Potassium Availability Research Articles

Potassium availability in relation to mineralogy in two benchmark vertisols of India

Potassium availability in relation to mineralogy in two benchmark vertisols of India

人参种植对林地土壤细菌群落结构和代谢功能的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 人参种植对林地土壤细菌群落结构和代谢功能的影响 DOI: 10.5846/stxb201909201963 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31670614） Effects of Ginseng cultivation on soil microbial community structure and metabolic functions in forest land Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:揭示人参种植对土壤微生物群落结构和代谢功能的影响，对防治人参连作障碍具有重要的理论意义。利用高通量测序技术研究了林地和由林地开垦耕种人参3a和4a后土壤微生物群落结构和代谢功能的变化。结果表明，变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、酸杆菌门（Acidobacteria）、疣微菌门（Verrucomicrobia）、绿弯菌门（Chloroflexi）是林地和人参种植土壤微生物的主要优势类群。林地开垦种植人参后，土壤放线菌门和疣微菌门的相对丰度显著增加，土壤酸杆菌门的相对丰度显著降低；而土壤微生物多样性指数明显降低。除趋势对应分析（DCA）显示不同种植a限人参的土壤微生物群落结构存在明显差异。Tax4Fun功能预测表明，人参种植后土壤微生物的萜类化合物和聚酮类化合物代谢与信号转导功能的相对丰度显著降低，而膜转运功能的相对丰度增加。典范对应分析（CCA）和Partial Mantel Test分析表明，土壤速效钾、全钾含量和土壤pH值是影响土壤微生物群落结构的重要因子。因此，林地开垦种植人参对土壤微生物群落结构、多样性以及代谢功能产生了显著影响，土壤速效钾、全钾含量和pH值是影响土壤微生物群落结构的重要因素。 Abstract:The aim of this research is to reveal changes in soil microbial community structure and metabolic function in forested land after planting Panax ginseng. This study used high-throughput sequencing technology to analyze the soil microbial community structure and metabolic function of forested land and forested land cultivated with ginseng for 3 and 4 years. The results showed that Proteobacteria, Actinobacteria, Acidobacteria, Verrucomicrobia, and Chloroflexi were the dominant phyla. After ginseng was planted, the relative abundance of Actinomycetes and Verrucomicrobia significantly increased while the relative abundance of Acidobacteria significantly decreased. Overall soil bacteria diversity also significantly decreased. Detrended correspondence analysis (DCA) showed significant differences in soil bacteria community structure of ginseng across different cultivation years. The relative abundance of metabolism of terpenoids and polyketides and signal transduction significantly decreased, while the relative abundance of membrane transport significantly increased. Canonical correspondence analysis (CCA) and the Partial Mantel Test showed that potassium availability, total potassium content and soil pH were key factors affecting soil microbial community structure. The results show that soil microbial community structure, diversity and metabolic function changed significantly after planting ginseng in forested land. This work has important theoretical significance for the prevention and treatment of ginseng continuous cropping obstacles. 参考文献 相似文献 引证文献

ДОБІР ПОСУХОСТІЙКИХ КУЛЬТУР ДЛЯ ПІВДЕННОГО СТЕПУ УКРАЇНИ

The cultivation expediency of more drought-resistant crops, in particular sorghum, millet, false flax, safflower and others, instead of sunflower in the area of the Southern Steppe of Ukraine is substantiated. This is, first of all, required by climate change both in Ukraine and in the world. Since 2004, researches of field crops were carried out in the conditions of the Educational and Scientific Practical Center of the Mykolaiv National Agrarian University. Soil phase is the southern chernozem with humus content in the 0–30 cm soil layer which consist of 2.96–3.21 %, with medium and high level of availability of mobile phosphorus and potassium and low – mobile nitrogen. Experiments with soriz (Oksamyt hybrid) were conducted during 2004–2006, millet (Tavriiske, Kostantynivske, Skhidnevarieties) in 2008–2010, grain sorghum (Stepovyi 5 hybrid) in 2014–2016, safflower dye (Lahidnyi variety) in 2017–2019. The years of research differed significantly in temperature and even more in the amount of precipitation before sowing and during the growing season of crops. However, the weather conditions were typical of the Southern Steppe zone of Ukraine. It is established that all studied drought-resistant crops respond positively to nutrition optimization – the level of yield and quality of grain or seeds increases. It was found that the soriz productivity depending on the application of fertilizers and sowing dates increased by 37.6–39.2 %, millet –by 33.3–41.6 %, grain sorghum depending on the background of nutrition and growing conditions – by 8.2–33.2 %, dye safflower – by 11.1–64.6 %. It was determined that the optimization of nutrition of cultivated crops allows to increase their resistance to adverse conditions and productivity in the case of application of low doses of the mineral fertilizers before sowing, pre-sowing treatment of seeds, and growth-regulating chemical application of plants on the main stages of the growing season. Key words: drought-resistant plants, climatic conditions, nutrition optimization, yield, crop quality, varieties, sowing dates.

