Mechanisms of nitrogen limitation affecting maize growth: a comparison of different modelling hypotheses

2009 ◽  
Vol 60 (8) ◽  
pp. 738 ◽  
Author(s):  
F. Y. Li ◽  
P. D. Jamieson ◽  
P. R. Johnstone ◽  
A. J. Pearson

Two hypothetical mechanisms exist for quantifying crop nitrogen (N) demand and N-deficit effects on crop growth. The Critical N mechanism uses a critical N concentration, while the Leaf N mechanism distinguishes active N in leaves from the N elsewhere in shoots. These two mechanisms were implemented in parallel in a maize model (Amaize) to evaluate their adequacy in predicting crop growth and development. In the Leaf N mechanism, two approaches for quantifying N-deficit effects, by reducing green leaf area (GAI) or diluting specific leaf nitrogen (SLN), were also examined. The model-predicted plant biomass, grain yield, and N uptake were compared with measurements from 47 maize crops grown on 16 sites receiving different N fertiliser treatments. The results showed that model-predicted plant biomass, grain yield and N uptake were insensitive to the approaches used for quantifying N-deficit effects in the Leaf N mechanism. The model-predicted plant biomass, grain yield and N uptake using either N approach were significantly related to measurements (P < 0.01) but had considerable deviations (r2 = 0.66–0.69 for biomass, 0.50–0.54 for grain yield: 0.17–0.33 for N uptake). The linear fits of the predicted against measured values showed no significant difference (P > 0.1) among the three N approaches, with the Leaf N mechanism predicting smaller deviation than the Critical N mechanism. However, the Critical N mechanism was better in simulating plant growth dynamics in early plant growth stages. The Leaf N mechanism distinguished functional from structural N pools in plants, having a sound physiological base. The simulation using the Leaf N mechanism with both SLN dilution and GAI reduction for quantifying N-deficit effects was the best in predicting crop growth and yield.

2014 ◽  
Vol 153 (5) ◽  
pp. 862-875 ◽  
Author(s):  
J. BRENNAN ◽  
P. D. FORRISTAL ◽  
T. McCABE ◽  
R. HACKETT

SUMMARYField experiments were conducted between 2009 and 2011 in Ireland to compare the effects of soil tillage systems on the grain yield, nitrogen use efficiency (NUE) and nitrogen (N) uptake patterns of spring barley (Hordeum vulgare) in a cool Atlantic climate. The four tillage treatments comprised conventional tillage in spring (CT), reduced tillage in autumn (RT A), reduced tillage in spring (RT S) and reduced tillage in autumn and spring (RT A+S). Each tillage system was evaluated with five levels of fertilizer N (0, 75, 105, 135 and 165 kg N/ha). Grain yield varied between years but CT had a significantly higher mean yield over the three years than the RT systems. There was no significant difference between the three RT systems. Tillage system had no significant effect on the grain yield response to fertilizer N. As a result of the higher yields achieved, the CT system had a higher NUE than the RT systems at all N rates. There was no significant difference in NUE between the three RT systems. Conventional tillage had significantly higher nitrogen uptake efficiency (NUpE) than RT A and a significantly higher nitrogen utilization efficiency (NUtE) than all three RT systems. Crop N uptake followed a similar pattern each year. Large amounts of N were accumulated during the vegetative growth stages while N was lost after anthesis. Increased N rates had a positive effect on N uptake in the early growth stages but tended to promote N loss later in the season. The CT system had the highest N uptake in the initial growth stages but its rate of uptake diminished at a faster rate than the RT systems as the season progressed. Tillage system had an inconsistent effect on crop N content during the later growth stages. On the basis of these results it is concluded that the use of non-inversion tillage systems for spring barley establishment in a cool oceanic climate remains challenging and in certain conditions may result in a reduction in NUE and lower and more variable grain yields than conventional plough-based systems.


