Understorey competition affects tree growth and fate of fertilizer-applied 15N in a Coastal British Columbia plantation forest: 6-year results

2000 ◽  
Vol 30 (9) ◽  
pp. 1379-1388 ◽  
Author(s):  
Scott X Chang ◽  
Caroline M Preston
Keyword(s):  
Tree Growth ◽  
Fertilizer Application ◽  
Thuja Plicata ◽  
Diameter Growth ◽  
N Availability ◽  
Fertilizer N ◽  
Plantation Forest ◽  
Understorey Vegetation ◽  
Growing Seasons ◽  
N Concentration

Growth of planted seedlings in cutovers dominated by salal (Gaultheria shallon Pursh) is poor largely because of low N availability and understorey competition. In this paper, the response of tree growth and fertilizer recovery to understorey competition was studied. The trees were four years old when (15NH4)2SO4 (200 kg N/ha, 3.38004% enrichment) was applied in 1991 to single-tree plots, with either understorey removed from (treated) or left (control) in the plots. Half of the plots were either sampled after two (1992) or six (1996) growing seasons. Understorey competition continued to significantly reduce height and diameter growth between 1992 and 1996, except diameter growth for western redcedar (Thuja plicata Donn.). Nitrogen and 15N concentration in both tree and understorey components decreased from 1992 to 1996 and N concentration in 1-year-old foliage in 1996 (but not in 1992) was significantly lower in the control than in the treated plots, indicating that the site was low in N supply and the effect of fertilizer application on tissue N concentration did not last for 6 years. Results strongly indicated that the trees or understorey vegetation had no net uptake of fertilizer N beyond the second growing season. Understorey vegetation components played a significant role in the uptake and recycling of fertilizer N in this forest ecosystem.

Managing inoculation failure of field pea and chickpea based on spectral responses

2002 ◽  
Vol 82 (2) ◽  
pp. 273-282 ◽  
Author(s):  
J. T. McConnell ◽  
P. R. Miller ◽  
R. L. Lawrence ◽  
R. Engel ◽  
G. A. Nielsen
Keyword(s):  
Spectral Reflectance ◽  
Crop Production ◽  
Fertilizer Application ◽  
N Fertilizer ◽  
Field Pea ◽  
Yield Potential ◽  
Shoot Biomass ◽  
Fertilizer N ◽  
Logistic Regression Models ◽  
N Concentration

Pulse crop production is expanding in semiarid regions of the Northern Plains, and depends on successful biological N2-fixation. Inoculation failure, resulting in plant N deficiency and economic crop loss, might be alleviated by remedial N fertilizer application. The experiment was conducted using no-till management at two dryland sites in Montana in 1999 and 2000, where field pea and chickpea were grown in cereal stubble. Shoot biomass, shoot biomass N concentration, seed yield and seed N concentration were measured for uninoculated and inoculated controls and compared with remedial fertilizer N applied 0, 4, 6, and 8 wk after seeding. Spectral reflectance was compared for the inoculated and uninoculated controls. For field pea and chickpea, the critical period for fertilizer N application to prevent yield loss occurred within 6 wk of seeding (P ≤ 0.05). Logistic regression models derived from spectral reflectance had overall accuracies of 84 and 60% for detecting uninoculated control treatments in field pea and chickpea, respectively. The field pea model had a high degree of accuracy 6 wk after seeding, indicating it was capable of assisting a decision to apply remedial N fertilizer. Spectral reflectance provided a window of opportunity of 1 wk to apply remedial N fertilizer to attain full yield potential. Key words: Chickpea, field pea, inoculant failure, nitrogen, spectral reflectance

DIFFERENTIAL FERTILIZER N IMMOBILIZATION IN TWO TILLAGE SYSTEMS INFLUENCES GRAIN N CONCENTRATION

1990 ◽  
Vol 70 (2) ◽  
pp. 215-225 ◽  
Author(s):  
J. M. CAREFOOT ◽  
C. W. LINDWALL ◽  
M. NYBORG
Keyword(s):  
Triticum Aestivum ◽  
Winter Wheat ◽  
Production Systems ◽  
Triticum Aestivum L ◽  
N Immobilization ◽  
N Availability ◽  
Fertilizer N ◽  
Hordeum Vulgare L ◽  
No Till ◽  
N Concentration

