scholarly journals Compost and Biochar to Promote Soil Biological Activities under Sweet Potatoes Cultivation in a Subtropical Semiarid Region

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Josabeth Navarro ◽  
Jahdiel Salazar ◽  
James Jihoon Kang ◽  
Jason Parsons ◽  
Chu-Lin Cheng ◽  
...  

South Texas is located in a subtropical semiarid climate, and due to high temperature and irregular precipitation, farmers opt to leave their fields fallow during the summer months jeopardizing overall soil health. We evaluated whether sweet potato (Ipomoea batatas) cultivation coupled with drip irrigation could restore soil biological activities compared with bare fallow. Additionally, because sweet potatoes have high demand of soil nutrients, especially potassium (K), we evaluated the nutrient supply of locally sourced soil amendments. Sweet potato was cultivated during summer 2018 in McAllen, Texas, under control (no fertilizer), NPK (synthetic fertilizer), RC (yard-waste compost), and AC (compost produced under an enhanced composting process), and biochar (gasified walnut shell at 900°C), each with three replicates. Soil amendments were applied at different amounts to result in a rate of 80 kg K ha−1. Soil biological indicators were microbial biomass phosphorous, phosphatase activity, and the rate of fluorescein diacetate hydrolysis (FDA). Available nitrogen, phosphorus, potassium, and sodium were also quantified. Aboveground biomass and storage root yield estimated sweet potato’s agronomic performance. Cultivation and irrigation stimulated soil enzyme activities and microbial biomass-phosphorous. Sweet potato yields were the highest in NPK treatment but still 2.8 times lower than variety’s potential yield. Storage root yield was inversely related to aboveground biomass, suggesting that growing conditions benefited the production of shoot versus roots. Both biochar and AC treatments stimulated FDA rates and K availability. Soil pH and sodium concentration increased in all treatments over the growing season, possibly due to river-sourced irrigation water. Together, these findings show that crop cultivation promoted soil biological activities and the maintenance of nutrient cycling, compared to bare-fallow conditions. For a better agronomic performance of sweet potato, it would be necessary to identify management practices that minimize increase in soil pH and salinity.

2021 ◽  
Vol 22 (9) ◽  
pp. 4826
Author(s):  
Yang Gao ◽  
Zhonghou Tang ◽  
Houqiang Xia ◽  
Minfei Sheng ◽  
Ming Liu ◽  
...  

A field experiment was established to study sweet potato growth, starch dynamic accumulation, key enzymes and gene transcription in the sucrose-to-starch conversion and their relationships under six K2O rates using Ningzishu 1 (sensitive to low-K) and Xushu 32 (tolerant to low-K). The results indicated that K application significantly improved the biomass accumulation of plant and storage root, although treatments at high levels of K, i.e., 300–375 kg K2O ha−1, significantly decreased plant biomass and storage root yield. Compared with the no-K treatment, K application enhanced the biomass accumulation of plant and storage root by 3–47% and 13–45%, respectively, through promoting the biomass accumulation rate. Additionally, K application also enhanced the photosynthetic capacity of sweet potato. In this study, low stomatal conductance and net photosynthetic rate (Pn) accompanied with decreased intercellular CO2 concentration were observed in the no-K treatment at 35 DAT, indicating that Pn was reduced mainly due to stomatal limitation; at 55 DAT, reduced Pn in the no-K treatment was caused by non-stomatal factors. Compared with the no-K treatment, the content of sucrose, amylose and amylopectin decreased by 9–34%, 9–23% and 6–19%, respectively, but starch accumulation increased by 11–21% under K supply. The activities of sucrose synthetase (SuSy), adenosine-diphosphate-glucose pyrophosphorylase (AGPase), starch synthase (SSS) and the transcription of Susy, AGP, SSS34 and SSS67 were enhanced by K application and had positive relationships with starch accumulation. Therefore, K application promoted starch accumulation and storage root yield through regulating the activities and genes transcription of SuSy, AGPase and SSS in the sucrose-to-starch conversion.


