration. This study investigated GSH and MT’s regulatory mechanisms in sweetpotato under salt stress. Salt stress significantly reduces both growth and biomass by hindering photosynthesis, root traits, K+ content, and K+/Na+ balance, leading to oxidative stress and excessive hydrogen peroxide (H2O2), superoxide ion (O2•−), and malondialdehyde (MDA) production and Na+ accumulation. Nevertheless, GSH (2 mM) and MT (25 μM) pre-treatments effectively mitigated salt-induced oxidative damage and protected the plasma membrane. They reduced osmotic pressure by enhancing K+ uptake, K+/Na+ regulation, osmolyte accumulation, and reducing Na+ accumulation. Improved stomatal traits, chloroplast and grana lamella preservation, and maintenance of mesophyll cells, cell wall, and mitochondrial structure were observed with GSH and MT pre-treatments under salt stress, therefore boosting the photosynthetic system and enhancing plant growth and biomass. Moreover, the findings also indicate that the positive outcomes of GSH and MT pre-treatments result from elevated antioxidant levels, enhanced enzymatic activity, and upregulated expression of sodium hydrogen exchanger 2 (NHX2), K+transporter 1 (AKT1), and cation/H+exchanger (CHX), CBL-interacting protein kinase 1 (CIPK1), and antioxidant enzyme genes. These mechanisms enhance structural stability in photosynthesis and reduce salt stress. Evidently, MT pre-treatment exhibited superior effects compared to GSH. These findings provide a firm theoretical basis for employing GSH and MT to enhance salt tolerance in sweetpotato cultivation.

A Multifunctional Perspective to Explain the Survival of Neglected Plants: The Case of the Sweet Potato in Benin

Neglected crops have great potential to improve agricultural diversity and contribute to food security. In Benin, sweet potato is one of these crops that is still not widely adopted. Although the benefits of sweet potato are widely known, it is only grown on small areas in Benin. This study aims to analyze the rationale behind farmers' decisions to allocate land for sweet potato production. 320 farmers were interviewed in Gogounou and Boukoumbé in North Benin. Data were analyzed using chi² tests and a structural equation model. Quotations were used to illustrate the findings. Farmers' individual characteristics, perceptions of the crop, its production and the benefits they expect from it, have a significant influence on the decision to allocate land to sweet potato cultivation. Thus, farmers grow sweet potato because it fulfils a food and/or commercial function. However, due to the neglect of agricultural policies, the sector is plagued by challenges that their low level of knowledge does not allow them to meet. To deal with the uncertainties, farmers are implementing risk mitigation strategies that lead them to limit the area sown. The survival of a neglected plant can be explained by its importance as a food source for the communities. However, in order to increase acreage and scale up, the plant must also fulfil a commercial function.

Intensified cropping reduces soil erosion and improves rainfall partitioning and soil properties in the marginal land of the Indian Himalayas

Environmental crises, land degradation, declining factor productivity, and farm profitability questioned the sustainability of linear economy-based existing agricultural production model. Hence, there is a dire need to design and develop circular economy-based production systems to meet the twin objectives of environmental sustainability and food security. Therefore, the productive capacity, natural resource conserving ability, and biomass recycling potential of four intensified maize-based systems viz. maize (Zea mays) + sweet potato (Ipomoea batatas)-wheat, maize + colocasia (Colocasia esculenta)-wheat, maize + turmeric (Curcuma longa), and maize + ginger (Zingiber officinale) were tested consecutively for three years (2020, 2021 and 22) in a fixed plot manner at Dehradun region of the Indian Himalaya against the existing maize-wheat systems. The result showed that the maize + sweet potato-wheat system significantly reduced runoff loss (166.3 mm) over the maize-wheat system. The highest through fall (68.12 %) and the lowest stem flow (23.54 %) were recorded with sole maize. On the contrary, the maize + sweet potato system has the highest stem flow (36.15 %) and the lowest through fall. Similarly, the maize + sweet potato system had 5.6 times lesser soil erosion and 0.77 t ha−1 higher maize productivity over the maize-wheat system. Furthermore, the maize + sweet potato system recorded significantly higher soil moisture (19.3%), infiltration rate (0.95 cm h−1), and organic carbon (0.78%) over the rest of the systems. The maize + sweet potato system also recycled the highest nitrogen (299.2 kg ha−1), phosphorus, (31.0 kg ha−1), and potassium (276.2 kg ha−1) into the soil system. Hence, it can be inferred that concurrent cultivation of sweet potato, with maize, is a soil-supportive, resource-conserving, and productive production model and can be recommended for achieving the circular economy targets in the Indian Himalayas.

Sweetpotato cultivation: characteristics, constraints and preferred traits of producers and consumers in Côte d'Ivoire.