Differential N immobilization between conventional tillage (CT) and no-till (NT) systems has been suggested as a possible mechanism for differences in crop response to N. To examine this effect, immobilization of N fertilizer was compared in NT and CT cereal production systems at two sites in southern Alberta (Lethbridge and Vauxhall) from 1983 to 1985. Fertilizer N, labelled with 15N, was applied at rates ranging from 25 to 50 kg N ha−1 to winter wheat (Triticum aestivum L. 'Norstar'), barley (Hordeum vulgare L. 'Galt'), or spring wheat (Triticum aestivum L. 'Chester') in various rotations. Nitrogen immobilization was subsequently quantified by 15N analysis of crop tissues and soil N fractions. The amount of N immobilized was strongly influenced by climatic variables. In 1984, characterized by drought in the spring but significant precipitation during June, mean N immobilization losses for winter wheat and barley in the CT treatments averaged much less than those in NT treatments (20 vs. 34% of N applied). Conversely, in 1985, which was characterized by a wet spring and a very dry summer, N immobilization losses were comparable in the two barley tillage treatments (mean = 29% of N applied). Lack of precipitation early in the season appears to restrict immobilization less in CT than in NT treatments because of greater fertilizer-residue contact in the latter. Despite the trends in immobilized N, grain yields were often higher in the NT than in the CT treatments, indicating that yield differences were likely related to the availability of moisture rather than to N fertility. Restricted N availability resulting from immobilization losses, however, reduced grain N concentration in NT relative to CT treatments. Key words: No-till, conventional till, N immobilization, N response, residual N

FARMERS' PERCEPTIONS, PRACTICES AND PERFORMANCE IN A SAHELIAN IRRIGATED RICE SCHEME

2002 ◽  
Vol 38 (2) ◽  
pp. 197-210 ◽  
Author(s):  
S. M. Haefele ◽  
M. C. S. Wopereis ◽  
C. Donovan
Keyword(s):  
Weather Conditions ◽  
Fertilizer Application ◽  
Optimal Timing ◽  
Access To Information ◽  
Fertilizer N ◽  
Irrigation Scheme ◽  
Irrigated Rice ◽  
Growing Seasons ◽  
Management Interventions ◽  
And Performance

Combined socio-economic and agronomic surveys were conducted during two growing seasons with 20 rice (Orgyza sativa) farmers in the irrigation scheme of Guédé, northern Senegal. Farmers' knowledge of recommended cropping practices was relatively poor. The surveys identified sub-optimal timing of N fertilizer application and late harvesting as major constraints. Before the start of the second season, farmers were given field-specific recommendations on timing of key crop-management interventions. Average yield compared with the first season increased by more than 1 t ha−1, which was attributed to a slightly higher recovery efficiency of fertilizer N (REN) (average: 0.47 kg crop N kg−1 fertilizer N), a change in cultivars used (resulting in a better uptake of indigenous soil N) and more favourable weather conditions in general. It is concluded that if farmers are given better access to information, improved rice technologies, inputs and decision making, rice production on irrigated land in West Africa may leap forward rapidly, as potential production gains are still large.

scholarly journals A Weed Compaction Roller System for Use with Mechanical Herbicide Application

2006 ◽  
Vol 23 (1) ◽  
pp. 66-69 ◽  
Author(s):  
Adam H. Wiese ◽  
Daniel A. Netzer ◽  
Don E. Riemenschneider ◽  
Ronald S. Zalesny
Keyword(s):  
Tree Plantations ◽  
Diameter Growth ◽  
Herbicide Application ◽  
Treatment Combination ◽  
Invasive Weed ◽  
Vegetation Control ◽  
Growing Seasons ◽  
Herbicide Treatments ◽  
Roller System ◽  
The Cost

