scholarly journals Potassium Response in some Malawi Soils

2013 ◽  
Vol 13 ◽  
pp. 175-181 ◽  
Author(s):  
Deliwe Dinah Lakudzala
Keyword(s):  
Smallholder Farmers ◽  
Maximum Yield ◽  
Maximum Response ◽  
Optimum Level ◽  
Potassium Fertilizer ◽  
Response Curves ◽  
Fertilizer Recommendations ◽  
Potassium Response ◽  
K Response ◽  
Different Soils

Potassium (K) response curves were generated for some Malawi soils using four different rates of potassium fertilizer, with grass being used to estimate plant availability. The study was conducted to find the point of maximum response for potassium. The soils were characterized, limed and fertilized with equal amounts of nitrogen. Potassium was applied at four rates: 0.0, 0.1, 0.2 and 0.4 me K/100 cm3 soil. The K treated soils were put in pots and cropped with grass. The grass was harvested six weeks after planting, dried and weighed. In general, addition of potassium resulted in increased growth of grass in all soils, with some soils showing better response than others. For montmorillonitic soils and soils with mixed mineralogy response was linear up to the highest rate of 0.4 me K/100 cm3. Apparently the 0.4 me K/100 cm3 soil was not enough to give maximum yield for these potassium depleted soils. For the kaolinitic soils 0.4 me K/100 cm3 soil was beyond point of maximum response. The variation of response to added potassium in the different soils calls for soil specific fertilizer additions. Smallholder farmers should move from blanket (crop specific) fertilizer recommendations currently being used to crop and soil specific fertilizer recommendations. Basal fertilizer dressings (starter packs) should always contain potassium. Correlation and calibration studies should be conducted to establish a potassium low optimum level for Malawi soils.

scholarly journals Online Fertilizer Recommendation System (OFRS): A Step Towards Precision Agriculture And Optimized Fertilizer Usage By Smallholder Farmers In Bangladesh

2020 ◽  
Vol 1 (4) ◽  
Author(s):  
M. A. Hossain ◽  
M. N. A. Siddique
Keyword(s):  
Precision Agriculture ◽  
Recommendation System ◽  
Smallholder Farmers ◽  
Fertilizer Application ◽  
Soil Test ◽  
Total Production ◽  
Soil Database ◽  
Fertilizer Recommendation ◽  
Fertilizer Recommendations ◽  
Input Cost

The recent progression and Green Revolution (approx. between the 1990s-2010s) in agriculture of Bangladesh resulted in an increase of total production despite yield-gap to ensure food security. But agriculture in Bangladesh is still backed-up by higher use of inputs (agrochemicals-fertilizers, pesticides; modern varieties, irrigation etc.) and inversion tillage. This conventional agrochemical-based smallholder agriculture may lead to soil and environmental degradation, soil acidification, and a decline in soil fertility. Therefore, it is significant to optimize input application in intensive agriculture, especially fertilizers. This paper introduces the potential online facilities of generating online fertilizer recommendations for smallholder farmers in Bangladesh to ensure proper usage of fertilizers and enable sustainable agricultural production. We also highlighted how the usage of fertilizers increased with an increase in total production over time. But the sustainability of production in the years to come still remain challenging. With the aim of sustainable crop production, reduction in the misuse of fertilizers and reduction of input cost by optimizing the present pattern of excessive fertilizer application, the Soil Resource Development Institute (SRDI) provides location-specific fertilizer recommendation through both the manual and soil test based interpretation of plant nutrients: soil database in Upzazila Nirdeshika and static laboratory soil analysis. Recently, SRDI developed web-based software named Online Fertilizer Recommendation System (OFRS). The system is capable of generating location-specific fertilizer recommendations for selected crops by analyzing the national soil database developed by this governmental institute. The software requires farmer field location, respective soil and land type, and crop type and variety information to generate crop-specific instant fertilizer recommendation. It was observed that by using fertilizer according to the recommended dose calculated on the basis of soil test values, farmers could harvest approx. 7-22% higher yield of different crops over usual farmers practice. If this system can be popularized and disseminated by effective agricultural extension, this would immensely contribute to the promotion of precision agriculture, input cost reduction and it would certainly enable us to optimize fertilizer application by the smallholder farmers in Bangladesh.

