Within-season grass yield and nitrogen uptake, and soil nitrogen as affected by nitrogen applied at various rates and distributions in a high rainfall environment

2000 ◽  
Vol 80 (2) ◽  
pp. 287-301 ◽  
Author(s):  
C. G. Kowalenko ◽  
S. Bittman
Keyword(s):  
N Uptake ◽  
Growing Season ◽  
N Fertilizer ◽  
Residual Effects ◽  
Ammonium Concentration ◽  
N Leaching ◽  
Soil Nitrate ◽  
Inorganic N ◽  
Environmental Implications ◽  
N Application

A study was conducted to assess the effect of rates of nitrogen (N) fertilizer, and to compare the effectiveness of single and split applications of N on yield and quality of forage grass and on the potential for nitrate leaching. Three field trials were conducted at different sites in successive years, with plant and soil measurements made at each of four harvests. Extractable inorganic N was measured to 0.6 m in three depth increments prior to spring N application and after each cut in order to evaluate immediate and residual effects of the N fertilizer on plant growth, and the environmental implications of the applications. Response of yield and N uptake to N applications differed in the three trials. In all trials, the effect of N rate was greater than the effect of N distribution during the growing season. Although there were only small, whole-season yield increases associated with distributing the N over the season, the distribution of yield within the season was changed considerably. Soil data showed relatively little leaching of N during the growing season under contrasting weather conditions of the three growing seasons. Retention of N within the soil root zone contributed to residual effects on yield and plant uptake, and these effects frequently lasted to the end of the growing season. Crop response to N applications was apparently influenced by the N supplying capacity of the soil and the effect of weather on crop growth rate. Soil nitrate at harvest did not vary consistently with N application treatments in the three trials, other than having highest concentrations at the highest fertilizer rate. Soil nitrate was greatest after cut 1 and decreased sharply toward the end of the season following the single spring applications, whereas plots receiving equal distributions of N through the season had relatively high concentrations at all sampling times during the season. Soil extractable ammonium concentration was influenced by high rates of N application, but the effect was small and largely confined to the sampling after cut 1. The soil always contained about 10–15 mg kg−1 extractable ammonium in surface 0.3 m depth, with a tendency for slightly greater concentrations in early spring. Soil ammonium appears to be involved in soil and plant processes, but the exact magnitude and significance of its involvement could not be determined from the measurements made. The redistribution of grass yield by splitting the application of fertilizer N within the growing season would be beneficial for grazing systems. Unfortunately, soil inorganic N measurements will not greatly assist in determining the precise rate and distribution of fertilizer for varying field conditions. Key words: N response, N uptake, residual N effect, soil extractable N, N leaching

scholarly journals Nitrogen Leaching and Nitrogen Balance under Differing Nitrogen Fertilization for Sugarcane Cultivation on a Subtropical Island

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 740
Author(s):  
Ken Okamoto ◽  
Shinkichi Goto ◽  
Toshihiko Anzai ◽  
Shotaro Ando
Keyword(s):  
N Uptake ◽  
Fertilizer Application ◽  
Application Rate ◽  
N Fertilizer ◽  
N Leaching ◽  
N Recovery ◽  
N Application ◽  
Fertilizer Application Rate ◽  
Sugarcane Yield ◽  
Cropping Seasons