Abstract We designed, constructed, and field-tested a versatile and unique weed compaction roller system that can be used with mechanical herbicide application for invasive weed control in tree plantations, agronomic settings, and areas where localized flora and fauna are in danger of elimination from the landscape. The weed compaction roller system combined with herbicide application generally had greater vegetation control compared with using only herbicide treatments or the unsprayed control. The roller system-herbicide treatment combination showed substantial total vegetation control two growing seasons after application without impacting diameter growth of the crop trees, which supports the need for less frequent entries into the field. The cost of the roller system was approximately $300.00.

scholarly journals Nutrient Management Programs, Nitrogen Fertilizer Practices, and Groundwater Quality in Nebraska’s Central Platte Valley (U.S.), 1989–1998

2001 ◽  
Vol 1 ◽  
pp. 750-757 ◽  
Author(s):  
Stan Daberkow ◽  
Harold Taylor ◽  
Noel Gollehon ◽  
Milt Moravek
Keyword(s):  
Irrigation Water ◽  
Fertilizer Application ◽  
Management Program ◽  
N Fertilizer ◽  
N Availability ◽  
Modest Improvement ◽  
Total N ◽  
Drinking Water Standard ◽  
Irrigation Water Use ◽  
Farmer Behavior

Given the societal concern about groundwater pollution from agricultural sources, public programs have been proposed or implemented to change farmer behavior with respect to nutrient use and management. However, few of these programs designed to change farmer behavior have been evaluated due to the lack of detailed data over an appropriate time frame. The Central Platte Natural Resources District (CPNRD) in Nebraska has identified an intensively cultivated, irrigated area with average groundwater nitrate-nitrogen (N) levels about double the EPA’s safe drinking water standard. The CPNRD implemented a joint education and regulatory N management program in the mid-1980s to reduce groundwater N. This analysis reports N use and management, yield, and groundwater nitrate trends in the CPNRD for nearly 3000 continuous-corn fields from 1989 to 1998, where producers faced limits on the timing of N fertilizer application but no limits on amounts. Groundwater nitrate levels showed modest improvement over the 10 years of this analysis, falling from the 1989–1993 average of 18.9 to 18.1 mg/l during 1994–1998. The availability of N in excess of crop needs was clearly documented by the CPNRD data and was related to optimistic yield goals, irrigation water use above expected levels, and lack of adherence to commercial fertilizer application guidelines. Over the 10-year period of this analysis, producers reported harvesting an annual average of 9729 kg/ha, 1569 kg/ha (14%) below the average yield goal. During 1989�1998, producers reported annually applying an average of 162.5 kg/ha of commercial N fertilizer, 15.7 kg/ha (10%) above the guideline level. Including the N contribution from irrigation water, the potential N contribution to the environment (total N available less estimated crop use) was estimated at 71.7 kg/ha. This is an estimate of the nitrates available for denitrification, volatilization, runoff, future soil N, and leaching to groundwater. On average, between 1989–1993 and 1994–1998, producers more closely followed CPNRD N fertilizer recommendations and increased their use of postemerge N applications � an indication of improved synchrony between N availability and crop uptake.

Use of hot KCl-NH4-N to estimate fertilizer N requirements

1997 ◽  
Vol 77 (2) ◽  
pp. 161-166 ◽  
Author(s):  
C. A. Campbell ◽  
Y. W. Jamel ◽  
A. Jalil ◽  
J. Schoenau
Keyword(s):  
N Mineralization ◽  
Growth Models ◽  
Growing Season ◽  
Order Rate Constant ◽  
Weather Data ◽  
N Availability ◽  
Fertilizer N ◽  
Available N ◽  
Mineralizable N ◽  
Potentially Mineralizable N