Detergent pollutants decrease nutrient availability in soil

Household detergents contain potentially harmful surfactants that can alter microbial activity and interfere with biogeochemical cycles. Surfactants have previously been found to inhibit enzyme activity and plant growth and alter the physical properties of soil. Because detergent pollution poses a threat to ecosystems but has not been extensively studied, this study investigated the short-term effects of detergent pollution on pH and nutrient availability in soil by utilizing silty clay loam soil. Here we observed pH, phosphorus, nitrogen, and potassium levels in soil polluted with either a plant-based green detergent or a less eco-friendly detergent. Nitrogen and potassium availability levels decreased in the polluted groups. These findings support the idea that although green detergents are considered an environmentally safer choice, even these eco-friendly products have an effect on nutrient availability when introduced into soil. Overall, this study indicates that proper disposal of household products is crucial, as pollutants released into the environment can have an impact on nutrient cycling in ecosystems even in a short time period.

The effectiveness of application of phosphorous and potassium solubilizing multifunctional microbes (Aspergillus costaricaensis and Staphylococcus pasteuri mutants) on maize growth

The use of phosphorus and potassium-solubilizing microbes as biofertilizers is an alternative method to increase the availability of phosphorus and potassium in soils. This study aimed to explore the effectiveness of phosphorus (P) and potassium (K)-solubilizing multifunctional microbes (Aspergillus costaricaensis and Staphylococcus pasteuri mutants) on maize growth. The stages of this study consisted of viability test of P and K solubilizing A. costaricaensis and S. pasteuri mutants in peat and effectiveness test of P and K solubilizing A. costaricaensis and S. pasteuri mutants on maize growth. The results showed that peat carriers could keep the fungi population stable until 18 weeks of storage times. While the bacteria at 6 and 8 weeks storage times showed a slight decrease and stable in the 10 to 12 weeks storage time. The addition of P and K-solubilizing multifunctional microbes could reduce the use of fertilizer up to 50% in the treatment with a combination of easily soluble P or K sources with not-easily soluble P or K sources, as well as a combination of treatments of not-easily soluble P and K sources. This tended to occur in the treatment with the addition of A. costaricaensis mutant.

Soil Quality Engineering Using Vermicompost and its Effect on the Corn (Zea mays L.) Production in Coastal Area

The low quality of Entisol is caused by low availability of nitrogen, phosphorus, and potassium as well as low soil pH, so the addition of vermicompost is necessary. The purpose of this study was to determine the effect of vermicompost application on soil quality and to obtain the highest vermicompost dosage on the availability of nutrients such as N, P, K, and the yield of corn. The field experiment used a Randomized Completely Block Design (RCBD) with 7 dosages of vermicompost and three replications. The treatments were V0 = 0; V1 = 5; V2 = 10; V3 = 15; V4 = 20; V5 = 25; V6 = 30 Mg ha-1. Variables observed consisted of 1) initial soil and vermicompost characterization analysis, 2) soil analysis and N, P, and K content in leaves, and yield of corn. The results showed that Entisol was classified as low quality; however, vermicompost quality complied with the requirements of quality organic fertilizer. The experiment also indicated that the highest pH of Entisol (5.31) and K content in corn leaves (2.12%) were obtained at a dose of vermicompost 25 Mg ha-1. Meanwhile, the highest weight of husked corn cobs (415.55 g plant-1) and weight of unhusked corn cob (351.11 g plant-1) were obtained at a vermicompost dose of 15 Mg ha-1.

