PREDICTION DES BESOINS EN ENGRAIS N, P ET K DES LEGUMES CULTIVES EN SOL MINERAL: POIS ET HARICOTS

1982 ◽  
Vol 62 (4) ◽  
pp. 663-672
Author(s):  
EMILE CHAMBERLAND
Keyword(s):  
Field Studies ◽  
Field Trials ◽  
Soil Test ◽  
Vegetable Production ◽  
Snap Beans ◽  
Green Pea ◽  
Low Levels ◽  
Phosphorus And Potassium ◽  
K Fertilization ◽  
Green Peas

Recommendations of N, P and K fertilization presently made for vegetable production in Quebec need to be verified through local field studies. To this end field trials were made on 11 soils located in the Montreal, Nicolet and Quebec-Portneuf areas, through the year 1978–1980. Fertilization increased green pea yields in seven trials out of 16; most of these increases were caused by phosphorus applications. Similar results were obtained with snap beans, except that this crop tended to require a somewhat greater quantity of applied N. Fertilizer requirements of these crops were obtained by fitting Mitscherlich or polynomial equations to field data. Accordingly 15–30 kg N/ha seem to be required by green peas and snap beans, respectively, to obtain optimum yields. Modification of present soil test norms is suggested for phosphorus and potassium fertilization. For these crops the suggested rates are 20, 40 and over 60 kg P/ha for soils with high, moderate or low levels of available P and the minimum rate of 20 kg K/ha for every level of K except for the low level which would require about 40 kg K/ha for green peas.

An economic assessment of maintaining high phosphorus and potassium soil test levels

1991 ◽  
Vol 6 (2) ◽  
pp. 83-86 ◽  
Author(s):  
Craig Chase ◽  
Michael Duffy ◽  
John Webb ◽  
Regis Voss
Keyword(s):  
Economic Assessment ◽  
High Rate ◽  
Control Treatment ◽  
Soil Test ◽  
Test Results ◽  
Economic Returns ◽  
Net Returns ◽  
Phosphorus And Potassium ◽  
The Cost ◽  
K Fertilization

AbstractPhosphorus (P) and potassium (K) fertilization costs, yields, and economic returns associated with various P and K fertilization levels were evaluated on corn and soybeans in rotation in northeastern Iowa from 1979 to 1989. The treatments were 0, 20, and 40 lb P/acre and 0, 60, and 120 lb K/acre, in all nine combinations, plus the high rate (40+120) applied on alternate years. (The latter treatment applied, respectively, in odd or even years was averaged into one treatment.) The initial soil test levels averaged 57 pounds of P and 355 pounds ofK. The P-K treatments did not significantly explain the variation in corn or soybean yields. Net returns were found directly related to the cost of the treatment, so that the control treatment (0+0) achieved the highest returns. The cost of using the 20+60 treatment to maintain soil test levels in the high to very high range was $24/acre per year. Annual application of 40+120 cost $45/acre. A sufficiency approach to applying P and K could drastically reduce fertilizer costs for high-testing soils. Further research is needed to determine if recommendations from this approach can be lowered in some cases. Extension workers must continue to develop ways to aid farmers in realizing the usefulness of soil testing. Farmers must carefully evaluate their fertilization needs in conjunction with soil test results. Together, a more sustainable approach to P and K fertilization for corn and soybeans may be attained.

scholarly journals 350 Response of Dominican Oregano (Lippia micromera Schan.) to Nitrogen, Phosphorus, and Potassium Fertilization

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 452D-452
Author(s):  
J. Pablo Morales-Payan
Keyword(s):  
Block Design ◽  
Biomass Accumulation ◽  
Field Studies ◽  
Mineral Fertilization ◽  
Crop Field ◽  
Commercial Crop ◽  
Treatment Analysis ◽  
Phosphorus And Potassium ◽  
K Fertilization ◽  
Term Response