2021 ◽  
Vol 39 (2) ◽  
pp. 186-191
Author(s):  
Jhonatan M Goulart ◽  
Adriano A Rocha ◽  
José Antonio A Espindola ◽  
Ednaldo da S Araújo ◽  
José Guilherme M Guerra

ABSTRACT This study aimed to evaluate sweet potato performance in succession to annual herbaceous leguminous plants, in monocropping or intercropped with corn, under agroecological management, under Baixada Fluminense conditions. The experimental design was randomized blocks, with five treatments and four replicates. The treatments consisted of pre-cropping with the following species: crotalária (Crotalaria juncea) under monocropping system, crotalária intercropped with corn (Zea mays), jack bean (Canavalia ensiformis) under monocropping system, jack bean intercropped with corn and spontaneous vegetation. The results showed that monocropped crotalária reached the greatest dry biomass accumulation during two consecutive years of succession. In the second year, this treatment provided greater accumulated amounts of N, K and Mg in plant biomass. Growing sweet potatoes in succession to the pre-cropping of crotalária is advantageous, as it provided an increase in vegetable productivity in the second year of succession.


2020 ◽  
Author(s):  
Zhiyuan Gao ◽  
Yaya Hu ◽  
Meikun Han ◽  
Junjie Xu ◽  
Xue Wang ◽  
...  

Abstract Background: Continuous cropping obstacles from sweet potato are widespread, which seriously reduce the yield and quality, cause certain economic losses. Bacteria of Rhizospheric soil are the richest and are associated with obstacles to continuous cropping. However, few studies on how continuous sweet potato cropping affects the rhizospheric soil bacterial community structure. In the study, Illumina Miseq method was used to explore rhizosphere soil bacterial community structure changes with different sweet potato varieties, and the correlation between soil characteristics and this bacterial community after continuous cropping, to provide theoretical guidance for prevention and treatment of sweet potatoes continuous cropping obstacles. Results: After continuous cropping two years, the results showed that (1) the dominant bacterial phlya in rhizospheric soils from both Xushu18 and Yizi138 were Proteobacteria, Acidobacteria, and Actinobacteria. The most dominant genus was Subgroup 6_norank. The relative abundance of rhizospheric soil bacteria of two sweet potato varieties changed significantly. (2) The richness and diversity indexes of bacteria in Xushu18 rhizospheric soil were higher than those from Yizi138 after continuous cropping. Moreover, the beneficial Lysobacter and Bacillus were more prevalent in Xushu18, but Yizi138 contained more harmful Gemmatimonadetes. (3) Soil pH decreased after continuous cropping, and redundancy analysis result indicated that soil pH was correlated significantly with bacterial community. Spearman’s rank correlations coefficients analysis demonstrated that pH was positively associated with Planctomycetes and Acidobacteria, but negatively associated with Actinobacteria and Firmicutes.Conclusions: After continuous cropping, the bacterial community structure and physicochemical properties of sweet potato rhizospheric soil were unbalanced, and the changes from different sweet potato varieties were different. The contents of Lysobacter and Bacillus were higher in the sweet potato variety resistant to continuous cropping. It provides a basis for developing new microbial fertilizer for sweet potatoes to alleviate continuous cropping obstacle.


2018 ◽  
Vol 3 (1) ◽  
pp. 644-651
Author(s):  
A.O. Adekiya ◽  
C.M. Aboyeji ◽  
T.M. Agbede ◽  
O. Dunsin ◽  
O.T.V. Adebiyi