Fertilizer application during sugarcane cultivation is a main source of nitrogen (N) loads to groundwater on small islands in southwestern Japan. The aim of this study was to quantify the effect of reducing the N fertilizer application rate on sugarcane yield, N leaching, and N balance. We conducted a sugarcane cultivation experiment with drainage lysimeters and different N application rates in three cropping seasons (three years). N loads were reduced by reducing the first N application rate in all cropping seasons. The sugarcane yields of the treatment to which the first N application was halved (T2 = 195 kg ha−1 N) were slightly lower than those of the conventional application (T1 = 230 kg ha−1 N) in the first and third seasons (T1 = 91 or 93 tons ha−1, T2 = 89 or 87 tons ha−1). N uptake in T1 and T2 was almost the same in seasons 1 (186–188 kg ha−1) and 3 (147–151 kg ha−1). Based on the responses of sugarcane yield and N uptake to fertilizer reduction in two of the three years, T2 is considered to represent a feasible fertilization practice for farmers. The reduction of the first N fertilizer application reduced the underground amounts of N loads (0–19 kg ha−1). However, application of 0 N in the first fertilization would lead to a substantial reduction in yield in all seasons. Reducing the amount of N in the first application (i.e., replacing T1 with T2) improved N recovery by 9.7–11.9% and reduced N leaching by 13 kg ha−1. These results suggest that halving the amount of N used in the first application can improve N fertilizer use efficiency and reduce N loss to groundwater.

scholarly journals Presidedress Soil Nitrate Testing Reduces Nitrogen Fertilizer Use and Nitrate Leaching Hazard in Lettuce Production

HortScience ◽  
2002 ◽  
Vol 37 (7) ◽  
pp. 1061-1064 ◽  
Author(s):  
S.J. Breschini ◽  
T.K. Hartz
Keyword(s):  
N Uptake ◽  
Substantial Reduction ◽  
N Fertilization ◽  
Management Tool ◽  
Postharvest Quality ◽  
N Leaching ◽  
Soil Nitrate ◽  
N Application ◽  
Available N ◽  
Significant Difference

Trials were conducted in 15 commercial fields in the central coast region of California in 1999 and 2000 to evaluate the use of presidedress soil nitrate testing (PSNT) to determine sidedress N requirements for production of iceberg and romaine lettuce (Lactuca sativa L.). In each field a large plot (0.2-1.2 ha) was established in which sidedress N application was based on presidedress soil NO3-N concentration. Prior to each sidedress N application scheduled by the cooperating growers, a composite soil sample (top 30 cm) was collected and analyzed for NO3-N. No fertilizer was applied in the PSNT plot at that sidedressing if NO3-N was >20 mg·kg-1; if NO3-N was lower than that threshold, only enough N was applied to increase soil available N to ≈20 mg·kg-1. The productivity and N status of PSNT plots were compared to adjacent plots receiving the growers' standard N fertilization. Cooperating growers applied a seasonal average of 257 kg·ha-1 N, including one to three sidedressings containing 194 kg·ha-1 N. Sidedressing based on PSNT decreased total seasonal and sidedress N application by an average of 43% and 57%, respectively. The majority of the N savings achieved with PSNT occurred at the first sidedressing. There was no significant difference between PSNT and grower N management across fields in lettuce yield or postharvest quality, and only small differences in crop N uptake. At harvest, PSNT plots had on average 8 mg·kg-1 lower residual NO3-N in the top 90 cm of soil than the grower fertilization rate plots, indicating a substantial reduction in subsequent NO3-N leaching hazard. We conclude that PSNT is a reliable management tool that can substantially reduce unnecessary N fertilization in lettuce production.

scholarly journals Effects of Combined Application of Cow Manure And Inorganic Nitrogen Fertilizer on Growth, Yield and Nitrogen Uptake of Black Rice

Akta Agrosia ◽  
2018 ◽  
Vol 21 (2) ◽  
pp. 55-60
Author(s):  
Marwanto Marwanto ◽  
Nasiroh Nasiroh ◽  
Bambang G. Mucitro ◽  
Merakati Handajaningsih
Keyword(s):  
Growth Parameters ◽  
N Uptake ◽  
Fertilizer Application ◽  
N Fertilizer ◽  
Root Weight ◽  
Cow Manure ◽  
Black Rice ◽  
Inorganic N ◽  
Yield Attributes ◽  
Shoot Weight

