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2022 ◽  
Vol 12 (1) ◽  
Zhaolong Ding ◽  
Xu Liu ◽  
Lu Gong ◽  
Xin Chen ◽  
Jingjing Zhao ◽  

AbstractHuman activities have increased the input of nitrogen (N) to forest ecosystems and have greatly affected litter decomposition and the soil environment. But differences in forests with different nitrogen deposition backgrounds. To better understand the response of litter decomposition and soil environment of N-limited forest to nitrogen deposition. We established an in situ experiment to simulate the effects of N deposition on soil and litter ecosystem processes in a Picea schrenkiana forest in the Tianshan Mountains, China. This study included four N treatments: control (no N addition), low N addition (LN: 5 kg N ha−1 a−1), medium N addition (MN: 10 kg N ha−1 a−1) and high N addition (HN: 20 kg N ha−1 a−1). Our results showed that N addition had a significant effect on litter decomposition and the soil environment. Litter mass loss in the LN treatment and in the MN treatment was significantly higher than that in the control treatment. In contrast, the amount of litter lost in the HN treatment was significantly lower than the other treatments. N application inhibited the degradation of lignin but promoted the breakdown of cellulose. The carbon (C), N, and phosphorus (P) contents of litter did not differ significantly among the treatments, but LN promoted the release of C and P. Our results also showed that soil pH decreased with increasing nitrogen application rates, while soil enzyme activity showed the opposite trend. In addition, the results of redundancy analysis (RDA) and correlation analyses showed that the soil environment was closely related to litter decomposition. Soil enzymes had a positive effect on litter decomposition rates, and N addition amplified these correlations. Our study confirmed that N application had effects on litter decomposition and the soil environment in a N-limited P. schrenkiana forest. LN had a strong positive effect on litter decomposition and the soil environment, while HN was significantly negative. Therefore, increased N deposition may have a negative effect on material cycling of similar forest ecosystems in the near future.

2022 ◽  
Vol 12 ◽  
Yushi Zhang ◽  
Yubin Wang ◽  
Churong Liu ◽  
Delian Ye ◽  
Danyang Ren ◽  

Increasing use of plant density or/and nitrogen (N) application has been introduced to maize production in the past few decades. However, excessive planting density or/and use of fertilizer may cause reduced N use efficiency (NUE) and increased lodging risks. Ethephon application improves maize lodging resistance and has been an essential measure in maize intensive production systems associated with high plant density and N input in China. Limited information is available about the effect of ethephon on maize N use and the response to plant density under different N rates in the field. A three-year field study was conducted with two ethephon applications (0 and 90 g ha−1), four N application rates (0, 75, 150, and 225 kg N ha−1), and two plant densities (6.75 plants m−2 and 7.5 plants m−2) to evaluate the effects of ethephon on maize NUE indices (N agronomic efficiency, NAE; N recovery efficiency, NRE; N uptake efficiency, NUpE; N utilization efficiency, NUtE; partial factor productivity of N, PFPN), biomass, N concentration, grain yield and N uptake, and translocation properties. The results suggest that the application of ethephon decreased the grain yield by 1.83–5.74% due to the decrease of grain numbers and grain weight during the three experimental seasons. Meanwhile, lower biomass, NO3- and NH4+ fluxes in xylem bleeding sap, and total N uptake were observed under ethephon treatments. These resulted in lower NAE and NUpE under the ethephon treatment at a corresponding N application rate and plant density. The ethephon treatment had no significant effects on the N concentration in grains, and it decreased the N concentration in stover at the harvesting stage, while increasing the plant N concentration at the silking stage. Consequently, post-silking N remobilization was significantly increased by 14.10–32.64% under the ethephon treatment during the experimental periods. Meanwhile, NUtE significantly increased by ethephon.

2022 ◽  
pp. 246-255
Leonard Rusinamhodzi ◽  
James Njeru ◽  
John E. Sariah ◽  
Rama Ngatoluwa ◽  
Phlorentin P. Lagwen

Abstract Nitrogen (N) deficiency is a common feature in soils managed by smallholder farmers in Africa. Crop residue retention, in combination with no-till (NT), may be a pathway to improve agronomic use efficiency of applied N for small-scale farmers under the predominant rainfed conditions. This chapter reports on the results of a study carried out over two cropping seasons in the long rains of 2014 and 2015 on two sites: (i) on-farm (Mandela); and (ii) a research station (SARI) in eastern Tanzania. The experiment consisted of two tillage systems, conventional tillage (CT) and Conservation Agriculture (CA), with a minimum of 2.5 t ha-1 crop residue cover maintained in the plots during the experiment. CT consisted of soil inversion through tillage and removal of crop residues. In the on-farm experiment, maize was grown in plots with four rates of N application: 0, 27, 54 and 108 kg N ha-1. In the on-station trial, five rates were used: 0, 20, 40, 60 and 100 kg N ha-1. Maize yield and agronomic efficiency (AE) of N were used to assess and compare the productivity of the tested treatments. The results showed that tillage, soil type and rate of N application influenced crop productivity. In the clay soils, the differences between tillage practices were small. Under CT, AE ranged between 21.6 and 53.9 kg/kg N, and it was 20.4-60.6 kg/kg N under CA. The lowest fertilizer application rate of 27 kg ha-1 often had the largest AE across the soil types and tillage practices. In the on-station trials at SARI, the largest AE of 24.6 kg/kg N was recorded under CA with 40 kg N ha-1. As in the on-farm trials, the highest N application rate on-station did not lead to the largest AE. In the CT, AE ranged between 11.5 and 16.8 kg/kg N compared with a range of 15.1 to 24.6 kg/kg N for the CA treatment. Overall, crop residue retention, in combination with NT, is important to improve soil moisture and use efficiency of applied nutrients. Additionally, the initial soil fertility status is also important in determining the magnitude of short-term crop response to applied nutrients. Innovative pathways are needed to achieve the multiple objectives played by maize crop residues for results reported here to be sustainable. However, efficiency of nutrient use needs to be assessed, together with returns on investments, as small yields may mean high nutrient use efficiency but not necessarily significant increased returns at the farm level.