Abstract Micro-nutrients especially zinc can not only increase the yield of sweet potato but can also improve the quality of tubers. Hence, experiments were carried out in 2015 and 2016 cropping seasons to determine the impact of various levels of ZnSO4 fertilizer on soil chemical properties, foliage and storage root yields and proximate qualities of sweet potato (Ipomoea batatas L.). The experiments consisted of 5 levels (0, 5, 10, 15 and 20 kg ha-1) of ZnSO4 fertilizer. These were arranged in a randomized complete block design and replicated three times. ZnSO4 increased (with the exception of P) soil chemical properties compared with the control. N, K, Ca, Mg and Zn were increased up to the 20 kg ha-1 ZnSO4 level in both years. ZnSO4 reduced P concentrations in soil as the level increased. For sweet potato performance, 5 kg ha-1 ZnSO4 fertilizer had the highest values of foliage yield (vine length and vine weight) and storage root yield. Using the mean of the two years and compared with the control, ZnSO4 fertilizer at 5 kg ha-1 increased storage root yield of sweet potato by 17.4%. On fitting the mean storage root yield data of the two years with a cubic equation, the optimum rate of Zn for sweet potato was found to be 3.9 kg ha-1 to achieve the maximum sweet potato yield. In this study, relative to the control, ZnSO4 fertilizer increased moisture and decreased the fibre contents of sweet potato. There were no consistent patterns of variation between the 5, 10, 15 and 20 kg ha-1 ZnSO4 treatments for proximate qualities except that the highest values of fat, protein, carbohydrate and ash was at 5 kg ha-1 ZnSO4.


HortScience ◽  
1990 ◽  
Vol 25 (8) ◽  
pp. 857g-857
Author(s):  
Desmond Mortley ◽  
Conrad Bonsi ◽  
Philip Loretan ◽  
Walter Hill ◽  
Carlton Morris

Greenhouse experiments were conducted to evaluate the effects of spacing within and between growth channels on the yield of `TI-1551 sweet potatoes grown hydroponically using the nutrient film technique (NFT). Spacings within channels were 12.7, 17.8 and 25.4 cm whereas between growth channels the spacings were 12.7, 25.4 and 38.1 cm. Vine cuttings (15 cm) placed in each channel (0.15×0.15×1.2 m) were supplied with a modified half-Hoagland solution and grown for 120 days. Storage root number, fresh and dry weights and foliage fresh and dry weights tended to increase as spacing between channels increased. Spacing of plants within channels had no significant effect on any sweet potato growth responses.


HortScience ◽  
1990 ◽  
Vol 25 (8) ◽  
pp. 858g-858
Author(s):  
Desmond Mortley ◽  
Conrad Bonsi ◽  
Philip Loretan ◽  
Walter Hill ◽  
Edwin Martinez

Hydroponic experiments using the nutrient film technique (NFT) were conducted in environmental growth chambers to evaluate the response of two sweet potato cultivars, `Georgia Jet' and `TI-155', to two photoperiod and temperature regimes. Vine cuttings of these cultivars were planted in growth channels supplied with modified half-Hoagland nutrient solution using NFT. Plants were subjected to a 24 h photoperiod or a 12:12 h light:dark photoperiod, a constant temperature of 28C or light:dark temperature of 28/22C. Plants were exposed to irradiance levels of 400 umol m-2 s-1 at canopy level and 70% RH. Storage root fresh and dry weights were increased for both cultivars under the 24 h photoperiod at the 28C constant temperature. `Georgia Jet' storage root numbers were not affected by any treatment while those for `TI-155' were reduced under continuous light for both temperature regimes. Foliage fresh and dry weights were not affected by any treatment.


2020 ◽  
Vol 35 (2) ◽  
pp. 289
Author(s):  
Edyson Indawan ◽  
Sri Umi Lestari ◽  
Nurita Thiasari ◽  
Pramono Sasongko

Sweet potato is a dual-purpose crop, which could produce both food and feed. The vine pruning prior to storage root harvesting was intended to increase the quantity and quality of fresh forage for animal feed. This study aims to evaluate whether periodic pruning can affect the storage root yield and its starch content. This experiment employed split-plot design with two factors and three replications. The first factor as main plot was vine pruning which consisted of four distinct pruning times (four times, three times, twice and once). The second factor as sub-plot was cultivars which consisted of six dual-purpose cultivars and two controls. The storage root yields, vine yields, starch yields and the reduction in storage root yields were observed. The results showed that the vine pruning decreased the storage root yields, with small increases the vine yields. The percentage of the reduction in storage root yields were 4-58%, while the decrease vine yields are relatively inconsistent. The starch yield of the cultivars with one pruning time were in the range of 2.34-6.67 ton ha<sup>-1</sup>. On the contrary, the three times pruning or more since 80 days after transplanted can reduce the starch yields for more than 50%. The slight increase in vines yield due to pruning was followed by the decrease in storage root yields and starch content of the sweet potato.


