[Objective] The aim was to modify the application amount of N,P and K fertilizer so as to provide a reference for establishing balanced fertilization index system of banana.[Method]The N,P and K fertilizer "3414" te...[Objective] The aim was to modify the application amount of N,P and K fertilizer so as to provide a reference for establishing balanced fertilization index system of banana.[Method]The N,P and K fertilizer "3414" test was carried out on banana,and then regression analysis was performed on the fertilizer effect.Ternary quadratic,binary quadric and one-variable quadratic regression equations for the fertilizer effect on the banana yield were constructed.[Result]Suitable amount of N,P and K fertilizer had significant yield improving effect,whereas overdose of fertilizer application led to decreasing of utilization rate of fertilizer.Therefore,suitable amount of N,P and K fertilizer should be selected in production.It could be concluded that one-variable quadratic regression equations was the best model to calculate the suitable fertilizer amount.The best yield range of banana in the tested field was 44.193-45.904 t/hm2,while the corresponding optimum application amount of N,P2O5 and K2O was 795.1,262.3 and 1 236.9 kg/hm2 respectively,and the ratio among nitrogen,phosphorus and potassium are 1∶0.33∶1.55.[Conclusion]The result in this study could provide references for the soil types similar to the tested field.展开更多
The aim of the study is to investigate the absorption laws of nitrogen, phosphorus, and potassium, and proper nitrogen application in Chuanxiangyou 9838 under no-tillage cultivation. Five nitrogen application treatmen...The aim of the study is to investigate the absorption laws of nitrogen, phosphorus, and potassium, and proper nitrogen application in Chuanxiangyou 9838 under no-tillage cultivation. Five nitrogen application treatments were designed to analyze the absorption laws of N, P and K, and to discuss the effects of different N fertilizer application amounts on yield and yield composition factors of Chuanxiangyou 9838. The results showed that gross nutrient absorption in Chuanxiangyou 9838 was greatly varied at different developmental stages under rice-rape rotation with no-tillage. The maximum N absorption in Chuanxiangyou 9838 appeared at jointing stage followed by heading stage, thirdly the tillefing stage ; the P absorption in Chuanxiangyou 9838 presented the consecutively slight increase during seedling stage and mature stage ; the K absorption in Chuanxiangyou 9838 was mainly conducted from jointing stage to heading stage, during which K absorption accounts for 73.4% of the total absorption in whole developmental stage. Consequently, N fertilizer should be applied earlier ( before jointing stage), P fertilizer is suitable as base fertilizer and application of K fertilizer should be preferably conducted at early-middle period. When the yield reached 11 t/hm^2, the optimal N application amount in Chuanxiangyou 9838 was about 165 kg/hm^2.展开更多
The success of the Green Revolution largely relies on fertilizers, and a new Green Revolution is very much needed to use fertilizers more economically and efficiently, as well as with more environmental responsibility...The success of the Green Revolution largely relies on fertilizers, and a new Green Revolution is very much needed to use fertilizers more economically and efficiently, as well as with more environmental responsibility. The use efficiency of nitrogen, phosphorus, and potassium is controlled by complex gene networks that co-ordinate uptake, re-distribution, assimilation, and storage of these nutrients. Great progress has been made in breeding nutrient-efficient crops by molecularly engineering root traits desirable for efficient acquisition of nutrients from soil, transporters for uptake, redistribution and homeostasis of nutrients, and enzymes for efficient assimilation. Regulatory and transcription factors modulating these processes are also valuable in breeding crops with improved nutrient use efficiency and yield performance.展开更多
The brown planthopper(BPH),Nilaparvata lugens(St?l),appeared as a devastating pest of rice in Asia. Experiments were conducted to study the effects of three nutrients,nitrogen(N),phosphorus(P) and potassium(K),on BPH ...The brown planthopper(BPH),Nilaparvata lugens(St?l),appeared as a devastating pest of rice in Asia. Experiments were conducted to study the effects of three nutrients,nitrogen(N),phosphorus(P) and potassium(K),on BPH and its host rice plants. Biochemical constituents of BPH and rice plants with varying nutrient levels at different growth stages,and changes in relative water content(RWC) of rice plants were determined in the laboratory. Feeding of BPH and the tolerance of rice plants to BPH with different nutrient levels were determined in the nethouse. Concentrations of N and P were found much higher in the BPH body than in its host rice plants,and this elemental mismatch is an inherent constraint on meeting nutritional requirements of BPH. Nitrogen was found as a more limiting element for BPH than other nutrients in rice plants. Application of N fertilizers to the rice plants increased the N concentrations both in rice plants and BPH while application of P and K fertilizers increased their concentrations in plant tissues only but not in BPH. Nitrogen application also increased the level of soluble proteins and decreased silicon content in rice plants,which resulted in increased feeding of BPH with sharp reduction of RWC in rice plants ultimately caused susceptible to the pest. P fertilization increased the concentration of P in rice plant tissues but not changed N,K,Si,free sugar and soluble protein contents,which indicated little importance of P to the feeding of BPH and tolerance of plant against BPH. K fertilization increased K content but reduced N,Si,free sugar and soluble protein contents in the plant tissues which resulted in the minimum reduction of RWC in rice plants after BPH feeding,thereby contributed to higher tolerance of rice plants to brown planthopper.展开更多