Potassium isotherm partitioning based on modified quantity‐intensity relation and potassium buffering characterization of soils of North India

AbstractBackground: Potassium (K) availability in soil and plant uptake is restrained by the dynamic interactions among the different pools of K.Aims: To understand these interactions, a study was undertaken to assess the quantity–intensity (Q/I) and buffering characteristics of rainfed maize (Zea mays L.) growing soils. Ten contrasting soils were evaluated for K partitioning changes in exchangeable K (ΔEK) and non‐exchangeable K (ΔNEK) pools in the soil‐solution phase and buffering characteristics using a modified version of Q/I approach.Results: The partitioned Q/I isotherms showed strong adsorption with the increase in K concentration ratio (CRK) and the changes due to ΔEK were higher than changes due to ΔNEK. Total buffering capacity (PBCK) significantly correlated (r = 0.92, p <0.01) with clay content with a major share contributed by buffering capacity owing to non‐exchangeable K () rather than exchangeable K (). The fixation capacity (β) factor, the magnitude of added K converted into a non‐exchangeable pool, ranged from 41 to 63%, whereas release (α) factor, the magnitude of added K converted to the exchangeable pool, ranged from 19 to 36%. Both threshold solution K (CKr) and threshold exchangeable K (EKr) values were found to be high in Satran clay loam (S2) and lower in Doon silty clay loam (S3) soils. The equilibrium exchangeable K (EKo) was found close to minimum exchangeable K (Emin) in Doon silty clay loam (S3) and Babaweyl sandy clay loam (S1) soils and overall Emin constituted about 8.94 to 0.57% of the EKo.Conclusion: It may be concluded that K Q/I isotherm partitioning provides a valuable insight to assess the dynamic relations. The ratio of α/β (K recharge index) could be used to evaluate the K enrichment capacity of soil to K additions while EKr and Emin can be potentially useful in the elucidation of exchangeable K as K fertility index especially in soils with poor K fertilizer management.

Influence of potassium on the productivity and quality of potato: A Review

Potato ranks one of the most important food crops after rice, wheat, and other field crops. A healthy potato crop removes about 1.7 to 2.3 quintals of potassium ha-1, illustrating that the potassium requirement for potatoes is much higher than that of grains. Being a shallow root crop, the effectiveness of using potassium fertilizers on potatoes varies from 50 to 60 percent. Potassium nutrition plays an important role in increasing the potato yield, either due to the formation of large tubers or the increase in the number of tubers per plant. Among the integrated nutrient management in potatoes, farmyard manure improves the absorption and availability of potassium for potato plants. Potassium protects against frost and drought stress in plants and reduces the incidence of diseases or pests. Potassium availability also decreases the concentration of reducing sugar and improves the colour and quality of potato chips. Potassium sulfate improves potato quality better than sources of potassium chloride.

Estimation of plant available potassium in loamy soils by extraction with magnesium sulfate solution

The aim of the study. To find a method to estimate plant available potassium for soil testing that does not require expensive flame photometry or atomic absorption spectrometry. Location and time of the study. Southern parts of West and Central Siberia, 2016-2019. Methodology. Comparison the potassium pool, extractable by 0,1M MgSO4 solution, with exchangeable potassium, extractable by 1M NH4OAc solution (according to GOST 26210-91) by regression analysis of the contents in 100 soil samples of arable soils (Luvic, Haplic and Calcic Chernozems, and Luvic Phaeozems) with different granulometric composition. Results. Exchangeable potassium showed the best correlation with the uptake of the element by plants and with yield in a variety of soil and climatic conditions. It was found that the relationship between potassium availability indices KAIAc (potassium extracted by 1M NH4OAc) and KAIMg (potassium extracted by 0,.1M MgSO4) was satisfactorily described (R2 = 0.88) by a simple linear function for soils with texture classes from sandy loam to sandy/silty clay and well described (R2 = 0.92) by a power function for silt loam, clay loam and sandy/silty clay. In 81% of the soils surveyed the difference between the calculated (according to the power equation) and actual KAIAc values was no more than 20%, and for 97% of the studied soils it did not exceed 30%. The cost of analytical equipment required for potassium analysis for soil testing is 7-60 times lower for KAIMg determination as compared with KAIAc. Conclusions. The KAIMg potassium availability index can be used alongside the standard KAIAc availability index for soils with soil texture classes from silt loam to sandy/silty clay. Conversion of KAIMg into KAIAc can be made by the following formula: KAIAc = 8,.108 • KAIMg0,793.

