Effects of nitrogen application rate on soil and plant characteristics in pastures of perennial grass mixtures in the alpine region of the Qinghai-Tibetan Plateau, China

Soil Research ◽  
2004 ◽  
Vol 42 (7) ◽  
pp. 727 ◽  
Author(s):  
S. K. Dong ◽  
Y. Jiang ◽  
M. J. Wei ◽  
R. J. Long ◽  
Z. Z. Hu ◽  
...  

To illustrate the effect of nitrogen (N) application on soil physical and chemical characteristics, herbage yield and quality, and nitrogen and water use efficiency in the alpine region of Qinghai-Tibetan Plateau, a 3-year experiment was conducted on 3 mixtures of 4 perennial grasses commonly cultivated on the Plateau, Bromus inermis (BI) + Elymus nutans (EN), BI + E. sibricus (ES) + Agropyron cristatum (AC), and BI + ES + EN + AC by applying 4 levels of N fertiliser, 0, 115, 230, and 345 kg/ha from 1998 to 2000 in a randomised design. At harvesting time, soil pH and soil dry bulk density at 0–30 cm depth did not vary with N application rate. Soil organic carbon at 0–30 cm was not significantly variable under different N rates. Total soil N at 0–30 cm increased with N application rate and application year. After 3 years’ consecutive N treatment, total soil N reached 13 g/kg at an N application rate of 345 kg/ha. Soluble soil N at 0–30 cm increased with application rate but decreased with application year. At 345 kg N/ha application rate, soluble soil N was >100 mg/kg in 1998, but decreased to around 80 mg/kg in 2000. Herbage DM yields increased linearly with the N application rate. Compared with no fertiliser, 1.5 times more DM yield in 1998 and nearly double the DM yield in 1999 and 2000 were harvested for all grass mixtures at 345 kg N/ha. N concentrations in the herbages were significantly improved by N application. Each N fertiliser rate increased N contents in grass herbages by ≈3 g organic matter/kg. Apparent nitrogen recovery (ANR) decreased with N application rate in the establishment year of 1998, but increased with N application rate in 1999 and 2000. N use efficiency (NUE) decreased with N application throughout the experiment. Precipitation use efficiency (PUE) was significantly improved by N application for each grass mixture. Positive residual N-fertiliser effects were observed on herbage DM yield, ANR, NUE, and PUE in this study. BI + ES + AC showed higher DM yields, ANR, NUE, and PUE than the other 2 grass mixtures, and thus was proposed for N-input grassland systems in the alpine region of the Qinghai-Tibetan Plateau.

HortScience ◽  
1990 ◽  
Vol 25 (10) ◽  
pp. 1293-1296 ◽  
Author(s):  
C.M. Tankou ◽  
B. Schaffer ◽  
S.K. O'Hair ◽  
C.A. Sanchez

The effects of applied N and shading duration on net gas exchange and growth of two southern Florida cassava (Manihot esculenta Crantz.) cultivars grown in containers were determined. Both cultivars responded similarly to shading and N with respect to the measured variables. There were no interactions between shading duration and N application rate for any of the variables measured. Tissue dry weights, total leaf N and chlorophyll concentrations, net CO2 assimilation (A), transpiration (E), water-use efficiency (WUE), and stomatal conductance (gs) were quadratically related to the concentration of N applied to the soil. The optimum N application rate for maximum growth of both cultivars was 60 mg/plant per day. Increased shading duration reduced A, E, gs, WUE, storage root number, and weight and increased the shoot : root ratio.


2001 ◽  
Vol 1 ◽  
pp. 682-690 ◽  
Author(s):  
J.L. Hatfield ◽  
J.H. Prueger

Nitrogen (N) loss from agricultural systems raises concerns about the potential impact of farming practices on environmental quality. N is a critical input to agricultural production. However, there is little understanding of the interactions among crop water use, N application rates, and soil types. This study was designed to quantify these interactions in corn (Zea mays L.) grown in production-size fields in central Iowa on the Clarion-Nicollet-Webster soil association. Seasonal water use varied by soil type and N application rate. Yield varied with N application rate, with the highest average yield obtained at 100 kg ha-1. N use efficiency (NUE) decreased with increasing N application rates, having values around 50%. Water use efficiency (WUE) decreased as N fertilizer rates increased. Analysis of plant growth patterns showed that in the low organic matter soils (lower water-holding capacities), potential yield was not achieved because of water deficits during the grain-filling period. Using precipitation data coupled with daily water use throughout the season, lower organic matter soils showed these soils began to drain earlier in the spring and continued to drain more water throughout the season. The low NUE in these soils together with increased drainage lead to greater N loss from these soils. Improved management decisions have shown that it is possible to couple water use patterns with N application to increase both WUE and NUE.