[Objective] To study the effects of Zinc on the yield,nitrogen/phosphorus/potassium/Zinc uptake and distribution of different genotypes of maize.[Method] Using two different genotypes of maize as materials,the effects...[Objective] To study the effects of Zinc on the yield,nitrogen/phosphorus/potassium/Zinc uptake and distribution of different genotypes of maize.[Method] Using two different genotypes of maize as materials,the effects of Zn on the yield,N/P/K /Zn uptake and distribution of different genotypes of maize were studied by pot cultivation.[Result] Appropriate Zn supply could improve the grain number per kernel.The Zn content in different organs of maize showed little difference under low Zn treatment (Zn0,Zn1).With the increase of Zn supply,Zn content in leaf,stem and sheath rapidly increased,but the increasing amplitude of Zn content in the kernel and bract were less.The excessive Zn in maize was mainly translocated in lower organs to reduce the damage of them to plants.Different Zn supply levels had less effects on the absorption and translocation of N,P and K in low-Zn insensitive variety Mudan 9.While the absorption and translation of N,P,K in low Zn sensitive variety (Sidan 19) was more easily influenced by the amount of Zn supplied.[Conclusion] Appropriate Zn supply could enhance the maize yield and utilization rate of N and K,and reduce the absorption and utilization of P.展开更多
The studies show that in the whole community, P is deficient, and N and K are basically balanced. N, P and K are accumulated in plant tissues and litters, but depleted in soil. N and P contents in surface soil(0—20 ...The studies show that in the whole community, P is deficient, and N and K are basically balanced. N, P and K are accumulated in plant tissues and litters, but depleted in soil. N and P contents in surface soil(0—20 cm) are the main factors affecting crop growth, and P contents in 20 80 cm soil layer is the major affecting Paulownia elongata growth. The absorption coefficients of N, P and K in the communities are 0 078, 0 014 and 0 052 respectively, their utilization coefficients are 0 95, 0 90 and 0 94, and the recycling coefficients are 0 042, 0 05 and 0 063 respectively.展开更多
Microalgal lipids are regarded as main future feedstock of biofuels for its higher efficiency of accumulation and sus- tainable production. In order to investigate the effect of various nitrogen to phosphorus ratios o...Microalgal lipids are regarded as main future feedstock of biofuels for its higher efficiency of accumulation and sus- tainable production. In order to investigate the effect of various nitrogen to phosphorus ratios on cells growth, chlorophyll content and accumulation of lipids in Dunaliella tertiolecta, experiments were carried out in modified microalgal medium with inorganic nitrogen (nitrate-nitrogen) or organic nitrogen (urea-nitrogen) as the sole nitrogen source at initial N:P ratios ranging from 1:1 to 32:1. The favorable N:P of 16:1 in the nitrate-N or urea-N medium yielded the maximum cell density and specific growth rate. Decrease in chlorophyll content were observed at the N:P of 4:1 in both nitrate-N and urea-N cultures. It was also observed that the maximum lipids concentration was obtained at the N:P of 4:1 in both nitrate and urea nutrient medium. The lipid productivity and lipid content of cultures in the urea-N medium at the N:P of 4: lwere markedly higher than those from cultures with other N:P ratios (p〈 0.05). The results of this work illustrate the possibility that higher ratios of nitrogen to phosphorus have enhancing effect on cells growth of D. tertiolecta. Conversely, higher lipid accumulation is associated with a decrease in chlorophyll content under lower ratios of nitro- gen to phosphorus. The results confirm the hypothesis of this study that a larger metabolic flux has been channeled to lipid accumu- lation in D. tertiolecta cells when the ratios of nitrogen to phosphorus drop below a critical level.展开更多
[Objectives]This study was conducted to explore the rational formula for rice fertilization in Jianghan Plain.[Methods]An experiment on the combined application of nitrogen,phosphorus and potassium fertilizers was car...[Objectives]This study was conducted to explore the rational formula for rice fertilization in Jianghan Plain.[Methods]An experiment on the combined application of nitrogen,phosphorus and potassium fertilizers was carried out in Jianghan Plain,an important rice producing area in Hubei,with a total of five treatments to study the effects of nitrogen,phosphorus and potassium fertilizers on the fertilizer use efficiency and yield of rice.[Results]Fertilization had a significant effect on improving rice yield,and nitrogen fertilizer had the greatest effect on rice yield,followed by potassium fertilizer and phosphorous fertilizer.[Conclusions]This study provides a scientific basis for the application of rice fertilizers and the reduction and efficiency improvement of chemical fertilizers in Jianghan Plain.展开更多
To study the accumulation regularity of nitrogen and phosphorus in typical constructive plants in coastal wetland,samples of Suaeda glauca(Bunge) Bunge,Phragmites austrahs and Tamarix chinensis Lour,were taken from th...To study the accumulation regularity of nitrogen and phosphorus in typical constructive plants in coastal wetland,samples of Suaeda glauca(Bunge) Bunge,Phragmites austrahs and Tamarix chinensis Lour,were taken from the Yellow River Delta National Coast Wetland Nature Reserve,nitrogen and phosphorus content in plants was measured and analyzed.The results showed that ① nitrogen and phosphorus content in different wetland plants is correlated;② different species in the same place and the same species in different spaces show different accumulation regularity of nitrogen and phosphorus;③ nitrogen and phosphorus content in plants is closely related to nitrogen and phosphorus content in the habitat;④ nitrogen content in T.chinensis Lour,is the highest,the mean is 11.63 g/kg,and phosphorus content in S glauca(Bunge) Bunge is the highest,the mean is 1.38 g/kg;⑤ nitrogen content in the 3 species:T.chinensis Lour.> S.glauca(Bunge) Bunge > P.australis;⑥ nitrogen content in aboveground parts of all plants is significantly higher than that in underground parts,and phosphorus content in aboveground parts of all plants except S.glauca(Bunge) Bunge is significantly higher than that in underground parts;⑦ nitrogen content in the 3 species in the study area is significantly higher than phosphorus content in these species.展开更多