Dominican oregano is a traditional seasoning leaf in Caribbean cuisine. However, little information is available regarding its mineral nutrition when grown as a commercial crop. Field studies were conducted to determine the short-term response of recently transplanted Dominican oregano to N, P, and K in a clay soil. Dominican oregano plants 15 to 20 cm tall were used. A randomized complete-block design with 13 treatments and three replications was utilized. Treatments were 0 fertilization (control) and 20, 40, 60, and 80 kg/ha of N, P2O5, or K2O applied 20 days after transplanting. Experimental units consisted of 12 plants at with a distancing of 1.0 × 1.0 m. Above-ground biomass accumulation was determined 3 months after treatment. Analysis of variance and regression analysis was performed on the resulting data. Biomass accumulation in Dominican oregano was significantly influenced by N, P, and K fertilization rates. Crop yield increased linearly as nutrient rates increased. Nitrogen fertilization had a stronger influence on Dominican oregano biomass accumulation than P and K fertilization. Results indicate that fertilizing Dominican oregano increases its biomass yield. However, due to its seasoning nature, the effect of mineral fertilization on the essential oils of this crop must be analyzed.

Response of `Spineless Beauty' Zucchini (Cucurbita sp.) to Nitrogen, Phosphorus, and Potassium Fertilization

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 445d-445
Author(s):  
J. Pablo Morales-Payan
Keyword(s):  
Field Trials ◽  
Fruit Yield ◽  
Yield Response ◽  
K Fertilizer ◽  
Direct Seeded ◽  
Phosphorus And Potassium ◽  
Fruit Harvest ◽  
Fertilizer Rates ◽  
Nitrogen Phosphorus ◽  
K Fertilization

Field trials were conducted in Nigua, San Cristobal, Dominican Republic, to determine the yield response of `Spineless Beauty' zucchini (Cucurbita sp.) to nitrogen (N), phosphorus (P), and potassium (K) soil applications in a loamy clay soil containing 4.3% organic matter, 3 parts per million (ppm) of P, and 155 ppm of K. Zucchini was direct-seeded at a distance of 1 m between rows and 0.5 m within rows. Except for N, P, and K fertilization, the crop was grown according to recommended practices. A factorial design (4 × 4 × 4) with four replications was utilized. Rates of N, P, and K were 50, 100, 150, and 200 kg·ha–1, applied as a side dressing 7 days after zucchini emergence. Zucchini fruit harvest started 40 days after crop emergence and every other day thereafter during 20 days. Analysis of variance was performed on the resulting data. Results indicate that there were significant interactions of N, P, and K fertilizer rates on `Spineless Beauty' fruit yield; therefore, nutrient combinations were considered as individual treatments. Significantly superior (lsd 5%) fruit yield was obtained with 150, 150, and 50 kg·ha–1 N, P, and K, respectively.

scholarly journals RESPONSE OF FIVE LETTUCE TYPES TO K FERTILIZERS ON HISTOSOLS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 665b-665
Author(s):  
N.M. El-Hout ◽  
C.A. Sanchez ◽  
S. Swanson
Keyword(s):  
Crop Production ◽  
Field Studies ◽  
Organic Soils ◽  
Soil Test ◽  
Nutrient Element ◽  
Optimal Production ◽  
Fertilizer Recommendations ◽  
K Fertilizer ◽  
Southern Florida ◽  
K Fertilization

Potassium is often considered the nutrient element most limiting to crop production on organic soils. On Histosols in southern Florida, K2SO4, rather than KCl, is often used for lettuce (Lactuca sativa L.) production to minimize the risk of salt injury. However, recent soil-test calibration research suggests that current K fertilizer recommendations for lettuce may be too high. Four field studies were conducted from 1989 to 1991 to evaluate the response of five lettuce types to K rate and source. The five lettuce types evaluated were leaf, bibb, boston, romaine (cos), and crisphead. Two sources of fertilizer K (K2SO4 and KCl) were evaluated at rates ranging from 0 to 600 kg K ha-1. Lettuce showed a minimal or no response to K fertilization. Potassium chloride had detrimental effects on lettuce only when applied at rates in excess of those required for optimal production. These studies showed that K fertilizer recommendations for lettuce produced on Histosols in Florida can be reduced. Furthermore, KCl, a more economical source, is suitable when the K is applied at appropriate rates.

scholarly journals Dynamics of the Degradation of Acetyl-CoA Carboxylase Herbicides in Vegetables