The beneficial effects of manure on soil properties, growth, and crop productivity have promoted its use for replacing the application of N fertilizer. However, it is not well understood to what extent N fertilizer was able to be substituted by cow manure. Accordingly, this pot experiment aimed to compare the effect of inorganic N fertilizer application alone with that of the combined use of inorganic N fertilizer with cow manure based on the same amount of total N on growth parameters, yield attributes, and nitrogen (N) uptake of black rice. The experiment was conducted under a screen house condition in Agriculture Faculty, Bengkulu University located at 15 meters altitude above sea level during the summer season of 2015. There were six treatments viz. T1 = 100% N from urea + 0% N from cow manure (0.52 g N + 0.00 g cow manure) pot-1, T2 = 80% N from urea  + 20% N from cow manure  (0.42 g N + 9.55 g cow manure) pot-1, T3 = 60% N from urea + 40% N from cow manure (0.31 g N  + 19.10 g cow manure) pot-1, T4 = 40% N from urea + 60% N from cow manure (0.21 g N + 28.65 g cow manure) pot-1, T5 = 20% N from urea + 80% N from cow manure (0.10 g N+ 38.20 g cow manure) pot-1, and T6 = 0% N from urea + 100% N from cow manure (0.00 g N  + 47.75 g cow manure) pot-1. The amount of inorganic N fertilizer in the form of urea and cow manure applied was calculated based on the recommended rate of 115.00 kg ha-1 for N fertilizer and 10.50 ton ha-1 for cow manure. These treatments were arranged in a Completely Randomized Design and repeated three times. The results showed that the treatments significantly (P ?0.005) affected growth parameters as measured by plant height, the number of leaves, fresh shoot weight, fresh root weight, dry shoot weight, dry root weight, yield attributes as determined by the total number of tillers, the total number productive tillers, grain yield per pot, and N uptake. The highest values for all these variables were obtained in the treatment receiving recommended rate of urea only (100% N from urea + 0% N from cow manure as equivalence) and the lowest in the treatment receiving a100% N from cow manure (0% N from urea + 100% N from cow manure). However, combined treatments of cow manure and inorganic N fertilizer such as 80% N from urea  + 20% N from cow manure, 60% N from urea + 40% N from cow manure 40% N from urea + 60% N from cow manure showed a parity statistically with the treatment receiving 100% N from urea only in maintaining the values for all these variables. Overall, the combined use of inorganic N fertilizer (urea) and cow manure as an equivalence promoted growth and yield of black rice by improving N uptake. Keywords: integrated nutrient management, soil chemical property, Nitrogen uptake, combined fertilizer application, black rice

Residual effects of nitrogen fertiliser on the yield and N composition of succeeding cereal crops and on soil chemical properties of an Ethiopian highland Vertisol

2000 ◽  
Vol 80 (1) ◽  
pp. 63-69 ◽  
Author(s):  
Selamyihun Kidanu ◽  
D. G. Tanner ◽  
Tekalign Mamo
Keyword(s):  
N Uptake ◽  
Chemical Properties ◽  
Residual Effect ◽  
Residual Effects ◽  
Cereal Crops ◽  
N Recovery ◽  
N Application ◽  
Total N ◽  
Current Season ◽  
The Mean

A trial was conducted on an Ethiopian Vertisol from 1990 to 1995 to determine the residual effects of fertiliser N applied to tef [Eragrostistef (Zucc.) Trotter] on the grain and straw yield, N content, and total N uptake of succeeding crops of durum wheat (Triticum turgidum var. durum) and tef. The mean agronomic efficiency of 60 kg fertiliser N ha−1 was 13.1 kg grain kg−1 fertiliser N applied in the current year and 5.4 kg grain kg−1 fertiliser N applied in the previous year. Thus, the residual fertiliser N benefit was equivalent to 41.2% of the response to current season N application for the two cereal crops. The mean rates of apparent recovery of fertiliser N were 65.8% for current season N application and 31.0% for previous season N application. Soil organic matter and nitrate levels increased linearly in response to both previous and current season N application rates. The current study demonstrates that the residual effect of fertiliser N enhanced the yields and N contents of the grain and straw of both wheat and tef, resulting in a significant increase in total N uptake. Any analysis of the profitability of fertiliser N response should reflect the multi-year benefit period. Key words: N recovery, N residue, N uptake, tef, wheat

scholarly journals Fresh Market Tomato Yield and Soil Nitrogen as Affected by Tillage, Cover Cropping, and Nitrogen Fertilization