Gesso em terras baixas: alterações químicas do solo e resposta do arroz irrigado e da soja

Estudos que avaliam a resposta dos cultivos agrícolas às modificações do solo com a gessagem são relativamente abundantes, mas concentrados majoritariamente em terras altas. Este trabalho objetivou avaliar a acidez e a disponibilidade de fósforo (P) e potássio (K) do solo e a produtividade do arroz irrigado e da soja, cultivados em terras baixas, com aplicação de doses de gesso agrícola. Os experimentos foram conduzidos em um Planossolo Háplico (Triunfo/Rio Grande do Sul). Os tratamentos consistiram em seis doses de gesso agrícola (0,00; 0,25; 0,50; 1,00; 2,00; e 4,00 t ha-1) e o delineamento experimental foi o de blocos casualizados. O solo foi coletado após a colheita das lavouras, nas camadas de 0–5, 5–10, 10–20 e 20–40 cm. O pH em água, a acidez potencial (H+Al) e o P disponível (Mehlich 1) não foram alterados com a aplicação de gesso agrícola. Após o cultivo de arroz irrigado e na camada de 0–5 cm, houve aumento do teor de K disponível (Mehlich 1) para doses até 1,00 t ha-1 e diminuição do teor para doses maiores (2,00 e 4,00 t ha-1). Após o cultivo de soja, o teor de K disponível não foi alterado com a gessagem. A aplicação de gesso agrícola não influenciou a produtividade do arroz irrigado e da soja na safra avaliada, onde não houve déficit hídrico.

Straw-based biochar mediated potassium availability and increased growth and yield of cotton (Gossypium hirsutum L.)

Potassium (K) being the major limiting factor affecting cotton yield and quality has received massive research attention and the effects of various K fertilization techniques/organic amendments have been studied extensively. However, it is not clear whether the straw based, high pH biochar affects K availability, lint yield and quality of the cotton crop in alkaline calcareous soils. In the present study, we carried out a field experiment on a moderate to strongly calcareous silt loam soil to demonstrate the effect of straw-based biochar and potassium application levels on the growth, seed cotton yield and the lint quality. The experimental treatments comprised of two factors, A) biochar types i) Control no biochar, ii) Rice husk biochar (RHB), iii) Wheat straw biochar (WSB), and iv) Rice straw biochar (RSB), factor B) potassium application levels (i) control, no K fertilizer application, ii) K at 15 kg ha−1, and iii) K at 30 kg ha−1 (4 × 3 × 3, n = 36). Results showed that overall cotton growth and yield was significantly improved with increasing rates of potassium application. Three biochar sources affected seed cotton yield and quality with varying effects. For instance, the RSB increased plant height (11.71% to 22.47%), number of bolls per plant (0.74% to 13.75%), average boll weight (35.44% to 36.22%), the seed cotton yield was increased by 14.48% over the control when rice straw biochar was applied in combination with potassium at 30 kg ha−1. However, the ginning out turn (%) was declined with potassium application in combination with all three-biochar compared to control (no biochar addition). The WSB increased staple length and micronaire by 4.32% and 24.50% without potassium application. The potential effects of straw based biochar and potassium application on seed cotton yield and quality deserve further studies to identify the most suitable biochar as per soil chemical properties.