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 405
Author(s):  
Miroslav Jursík ◽  
Kateřina Hamouzová ◽  
Jana Hajšlová
Keyword(s):  
Linear Models ◽  
Growing Season ◽  
Field Trials ◽  
Baby Food ◽  
Vegetable Production ◽  
The Czech Republic ◽  
Herbicide Residues ◽  
Harvest Intervals ◽  
Small Plot

(1) Background: Aryloxyphenoxy-propionates and cyclohexanediones are herbicides most widely used in dicot crops worldwide. The main objective of the study was to determine the dynamics of herbicide residues in carrot, lettuce, cauliflower, and onion in order to suggest a low level of residues in harvested vegetables. (2) Methods: Small plot field trials were carried out in four vegetables in the Czech Republic. The samples of vegetables were collected continuously during the growing season. Multiresidue methods for the determination of herbicide residues by LC-MS/MS were used. Non-linear models of degradation of individual herbicides in vegetables were calculated using the exponential decay formula. Action GAP pre-harvest intervals for the 25% and 50% maximum residue limit (MRL) and 10 µg kg−1 limit (baby food) were established for all tested herbicides. (3) Results: The degradation dynamics of fluazifop in carrot, onion, and cauliflower was significantly slower compared to quizalofop and haloxyfop. The highest amount (2796 µg kg−1) of fluazifop residues was detected in cauliflower 11 days after application. No residue of propaquizafop and cycloxydim was detected in any vegetable samples. (4) Conclusions: Aryloxyphenoxy-propionate herbicide (except propaquizafop) could contaminate vegetables easily, especially vegetables with a short growing season. Vegetables treated with fluazifop are not suitable for baby food. Lettuce and cauliflower treated by quizalofop are not suitable for baby food, but in onion and carrot, quizalofop could be used. Propaquizafop and cycloxydim are prospective herbicides for non-residual (baby food) vegetable production.

scholarly journals Managing Bees for Delivering Biological Control Agents and Improved Pollination in Berry and Fruit Cultivation

2015 ◽  
Vol 4 (3) ◽  
pp. 89 ◽  
Author(s):  
Heikki M. T. Hokkanen ◽  
Ingeborg Menzler-Hokkanen ◽  
Marja-Leena Lahdenpera
Keyword(s):  
Crop Protection ◽  
Field Tests ◽  
Weather Conditions ◽  
Field Studies ◽  
Field Trials ◽  
Marketable Yield ◽  
Dissemination Activity ◽  
Grey Mold ◽  
Commercial Farms ◽  
Disease Pressure

<p>Targeted precision biocontrol and improved pollination were studied Europe-wide in the EU ERA-NET CORE ORGANIC 2 project BICOPOLL (Biocontrol and Pollination). A case study was conducted on the management of strawberry grey mold <em>Botrytis cinerea</em>, with the biocontrol fungus, <em>Gliocladium catenulatum</em>, vectored by honey bees or bumble bees. A joint field trial carried out in five countries targeted strawberry cultivations in open field, and included four treatments: untreated control, chemical fungicide, entomovectored biocontrol, and chemical and biocontrol combined. In organic fields, no pesticide treatments were included. The proportion of moldy berries, and/or the marketable yield of healthy berries were recorded from each treatment, along with other parameters of local interest. A pilot study was started in Finland in 2006, and, by 2012, large commercial farms were using entomovectoring. In 2012, field trials were started in Estonia and in Italy, and in 2013-14, these experiments were expanded to Slovenia and Turkey. In total, 26 field tests were conducted using entomovectoring and <em>Gliocladium catenulatum</em> (Prestop<sup>®</sup> Mix) on strawberry, with five additional trials on raspberry. Efficacy results have been excellent throughout the field studies. The results show crop protection equalling or exceeding that provided by a full chemical fungicide program, under all weather conditions, and over a wide geographical range (from Finland to Turkey). Under heavy disease pressure, entomovectoring provided on average a 47% disease reduction, which was the same as multiple fungicide sprays. Under light disease pressure, biocontrol decreased grey mold by an average of 66%, which was greater than fungicide sprays. The concept has proven to be effective on strawberries, raspberries, pears, apples, blueberries, cherries, and grapes. A conservative estimate for Finland is that over 500 ha of strawberry cultivation currently use the technique (≈15% of the strawberry growing area). To make full use of the entomovectoring technique, organic berry and fruit growers are encouraged to (i) keep bees, or to hire the service from local beekeepers for entomovectoring; and (ii) manage vegetation within and around the target crop to support the activity of bees and other pollinators, which can help to disseminate the beneficial microbial populations within the crop. Beekeepers are encouraged to (i) market pollination and biocontrol services to fruit and berry growers, and (ii) ensure that all operations are effective in mananging bees and their microbe dissemination activity. Biocontrol product manufacturers are encouraged to further develop products and their formulations specifically for entomovectoring, because current formulations are suboptimal as they are initially optimized for other uses (e.g., mixing into the soil).</p>