2018 ◽  
Vol 14 (3) ◽  
pp. 211
Author(s):  
Maimunah Maimunah ◽  
Gusti Rusmayadi ◽  
Bambang F. Langai

Soybean is categorized as a plant which sensitive to water deficit or surplus in its life cycle. If water requirement is not sufficient for the growth and development, the soybean will be subjected to stress. Water stress, such deficiency or excess of water in the plant environment is a condition that disrupts the balance of plant growth. Therefore, it is necessary to observe the interaction between drought stress at various growth stages and soybean varieties, and observe which growth stages that would provide the highest yield of soybean know the differences in drought stress in various stadia of plant growth on the growth and yield of two varieties of soybean crops and which currently can give the highest yield in various stadia grow. This research was carried out by using polybag in the greenhouse of Faculty of Agriculture Universitas Lambung Mangkurat Banjarbaru for 4 months from March to June 2017. The experimental design was Randomized Completely Design with Split Plot Design Factorial. The first factor is soybean varieties (V) as main plot, i.e. Grobogan (v1) and Anjasmoro (v2), and the second factor is the growth stages those subjected to drought stress (C) as subplot, i.e. c1 : vegetative stage 3 (29 DAS and 36 DAS), c2 : flowering stage (35 DAS and 46 DAS), c3 pods appearance/emergence (42 DAS and 53 DAS), and c4 : pods filling stage (68 DAS and 76 DAS). The treatment was repeated 3 times and each experiment unit consists of 5 polybags, thus there were 120 plants in total. The crop growth rate, number of main branch nodes, number of effective root nodules, shoot root ratio, the first flowering time, the harvest time, number of pods per plant, number of seed per plant, 100 seed dry weight, and the number of dry seed per plant. The result showed there was no interaction effect between drought stress in various stages and soybean varieties on all variables. Drought stress at vegetative stage 3 (c1) caused the number of main branch nodes, the number of pods per plant, the number of seed per plant, the 100 seed dry weight and the number of dry seed per plant are lower if they are compared to the plants those subjected to drought stress at pod filling stage (c4). Nevertheless, those variables were not different at drought stress at flowering stage (c2), pods appearance (c3) and pod filling stage  (4). Soybean varieties observation showed that the Grobogan were faster in flowering time and higher in crop growth (26.49 DAS and 3.08 g d-1 respectively) compared to the Anjasmoro (34.08 DAS and 2.73 g d-1 respectively).


Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1094
Author(s):  
Kai Yue ◽  
Lingling Li ◽  
Junhong Xie ◽  
Setor Kwami Fudjoe ◽  
Renzhi Zhang ◽  
...  

Nitrogen (N) is the most limiting nutrient for maize, and appropriate N fertilization can promote maize growth and yield. The effect of N fertilizer rates and timings on morphology, antioxidant enzymes, and grain yield of maize (Zea mays L.) in the Loess Plateau of China was evaluated. The four N levels, i.e., 0 (N0), 100 (N1), 200 (N2), and 300 (N3) kg ha−1, were applied at two timings (T1, one-third N at sowing and two-thirds at the six-leaf stage of maize; T2, one-third applied at sowing, six-leaf stage, and eleven-leaf stage of maize). The results show that N2 and N3 significantly increased the plant height, stem and leaf dry weight, and leaf area index of maize compared with a non-N-fertilized control (N0). The net photosynthetic rate, transpiration rate, stomatal conductance, and leaf chlorophyll contents were lower, while the intercellular carbon dioxide concentration was higher for non-fertilized plants compared to fertilized plants. The activities of peroxidase (POD) and superoxide dismutase (SOD) increased with N rate, but the difference between 200 and 300 kg ha−1 was not significant; further, the isozyme bands of POD and SOD also changed with their activities. Compared with a non-N-fertilized control, N2 and N3 significantly increased grain yield by 2.76- and 3.11-fold in 2018, 2.74- and 2.80-fold in 2019, and 2.71- and 2.89-fold in 2020, and there was no significant difference between N2 and N3. N application timing only affected yield in 2018. In conclusion, 200 kg N ha−1 application increased yield through optimizing the antioxidant enzyme system, increasing photosynthetic capacity, and promoting dry matter accumulation. Further research is necessary to evaluate the response of more cultivars under more seasons to validate the results obtained.