2013 ◽  
Vol 6 (4) ◽  
pp. 454-467 ◽  
Author(s):  
Wei Min ◽  
ZhenAn Hou ◽  
LiJuan Ma ◽  
Wen Zhang ◽  
SiBo Ru ◽  
...  

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11077
Author(s):  
Guoying Yang ◽  
Hongting Ji ◽  
Hongjiang Liu ◽  
Yanfang Feng ◽  
Yuefang Zhang ◽  
...  

Background Excessive nitrogen (N) application rate with low N use efficiency (NUE) caused a considerable amount of N losses, especially ammonia volatilization (AV). Proper N fertilizer reduction (RN) could significantly reduce AV. However, continuous RN led to a nutrient deficiency in the soil and therefore negatively impacted the NUE and rice yield. Paddy Azolla, a good green manure, is considered as a promising measure to decrease AV and improve NUE and grain yield of rice. However, there is limited information on the integrated effects of RN and Azolla cover on the AV, NUE, and rice yield, especially in the highly fertilized rice-growing systems. Methods The experiment was conducted including eight treatments: the control (without N fertilizer and Azolla cover), Azolla cover without N fertilizer (A), farmer’s N application rate (FN), FN + Azolla cover (FNA), 15% RN from FN (RN15), RN15 + Azolla cover (RN15A). 30% RN from FN (RN30), RN30 + Azolla cover (RN30A). The integrated effects of N fertilizer reduction and Azolla cover on AV, NUE, and rice grain was evaluated. Results RN15A and RN30A substantially reduced total AV by 50.3 and 66.9% compared with FN, respectively, primarily due to the lower surface water ammonia concentrations and pH. RN improved the efficiency of Azolla cover on reducing AV, with 4.1–9.9% higher than for FN. Compared with the FN, RN15A and RN30A enhanced apparent N recovery efficiency (ANRE) by 46.5 and 39.1%, which might be responsible for the lower NH3 emission and the increased total N uptake / total chemical N applied. Furthermore, RN15A and RN30A reduced yield-scaled volatilization by 52.3 and 64.3% than for FN, respectively. Thus, combining 15–30% RN with Azolla cover may be a way to reduce AV and improve ANRE without decreasing rice grain yield.


2021 ◽  
Author(s):  
Xiangfei Han ◽  
Lina Dong ◽  
Peng Liu ◽  
Shuting Dong ◽  
Jiwang Zhang ◽  
...  

Abstract Exploring the optimal method of water and fertilizer application and N application rate for summer maize is important for achieving the high water and N efficiency in the North China Plain. We tested that the hypothesis that optimizing water and nitrogen application system could improve nitrogen (N) use efficiency and water productivity, and ensure sustainable yield of summer maize. The results showed that: the 216 kg N ha-1 of drip irrigation (DI) and micro-sprinkling irrigation (SI) could obtain the high grain yield compared with 270 kg N ha-1 of flooding irrigation (FI), which was achieved by maintaining a high 1000-grain weight and kernel number. However, the grain yield of 162 kg N ha-1 would be decreased significantly. Irrigation methods and N application rates had significant effects on the ammonia volatilization rate and ammonia volatilization accumulation of soil, N harvest index (NHI), N partial productivity and water productivity. Compared with FI, DI and SI could reduce the ammonia volatilization rate through applying little fertilizer-N by times, and reduce the ammonia volatilization accumulation of 19.5%-54.9%. In addition, under the same irrigation method, the NHI reached the maximum when the N application rate was 216 kg ha−1. Considering comprehensively, under the condition of this experiment, 216 kg N ha−1 is the best N application rate under DI or SI for maize.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6484 ◽  
Author(s):  
Dongqing Yang ◽  
Tie Cai ◽  
Yongli Luo ◽  
Zhenlin Wang