HortScience ◽  
2000 ◽  
Vol 35 (7) ◽  
pp. 1258-1262 ◽  
Author(s):  
Sidat Yaffa ◽  
Bharat P. Singh ◽  
Upendra M. Sainju ◽  
K.C. Reddy
Keyword(s):  
Soil Erosion ◽  
N Uptake ◽  
N Fertilization ◽  
N Leaching ◽  
Hairy Vetch ◽  
Inorganic N ◽  
Cover Cropping ◽  
Tomato Yield ◽  
Soil Inorganic N ◽  
Soil Inorganic

Sustainable practices are needed in vegetable production to maintain yield and to reduce the potential for soil erosion and N leaching. We examined the effects of tillage [no-till (NT), chisel plowing (CP), and moldboard plowing (MP)], cover cropping [hairy vetch (Vicia villosa Roth) vs. winter weeds], N fertilization (0, 90, and 180 kg·ha-1 N), and date of sampling on tomato (Lycopersicon esculentum Mill.) yield, N uptake, and soil inorganic N in a Norfolk sandy loam in Fort Valley, Ga. for 2 years. Yield was greater with CP and MP than with NT in 1996 and was greater with 90 and 180 than with 0 kg·ha-1 N in 1996 and 1997. Similarly, aboveground tomato biomass (dry weight of stems + leaves + fruits) and N uptake were greater with CP and MP than with NT from 40 to 118 days after transplanting (DAT) in 1996; greater with hairy vetch than with winter weeds at 82 DAT in 1997; and greater with 90 or 180 than with 0 kg·ha-1 N at 97 DAT in 1996 and at 82 DAT in 1997. Soil inorganic N was greater with NT or CP than with MP at 0- to 10-cm depth at 0 and 30 DAT in 1996; greater with hairy vetch than with winter weeds at 0- to 10-cm and at 10- to 30-cm at 0 DAT in 1996 and 1997, respectively; and greater with 90 or 180 than with 0 kg·ha-1 N from 30 to 116 DAT in 1996 and 1997. Levels of soil inorganic N and tomato N uptake indicated that N release from cover crop residues was synchronized with N need by tomato, and that N fertilization should be done within 8 weeks of transplanting. Similar tomato yield, biomass, and N uptake with CP vs. MP and with 90 vs. 180 kg·ha-1 N suggests that minimum tillage, such as CP, and 90 kg·ha-1 N can better sustain tomato yield and reduce potentials for soil erosion and N leaching than can conventional tillage, such as MP, and 180 kg·ha-1 N, respectively. Because of increased vegetative cover in the winter, followed by increased mulch and soil N in the summer, hairy vetch can reduce the potential for soil erosion and the amount of N fertilization required for tomato better than can winter weeds.

scholarly journals Seasonal Nitrogen Partitioning and Nitrogen Uptake of Carrots as Affected by Nitrogen Application in a Mineral and an Organic Soil

HortScience ◽  
2006 ◽  
Vol 41 (5) ◽  
pp. 1332-1338 ◽  
Author(s):  
Sean M. Westerveld ◽  
Alan W. McKeown ◽  
Mary Ruth McDonald
Keyword(s):  
N Uptake ◽  
Mineral Soil ◽  
Growing Season ◽  
Organic Soil ◽  
Nitrogen Partitioning ◽  
N Budget ◽  
N Application ◽  
Total N ◽  
Application Rates ◽  
N Removal