Potassium Influencing Physiological Parameters, Photosynthesis and Sugarcane Yield in Subtropical India

Potassium plays an important role in the metabolism of plants, growth, development and yields. Worldwide, KCl is commonly used as source of K fertilizer in agricultural crops. The present experiment was taken up to assess the response of various sources of K on physiological attributes, yield and quality parameters of sugarcane. Treatments were no K application, potassium ammonium sulphate (H4KNO4S-9:0:30:20, NPKS ratio), slow release K fertilizer (0:0:45:0), sulphate of potash/potassium sulphate (K2SO4-0:0:50:17.5), muriate of potash (KCl-0:0:50:0) and muriate of potash (KCl) + elemental S @ 40 kg ha−1. Application of K2SO4 recorded 15.8% improvement in tiller population (during peak tillering stage) and 22.2% improvement in dry matter accumulation (at the harvest stage) over the KCl. About 12.33–24.16% increments in crop growth rate and the highest net photosynthetic rate (19.91 µmol m−2 s−1) were also recorded with application of K2SO4. Application of K fertilizers improved the availability of potassium in soil by 8.17% (254.2 kg ha−1). Potassium uptake in sugarcane crop ranged from 245 to 347 kg ha−1. The highest individual cane length (311 cm) was measured with application of K2SO4. Application of K2SO4 brings forth about 23.8% increments in millable canes, 14% in cane weight and 33.8% in cane yield over no K. Application of K also increased mean sucrose content in juice by 0.58 unit (17.0 pol per cent juice) over no use of K. Overall effect of K application on increasing sugarcane yield and sucrose content simultaneously brought forth improvement in commercial cane sugar (CCS) by 29.43% (10.50 t/ha) over no use of K. However, application of K2SO4 also improved CCS by 25.89% (11.67 t/ha) over the application of KCl.

The dual beneficial effects of vermiremediation: Reducing soil bioavailability of cadmium (Cd) and improving soil fertility by earthworm (Eisenia fetida) modified by seasonality

This study aimed to assess earthworm's capability of reducing the bioavailability of cadmium (Cd) in soil and increasing soil fertility with the modification of seasonal variations of ambient temperatures on the efficacy of vermiremediation. Earthworms were exposed in soil fortified with 0, 5, 10, and 20 mg Cd kg−1, for 7, 14 and 21 days in winter and spring. The bioavailability of Cd in soil, which is represented in the form of diethylenetriaminepentaacetic acid-extractable fraction (DTPA-Cd), were significantly reduced, ranging from 7.9 to 18.3% in winter and 8.8 to 20.8% in spring. Meanwhile, we found earthworm activities could significantly improve the soil fertility as the results of increasing the availability of nitrogen, phosphorous, and potassium in soil, a prominent advantage of vermiremediation in heavy metal-contaminated soil. Although seasonality could increase Cd toxicity in earthworms, higher ambient temperature in spring season also promoted the reduction of Cd bioavailability and the increase of soil fertility, due to significant increase of microbial populations. In conclusion, we reported the dual beneficial effects of vermiremediation in reducing bioavailability of Cd in soil and simultaneously improving soil fertility in which both outcomes were modified by seasonality.

EFFECT OF POTASSIUM HUMATE AND PHOSPHORUS FERTILIZATION ON FABA BEAN PLANTS OF YIELD AND ITS CONTENT OF NUTRIENTS

A field experiment was carried out in the in winter season of 2015/2016 at sandy soil in El-Sadat city, El Minufia Governorate, 30.3594° N, 30.5327° E, Egypt to evaluate the effect of phosphorus fertilization and potassium humate on the growth and yields of faba bean as well as its content of N, P and K. The experiment factors were phosphorus application at three different levels (0, 10, 15 and 30 P2O5 kg kg Fed-1) and potassium humate at rate of 0, 5 and 10 kg fed-1. Also, the phosphorus use efficiency evaluated. The obtained results could be summarized as follows: Growth and yield parameters (plant height, No. of branches, No. of pods plant No. of seed pods) were significantly increased by increasing by increasing rates of added P potassium humate individually and in combination, where the highest values were resulted from their combined treatments especially at high application rates. The combination between phosphorus at 30 kg P2O5 fed-1and potassium humate at rate of 10 kg fed-1 recorded the highest growth and production as well as minerals composition (N, P and K) content compared to the other treatments. On the other hand, potassium humate at high level combined with super phosphate recorded increased in the availability of nitrogen, phosphors and potassium. Concerning, the P-efficiency the results showed that, both agronomic efficiency and apparent recovery efficiency were recorded by the highest values when compared the P fertilizer alone.