scholarly journals Nutrient Management Effects on Wine Grape Tissue Nutrient Content

Plants ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 158
Author(s):  
John L. Havlin ◽  
Robert Austin ◽  
David Hardy ◽  
Adam Howard ◽  
Josh L. Heitman
Keyword(s):  
Nutrient Management ◽  
Nutrient Status ◽  
Nutrient Content ◽  
Field Studies ◽  
Soil Test ◽  
Full Bloom ◽  
Management Decisions ◽  
Late Season ◽  
Foliar N ◽  
N Management

With limited research supporting local nutrient management decisions in North Carolina grape (Vitis vinifera) production, field studies (2015–17) were conducted to evaluate late season foliar nitrogen (N) application on leaf and petiole N concentration and yeast assimilable N (YAN) in the fruit. Foliar urea (1% v/v) was applied at different rates and application times beginning pre-and post-veraison. Compared to soil applied N, late season foliar N substantially enhanced petiole N and grape YAN. Smaller split N applications were generally more effective in increasing YAN than single larger N rates. These data demonstrate the value of assessing plant N content at full bloom with petiole N analysis or remote sensing to guide foliar N management decisions. Additional field studies (2008–11) were conducted to evaluate pre-bud soil applied phosphorus (P) and potassium (K) effects on petiole P and K nutrient status. Fertilizer P and K were initially broadcast applied (0–896 kg P2O5 ha−1; 0–672 kg K2O ha−1) prior to bud-break in 2008–09 and petiole P and K at full bloom soil test P and K were monitored for three to four years after application. Soil test and petiole P and K were significantly increased with increasing P and K rates, which subsequently declined to near unfertilized levels over the sampling time depending on site and P and K rate applied. These data demonstrate the value of annually monitoring petiole P and K levels to accurately assess plant P and K status to better inform nutrient management decisions.

Mycotoxins in organically versus conventionally produced cereal grains and some other crops in temperate regions

2016 ◽  
Vol 9 (5) ◽  
pp. 755-770 ◽  
Author(s):  
G. Brodal ◽  
I.S. Hofgaard ◽  
G.S. Eriksen ◽  
A. Bernhoft ◽  
L. Sundheim
Keyword(s):  
Farming Systems ◽  
Weather Conditions ◽  
Field Trials ◽  
Cereal Grains ◽  
Organic System ◽  
Mycotoxin Contamination ◽  
Significant Difference ◽  
Apple Products ◽  
Low Levels ◽  
The Difference

This paper presents peer-reviewed studies comparing the content of deoxynivalenol (DON), HT-2+T-2 toxins, zearalenone (ZEA), nivalenol (NIV), ochratoxin A (OTA) and fumonisins in cereal grains, and patulin (PAT) in apple and apple-based products, produced in organically and conventionally grown crops in temperate regions. Some of the studies are based on data from controlled field trials, however, most are farm surveys and some are food basket surveys. Almost half of the studies focused on DON in cereals. The majority of these studies found no significant difference in DON content in grain from the two farming systems, but several studies showed lower DON content in organically than in conventionally produced cereals. A number of the investigations reported low DON levels in grain, far below the EU limits for food. Many authors suggested that weather conditions, years, locations, tillage practice and crop rotation are more important for the development of DON than the type of farming. Organically produced oats contained mainly lower levels of HT-2+T-2 toxins than conventionally produced oats. Most studies on ZEA reported no differences between farming systems, or lower concentrations in organically produced grain. For the other mycotoxins in cereals, mainly low levels and no differences between the two farming systems were reported. Some studies showed higher PAT contamination in organically than in conventionally produced apple and apple products. The difference may be due to more efficient disease control in conventional orchards. It cannot be concluded that any of the two farming systems increases the risk of mycotoxin contamination. Despite no use of fungicides, an organic system appears generally able to maintain mycotoxin contamination at low levels. More systematic comparisons from scientifically controlled field trials and surveys are needed to clarify if there are differences in the risk of mycotoxin contamination between organically and conventionally produced crops.