A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter (A^2/O-BAF) combined system was carded out to treat wastewater with lower C/N and C/P ratios. The A^2/O process was operated in a short aerobi...A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter (A^2/O-BAF) combined system was carded out to treat wastewater with lower C/N and C/P ratios. The A^2/O process was operated in a short aerobic sludge retention time (SRT) for organic pollutants and phosphorus removal, and denitrification. The subsequent BAF process was mainly used for nitrification. The BAF effluent was partially returned to anoxic zone of the A^2/O process to provide electron acceptors for denitrification and anoxic P uptake. This unique system formed an environment for reproducing the denitdfying phosphate-accumulating organisms (DPAOs). The ratio of DPAOs to phosphorus accumulating organisms (PAOs) could be maintained at 28% by optimizing the organic loads in the anaerobic zone and the nitrate loads into the anoxic zone in the A^2/O process. The aerobic phosphorus over-uptake and discharge of excess activated sludge was the main mechanism of phosphorus removal in the combined system. The aerobic SRT of the A^2/O process should meet the demands for the development of aerobic PAOs and the restraint on the nitrifiers growth, and the contact time in the aerobic zone of the A^2/O process should be longer than 30 min, which ensured efficient phosphorus removal in the combined system. The adequate BAF effluent return rates should be controlled with 1--4 mg/L nitrate nitrogen in the anoxic zone effluent of A^2/O process to achieve the optimal nitrogen and phosphorus removal efficiencies.展开更多
Constructed wetlands with Cyperus altrnlifolius,Pennisetum sinese Roxb and elephant grass as vegetation were built to study the nitrogen and phosphorous removal from domestic sewage in cold climate.It was found that t...Constructed wetlands with Cyperus altrnlifolius,Pennisetum sinese Roxb and elephant grass as vegetation were built to study the nitrogen and phosphorous removal from domestic sewage in cold climate.It was found that these three plants could all grow slowly and stably under low temperature stress in winter,and the biomass,nitrogen and phosphorus absorption characteristics and absorbing capacity of the three plants were different.The growth rate and biomass were as follows:P.sinese Roxb>elephant grass>C.altrnlifolius,and these three plants could be used as winter wetland decontamination plants in Southwest China;the absorption characteristics of nitrogen and phosphorus in different tissues of the three plants were as follows:nitrogen content in leaf>nitrogen content in stem,phosphorus content in stem>phosphorus content in leaf;the removal of total nitrogen(TN)by three plants in the wetland was ranged form 4.3%to 7.8%,and the removal of total phosphorus(TP)was ranged from 3.3%to 5.3%.Different plants had different absorption effects on nitrogen and phosphorus.There was a significantly positive correlation between plant nitrogen and phosphorus accumulation and biomass,and nitrogen removal rate in wetland showed a significantly positive correlation with biomass.展开更多
Different ratios of NPK were adopted in this research to study its effects on the objective traits of 2 early forage-rice varieties, and to obtain the optimum ratio to further improve the application technique in theo...Different ratios of NPK were adopted in this research to study its effects on the objective traits of 2 early forage-rice varieties, and to obtain the optimum ratio to further improve the application technique in theory. At the same time, the possibility of increasing yield and protein content in the grain through cultivation technique was also studied. The conclusions were:展开更多
Nutritional characteristics determine tree stock quality to a considerable extent. Exponential fertilization can induce nutrient reserves within juvenile trees, but its validity on poplar is contingent on interaction ...Nutritional characteristics determine tree stock quality to a considerable extent. Exponential fertilization can induce nutrient reserves within juvenile trees, but its validity on poplar is contingent on interaction with a scientific irrigation regime due to limited water resources under global warming. In the present study, we raised 3200 Populus 9 euramericana cv. '74/76' cuttings under four irrigation regimes of 0(I0), 60 %(I60), 80 %(I80), and100 %(I100) of field capacity for soil moisture content with or without(control) the employment of nitrogen(N) addition delivered as exponential fertilization at the rate of 8 g N cutting^(-1)(E8) in an open-air nursery in Beijing, China. Both height and diameter increased with the increment of soil moisture ratio or in response to exponential fertilization(EF) without any interactive effects. In general, concentrations of N, phosphorus(P),and potassium(K) declined with time in stem but foliar N concentration did not change. Under the I100 regime, EF increased foliar N concentration relative to the control but failed to affect N concentration in stem in September, when both N concentration and N content were increased by EF under the I80 regime. Stem-K content and concentration by EF under the I80 regime also increased in September,therefore EF-treated cuttings had a higher ratio of K content in stem to that in whole plant(%ANAR). Vector diagnosis for nutritional status indicated that EF resulted in dilution of K concentration but induced a steady-state P uptake in leaves under all irrigation regimes. Therefore, EF of N addition could promote N uptake to leaves of P. 9 euramericana cv. '74/76' cuttings, but it had a null effect on N and P reserves in stem and impaired K reserves.In conclusion, the irrigation regime of 80 % field capacity of soil moisture content was suggested for the culture of juvenile P. 9 euramericana cv. '74/76' cuttings. As the interactive meaning, EF was also suggested for its excellent promotion on both N and K uptakes.展开更多