Validation of Soil‐Test‐Based Phosphorus and Potassium Fertilizer Recommendations for Flood‐Irrigated Rice

2019 ◽  
Vol 111 (5) ◽  
pp. 2523-2535 ◽  
Author(s):  
Matthew S. Fryer ◽  
Nathan A. Slaton ◽  
Trenton L. Roberts ◽  
Jarrod T. Hardke ◽  
Richard J. Norman
Keyword(s):  
Soil Test ◽  
Potassium Fertilizer ◽  
Irrigated Rice ◽  
Fertilizer Recommendations ◽  
Phosphorus And Potassium

Validation of Soil-Test-Based Phosphorus and Potassium Fertilizer Recommendations for Irrigated Soybean

2019 ◽  
Vol 83 (3) ◽  
pp. 825-837 ◽  
Author(s):  
Matthew S. Fryer ◽  
Nathan A. Slaton ◽  
Trenton L. Roberts ◽  
W. Jeremy Ross
Keyword(s):  
Soil Test ◽  
Potassium Fertilizer ◽  
Fertilizer Recommendations ◽  
Phosphorus And Potassium

Effect of breathing dry air on structure and function of airways

1986 ◽  
Vol 61 (1) ◽  
pp. 312-317 ◽  
Author(s):  
J. C. Van Oostdam ◽  
D. C. Walker ◽  
K. Knudson ◽  
P. Dirks ◽  
R. W. Dahlby ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Connective Tissue ◽  
Water Loss ◽  
Structure And Function ◽  
Maximum Response ◽  
Response Curves ◽  
Loose Connective Tissue ◽  
Dry Air ◽  
And Function ◽  
Breathing Room

We compared the effect of breathing dry air (0.70 mg H2O/l) with that of breathing room air (8.62 mg H2O/l) in guinea pigs anesthetized with urethane. The data showed that breathing dry air caused a reduction of extravascular water (EVW) in the trachea (P less than 0.01) but not the lung. Structural analysis showed that this water loss occurred from the loose connective tissue of the submucosa. Histamine dose response curves performed on the animals showed that breathing dry air caused an increase in the maximum response (delta max RL) (P less than 0.01) without changing either the dose required to produce 50% of the delta max RL or the ratio of delta max RL to this dose. We conclude that breathing dry air produces an acute reduction of EVW of the loose connective tissue of the airways and an increase in the maximum response to histamine.

scholarly journals Pharmacological Basis for the Medicinal Use ofLepidium sativumin Airways Disorders

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Najeeb-ur Rehman ◽  
Arif-ullah Khan ◽  
Khalid M. Alkharfy ◽  
Anwarul-Hassan Gilani
Keyword(s):  
Crude Extract ◽  
Folk Medicine ◽  
Maximum Response ◽  
Lepidium Sativum ◽  
Response Curves ◽  
Leftward Shift ◽  
Inhibitory Pathways ◽  
Low Concentrations ◽  
Medicinal Use ◽  
Pharmacological Basis

Lepidium sativumis widely used in folk medicine for treatment of hyperactive airways disorders, such as asthma, bronchitis and cough. The crude extract ofLepidium sativum(Ls.Cr) inhibited carbachol (CCh, 1 μM-) and K+(80 mM-) induced contractions in a pattern similar to that of dicyclomine. Ls.Cr at 0.03 mg/mL produced a rightward parallel shift of CCh curves, followed by nonparallel shift at higher concentration (0.1 mg/mL), suppressing maximum response, similar to that caused by dicyclomine. Pretreatment of tissues with Ls.Cr (0.1–0.3 mg/mL) shifted Ca++concentration-response curves (CRCs) to right, as produced by verapamil. Ls.Cr at low concentrations (0.03–0.1 mg/mL) caused leftward shift of isoprenaline-induced inhibitory CRCs, like that caused by rolipram, a phosphodiesterase (PDE) inhibitor. These results indicate that bronchodilatory effect ofLepidium sativumis mediated through a combination of anticholinergic, Ca++antagonist and PDE inhibitory pathways, which provides sound mechanistic background for its medicinal use in the overactive airways disorders.

Potassium nutrition, ionic relations, and oxalic acid accumulation in three cultivars of Setaria sphacelata

1972 ◽  
Vol 23 (6) ◽  
pp. 969 ◽  
Author(s):  
FW Smith
Keyword(s):  
Oxalic Acid ◽  
Nitrogen Fertilization ◽  
Response Curves ◽  
Potassium Nutrition ◽  
Potassium Fertilization ◽  
Inorganic Cation ◽  
Setaria Sphacelata ◽  
Calcium Magnesium ◽  
Ionic Relations ◽  
Potassium Response