scholarly journals Optimizing Sowing Depth of Tef for Irrigated Mediterranean Conditions: From Laboratory to Field Studies

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1983
Author(s):  
Shiran Ben-Zeev ◽  
Shane Kerzner ◽  
Onn Rabinovitz ◽  
Yehoshua Saranga
Keyword(s):  
Field Experiments ◽  
Field Studies ◽  
Field Trials ◽  
Eragrostis Tef ◽  
Sowing Depth ◽  
New Crops ◽  
Different Depths ◽  
Plant Emergence ◽  
Increasing Demand ◽  
Mediterranean Conditions

Developing new crops adapted to arid conditions is a promising approach to meet the increasing demand for food production under expanding aridity. Tef [Eragrostis tef (Zucc.) Trotter] is a C4 cereal crop cultivated mainly in Ethiopia and the Horn of Africa, and known for its high resilience to stressful environments. Due to their tiny size, tef seeds are traditionally sown by broadcasting and lightly covering with soil. Under semiarid Mediterranean conditions, a deeper sowing may guarantee seedling establishment while saving on irrigation water. The objective of this study was, therefore, to determine the effects of sowing depth on tef emergence, development, lodging, and productivity. Tef seeds were sown at different depths in test tubes and pots, and in two field experiments. In tubes and pots, time from sowing to emergence increased about twofold and emergence rate decreased in the deepest sowing (3 cm) treatment compared to controls (0 cm). In the pot and field trials, deep sowing (3 cm) significantly reduced plant height, shoot and root biomass, and lodging. Sowing depths of 1–2 cm allowed successful plant establishment while not exacting penalties on plant emergence or development; hence this range appears to be optimal for sowing irrigated tef.

Reliability of Singing Bird Surveys: Changes in Observer Efficiency with Avian Density

The Auk ◽  
1984 ◽  
Vol 101 (2) ◽  
pp. 307-318 ◽  
Author(s):  
Jonathan Bart ◽  
James D. Schoultz
Keyword(s):  
Measurement Error ◽  
General Procedure ◽  
Field Studies ◽  
Abundant Species ◽  
Common Species ◽  
Field Trials ◽  
Bird Songs ◽  
Auditory Cues ◽  
Basic Assumptions ◽  
Maximum Estimate

Abstract Field trials in which paired observers were used and indoor simulations in which recorded bird songs were used indicated that, as the number of singing birds audible from a listening station increased from 1 to 4, the fraction of them recorded by observers declined by up to 50%. This reduction in efficiency violates one of the basic assumptions of any index-that the proportion of animals detected remains constant-and could cause surveyors who rely primarily on auditory cues to underestimate changes in population density by up to 25% for common species and 33% for abundant species. The change in efficiency, which is best regarded as measurement error, cannot be detected by a statistical examination of the data and thus may pass undetected in many field studies. It seems unlikely that any general procedure for "correcting" the error would be reliable. The results indicate that singing bird surveys of common species should be supplemented by other methods if accurate estimates of changes in density are needed. A general conclusion of the study is that whenever animals "compete" for a place in the survey, for example by filling up traps or suppressing one another's songs, then the index tends to underestimate a change in density. If efficiency increases with density, then the survey tends to overestimate a change in density. If the sign of the bias can be determined, the survey can be used to provide a minimum or maximum estimate of a change in density even if the magnitude of the bias cannot be estimated.

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