In order to generate scientifically-based comparative information to improve fertilization efficiency and reduce nutrient loss, 610 samples of 122 soil profiles were collected at the 0–60 cm depth to compare soil nut...In order to generate scientifically-based comparative information to improve fertilization efficiency and reduce nutrient loss, 610 samples of 122 soil profiles were collected at the 0–60 cm depth to compare soil nutrient contents including soil organic matter(SOM), total nitrogen(TN), total phosphorus(TP), available phosphorus(AP), and available potassium(AK) among different slope positions in a Mollisol farmland area of Northeast China. The contents of SOM and TN typically decreased with increased soil depth at back and bottom slope. Soil loss and deposition tended to decrease SOM and TN at the 0–20 cm soil depth on both the back slope and the slope bottom. The TP firstly decreased from 0–20 cm to 30–40 cm, and then not constantly increased at the back slope and the bottom slope. Due to the characteristics of soil nutrients and crop absorption, the contents of both AP and AK were typically the highest at the summit, followed by the slope bottom and the back slope in the 0–20 cm layer. Generally, in order to sustain the high soil productivity and protect the environment, attention should be paid to soil conservation on back slope; in addition, additional N and P fertilizer is necessary on the back slope.展开更多
Nutrient addition can affect the structure and diversity of grassland plant communities, thus alter the grassland productivity. Studies on grassland plant community composition, structure and diversity in response to ...Nutrient addition can affect the structure and diversity of grassland plant communities, thus alter the grassland productivity. Studies on grassland plant community composition, structure and diversity in response to nutrient addition have an important theoretical and practical significance for the scientific management of grassland, protection of plant diversity and the recovery of degraded grassland. A randomized block design experiment was conducted with six blocks of eight treatments each: control(no nutrient addition) and K, P, N, PK, NK, NP, and NPK addition. We evaluated plant composition, height, coverage, density, and aboveground biomass to estimate primary productivity and plant diversity. Results showed that all treatments increased primary productivity significantly(P〈0.05) with the exception of the K and the NPK treatments had the greatest effect, increasing aboveground biomass 2.46 times compared with the control(P〈0.05). One-way ANOVA and factorial analysis were used for the species richness, Shannon-Wiener index, Pielou index and aboveground biomass, and the relationships between the diversity indices and aboveground biomass were determined through linear regression. We found that fertilization altered the community structure; N(but not P or K) addition increased the proportion of perennial rhizome grasses and significantly reduced that of perennial forbs(P〈0.05), thus it presented a trend of decrease in species richness, Shannon-Wiener and Pielou indexex, respectively. Only the main effects of N had significant impacts on both the diversity indices and the aboveground biomass(P〈0.05), and the interactions between N-P, N-K, P-K and N-P-K could be neglected. With fertilization, plant diversity(correlation coefficient, –0.61), species richness(–0.49), and species evenness(–0.51) were all negatively linearly correlated with primary productivity. The correlations were all significant(P〈0.01). Scientific nutrient management is an effective way to improve grassland productivity, protect the plant diversity as well as recover the degraded grassland.展开更多
The study of floral diversity in forest and its development are incomplete without taking consideration of plant-soil interactions. So with this view in mind, the present study was conducted in tropical semi-evergreen...The study of floral diversity in forest and its development are incomplete without taking consideration of plant-soil interactions. So with this view in mind, the present study was conducted in tropical semi-evergreen forests of the Mokukchung district, Nagaland, in eastern Himalaya. The aim of the study was to investigate the phytosociological parameters Seven sites were randomly in relation to soil properties. selected to study the soil properties at up to one meter in depth and a phytosociological study was carried out in nearby areas via the quadrate method. In the studied sites, the richness of tree species varied from 4 to 15 ha^-1, with Gmelina arborea and Duabanga grandifloras being the common species. The highest total basal area was recorded in 10 mile village (47,998.16 cm^2 ha^-1) followed by Minkong village site (32,704.66 cm^2 ha^-1). Soil physical and chemical properties-i.e, bulk density (BD), soil pH, organic carbon (OC), available nitrogen (N), available phosphorus (P), and available potassium (K) were analyzed using standard procedures. Significant differences were observed in the soil properties. The basal area of species showed significant positive correlation in terms of available K (0.754) and OM (0.302) content in soil, and the Shannon-Wiener diversity index (H) is also positively correlated with the available N content (0.402). The undisturbed nature of the sites played an important role in maintaining the soil fertility and floral diversity of the sites. Moreover, sites with maximum productivity and soil fertility are considered as potential carbon sequestration areas in the region while sites with the low soil fertility need restoration.展开更多