An understanding of nitrogen (N) uptake and the partitioning of N during the season by the carrot crop (Daucus carota subsp. sativus [Hoffm.] Arkang.) is required to develop more efficient N fertilization practices. Experiments were conducted on both organic and mineral soils to track the accumulation of dry matter (DM) and N over the growing season and to develop an N budget of the crop. Treatments included two carrot cultivars (`Idaho' and `Fontana') and 5 N rates ranging from 0% to 200% of the provincial recommendations in Ontario. Foliage and root samples were collected biweekly from selected treatments during the growing season and assessed for total N concentration. Harvest samples were used to calculate N uptake, N in debris, and net N removal values. Accumulation of DM and N in the roots was low until 50 to 60 days after seeding (DAS) and then increased linearly until harvest for all 3 years regardless of the soil type, cultivar, and N rate. Foliage dry weight and N accumulation were more significant by 50 to 60 DAS, increased linearly between 50 and 100 DAS, and reached a maximum or declined slightly beyond 100 DAS in most cases. The N application rates required to maximize yield on mineral soil resulted in a net loss of N from the system, except when sufficient N was available from the soil to produce optimal yield. On organic soil, a net removal of N occurred at all N application rates in all years. Carrots could be used as an N catch crop to reduce N losses in a vegetable rotation in conditions of high soil residual N, thereby improving the N use efficiency (NUE) of the crop rotation.

EFFECTS OF MANURES, AMMONIUM NITRATE AND S-COATED UREA ON YIELD AND UPTAKE OF N BY CORN AND ON SUBSEQUENT INORGANIC N LEVELS IN SOILS IN SOUTHERN QUEBEC

1978 ◽  
Vol 58 (2) ◽  
pp. 153-158 ◽  
Author(s):  
P. L. MILLER ◽  
A. F. MacKENZIE
Keyword(s):  
Ammonium Nitrate ◽  
Zea Mays L ◽  
N Uptake ◽  
Residual Effects ◽  
Cow Manure ◽  
Pollution Potential ◽  
Inorganic N ◽  
Mineral N ◽  
Hog Manure ◽  
Coated Urea

Effects of added N in the form of ammonium nitrate, S-coated urea, solid cow manure, liquid hog manure, and liquid hog manure plus straw on yield and N uptake of corn (Zea mays L.) were determined in 1971. Residual effects of the fertilizers were measured in 1972. Levels of added N were 150 kg/ha, on three soils varying in texture. In 1971, highest yield and N uptake was found using ammonium nitrate, followed by S-coated urea. The manures were not different than the control, and the average values with liquid manure plus straw were generally lowest. Ammonium nitrate treatments had the lowest mineral N levels in the soil profile in September. Thus, ammonium nitrate was considered to have the lowest pollution potential, assuming that fall-accumulated inorganic soil N was a hazard for pollution of groundwater.

Water and Nitrogen Budget Dynamics for a Maize-Peanut Rotation in Florida

2020 ◽  
Vol 63 (6) ◽  
pp. 2003-2020
Author(s):  
Maria I. Zamora Re ◽  
Sagarika Rath ◽  
Michael D. Dukes ◽  
Wendy Graham
Keyword(s):  
Crop Rotation ◽  
Root Zone ◽  
N Uptake ◽  
Irrigation Scheduling ◽  
N Fertilizer ◽  
N Leaching ◽  
Soil N ◽  
Fertilizer Rate ◽  
Irrigation Treatments ◽  
Fertilizer Rates