We need an easy-to-use chemical index for estimating the amount of N that becomes available during the growing season, to improve N use efficiency. This paper discusses how producers may, in future, use crop growth models that incorporate indices of soil N availability, to make more accurate, risk-sensitive estimates of fertilizer N requirements. In a previous study, we developed an equation, using 42 diverse Saskatchewan soils, that related potentially mineralizable N (N0) to NH4N extracted with hot 2 M KCl (X), (i.e., N0 = 37.7 + 7.7X, r2 = 0.78). We also established that the first order rate constant (k) for N mineralization at 35°C is indeed a constant for arable prairie soils (k = 0.067 wk−1). We modified the N submodel of CERES-wheat to include k and N0 (values of N0 were derived from the hot KCl test). With long-term weather data (precipitation and temperature) as input, this model was used to estimate probable N mineralization during a growing season and yield of wheat (grown on fallow or stubble), in response to fertilizer N rates at Swift Current. The model output indicated that the amount of N mineralized in a growing season for wheat on fallow was similar to that for wheat on stubble, as we hypothesized. Further the model indicated that rate of fertilizer N had only minimal effect on N mineralized. We concluded that, despite the importance of knowing the Nmin capability of a soil, it is available water, initial levels of available N and rate of fertilizer N that are the main determinants of yield in this semiarid environment. The theoretical approach we have proposed must be validated under field conditions before it can be adopted for use. Key words: N mineralization, Hot KCl-NH4-N, potentially mineralizable N, CERES-wheat model

Factors influencing grain N concentration of hard red spring wheat in the semiarid prairie

1997 ◽  
Vol 77 (1) ◽  
pp. 53-62 ◽  
Author(s):  
C. A. Campbell ◽  
F. Selles ◽  
R. P. Zentner ◽  
B. G. McConkey ◽  
R. C. McKenzie ◽  
...  
Keyword(s):  
Water Use ◽  
Spring Wheat ◽  
Soil Test ◽  
Fertilizer N ◽  
Degree Days ◽  
Hard Red Spring Wheat ◽  
Brown Soil ◽  
Soil Zone ◽  
Factors Influencing ◽  
N Concentration

Prairie producers are now being rewarded with significant premiums for producing wheat (Triticum aestivum L.) of high protein concentration. We analyzed data from two 12-yr experiments conducted on a medium-textured Orthic Brown Chernozem at Swift Current, Saskatchewan, to determine and quantify factors influencing grain N concentration of hard red spring wheat grown on stubble land. Results of one of the 12-yr studies, a snow management × fertilizer N, zero-tillage experiment, showed that under hot, dry conditions, grain N concentration was very high and increased with moderate rates of fertilizer N (FN), then levelled off at higher rates of N. Under cool, wet conditions, grain N first decreased (due to N dilution by yield) then increased with further addition of FN. Under warm intermediate moisture conditions, grain N concentration increased at moderate rates in response to FN. Data for the two 12-yr experiments were pooled and multiple regression, with backward elimination, and stepwise selection used to develop the relationship:Grain N (g kg−1) = −7.63 + 0.05 WU − 0.000094 WU2 + 0.30 SN − 0.0022 SN2 − (0.0010 SN × WU) + (0.0017 FN × SN) + 0.0189 DD (R2 = 0.64, P = 0.001, n = 262)where WU = water use (mm), SN = soil test N (kg ha−1), FN = (kg ha−1), and DD = degree-days >5 °C (°C-days) from 1 May to 31 August. WU was available spring soil water in 0- to 1.2-m depth plus 1 May to 31 July precipitation, and SN was NO3-N in the 0- to 0.6-m depth, measured in the fall. We attempted to validate this model using data from a long-term crop rotation and a fertilizer trial experiment in the Brown soil zone, a tillage × rotation experiment in the Dark Brown soil zone in Saskatchewan, and an irrigation × N fertilizer experiment in the Brown soil zone of southern Alberta. Validation met with only modest success (R2 up to 0.70, P = 0.001). Generally, estimated grain N concentrations were lower than the measured values. Water use (negatively related) and temperature (DD) (positively related) were the most important factors influencing grain N, while FN and SN (positively related) were much less important. Because of the complexity of response in grain N to the aforementioned factors, and since farmers cannot predict weather conditions, fertilizer management to achieve high protein remains a challenge under dryland conditions. Key words: Soil test N, fertilizer N, available water, degree-days

scholarly journals Effect of Winter Cover Crops on Soil Nitrogen Availability, Corn Yield, and Nitrate Leaching

2001 ◽  
Vol 1 ◽  
pp. 22-29 ◽  
Author(s):  
S. Kuo ◽  
B. Huang ◽  
R. Bembenek
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
N Fertilizer ◽  
N Leaching ◽  
Corn Yield ◽  
N Availability ◽  
Soil N ◽  
Soil N Availability ◽  
N Concentration ◽  
Fertilizer Rates