The effects of potassium and nitrogen fertilization on growth, chemical composition, ionic relations, and oxalic acid levels in the Nandi, Kazungula, and Narok cultivars of Setaria sphacelata have been studied. Potassium response curves have been derived and their use in predicting 'critical potassium levels' in these grasses discussed. Cation-anion balances (total inorganic cation concentrationndash;total inorganic anion concentration) have been calculated and the effects of potassium and nitrogen fertilization on ionic relations are discussed. The Kazungula and Narok cultivars contained higher levels of the cations calcium, magnesium, sodium, and ammonium when grown under limiting potassium conditions than when supplied with adequate potassium. The Nandi cultivar was similarly affected but did not accumulate sodium. All plants with high levels of potassium in their tissues also contained high levels of nitrate when the nitrogen supply was adequate. The cation-anion balance increased with increasing potassium fertilization in all cultivars but there was an interaction between potassium fertilization and nitrogen fertilization. Potassium and nitrogen fertilization resulted in large increases in oxalic acid levels. It is shown that the amount of oxalic acid accumulated is related to the cation-anion balance.

Intrarenal infusion of bradykinin elicits a pressor response in conscious rats via a B2-receptor mechanism

1999 ◽  
Vol 77 (8) ◽  
pp. 563-570 ◽  
Author(s):  
Kimberly M Hoagland ◽  
David A Maddox ◽  
Douglas S Martin
Keyword(s):  
Renal Artery ◽  
Pressor Response ◽  
Cardiovascular Responses ◽  
Nerve Fibers ◽  
Maximum Response ◽  
Left Renal Artery ◽  
Response Curves ◽  
Afferent Nerve Fibers ◽  
Pressor Responses ◽  
Hoe 140

Bradykinin (BK) is a peptide known to activate afferent nerve fibers from the kidney and elicit reflex changes in the cardiovascular system. The present study was specifically designed to test the hypothesis that bradykinin B2 receptors mediated the pressor responses elicited during intrarenal bradykinin administration. Pulsed Doppler flow probes were positioned around the left renal artery to measure renal blood flow (RBF). A catheter, to permit selective intrarenal administration of BK, was advanced into the proximal left renal artery. The femoral artery was cannulated to measure mean arterial pressure (MAP). MAP, heart rate (HR), and RBF were recorded from conscious unrestrained rats while five-point cumulative dose-response curves during an intrarenal infusion of BK (5-80 µg·kg-1·min-1) were constructed. Intrarenal infusion of BK elicited dose-dependent increases in MAP (maximum pressor response, 26 ± 3 mmHg), accompanied by a significant tachycardia (130 ± 18 beats/min) and a 28% increase in RBF. Ganglionic blockade abolished the BK-induced increases in MAP (maximum response, -6 ± 5 mmHg), HR (maximum response 31 ± 14 beats/min), and RBF (maximum response, 7 ± 2%). Selective intrarenal B2-receptor blockade with HOE-140 (50 µg/kg intrarenal bolus) abolished the increases in MAP and HR observed during intrarenal infusion of BK (maximum MAP response, -2 ± 3 mmHg; maximum HR response, 15 ± 11 beats/min). Similarly, the increases in RBF were prevented after HOE-140 treatment. In fact, after HOE-140, intrarenal BK produced a significant decrease in RBF (22%) at the highest dose of BK. Results from this study show that the cardiovascular responses elicited by intrarenal BK are mediated predominantly via a B2-receptor mechanism.Key words: bradykinin, blood pressure, renal hemodynamics, B2 receptors, autonomic nervous system.

Comparison of the effects of potassium fertilizer on the yield, potassium content and quality of 22 different vegetable and agricultural crops

1980 ◽  
Vol 95 (2) ◽  
pp. 441-456 ◽  
Author(s):  
D. J. Greenwood ◽  
T. J. Cleaver ◽  
Mary K. Turner ◽  
J. Hunt ◽  
K. B. Niendorf ◽  
...  
Keyword(s):  
Dry Matter ◽  
General Relation ◽  
Dry Weight ◽  
Fertilizer Application ◽  
Optimum Level ◽  
Potassium Fertilizer ◽  
Plant Weight ◽  
K Fertilizer ◽  
P Fertilizer ◽  
The Difference