Forest recovery may be influenced by several factors, of which fire is the most critical.However, moderate-and long-term effects of fire on forest recovery are less researched in Northwest China.Thus, the effects of d...Forest recovery may be influenced by several factors, of which fire is the most critical.However, moderate-and long-term effects of fire on forest recovery are less researched in Northwest China.Thus, the effects of different forest recovery time after fire(1917(served as the control), 1974, 1983 and 1995) and fire severities(low, moderate and high) on larch(Larix sibirica Ledeb.) forest were investigated in the Kanas National Nature Reserve(KNNR), Northwest China in 2017.This paper analyzed post-fire changes in stand density, total basal area(TBA), litter mass, soil organic carbon(SOC) and soil nutrients(total nitrogen, total phosphorus and total potassium) with one-way analyses of variance.Results indicate that litter mass, TBA, SOC and soil nutrients increased with increasing recovery time after fire and decreasing fire severity, while the stand density showed an opposite response.The effects of fire disturbance on SOC and soil nutrients decreased with increasing soil depth.Moreover, we found that the time of more than 43 a is needed to recover the litter mass, TBA, SOC and soil nutrients to the pre-fire level.In conclusion, high-severity fire caused the greatest variations in stand structure and soil of larch forest, and low-severity fire was more advantageous for post-fire forest stand structure and soil recovery in the KNNR.Therefore, low-severity fire can be an efficient management mean through reducing the accumulation of forest floor fuel of post-fire forests in the KNNR, Northwest China.展开更多
In order to reveal the impact of various fertilization strategies on carbon(C) and nitrogen(N) accumulation and allocation in corn(Zea mays L.), corn was grown in the fields where continuous fertilization manage...In order to reveal the impact of various fertilization strategies on carbon(C) and nitrogen(N) accumulation and allocation in corn(Zea mays L.), corn was grown in the fields where continuous fertilization management had been lasted about 18 years at two sites located in Central and Northeast China(Zhengzhou and Gongzhuling), and biomass C and N contents in different organs of corn at harvest were analyzed. The fertilization treatments included non-fertilizer(control), chemical fertilizers of either nitrogen(N), or nitrogen and phosphorus(NP), or phosphorus and potassium(PK), or nitrogen, phosphorus and potassium(NPK), NPK plus manure(NPKM), 150% of the NPKM(1.5NPKM), and NPK plus straw(NPKS). The results showed that accumulated C in aboveground ranged from 2 550–5 630 kg ha^–1 in the control treatment to 9 300–9 610 kg ha^–1 in the NPKM treatment, of which 57–67% and 43–50% were allocated in the non-grain organs, respectively. Accumulated N in aboveground ranged from 44.8–55.2 kg ha^-1 in the control treatment to 211–222 kg ha^–1 in the NPKM treatment, of which 35–48% and 33–44% were allocated in the non-grain parts, respectively. C allocated to stem and leaf for the PK treatment was 65 and 49% higher than that for the NPKM treatment at the both sites, respectively, while N allocated to the organs for the PK treatment was 18 and 6% higher than that for the NPKM treatment, respectively. This study demonstrated that responses of C and N allocation in corn to fertilization strategies were different, and C allocation was more sensitive to fertilization treatments than N allocation in the area.展开更多
The knowledge of the nutritional requirements and their relation to the physiology of marine algae growth is key to incorporate new species into aquaculture, whose dynamics tend to be largely unknown. The use of <i...The knowledge of the nutritional requirements and their relation to the physiology of marine algae growth is key to incorporate new species into aquaculture, whose dynamics tend to be largely unknown. The use of <i><span style="font-family:Verdana;">Alsidium triquetrum</span></i><span style="font-family:Verdana;"> in the pharmacological industry depends on its availability in the </span><span style="font-family:Verdana;">natural environment, occasionally scarce. As macroalgae cultivation gains</span><span style="font-family:Verdana;"> momentum worldwide, it is important to know how the effects of nutrients are modulated in the thallus during cultivation. The linking of the relative growth rates (RGR) of </span><i><span style="font-family:Verdana;">A. triquetrum</span></i><span style="font-family:Verdana;"> and their relation with the macronutrients N (nitrogen), P (phosphorus) and K (potassium) at the tissue level under culture conditions constitutes the main contribution of this article. P levels tend to decrease as the plant completes its development. Both the concentration of N and P are higher in the stipe for the month of July, N (25.31 ± 0.26) vs P (0.846 ± 0.02) period when the highest vegetative development is reached. The N and P modulate the patterns of the species’ development over the an</span><span style="font-family:Verdana;">nual cycle, unlike K, which is not considered a limiting factor. When the</span><span style="font-family:Verdana;"> tem</span><span style="font-family:Verdana;">perature and lighting are not favorable for growth, the plant simply accu</span><span style="font-family:Verdana;">mulates these compounds. As environmental conditions change, these </span><span style="font-family:Verdana;">stored</span><span style="font-family:Verdana;"> compounds are actively used in their growth. The specimens with an initial weight of 50 g present the best accumulated biomass (RGR) throughout the annual cycle.</span>展开更多