2014 ◽  
Vol 6 (4) ◽  
pp. 188 ◽  
Author(s):  
Joseph Adigun ◽  
A. O. Osipitan ◽  
Segun Toyosi Lagoke ◽  
Raphael Olusegun Adeyemi ◽  
Stephen Olaoluwa Afolami

Weed problem appears to be the most deleterious factor causing between 25 and 60% reduction in potential yield of cowpea. Field trials were therefore conducted to study the effect of inter-row spacing and period of weed interference on growth and yield of cowpea (Vigna unguiculata (L) Walp) at the Teaching and Research Farm of the Federal University of Agriculture, Abeokuta (07° 15'; 03° 25' E) in South Western Nigeria during the early and late wet seasons of 2009. The experiment consisted of eight main plots of weed interference which included initial weed removal for 3, 6, 9, and 12 weeks after sowing (WAS) and subsequently weed –infested until harvest as well as initial weed infestation for corresponding periods and thereafter kept weed free until harvest. There were also sub-plot treatments of three inter-row spacing of 60, 75, and 90 cm. All treatments in different combinations were laid out in a split-plot design with three replications. In both trials, the use of inter-row spacing of 60 cm resulted in significant reduction in weed growth as evident in lower weed dry matter production and subsequent higher cowpea pod and grain yields than those of 75 and 90 cm inter-row spacing. Initial weed infestation of up to 3 WAS did not have any adverse effect on crop growth and cowpea grain yields provided the weeds were subsequently removed. On the other hand, cowpea grain yield loss was not significantly averted by keeping the crop weed free for only 3 WAS without subsequent weed removal. In this study, initial weed-infestation for 6 WAS and beyond significantly depressed various crop growth parameter and cowpea grain yield compared with the crop kept weed free throughout its life cycle. In order to obtain optimum yields similar to that of the weed free cowpea field, it was required to keep the crop weed free for 6 WAS and beyond. However, frequent weeding beyond 9 weeks after sowing did not improve cowpea yield significantly and as a matter of fact it may even result in reduction of cowpea grain yield due to mechanical damage of hoe weeding. The practical implication of this finding is that early weeding starting from 3 WAS is very crucial for cowpea production while the critical period of weed removal for optimum yield in cowpea is between 3 and 9 WAS in the forest-savannah transitional zone of south Western Nigeria.


Author(s):  
Ahmad Raza ◽  
Muhammad Nawaz ◽  
Muhammad U. Chattha ◽  
Imran Khan ◽  
Muhammad B. Chattha ◽  
...  

Weeds are major threat to global wheat production and cause serious threat to food security. Likewise, water scarcity is also a major threat to food production and its intensity is continuously soaring up across the globe. Organic mulches have potential to reduce weeds growth and conserve the soil moisture thus ensures the better crop growth and yield. Therefore, present study was conducted to compare the performance of different organic mulches in improving wheat growth and productivity. The study was comprised of different organic mulches; M1= No mulch (control) M2= maize straw mulch, M3= wheat straw mulch, M4= sorghum straw mulch and M5= rice straw mulch and three nitrogen levels N1 = 90 kg, N2 = 120 kg and N3= 150 kg/ha. The results indicated that both organic mulches and N rates had significant impact on growth, and yield traits. The maximum leaf area index (LAI), crop growth rate (CGR), productive tillers (307 m-2), grains/spike (46.22), 1000 grain weight (42.33 g) biological yield (13.76 t/ha) and grain yield 4.75 t/ha was obtained with sorghum straw mulch and minimum productive tillers (255.33 m-2), grains/spike (36.22), biological yield (11.46 t/ha) and grain yield (3.59 t/ha) was recorded in no mulch (control). Among nitrogen levels maximum productive tillers (290.6 m-2), grains/spike (42.80), 1000 grain weight (40.65 g), biological yield (13.44 t/ha) and grain yield (4.32 t/ha) was obtained with 150 kg/ha N and minimum productive tillers (274 m-2), grains/spike (38.13), 1000 grain weight (36.94 g) biological yield (11.98 t/ha) and grain yield (3.90 t/ha) was obtained with 90 N kg/ha. Thus, farmers can use sorghum straw mulch and N (150 kg ha-1) to improve the wheat productivity. However, farmers must be educated by government institute and adoptive research farms in order to understand and adaption of this approach.