The Capacity of Soil Bacteria, Bacillus sprif and Pseudomonas sprif, in solubilizing Soil Phosphate and Potassium

Increasing availability of phosphate (P) and potassium (K) in soil can be driven by microbial activities, which are specifically able to dissolve P and K, known as nutrients hard to dissolve. The objectives of this research were to study the solubilising activity toward soil P and K by P- and K- solubilizing bacteria in sterilized and non-sterilized condition of Oxisol and Inceptisol. Marking procedure was performed on P- and K- solubilizing bacteria to scrutinize their activities in the soil. Marking process was conducted by utilizing resistance toward rifampicin antibiotica concentration of 50 µg.ml−1. The results of this study revealed that the increasing availability of P was evident in both soil conditions (sterilized and non-sterilized). In Oxisol, P availability increased by 48.86%, while in Inceptisol it reached an increase by 187.77%, compared to the initial concentration. Likewise, K availability in Oxisol increased by 4.53 times, and it rose by 5.26 times in Inceptisol. The activities of P solubilising bacteria, in addition to being able to increase soil P availability, were also able to enhance soil’s K content. Similarly, the K solubilizing bacteria were also capable of increasing P availabilityy in both soils.

Soil Temperature and Moisture Stress: Response of Some Selected Physico-chemical Properties of Soil Along with Practice of Plant and Microbes-derived Organic Fertilizers

In favor of assessing the influences of soil temperature elevation and moisture stress on physico-chemical properties of soil including soil reaction (pH), organic carbon (OC) content, availability of Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca) and Magnesium (Mg), field experiments were carried out over two seasons incorporated with organic materials of tricho-compost (TC), rice straw compost (RSC) and mustard meal (MM). Temperature elevation of 3°C from daily field temperature (23-25°C), and two different moisture levels - moist (70% moisture) and saturated (>100% moisture) - were considered simultaneously along with the application of TC at the dosages of 0, 2.5, 5; RSC at 0, 4, 8 and MM at 0, 3, 6 t ha-1. Elevated temperature markedly augmented OC (0.41 to 0.98%), N (1.07 to 4.98 m mol kg-1), P (0.39 to 0.86 m mol kg-1), K (0.12 to 0.34 c mol kg-1), Ca (2.13 to 5.97 c mol kg-1) and Mg (1.09 to 2.93 c mol kg-1) contents in soil during first season with RSC followed by MM and TC. The moist condition of soil, accompanied by the selected amendments had almost collateral effects on the aforesaid analyzed properties of soil in contrast to saturated condition. The carry-over effects of these treatments were most striking on selected properties in subsequent soil with TC succeeded by MM and RSC. Among the used amendments, TC exerted the most striking effect on nutrient availability because of the abundance of Trichoderma spp. even under stress conditions. The elevated temperature significantly (P ≤ .05) reduced the C/N ratios during both seasons which accelerated the organic matter decomposition and markedly influenced availability of N (45.39%), P (49.23%) and K (21.83%) revealed from regression analysis, irrespective of seasons. Moreover, the practice of tricho-compost over its sustainability – under climatic stress conditions - can therefore be good determinative over recovery of soil health via ameliorating soil organic matter and nutrient status.

Yield and grape must composition in ‘Cabernet Sauvignon’ grape vine subjected to potassium fertilization in high altitude soil

Potassium (K) increase in the soil can affect grape must yield and quality; and consequently, the quality of wine; however, studies in this field approaching altitude soil in Southern Brazil (used for viniculture) are scarce. The aim of the present study is to evaluate yield, critical K level in the leaves and their association with grape must composition in ‘Cabernet Sauvignon’ vines subjected to K application in high altitude soil in Southern Brazil. The experiment was performed in a ‘Cabernet Sauvignon’ vineyard subjected to the application of different K doses (0, 30 and 60 kg K2O ha-1) in three seasons. Potassium (K) availability in soil and leaves, as well as total soluble solids (TSS), pH, total titratable acidity (TA) content in grape must were evaluated. Potassium fertilizer applications increased K availability in the soil, but its concentration only increased in leaves collected at full bloom in the 2013/2014 season. Potassium applications in the soil did not affect yield, but K concentration increase in the leaves led to increased TSS and pH values in grape must, as well as to TA and tartaric acid decrease, a factor that can impair the quality of wine.