Seed quality is one of the most important factors for stand establishment in cotton (Gossypium Sp.), and the use of good-quality seeds is therefore essential to obtain an optimum plant population. Conditions prevailin...Seed quality is one of the most important factors for stand establishment in cotton (Gossypium Sp.), and the use of good-quality seeds is therefore essential to obtain an optimum plant population. Conditions prevailing during seed formation can affect the quality of seed produced, and hence crop establishment in the next growing season. These conditions can affect the germination of the seeds and the ability of the seedlings to emerge from soil. Field experiments were conducted to investigate the effect of nitrogen (N), phosphorus (P), potassium (K), foliar application of zinc (Zn) and calcium (Ca), and the use of plant growth retardants (PGR) [e.g., 1, 1-dimethyl piperidinium chloride (MC);2-chloroethyl trimethyl ammonium chloride (CC);or succinic acid 2, 2-dimethyl hydrazide (SADH)], during square initiation and boll setting stage, on growth, seed yield, seed viability, and seedling vigor of Egyptian cotton (G. barbadense). Dry matter yield, total chlorophyll concentration, K, Zn and P-uptake plant-1, were increased with the addition of K, foliar application of Zn, and different concentrations of P (576-1728 g·ha-1 of P). Seed yield plant-1 and plot-1, seed weight, seed viability, seedling vigor, and cool germination test performance increased as a result of the addition of the high N-rate (142.8 kg·ha-1 N), the high P-rate (74 kg·ha-1 P2O5), K (47 kg·ha-1 K), and from application of Zn, and Ca and the PGR. From the findings of the present study, band application of such treatments showed improved cotton-seed yield and affected the quality of seed produced, and hence crop establishment in the next growing season.展开更多
基金Supported by National Science and Technology Support Program(2007BAD89B14)Science and Technology Project of Guangdong Province(2009B020201011)~~
文摘[Objective] The aim was to modify the application amount of N,P and K fertilizer so as to provide a reference for establishing balanced fertilization index system of banana.[Method]The N,P and K fertilizer "3414" test was carried out on banana,and then regression analysis was performed on the fertilizer effect.Ternary quadratic,binary quadric and one-variable quadratic regression equations for the fertilizer effect on the banana yield were constructed.[Result]Suitable amount of N,P and K fertilizer had significant yield improving effect,whereas overdose of fertilizer application led to decreasing of utilization rate of fertilizer.Therefore,suitable amount of N,P and K fertilizer should be selected in production.It could be concluded that one-variable quadratic regression equations was the best model to calculate the suitable fertilizer amount.The best yield range of banana in the tested field was 44.193-45.904 t/hm2,while the corresponding optimum application amount of N,P2O5 and K2O was 795.1,262.3 and 1 236.9 kg/hm2 respectively,and the ratio among nitrogen,phosphorus and potassium are 1∶0.33∶1.55.[Conclusion]The result in this study could provide references for the soil types similar to the tested field.
基金Project of Scientific and Technical Supporting Programs (2006AD05B06)Key Technologies Research and Development Program of Sichuan Province during the 10th Five-year Plan During the 11th Five-year Plan(2006YZGG-28)the project from International Plant Nutrition Institute (IPNI)~~
文摘The aim of the study is to investigate the absorption laws of nitrogen, phosphorus, and potassium, and proper nitrogen application in Chuanxiangyou 9838 under no-tillage cultivation. Five nitrogen application treatments were designed to analyze the absorption laws of N, P and K, and to discuss the effects of different N fertilizer application amounts on yield and yield composition factors of Chuanxiangyou 9838. The results showed that gross nutrient absorption in Chuanxiangyou 9838 was greatly varied at different developmental stages under rice-rape rotation with no-tillage. The maximum N absorption in Chuanxiangyou 9838 appeared at jointing stage followed by heading stage, thirdly the tillefing stage ; the P absorption in Chuanxiangyou 9838 presented the consecutively slight increase during seedling stage and mature stage ; the K absorption in Chuanxiangyou 9838 was mainly conducted from jointing stage to heading stage, during which K absorption accounts for 73.4% of the total absorption in whole developmental stage. Consequently, N fertilizer should be applied earlier ( before jointing stage), P fertilizer is suitable as base fertilizer and application of K fertilizer should be preferably conducted at early-middle period. When the yield reached 11 t/hm^2, the optimal N application amount in Chuanxiangyou 9838 was about 165 kg/hm^2.
基金supported by the National Key Research and Development Program of China (2016YFD0100706)the National Transgenic Key Project from the Ministry of Agriculture of China (2016ZX08002-005)
文摘The success of the Green Revolution largely relies on fertilizers, and a new Green Revolution is very much needed to use fertilizers more economically and efficiently, as well as with more environmental responsibility. The use efficiency of nitrogen, phosphorus, and potassium is controlled by complex gene networks that co-ordinate uptake, re-distribution, assimilation, and storage of these nutrients. Great progress has been made in breeding nutrient-efficient crops by molecularly engineering root traits desirable for efficient acquisition of nutrients from soil, transporters for uptake, redistribution and homeostasis of nutrients, and enzymes for efficient assimilation. Regulatory and transcription factors modulating these processes are also valuable in breeding crops with improved nutrient use efficiency and yield performance.