HighlightsDSSAT simulations of final N uptake, biomass, and yield for a maize-peanut rotational field experiment with three irrigation treatments and three N fertilizer rates had good performance for the irrigated treatments (average nRMSE of 9%) but greater error for the rainfed treatments (average nRMSE of 15%).Experiments and DSSAT simulations demonstrated that N fertilizer and irrigation applications were reduced by 26% and 60%, respectively, when using a 247 kg N ha-1 fertilizer rate and a sensor-based irrigation schedule rather than conventional practices of 336 kg N ha-1 and a calendar-based irrigation method, with no impact on yield.Simulations demonstrated that N leaching during the crop rotation was reduced by 37% when an N fertilizer rate of 247 kg N ha-1 and sensor-based irrigation scheduling were used versus conventional practices.Soil N increased (=15 mg kg-1) when maize and peanut residues decayed and then leached during the fallow season. Cover or cash crops planted immediately after the maize and peanut harvests have potential to take up this N and reduce leaching.Abstract. Nitrogen (N) is an essential element for crop growth and yield; however, excessive N applications not taken up by crops can result in N leaching from the root zone, increasing N loads to waterbodies and leading to a host of environmental problems. The main objective of this study was to simulate water and N balances for a maize-peanut (Zea mays L. and Arachis hypogaea L.) rotational field experiment with three irrigation treatments and three N fertilizer rates. The irrigation treatments consisted of mimicking grower irrigation practices in the region (GROW), using soil moisture sensors to schedule irrigation (SMS), and non-irrigated (NON). The N fertilizer rates were low, medium, and high (157, 247, and 336 kg N ha-1, respectively) for maize with a constant 17 kg ha-1 for all peanut treatments. DSSAT maize genetic coefficients were calibrated using the SMS-high treatment combination under the assumption of no water or N stress. The other eight treatment combinations were used as independent data for model validation of the crop coefficients. All soil hydrologic parameters were specified based on measured values, and default DSSAT peanut genetic coefficients were used with no calibration. For the irrigated treatments, DSSAT models had good performance for N uptake, biomass, and yield (average nRMSE of 8%) and moderate performance for soil water content (average nRMSE of 18%). Soil nitrate RMSE was 21% lower than the standard deviation of the observed data (5.8 vs. 7.2 mg kg-1). For the rainfed treatments, DSSAT had greater error (average nRMSE of 15% for N uptake, biomass, and yield, and average nRMSE of 31% for soil water). Soil nitrate RMSE was 11% greater than the standard deviation of the observed data (8.0 vs. 7.2 mg kg-1), and nRMSE was >30% during the crop rotation. Simulations estimated that N leaching over the crop rotation was reduced by 24% on average when using the 247 kg N ha-1 fertilizer rate compared to 336 kg N ha-1 across the irrigation treatments. Furthermore, N leaching was reduced by 37% when using SMS to schedule irrigation and the 247 kg N ha-1 fertilizer rate for maize and 17 kg N ha-1 for peanut compared to conventional practices (GROW and 336 kg N ha-1 for maize and 17 kg N ha-1 for peanut). Moreover, this management practice reduced N fertilizer use by 26% and irrigation water use by up to 60% without negative impacts on yield. Observed and simulated soil N increased during maize and peanut residue decay, with simulations estimating that this soil N would leach below the root zone during the fallow season. This leaching could potentially be reduced if a cover crop or cash crop were planted between the maize and peanut crops to take up the mineralized N. Keywords: Agricultural best management practices, Bare fallow, BMPs, Maize-peanut rotation, N balance, N fertilization, N leaching, Sandy soils, Sensor-based irrigation scheduling, Water balance.

Season of year effect on response of orchardgrass to N fertilizer in a maritime climate

2004 ◽  
Vol 84 (1) ◽  
pp. 129-142 ◽  
Author(s):  
S. Bittman ◽  
B. J. Zebarth ◽  
C. G. Kowalenko ◽  
D. E. Hunt
Keyword(s):  
Crude Protein ◽  
N Uptake ◽  
Maximum Yield ◽  
Relative Yield ◽  
Dactylis Glomerata ◽  
N Fertilizer ◽  
Residual Soil ◽  
Soil Nitrate ◽  
Year Effect ◽  
Nitrate Concentrations