The growth of wheat tillers and plant nitrogen-use efficiency (NUE) will gradually deteriorate in response to high plant density and over-application of N. Therefore, in this study, a 2-year field study was conducted with three levels of plant densities (75 ×104plants ha−1, D1; 300 ×104plants ha−1, D2; 525 ×104plants ha−1, D3) and three levels of N application rates (120 kg N ha−1, N1; 240 kg N ha−1, N2; 360 kg N ha−1, N3) to determine how to optimize plant density and N application to regulate tiller growth and to assess the contribution of such measures to enhancing grain yield (GY) and NUE. The results indicated that an increase in plant density significantly increased the number of superior tillers and the number of spikes per m2(SN), resulting in a higher GY and higher partial factor productivity of applied N (PFPN). However, there was no significant difference in GY and PFPNbetween plant densities D2 and D3. Increasing the N application rate significantly increased the vascular bundle number (NVB) and area (AVB), however, excess N application (N3) did not significantly improve these parameters. N application significantly increased GY, whereas there was a significant decrease in PFPNin response to an increase in N application rate. The two years results suggested that increasing the plant density (from 75 ×104plants ha−1to 336 ×104plants ha−1) in conjunction with the application of 290 kg N ha−1N will maximize GY, and also increase PFPN(39.7 kg kg−1), compared with the application of 360 kg N ha−1N. Therefore, an appropriate combination of increased planting density with reduced N application could regulate tiller number and favor the superior tiller group, to produce wheat populations with enhanced yield and NUE.


1987 ◽  
Vol 108 (3) ◽  
pp. 609-615 ◽  
Author(s):  
I. Papastylianou ◽  
Th. Samios

SummaryUsing data from rotation studies in which barley or woollypod vetch were included, both cut for hay and preceding barley for grain, it is shown that forage barley gave higher dry-matter yield than woollypod vetch (3·74 v. 2·92 t/ha per year). However, the latter gave feedingstuff of higher nitrogen concentration and yield (86 kg N/ha per year for vetch v. 55 kg N/ha per year for barley). Rainfall was an important factor in controlling the yield of the two forages and the comparison between them in different years and sites. Barley following woollypod vetch gave higher grain yield than when following forage barley (2·36 v. 1·91 t/ha). Rotation sequences which included woollypod vetch had higher output of nitrogen (N) than input of fertilizer N with a positive value of 44–60 kg N/ha per year. In rotations where forage barley was followed by barley for grain the N balance between output and input was 5–6 kg N/ha. Total soil N was similar in the different rotations at the end of a 7-year period.


2004 ◽  
Vol 84 (2) ◽  
pp. 169-176 ◽  
Author(s):  
B. L. Ma ◽  
M. Li ◽  
L. M. Dwyer ◽  
G. Stewart

Little information is available comparing agronomic performance and nitrogen use efficiency (NUE) for N application methods such as foliar spray, soil application, and ear injection in maize (Zea mays L.). The objective of this study was to investigate the effects of various N application methods on total stover dry matter, grain yield, and NUE of maize hybrids using a 15N-labeling approach. A field experiment was conducted on a Dalhousie clay loam in Ottawa and a Guelph loam in Guelph for 2 yr (1999 and 2000). Three N application methods were tested on two maize hybrids, Pioneer 3893 and Pioneer 38P06 Bt. At planting, 60 kg N ha-1 as ammonium nitrate was applied to all treatments. In addition, 6.5 kg N ha-1 and 13.5 kg N ha-1 as 15N-labeled urea were applied to either foliage (Treatment I) or soil (Treatment II) at V6 and V12 stages, respectively. In Treatment III, 20 kg N ha-1 as 15N-labeled urea was injected into space between ear and husks at silking. The results showed that compared with soil N application neither foliar spray nor injection through ear affected grain yield or stover dry matter. The NUE values ranged from 12 to 76% for N fertilizer applied at V6 a nd V12 stages, or at silking for all treatments. There was no interaction of hybrid × N application methods on any variables measured with the only exception that for soil N application, grain NUE in Pioneer 38P06 Bt was significant higher than in Pioneer 3893. The difference in total N and NUE of grain and stover between soil N application and foliar N spray was inconsistent. However, NUE was substantially higher for N injection through the ear than for foliar or soil application without differential responses between the two hybrids. Nitrogen injection through the ear at silking might have altered N redistribution within the plant and improved NUE. Hence, it can potentially enhance grain protein content. Foliar N spray is not advocated for maize production in Ontario. Key words: Maize, Zea mays, nitrogen application methods, nitrogen-15, yield, nitrogen use efficiency


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