2021 ◽  
Vol 58 (4) ◽  
pp. 517-524
N Panda ◽  
AK Dash

Nitrogen (N) management is a key to sustain rice yield under submerged condition. Time and amount of N application boost rice production under adverse environmental situation. To test this hypothesis a field experiment was conducted at different villages in and around Hindustan Aluminium Company Ltd. (HINDALCO), Hirakud, Sambalpur, Odisha in the year 2015 and 2016. The rice ecosystems were selected on the basis of distance from the smelter plant. Different treatments were framed to test the hypothesis as T1-Farmers practice (60:30:30 kg N: P2 O5:K2O ha-1); T2- 75% recommended dose of fertilizer (RDF) of nitrogen(N) ; T3 -100% RDF of N; T4 -125% RDF of N; T5 -150% RDF of N. It was conducted in a randomized block design with four replications in the farmer's field. The test crop was rice cv.Tejaswinee. Growth parameters like plant height (cm), panicle length (cm) and number of effective tillers per hill were found to be highest in the plots where 125% RDF of N was applied. However the chlorophyll content(mg g-1 fresh)was estimated highest with 150 % RDF of N applied plots. The grain and straw yield (q ha-1) of rice were also observed highest with treatments receiving125% RDF of N.The rice ecosystems which are nearer to aluminium smelter plant were supposed to be affected with less yield as compared to far distance rice ecosystems. The grain quality parameterof rice like protein content (%) was also affected at smelter sites as compared to far distances. However with increasing the N level to 125 % RDF protein content was increased.

2021 ◽  
Vol 14 (1) ◽  
pp. 272
Md. Mizanur Rahman ◽  
Jatish Chandra Biswas ◽  
Mark A. Sutton ◽  
Julia Drewer ◽  
Tapan Kumar Adhya

To assess the status of and trends in agricultural nitrogen (N) flows and their wider consequences for Bangladesh, in this study, we analyzed data from national and international bodies. The increased rates of N fertilizer applied for increased food production leaves behind a huge amount of unutilized reactive N (Nr). N fertilizer use is the largest in the crop sector, an important sector, where current annual consumption is 1190 Gg. The present combined annual Nr production from crop, fishery, and livestock sectors is ~600 Gg, while emissions of nitrous oxide (N2O), a potent greenhouse gas, are ~200 Gg. Poor N management results in Nr leaking into the environment, which has increased approximately 16-fold since 1961. One potential consequence is the disruption of ecosystem functioning. The balanced tradeoff between food production and reducing Nr input needs to be achieved. One solution to reducing Nr may be a holistic approach that optimizes N application rates and incorporates waste of one subsector as an input to another applying the principle of the circular economy.

2021 ◽  
pp. 30-37
Christa M. Hoffmann ◽  
Gunnar Kleuker ◽  
André Wauters ◽  
William English ◽  
Martijn Leijdekkers

There is some evidence that sugar beet root tissue strength affects damage susceptibility and storage losses. This study aimed at analyzing the effect of N application and of irrigation on tissue strength of sugar beet varieties, on root composition, and on root tip breakage and storage losses. For this purpose, field trials in six replicates with three sugar beet varieties were carried out with three N doses in The Netherlands and Belgium in 2018 and 2019, alternatively with three irrigation treatments in Sweden in 2018 and 2019. Results show a low impact of N application and irrigation on puncture resistance, tissue firmness and compressive strength of the roots, while varieties differed always stronger and significantly. Cell wall composition (pectin, hemicellulose, cellulose, lignin) did not differ markedly in roots from different environments (sites, years) and varieties, giving no explanation for differences in tissue strength. However, the percentage of cell wall material (AIR, marc) and of dry matter were higher in roots with higher tissue strength. Root tip breakage and sugar losses during storage tended to be lower when root compressive strength of varieties was higher. Hence, root tissue strength could serve as an indirect selection criterion for reduced damage susceptibility and improved storability of sugar beet varieties.