SUMMARYSixty-one experiments with 15 levels of K fertilizer in the presence of excess N and P fertilizer were carried out on adjacent sites of the same field. Yield was always related to level of K fertilizer by a ‘diminishing returns’ type curve, and a derived equation, which defined relative responsiveness in terms of a single parameter, fitted the data for each crop very satisfactorily. Although the responsiveness of many of the crops was similar there were marked differences and the optimum levels of K (defined as the level at which a further 10 kg/ha increased yield by 1%) varied from 0 to 360 kg/ha, depending on the crop. Responsiveness was largely independent of the plant family to which the crop belonged, but was related to the mean plant weight atharvest; the larger the weight the less reponsive the crop. No general relation existed between responsiveness and duration of growth.The % K in the dry matter of leaves (including stems) at harvest of crops receiving the optimum levels of K fertilizer was mainly determined by the family. It was generally between 0·9 and 1·1 for the Amaryllidaceae, between 1·1 and 1·2 for the Leguminosae and between 1·9 and 2·5% for the Cruciferae. The difference between the % K in the dry matter with the optimum level of K fertilizer and that with no fertilizer was proportional to responsiveness. Percentage K at harvest was a good indicator of the extent to which crop growth was restricted by lack of potassium.At harvest crops receiving the optimum levels of K fertilizer contained between 29 and 220 kg/ha of K, but uptake increased asymptotically to a maximum as K applications were raised to higher levels. Maximum uptake for nearly all crops was almost double the uptake with the optimum fertilizer application.Percentage recovery of 100 kg/ha of added K fertilizer varied between 8 and 70%, roughly in proportion to the total crop dry weight, which varied between 1 and 15 t/ha.Effects of level of K fertilizer on crop quality were also measured and over the practical range of applications the effects were generally small.The differences between the K requirements of crops are discussed and it is argued that the responsiveness of one crop relative to that of another would be expected to be similar on a range of soils.

scholarly journals Potassium Fertilizer Recommendations for Sugarcane on Florida Organic Soils

EDIS ◽  
2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
James Mabry McCray
Keyword(s):  
Organic Matter ◽  
Plant Growth ◽  
Agricultural Area ◽  
Organic Soils ◽  
Plant Nutrient ◽  
Potassium Fertilizer ◽  
Everglades Agricultural Area ◽  
Low Concentrations ◽  
Fertilizer Recommendations ◽  
Mineralization Of Organic Matter

Potassium is a primary plant nutrient that is required in large amounts by sugarcane. About 74% of the 400,000 acres of Florida sugarcane is grown on organic soils in the Everglades Agricultural Area. Potassium is not a component of organic matter and virgin Histosols contain very low concentrations of K, so release of K through mineralization of organic matter in these soils is not an adequate K source for plant growth. This 7-page document presents revised potassium fertilizer recommendations for sugarcane grown on Florida organic soils along with supporting information. Written by J. Mabry McCray, and published by the UF/IFAS Agronomy Department, February 2019.  http://edis.ifas.ufl.edu/ag428

scholarly journals Effect of Different Rates of N and Intrarow Spacing on Growth Performance of Lettuce (Lactuca sativa L.) in Gurage Zone, Wolkite University, Ethiopia

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Bewuket Gashaw ◽  
Shewaye Haile
Keyword(s):  
Block Design ◽  
Maximum Yield ◽  
Dry Weight ◽  
Optimum Level ◽  
Plant Spacing ◽  
Fresh Weight ◽  
Randomized Complete Block Design ◽  
Main Effect ◽  
Demonstration Site ◽  
Four Levels

A field experiment was conducted in Wolkite University, Horticulture department practical demonstration site, from February to June 2019 with the objective of determining the optimum level of N and intrarow spacing for better growth of lettuce. The experiment consisted of four levels of N (N0 (0 kg/ha), N1 (50 kg/ha), N2 (100 kg/ha), and N3 (150 kg/ha)) and three levels of intrarow spacing (S1 (15 × 30 cm), S2 (20 × 30 cm), and S3 (25 × 30 cm)). The interrow spacing was maintained as 30 cm. The experiment was laid out in 3 × 4 factorial arrangement in a randomized complete block design (RCBD) and replicated three times. The main effect of nitrogen resulted maximum yield (9.45 ton/ha), dry weight per plant (28.75 g), and fresh weight per plant (57.57 g) which were recorded by the application of 150 kg/ha nitrogen. Likewise, the main effect of intrarow spacing gave maximum yield (8.01 ton/ha), dry weight per plant (21.31 g), and fresh weight per plant (59.15 g) from 25 × 30 cm plant spacing. For interaction effect, the highest yield (10.38 ton/ha), dry weight per plant (50.96 g), and fresh weight per plant (77.88 g) was found from N3S3 (150 kg/ha N and 25 × 30 cm plant spacing). Therefore, in the study, area using 150 kg/ha urea with 25 × 30 cm plant spacing could be advisable for optimum lettuce production.

Sign in / Sign up

Export Citation Format

Share Document