2020 ◽  
Author(s):  
Zhiyuan Gao ◽  
Yaya Hu ◽  
Meikun Han ◽  
Junjie Xu ◽  
Xue Wang ◽  
...  

Abstract Background: Continuous cropping obstacles from sweet potatoes are widespread, which seriously reduce the yield and quality, causing certain economic losses. Bacteria of rhizospheric soil are the richest and are associated with obstacles to continuous cropping. However, few studies have examined how continuous sweet potato cropping affects the rhizospheric soil bacterial community structure. Results: In the study, the Illumina MiSeq method was used to explore the variations inrhizospheric soil bacterial community structure of different sweet potato varieties after continuous cropping, as well as the correlation between soil characteristics and the bacterial community. The results showed that (1) the dominant bacterial phyla in rhizospheric soils from both Xushu 18 and Yizi 138 were Proteobacteria, Acidobacteria, and Actinobacteria. The most dominant genus was Subgroup 6_norank. The relative abundance of rhizospheric soil bacteria varied significantly between the two sweet potato varieties. (2) The richness and diversity indexes of bacteria were higher in Xushu 18 rhizospheric soil than in Yizi 138 soil after continuous cropping. Moreover, beneficial Lysobacter and Bacillus were more prevalent in Xushu 18, while Yizi 138 contained more harmful Gemmatimonadetes. (3) Soil pH decreased after continuous cropping, and redundancy analysis indicated that soil pH was significantly correlated with the bacterial community. Spearman’s rank correlation coefficient analysis demonstrated that pH was positively associated with Planctomycetes and Acidobacteria, but negatively associated with Actinobacteria and Firmicutes.Conclusions: After continuous cropping, the bacterial community structure and physicochemical properties of sweet potato rhizospheric soil were changed, and the changes from different sweet potato varieties were different. The contents of Lysobacter and Bacillus were higher in the sweet potato variety resistant to continuous cropping. It provides a basis for developing new microbial fertilizers for sweet potatoes to alleviate the continuous cropping obstacle.


2021 ◽  
Vol 2 (6) ◽  
Author(s):  
Gamaliel I. Harry ◽  
Joseph I. Ulasi

Ten sweet potato (Ipomoea batatas (L.) Lam) genotypes sourced from National Root Crops Research Institute, Umudike were evaluated under rainfed condition in 2020 and 2021 cropping seasons at the Teaching and Research Farm of the University of Uyo, Uyo, Akwa Ibom State to ascertain variability among ten sweet potato genotypes and identify traits which are positively and significantly associated with yield and also identify genotypes with high yield potential for cultivation on an ultisol of Akwa Ibom State, Nigeria. The ten genotypes: TIS87/0087, Naspoy-12, Umuspo-4, Umuspo-1, Naspoy-11, Lourdes, Erica, Delvia, Ex-Igbariam and Umuspo-3 were used as treatments and the experiment was laid out in a randomized complete block design with three replications. Data collected were subjected to analysis of variance, correlation and principal component analysis. The genotype differs significantly (P≤ 0.05) for number of marketable roots, weight of marketable roots and fresh roots yield. UMUSPO-3 was superior over all the other genotypes for the following character; number of marketable roots, weight of marketable root yield and fresh root yield. Umuspo-3 produced the highest storage root yield (28.78t/ha, 27.09t/ha) in 2020 and 2021 cropping seasons, respectively. The result of the correlation analysis also revealed that vine length, number of marketable roots, weight of marketable were highly significantly and positively (P<0.01) correlated with fresh root yield. Principal component analysis (PCA) had four main principal components explaining 81.55% of the total variation with number of marketable roots, weight of marketable tuber and storage root yield contributing the most to the first PCA. Umuspo-3 outperformed the other nine sweet potato genotypes in yield and yield related characters. Therefore, Umuspo-3 been a high yielding genotype adaptable to Uyo agro-ecology, could be recommended to sweet potato growers for fresh storage root production.


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