Agronomy ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 343 ◽  
Author(s):  
Muhammad Zafar-ul-Hye ◽  
Subhan Danish ◽  
Mazhar Abbas ◽  
Maqshoof Ahmad ◽  
Tariq Muhammad Munir

Drought stress retards wheat plant’s vegetative growth and physiological processes and results in low productivity. A stressed plant synthesizes ethylene which inhibits root elongation; however, the enzyme 1-Aminocyclopropane-1-Carboxylate (ACC) deaminase catabolizes ethylene produced under water stress. Therefore, the ACC deaminase producing plant growth promoting rhizobacteria (PGPR) can be used to enhance crop productivity under drought stress. Biochar (BC) is an organically active and potentially nutrient-rich amendment that, when applied to the soil, can increase pore volume, cation exchange capacity and nutrient retention and bioavailability. We conducted a field experiment to study the effect of drought tolerant, ACC deaminase producing PGPR (with and without timber waste BC) on plant growth and yield parameters under drought stress. Two PGPR strains, Agrobacterium fabrum or Bacillus amyloliquefaciens were applied individually and in combination with 30 Mg ha−1 BC under three levels of irrigation, i.e., recommended four irrigations (4I), three irrigations (3I) and two irrigations (2I). Combined application of B. amyloliquefaciens and 30 Mg ha−1 BC under 3I, significantly increased growth and yield traits of wheat: grain yield (36%), straw yield (50%), biological yield (40%). The same soil application under 2I resulted in greater increases in several of the growth and yield traits: grain yield (77%), straw yield (75%), above- and below-ground biomasses (77%), as compared to control; however, no significant increases in chlorophyll a, b or total, and photosynthetic rate and stomatal conductance in response to individual inoculation of a PGPR strain (without BC) were observed. Therefore, we suggest that the combined soil application of B. amyloliquefaciens and BC more effectively mitigates drought stress and improves wheat productivity as compared to any of the individual soil applications tested in this study.


2018 ◽  
Vol 156 (1) ◽  
pp. 46-58 ◽  
Author(s):  
Caixia Liu ◽  
Sabine Ravnskov ◽  
Fulai Liu ◽  
Gitte H. Rubæk ◽  
Mathias N. Andersen

AbstractDeficit irrigation (DI) improves water use efficiency (WUE), but the reduced water input often limits plant growth and nutrient uptake. The current study examined whether arbuscular mycorrhizal fungi (AMF) could alleviate abiotic stress caused by low phosphorus (P) fertilization and DI.A greenhouse experiment was conducted with potato grown with (P1) or without (P0) P fertilization, with AMF (M1+:Rhizophagus irregularisor M2+:Glomus proliferum) or AMF-free control (M−) and subjected to full irrigation (FI), DI or partial root-zone drying (PRD).Inoculation of M1+ and M2+ maintained or improved plant growth and P/nitrogen (N) uptake when subjected to DI/PRD and P0. However, the positive responses to AMF varied with P level and irrigation regime. Functional differences were found in ability of AMF species alleviating plant stress. The largest positive plant biomass response to M1+ and M2+ was found under FI, both at P1 and P0 (25% increase), while plant biomass response to M1+ and M2+ under DI/PRD (14% increase) was significantly smaller. The large growth response to AMF inoculation, particularly under FI, may relate to greater photosynthetic capacity and leaf area, probably caused by stimulation of plant P/N uptake and carbon partitioning toward roots and tubers. However, plant growth response to AMF was not related to the percentage of AMF root colonization. Arbuscular mycorrhizal fungi can maintain and improve P/N uptake, WUE and growth of plants both at high/low P levels and under FI/DI. If this is also the case under field conditions, it should be implemented for sustainable potato production.