This study compared the response of harvests taken in May, June, August and September-October in terms of crop responses (yield, N uptake, and concentrations of crude protein and nitrate) to N fertilizer and residual soil nitrate and ammonium. Three trials were conducted in south coastal British Columbia in 1990–1992 to evaluate the response of an established sward of orchardgrass (Dactylis glomerata L.) to a range of N fertilizer rates. Both yields and daily crop growth rates were highest in cut 1, lowest in cut 4 and intermediate in cuts 2 and 3. For all four cuts, 95 and 90% of maximum yield was attained at about 136 and 82 kg ha-1 of applied N, respectively. Crop N supply from non-fertilizer sources ranged from 36 to 90 kg N ha-1, of which about 52% was attributed to nitrate present in the soil prior to growth and about 48% was N released from the soil, translocated from roots or deposited from the atmosphere. At 95% of maximum yield, crude protein concentrations ranged from 147 g kg-1 in the higher yielding cut 1 to 189 g kg-1 in cuts 2 and 4, while at 90% of maximum yield concentrations were 10 g kg-1 lower in each cut. Plant nitrate concentrations were close to levels that are toxic to cattle for the 95% target yield, but relatively safe at the 90% yield. The crop removed about 50 kg ha-1 more N when fertilized for 95% of maximum yield than for 90%, which translates to over 300 kg ha-1 more crude protein. High relative yield leaves behind more soil nitrate after harvest. The results suggest that the first cut should be managed for 95% of maximum yield with about 130 kg N ha-1. Cuts 2 and 3 should be managed for 90% of maximum yield, to avoid high plant nitrate concentrations, with 100–110 kg N ha-1. Cut 4 should be given no more than 50 kg N ha-1 for less than 90% of maximum yield because of the risk of residual soil nitrates. This study shows for the first time the benefits and disadvantages of applying N at different rates for each harvest over the growing season. Key words: Plant nitrate, nitrogen use efficiency, nitrogen recovery, Dactylis glomerata, relative yield, maximum economic yield

scholarly journals Assessing the Effects of Nitrification Inhibitor DMPP on Acidification and Inorganic N Leaching Loss from Tea (Camellia sinensis L.) Cultivated Soils with Increasing Urea–N Rates

2021 ◽  
Vol 13 (2) ◽  
pp. 994
Author(s):  
Chunlian Qiao ◽  
Shamim Mia ◽  
Yeqin Wang ◽  
Jiajia Hou ◽  
Burenbayin Xu
Keyword(s):  
Soil Ph ◽  
Nitrification Inhibitor ◽  
N Leaching ◽  
Inorganic N ◽  
N Loss ◽  
N Application ◽  
Leaching Loss ◽  
N Management ◽  
N Rates ◽  
Cultivated Soils

The effects of nitrification inhibitor in tea gardens with different urea–N rates have rarely been assessed. For eight months, a glasshouse experiment was conducted to investigate the effects of a nitrification inhibitor (3, 4–dimethylpyrazole phosphate, DMPP) on the changes of soil pH and inorganic N loss. Urea (0, 300, 500, and 800 kg N ha−1) with or without DMPP (1% of urea–N applied) were added to pots that hosted six plants that were three years old. Next, three leaching events were conducted with 600 mL of water after 7, 35, and 71 days of intervention while soil samples were collected to determine pH and inorganic N. Averaged across sampling dates, urea–N application at an increasing rate reduced soil pH with the lowest values at 800 kg urea–N ha−1. Adding DMPP increased soil pH up to a rate of 500 kg ha−1. Irrespective of the addition of DMPP, gradient urea–N application increased the leaching loss of inorganic N. On overage, DMPP increased soil pH and decreased leaching losses of total inorganic N, suggesting a higher soil N retention. Therefore, we believe that this increase in soil pH is associated with a relatively lower proton release from the reduced nitrification in the DMPP–receiving pots. This nitrification reduction also contributed to the N loss reduction (NO3−–N). Altogether, our results suggest that DMPP can reduce N leaching loss while maintaining the pH of tea–cultivated soils. Therefore, DMPP application has a significant potential for the sustainable N management of tea gardens.

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