文摘The brown planthopper(BPH),Nilaparvata lugens(St?l),appeared as a devastating pest of rice in Asia. Experiments were conducted to study the effects of three nutrients,nitrogen(N),phosphorus(P) and potassium(K),on BPH and its host rice plants. Biochemical constituents of BPH and rice plants with varying nutrient levels at different growth stages,and changes in relative water content(RWC) of rice plants were determined in the laboratory. Feeding of BPH and the tolerance of rice plants to BPH with different nutrient levels were determined in the nethouse. Concentrations of N and P were found much higher in the BPH body than in its host rice plants,and this elemental mismatch is an inherent constraint on meeting nutritional requirements of BPH. Nitrogen was found as a more limiting element for BPH than other nutrients in rice plants. Application of N fertilizers to the rice plants increased the N concentrations both in rice plants and BPH while application of P and K fertilizers increased their concentrations in plant tissues only but not in BPH. Nitrogen application also increased the level of soluble proteins and decreased silicon content in rice plants,which resulted in increased feeding of BPH with sharp reduction of RWC in rice plants ultimately caused susceptible to the pest. P fertilization increased the concentration of P in rice plant tissues but not changed N,K,Si,free sugar and soluble protein contents,which indicated little importance of P to the feeding of BPH and tolerance of plant against BPH. K fertilization increased K content but reduced N,Si,free sugar and soluble protein contents in the plant tissues which resulted in the minimum reduction of RWC in rice plants after BPH feeding,thereby contributed to higher tolerance of rice plants to brown planthopper.
基金Supported by National "11th five-year" Plan Science and Technolo-gy Support Project (2006BAD02A11)"11th five-year plan" of Tackling Key Problems Projects of Heilongjiang Province(GA07B101)~~
文摘[Objective] To study the effects of Zinc on the yield,nitrogen/phosphorus/potassium/Zinc uptake and distribution of different genotypes of maize.[Method] Using two different genotypes of maize as materials,the effects of Zn on the yield,N/P/K /Zn uptake and distribution of different genotypes of maize were studied by pot cultivation.[Result] Appropriate Zn supply could improve the grain number per kernel.The Zn content in different organs of maize showed little difference under low Zn treatment (Zn0,Zn1).With the increase of Zn supply,Zn content in leaf,stem and sheath rapidly increased,but the increasing amplitude of Zn content in the kernel and bract were less.The excessive Zn in maize was mainly translocated in lower organs to reduce the damage of them to plants.Different Zn supply levels had less effects on the absorption and translocation of N,P and K in low-Zn insensitive variety Mudan 9.While the absorption and translation of N,P,K in low Zn sensitive variety (Sidan 19) was more easily influenced by the amount of Zn supplied.[Conclusion] Appropriate Zn supply could enhance the maize yield and utilization rate of N and K,and reduce the absorption and utilization of P.
文摘The studies show that in the whole community, P is deficient, and N and K are basically balanced. N, P and K are accumulated in plant tissues and litters, but depleted in soil. N and P contents in surface soil(0—20 cm) are the main factors affecting crop growth, and P contents in 20 80 cm soil layer is the major affecting Paulownia elongata growth. The absorption coefficients of N, P and K in the communities are 0 078, 0 014 and 0 052 respectively, their utilization coefficients are 0 95, 0 90 and 0 94, and the recycling coefficients are 0 042, 0 05 and 0 063 respectively.
基金partially supported by Tianjin Marine Revitalization Plan of Science and Technology (No.KJXH2013-16) from Tianjin Oceanic Administration,China
文摘Microalgal lipids are regarded as main future feedstock of biofuels for its higher efficiency of accumulation and sus- tainable production. In order to investigate the effect of various nitrogen to phosphorus ratios on cells growth, chlorophyll content and accumulation of lipids in Dunaliella tertiolecta, experiments were carried out in modified microalgal medium with inorganic nitrogen (nitrate-nitrogen) or organic nitrogen (urea-nitrogen) as the sole nitrogen source at initial N:P ratios ranging from 1:1 to 32:1. The favorable N:P of 16:1 in the nitrate-N or urea-N medium yielded the maximum cell density and specific growth rate. Decrease in chlorophyll content were observed at the N:P of 4:1 in both nitrate-N and urea-N cultures. It was also observed that the maximum lipids concentration was obtained at the N:P of 4:1 in both nitrate and urea nutrient medium. The lipid productivity and lipid content of cultures in the urea-N medium at the N:P of 4: lwere markedly higher than those from cultures with other N:P ratios (p〈 0.05). The results of this work illustrate the possibility that higher ratios of nitrogen to phosphorus have enhancing effect on cells growth of D. tertiolecta. Conversely, higher lipid accumulation is associated with a decrease in chlorophyll content under lower ratios of nitro- gen to phosphorus. The results confirm the hypothesis of this study that a larger metabolic flux has been channeled to lipid accumu- lation in D. tertiolecta cells when the ratios of nitrogen to phosphorus drop below a critical level.
文摘[Objectives]This study was conducted to explore the rational formula for rice fertilization in Jianghan Plain.[Methods]An experiment on the combined application of nitrogen,phosphorus and potassium fertilizers was carried out in Jianghan Plain,an important rice producing area in Hubei,with a total of five treatments to study the effects of nitrogen,phosphorus and potassium fertilizers on the fertilizer use efficiency and yield of rice.[Results]Fertilization had a significant effect on improving rice yield,and nitrogen fertilizer had the greatest effect on rice yield,followed by potassium fertilizer and phosphorous fertilizer.[Conclusions]This study provides a scientific basis for the application of rice fertilizers and the reduction and efficiency improvement of chemical fertilizers in Jianghan Plain.