2009 ◽  
Vol 57 (1) ◽  
pp. 57-65
Author(s):  
R. Thamizh Vendan ◽  
M. Thangaraju

The nitrogen-fixing rhizobacterium Azospirillum lives in close association with plant roots, where it exerts beneficial effects on the plant growth and yield of many crops of agronomic importance. As carrier-based inoculants have a short shelf life and poor quality, new liquid and cyst formulations of inoculants have been developed and standardized for Azospirillum . In the present investigation, experiments were conducted to study the effect of liquid and cyst formulations of Azospirillum , combined with inorganic nitrogen, on the growth and yield of rice. Inoculation with the cyst formulation of Azospirillum enhanced the plant height, biomass and N uptake of the plants, the available nitrogen content of the soil and the yield of rice to the greatest extent when compared to carrier-based Azospirillum , followed by the liquid formulation. The results of the present study clearly indicated that the cyst and liquid formulations of Azospirillum could be used as bioinoculants more effectively than the carrier-based one.


2017 ◽  
Vol 38 (04) ◽  
Author(s):  
K. Sivagamy ◽  
C. Chinnusamy ◽  
P. Parasuraman

Weeds are generally hardy species having fast growth, deep root system and capable of competing very efficiently with cultivated crops for the available resources and adversely affect the crop growth and yield. Weed management systems that rely on post emergence control assume that crops can tolerate competition for certain periods of time without suffering yield losses. Initial slow growth particularly at early crop growth stages and wider plant spacing of maize crop encourages fast and vigorous growth of weeds. It is of paramount importance that, competition from weeds must be minimized to achieve optimum yield. Among the different weed control methods, chemical method bears many advantages in suppressing weed growth and to get healthy and vigorous crop stand. Non-selective herbicide molecules with a variety of mode of action were discovered, developed and marketed for successful weed control programme.


2015 ◽  
Vol 48 (3) ◽  
pp. 23-31 ◽  
Author(s):  
◽  
I. Alam ◽  
I. Khan ◽  
M. Kumar ◽  
A. Shah ◽  
...  

Abstract Foliar nitrogen (N) application is considered an important factor affecting phenology, growth, yield, and yield components of dryland wheat (Triticum aestivum L.). A field experiment was conducted to study effects of foliar N on dryland wheat (cv. Prisabk-2004) at the Agronomy Research Farm, The University of Agriculture Peshawar, Pakistan, during winter 2010-2011. The experiment was laid out in randomized complete block design using four replications. A plot size of 3 m by 4 m, having 8 rows, 4 m long and 30 cm apart was used. A total of 80 kg N ha−1 in the form of urea was applied. Out of 80 kg N ha−1, 70 kg N ha−1 was applied to the soil at sowing time, and the remaining 10 kg N ha−1 was applied in the form of foliar spray (2% N). The required foliar N was applied in various combinations (splits) at different growth stages viz. 30, 60, 90 and 120 days after emergence (DAE). Phenological development (days to anthesis and physiological maturity) was delayed, yield components and yield increased significantly (p ≤ 0.05) with foliar N over control (water spray without N). Wheat grain yield increased to the highest level (4427 kg ha−1) when 100 % foliar N was applied (no split) at 90 DAE, followed by 4050 kg ha−1 at 120 DAE, while the control (no foliar N) resulted in the lowest grain yield (2573 kg ha−1). We concluded from this study that 2 % foliar N application in a single split either at 90 or 120 DAE could improve wheat productivity under dryland condition.


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