Biculture of nonlegumes and legumes could serve as cover crops for increasing main crop yield, while reducing NO3leaching. This study, conducted from 1994 to 1999, determined the effect of monocultured cereal rye (Secale cereale L.), annual ryegrass (Lolium multiflorum), and hairy vetch (Vicia villosa), and bicultured rye/vetch and ryegrass/vetch on N availability in soil, corn (Zea mays L.) yield, and NO3-N leaching in a silt loam soil. The field had been in corn and cover crop rotation since 1987. In addition to the cover crop treatments, there were four N fertilizer rates (0, 67, 134, and 201 kg N ha-1, referred to as N0, N1, N2, and N3, respectively) applied to corn. The experiment was a randomized split-block design with three replications for each treatment. Lysimeters were installed in 1987 at 0.75 m below the soil surface for leachate collection for the N0, N2, and N3treatments. The result showed that vetch monoculture had the most influence on soil N availability and corn yield, followed by the bicultures. Rye or ryegrass monoculture had either no effect or an adverse effect on corn yield and soil N availability. Leachate NO3-N concentration was highest where vetch cover crop was planted regardless of N rates, which suggests that N mineralization of vetch N continued well into the fall and winter. Leachate NO3-N concentration increased with increasing N fertilizer rates and exceeded the U.S. Environmental Protection Agency’s drinking water standard of 10 mg N l�1 even at recommended N rate for corn in this region (coastal Pacific Northwest). In comparisons of the average NO3-N concentration during the period of high N leaching, monocultured rye and ryegrass or bicultured rye/vetch and ryegrass/vetch very effectively decreased N leaching in 1998 with dry fall weather. The amount of N available for leaching (determined based on the presidedress nitrate test, the amount of N fertilizer applied, and N uptake) correlated well with average NO3-N during the high N leaching period for vetch cover crop treatment and for the control without the cover crops. The correlation, however, failed for other cover crops largely because of variable effectiveness of the cover crops in reducing NO3leaching during the 5 years of this study. Further research is needed to determine if relay cover crops planted into standing summer crops is a more appropriate approach than fall seeding in this region to gain sufficient growth of the cover crop by fall. Testing with other main crops that have earlier harvest dates than corn is also needed to further validate the effectiveness of the bicultures to increase soil N availability while protecting the water quality.

scholarly journals Using Soil Solution Monitoring to Determine the Effects of Irrigation Management and Fertigation on Nitrogen Availability in High-density Apple Orchards

1998 ◽  
Vol 123 (4) ◽  
pp. 706-713 ◽  
Author(s):  
D. Neilsen ◽  
P. Parchomchuk ◽  
G.H. Neilsen ◽  
E.J. Hogue
Keyword(s):  
Soil Solution ◽  
Irrigation Water ◽  
Root Zone ◽  
Irrigation Management ◽  
Sprinkler Irrigation ◽  
Loamy Sand ◽  
N Availability ◽  
Silt Loam ◽  
N Concentration ◽  
Loam Soil