2021 ◽  
Qingyun Zhou ◽  
Hui Wang ◽  
Chao Xu ◽  
Shen Zheng ◽  
Meiyan Wu ◽  

Abstract Cd pollution in paddy soils creates challenges in rice grain production, thereby threatening food security. The effectiveness of different base-tillering-panicle urea application ratio and the combined basal application of urea and Chinese milk vetch (CMV, Astragalus sinicus L.) in minimizing Cd accumulation in rice grains was explored in a Cd-contaminated acidic soil via a field experiment. The results indicated that under similar N application rates, an appropriate amount of urea applied at the panicle stage or the combined basal application of urea and CMV decreased Cd absorption by rice roots and its accumulation in rice grains, as compared with that of conventional N application (control). Furthermore, under a 3:4:3 base-tillering-panicle urea application ratio or for basal application of CMV at high levels, Cd concentrations in brown rice were significantly lower (40.7% and 34.1%, respectively) than that of control. Cd transport coefficient from root to straw was significantly higher than that of control when an appropriate amount of urea was applied at the panicle stage or urea and CMV were applied basally, whereas the Cd transport coefficient from straw to brown rice was relatively lower. Moreover, soil pH, or the concentrations of CEC and CaCl2-Cd under different N fertilizer treatment was not significantly different. However, rice grain yield increased by 29.4% with basal application of a high amount of CMV compared with that of control. An appropriate amount of urea applied at the panicle stage or the combined basal application of urea and CMV decreased Cd absorption by rice roots and inhibited its transport from straw to brown rice, thus reducing Cd concentration in brown rice. Therefore, combined with the key phase of Cd accumulation in rice, a reasonable urea application ratio or a basal application of high amounts of CMV can effectively reduce Cd concentration in brown rice.

2021 ◽  
Vol 13 (4) ◽  
pp. 1462-1469
K. Sathiya Bama ◽  
K. R. Babu ◽  
R. Sharmila ◽  
A. Anuradha

Direct seeded rice is a boon to farmers where the water release from the reservoir is delayed. Nitrogen fertiliser management is one of the strategies bto rectify the nutrient-related issue in Direct seeded rice. The present study aimed to optimize the nitrogen dose for direct-seeded rice in the new and old Cauvery delta zone of Tamil Nadu. Field experiments were conducted during kuruvai and samba seasons at Tamil Nadu Rice Research Institute, Aduthurai and Agricultural research station Thanjavur representing old and new Cauvery delta regions during 2019-20 and 2020-21. Totally from eight experiments, the results of four field experiments in each location revealed the highest grain yield in the treatment T6 -application of 150 kg Nha-1 (5596kg/ha) which was statistically on par with treatment T5 -125kg N/ha (5326 kg/ha) in old delta and new delta. The higher grain yield was recorded in the T6 (5140 kg/ha), statistically on par with T5 (4550 kg/ha). The higher available nitrogen content of 312 kg/ ha,292 kg/ha was recorded for N application @ 150kg/ha, which was statistically on par with  309 kg/ha and 289 kg/ha, respectively, both the kuruvai and samba seasons for N application of 125 kg/ha. In the new CDZ, the same trend was followed as that of the old delta. Based on economics, N applied @125 kg/ha recorded a higher BC ratio for direct-seeded rice. For the benefit of farmers of both deltaic regions, the nitrogen application of 125 kg ha-1 for direct-seeded rice is recommended.

2021 ◽  
Vol 13 (24) ◽  
pp. 13753
Niamat Ullah Khan ◽  
Aftab Ahmad Khan ◽  
Muhammad Arif Goheer ◽  
Izwa Shafique ◽  
Sadam Hussain ◽  

Long-term conservation tillage and straw incorporation are reported to improve the soil health, growth, and yield traits of crops; however, little is known regarding the optimal nitrogen (N) supply under conservation tillage with straw incorporation. The present study evaluated the effects of conservation tillage practices (ZTsas: zero tillage plus wheat straw on the soil surface as such, and MTsi: minimum tillage plus wheat straw incorporated) and different N application rates (50, 100, 150, and 200 kg ha−1) on the yield and quality traits of cotton and soil characteristics in a five-year field experiment. The results showed that ZTsas produced a higher number of bolls per plant, boll weight, seed cotton yield, 100-seed weight, ginning out-turn (GOT), fiber length, and strength than MTsi. Among different N application rates, the maximum number of bolls per plant, boll weight, seed cotton yield, GOT, 100-seed weight, fiber length, strength, and micronaire were recorded at 150 kg N ha−1. Averaged over the years, tillage × N revealed that ZTsas had a higher boll number plant−1, boll weight, 100-seed weight, GOT, fiber length, and strength with N application at 150 kg ha−1, as compared to other tillage systems. Based on the statistical results, there is no significant difference in total soil N and soil organic matter among different N rates. Further, compared to MTsi, ZTsas recorded higher soil organic matter (SOM, 8%), total soil N (TSN, 29%), water-stable aggregates (WSA, 8%), and mean weight diameter (MWD, 28.5%), particularly when the N application of 150 kg ha−1. The fiber fineness showed that ZTsas had no adverse impact on fiber fineness compared with MTsi. These results indicate that ZTsas with 150 kg N ha−1 may be the optimum and most sustainable approach to improve cotton yield and soil quality in the wheat–cotton system.

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