Chemical Extractors to Assess Potassium Availability in Glauconitic Siltstone

This paper aimed to evaluate the efficiency of chemical extractors to measure the availability of potassium (K) in glauconitic siltstone. An experiment with successive crops of beans and maize was installed under field conditions in Quirinópolis, Goiás State, Brazil, in a typical ortic Neossolo Quartzarênico. For both crops, the experimental design was a randomized block with four replications, resulting in a total of 24 experimental plots. Two sources and four doses of K2O were used, in addition to a control treatment with any K fertilization. The sources used were glauconitic siltstone and potassium chloride (KCl), and the doses applied through glauconitic siltstone corresponded to 1, 2, 4 and 8 times the dose of K2O applied via KCl as a reference. The following extractors were used: neutral ammonium citrate (NAC), citric acid 2% (CA), CA + ammonium fluoride 0.5% (NH4F), tartaric acid 5% (TA) + sodium fluoride 0.5% (NaF) (1:100), TA + NaF 0.5% (1:500), hydrochloric acid (HCl), and the method for extracting potassium from silicatic materials (MAPA-8.2.4.2). Among the tested extractors, the best one regarding productivity was the MAPA-8.2.4.2. The NAC and CA extractors showed the lowest correlations and should not be used henceforth to quantify soluble K from glauconitic siltstone.

Bacterial strains decrease solubility of potassium in the soil

Current study verifies whether inoculation with strains of diazotrophic bacteria, with proven ability to solubilize potassium (K) in vitro, contributes towards the release of K in the soil after fertilization with phonolite rock powder. The experiment was conducted in containers with 0.3 dm-3 of soil containing low potassium content. Fifteen treatments were used, namely, 12 inoculated with the bacterial strains, a control treatment (without phonolite and without inoculation), one containing phonolite without inoculation and one containing KCl, soluble fertilizer, without inoculation. In treatments with phonolite and KCl, the doses of these materials were applied to provide the soil with 195 mg dm-3 of K. A completely randomized design with four replications was used. The soil was incubated during 90 days at room temperature and humidity at about 70% retention capacity. After this period, the content of K+ (Mehlich and resin), pH value and potential acidity (H+Al) were evaluated. Phonolite, associated with inoculation with most bacterial strains, increased the availability of potassium in the soil, pH rate and reduced potential acidity. Among the strains tested, UNIFENAS 100-01, UNIFENAS 100-16, UNIFENAS 100-27, UNIFENAS 100-39 and UNIFENAS 100-93 were the most efficient for the solubilization of K+ of the phonolite. In spite of the observed results, K content released by the bacterial strains in the soil decreased when compared to in vitro conditions, thus justifying the need for studies on bio-solubilization of soil to select the most efficient strains in the process.

KAJIAN BIOFISIK LAHAN DAN PERFORMANS BISNIS PERTANIAN DATARAN TINGGI DI KABUPATEN KONSERVASI TAMBRAUW PROVINSI PAPUA BARAT

Tambrauw Regency is obliged to safeguard the policies of the central government, especially in food self-sufficiency efforts. Determine locations that have land suitability specifications for soybeans and analyze farming agribusiness as an important factor in agricultural development. The research activity was carried out in Kebar District and Senopi District. Peanut farmers are the focus of research, with the consideration that peanuts and soybeans are a family (leguminoseae). At this stage, the study of the characteristics and specifications of the Kebar District and Senopi District areas as potential areas for the development of soybean commodities was carried out. The study of the shape, pattern, type and pattern of farming, as well as the use of agricultural production facilities by the farming community is carriedout. Data and information from various branches of farming were held with community discussions in the form of FGD. Data analyzed descriptively. The results showed low availability of potassium in flat areas and forests and acidic soil pH in flat-savanna regions. The hindering area is the slope, and flat areas only lack potassium. Potential food crops to be developed are upland rice plants and yams. The results of evaluation of land suitability for horticultural plants (Peanuts, Mustard, Tomatoes and Chillies) show "quite suitable" to "according to the margins". The farming production of Kebar was dominated by agricultural commodities and provides enough income for the household economy.