In an environment where the adoption of improved varieties resulting from plant breeding programs is limited, it is essential to identify end-user preferences beforehand. A participatory survey was conducted in eight localities in Korhogo and Bouaké regions (central and northern Cote d'Ivoire respectively) to identify producers' preferences and increase the adoption of improved varieties. The study involved 160 producers and consumers through focus group discussions and individual interviews. Sweetpotato is mostly grown on small plots (<1 ha) of land (89.2%), with women (66%) as the main producers. In the Bouaké region, sweetpotatoes are grown on mounds (100%), whereas in Korhogo they are grown on ridges (86.2%). The main food products or forms of preparation from roots are fries (34.7%), boiled (34.3%), mashed (12.4%), and sweetpotato stew (9.1%). Major constraints, including low price of roots (26.3%), low productivity (16.2%), and post-harvest storage issues (14.5%), were identified as affecting sweetpotato production. The selection of new varieties should be oriented towards high-yielding varieties with high dry matter content, deployed stems, and roots of round, oblong, or elliptical shape with good culinary characteristics (dry matter, sweet taste, dry texture, absence of fiber). Plants must be drought resistant, be tolerant to poor soil, diseases, and pests, and have a good yield. The color of skin and flesh of the sweetpotato, although constituting criteria of choice, are not essential for the acceptance or the rejection of a variety by users. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The Effectiveness Of Agricultural Extension Methods And Techniques In The Application Of Cultivation Technology Sweet Potato (Ipomoea Batatas L.)

This research was conducted in Bandorasa Kulon Village, Cilimus District, Kuningan Regency, from January to February 2023. This study aims to find out: (1) the effect of the effectiveness of agricultural extension methods in the application of sweet potato cultivation technology, (2) the influence of agricultural extension techniques with the application of sweet potato cultivation technology, and (3) the effect of the effectiveness of agricultural extension methods and techniques with the application of sweet potato cultivation technology. The method used in this study is quantitative descriptive with a survey approach. The object of research in the boled flower farmer group of Bandorasa Kulon Village with a sample of 47 farmers. Primary data collection was obtained through interviews with respondents using a list of questions, and secondary data were obtained from agencies related to this study. To determine the variable relationship between the effectiveness of agricultural extension methods and agricultural extension techniques, with the application of sweet potato cultivation technology, the Spearman level correlation coefficient test is used. The results showed that: (1) there is a medium and real relationship between the effectiveness of agricultural extension methods and sweet potato cultivation technology as shown by the value of rs = 0.456, (2) there is a low and real relationship between agricultural extension techniques and sweet potato cultivation technology, which is indicated by the value of rs = 0.360, and (3) there is a very strong and real relationship between the effectiveness of agricultural extension methods and techniques with sweet potato cultivation technology, indicated by the value of rs = 0.943

Long-term nitrogen fertilization and sweetpotato cultivation in the wheat-sweetpotato rotation system decrease alkaline phosphomonoesterase activity by regulating soil phoD-harboring bacteria communities

The alkaline phosphomonoesterase (ALP)-harboring community (phoD-harboring community) plays a crucial role in the conversion of organic phosphorus (P) into available P (AP). However, the response mechanisms of phoD-harboring communities to fertilization strategies, crop types, and their interactions within the wheat-sweetpotato rotation are poorly understood. A nine-year field experiment of different fertilization strategies was established under the wheat-sweetpotato rotation. After harvesting the crop, we collected soil samples without fertilization (CK), inorganic NK fertilization (NK), inorganic NPK fertilization (NPK), and a combined application of inorganic NPK and organic fertilizer (NPKM). We employed high-throughput sequencing and enzymology techniques to analyze the composition and functional activity of phoD-harboring bacterial communities as well as their correlation with soil physicochemical properties. The results showed that long-term nitrogen (N) fertilization, especially inorganic N, significantly reduced soil pH and ALP activity while increasing AP compared with CK. The AP content in sweetpotato season was significantly higher than that in wheat season. Inorganic N fertilization dramatically reshaped the communities of phoD-harboring bacteria and decreased diversity. The phoD-harboring bacterial communities in sweetpotato season were significantly different from those in wheat season. The N fertilization significantly reduced the relative abundance of Acuticoccus, Methylibium, Rhizobacter, and Roseivivax, which was positively correlated with ALP activity. These groups in sweetpotato season decreased significantly compared with wheat season. A structural equation model indicates that pH and AP play a significant role in regulating the phoD-harboring bacteria communities, ALP activity, and their interactions. We demonstrate that fertilization strategies and crop types have a substantial impact on the phoD-harboring bacteria communities and functions, which are closely linked to soil pH and AP levels. Our study highlights the detrimental effects of soil acidification resulting from inorganic N fertilization on P-cycling bacterial communities and functions. However, the combination of inorganic and organic fertilizer can mitigate these adverse effects.