Direct application of fertilizers in irrigation water (fertigation) is an efficient method of supplying nutrients to fruit trees. Information is needed on the relationship between irrigation and N inputs on N availability in order to target nutrient applications to meet plant demands. Soil solution was collected from permanently installed suction lysimeters and NO3-N concentration was measured over the growing season in three experiments: 1) comparison of sprinkler irrigation + broadcast fertilizer with weekly fertigation + daily drip irrigation; 2) comparison of (NH4)2SO4 or Ca(NO3)2 as N sources under daily fertigation; and 3) comparisons of combinations of irrigation applied at either fixed rates or to meet evaporative demand and fertilizer (Ca(NO3)2) applied daily either at fixed rates or to maintain a given concentration in the fertigation solution in two soil types—loamy sand and silt loam. Trials are located in high density apple plantings of either `Gala' or `Empire' apple (Malus × domestica Borkh.) on M.9 rootstock. Nitrate-N concentration in the soil solution measured at 30 cm deep remained higher, over more of the growing season, for weekly fertigation + daily drip irrigation than for a single broadcast fertilizer application + sprinkler irrigation. With daily Ca(NO3)2 fertigation, soil solution NO3- N concentrations increased and decreased rapidly with the onset and end of fertigation respectively, remained relatively constant during the intervening period and were directly proportional to either the amount of N or the amount of irrigation water added. Daily fertigation with (NH4)2SO4 resulted in less control of NO3-N availability in the root-zone than with Ca(NO3)2, which may be problematic for precise timing of N nutrition. Except for the fixed irrigation rate applied to the loamy sand soil, soil solution NO3-N concentrations at 30 cm beneath the emitter were similar to average concentrations in the fertigating solution, for all methods of irrigation management in both soil types. Elevated NO3-N concentrations in soil solution below the root zone (75 cm deep) were detected in the loamy sand regardless of methods of N application and irrigation although there was some evidence of less leaching to this depth, under scheduled irrigation. In the silt loam soil, considerably lower concentrations of NO3-N were found beneath the root zone than at 30 cm deep for all of irrigation procedures and frequently there was insufficient water moving to 75 cm to provide sample. Tree growth in the loamy sand was less than in the silt loam soil; was limited by low application of irrigation water in 1992 and 1993; was unaffected by NO3-N concentration in the root zone, indicating that N inputs could be minimized by adding N to maintain concentrations of 75 μg·mL-1 or possibly less. Nitrogen inputs may also be reduced if fertilizer N and irrigation water could be retained within the root zone. For coarse-textured soils this will require precise additions of water and possibly soil amendments to improve water holding capacity.

scholarly journals Effect of Bokashi Fertilizer and Green Tonik Liquid Fertilizer on the Growth and Yield of Long Bean (Vigna sinensisL.)Parade Tavi Variety

AGRIFOR ◽  
2018 ◽  
Vol 17 (1) ◽  
pp. 81
Author(s):  
Elisabeth Elisabeth ◽  
Puji Astuti
Keyword(s):  
Fertilizer Application ◽  
Factorial Experiment ◽  
Bean Plant ◽  
Growth And Yield ◽  
Fertilizer Treatment ◽  
Fertilizer N ◽  
Liquid Fertilizer ◽  
Randomized Design ◽  
Interaction Treatment ◽  
Completely Randomized Design

The purpose of the research is to study the effect of bokashi fertilizer and Green Tonik liquid fertilizer and its interaction on the growth and yield of long bean plant, as well as to find the proper dosage of bokashi fertilizer and Green Tonik liquid fertilizer concentration for obtaining the best yield of long bean.The research was conducted using Completely Randomized Design (CRD) in 4 x 4 Factorial Experiment and four replications.  The factor was the dosage of bokashi fertilizer (B) consisting of 4 levels : no bokashi fertilizer application (b0), 100 g/polybag(b1), 200 g/polybag (b2), and 300 g/polybag(b3).   The second factor was the concentration of Green Tonik liquid fertilizer (N) consisting 4 levels : no Green Tonikfertilizer application (n0), 2 ml/ l water (n1),  4 ml/l water (n2), and 6 ml/lwater (n3).The results showed that: (1) the bokashi fertilizer treatment affected significantly on the plant lenght at age 15 days after planting, number of pods and weight of pods per plant, but it did not affect significantly on the plant lenght at age 22, 29 and 36 days after planting, age of plants flowered, and pods lenght; (2)the Green Tonik liquid treatment affected significantly on the plant lenght at age 22, 29, and 60 days after plantingand weight of pods per plant, but it did not affect significantly on the plant lenght at age 15 days after planting, age of plant flowered, and pods lenght;  (3) the interaction treatment between bokashi fertilizer and Green Tonik liquid fertilizer affected significantly on the plant lenght at age 15 days after planting, pods lenght, and weight of pods per plant, but did not affect significantly on the plant lenght at age 22, 29, and 36 after planting, age of plant flowered, and number of pods; and (4) the weighest weight of pods per plant was produced in b2n3 treatment of 401,75 g/plant, while the lighest one was produced in b0n0 treatment of 145,75 g/plant.

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