基金Sponsored by 2015 Safety Production and Major Accident Prevention Program of State Administration of Work Safety(shandong-0017-2015AQ)
文摘To study the accumulation regularity of nitrogen and phosphorus in typical constructive plants in coastal wetland,samples of Suaeda glauca(Bunge) Bunge,Phragmites austrahs and Tamarix chinensis Lour,were taken from the Yellow River Delta National Coast Wetland Nature Reserve,nitrogen and phosphorus content in plants was measured and analyzed.The results showed that ① nitrogen and phosphorus content in different wetland plants is correlated;② different species in the same place and the same species in different spaces show different accumulation regularity of nitrogen and phosphorus;③ nitrogen and phosphorus content in plants is closely related to nitrogen and phosphorus content in the habitat;④ nitrogen content in T.chinensis Lour,is the highest,the mean is 11.63 g/kg,and phosphorus content in S glauca(Bunge) Bunge is the highest,the mean is 1.38 g/kg;⑤ nitrogen content in the 3 species:T.chinensis Lour.> S.glauca(Bunge) Bunge > P.australis;⑥ nitrogen content in aboveground parts of all plants is significantly higher than that in underground parts,and phosphorus content in aboveground parts of all plants except S.glauca(Bunge) Bunge is significantly higher than that in underground parts;⑦ nitrogen content in the 3 species in the study area is significantly higher than phosphorus content in these species.
文摘A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter (A^2/O-BAF) combined system was carded out to treat wastewater with lower C/N and C/P ratios. The A^2/O process was operated in a short aerobic sludge retention time (SRT) for organic pollutants and phosphorus removal, and denitrification. The subsequent BAF process was mainly used for nitrification. The BAF effluent was partially returned to anoxic zone of the A^2/O process to provide electron acceptors for denitrification and anoxic P uptake. This unique system formed an environment for reproducing the denitdfying phosphate-accumulating organisms (DPAOs). The ratio of DPAOs to phosphorus accumulating organisms (PAOs) could be maintained at 28% by optimizing the organic loads in the anaerobic zone and the nitrate loads into the anoxic zone in the A^2/O process. The aerobic phosphorus over-uptake and discharge of excess activated sludge was the main mechanism of phosphorus removal in the combined system. The aerobic SRT of the A^2/O process should meet the demands for the development of aerobic PAOs and the restraint on the nitrifiers growth, and the contact time in the aerobic zone of the A^2/O process should be longer than 30 min, which ensured efficient phosphorus removal in the combined system. The adequate BAF effluent return rates should be controlled with 1--4 mg/L nitrate nitrogen in the anoxic zone effluent of A^2/O process to achieve the optimal nitrogen and phosphorus removal efficiencies.
基金Supported by Guizhou Tripartite Joint Fund(Qiankehe LH[2016]7283)Top Talent Project of Guizhou Province(Qianjiaohe KY[2016]097)Doctoral Research Start up Fund of Anshun University[(asubsjj 2016)07].
文摘Constructed wetlands with Cyperus altrnlifolius,Pennisetum sinese Roxb and elephant grass as vegetation were built to study the nitrogen and phosphorous removal from domestic sewage in cold climate.It was found that these three plants could all grow slowly and stably under low temperature stress in winter,and the biomass,nitrogen and phosphorus absorption characteristics and absorbing capacity of the three plants were different.The growth rate and biomass were as follows:P.sinese Roxb>elephant grass>C.altrnlifolius,and these three plants could be used as winter wetland decontamination plants in Southwest China;the absorption characteristics of nitrogen and phosphorus in different tissues of the three plants were as follows:nitrogen content in leaf>nitrogen content in stem,phosphorus content in stem>phosphorus content in leaf;the removal of total nitrogen(TN)by three plants in the wetland was ranged form 4.3%to 7.8%,and the removal of total phosphorus(TP)was ranged from 3.3%to 5.3%.Different plants had different absorption effects on nitrogen and phosphorus.There was a significantly positive correlation between plant nitrogen and phosphorus accumulation and biomass,and nitrogen removal rate in wetland showed a significantly positive correlation with biomass.
文摘Different ratios of NPK were adopted in this research to study its effects on the objective traits of 2 early forage-rice varieties, and to obtain the optimum ratio to further improve the application technique in theory. At the same time, the possibility of increasing yield and protein content in the grain through cultivation technique was also studied. The conclusions were:
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education(20120014130001)the Eleventh Five-Year Plan Projects of National Science and Technology(Grant No.2006BAD24B01)
文摘Nutritional characteristics determine tree stock quality to a considerable extent. Exponential fertilization can induce nutrient reserves within juvenile trees, but its validity on poplar is contingent on interaction with a scientific irrigation regime due to limited water resources under global warming. In the present study, we raised 3200 Populus 9 euramericana cv. '74/76' cuttings under four irrigation regimes of 0(I0), 60 %(I60), 80 %(I80), and100 %(I100) of field capacity for soil moisture content with or without(control) the employment of nitrogen(N) addition delivered as exponential fertilization at the rate of 8 g N cutting^(-1)(E8) in an open-air nursery in Beijing, China. Both height and diameter increased with the increment of soil moisture ratio or in response to exponential fertilization(EF) without any interactive effects. In general, concentrations of N, phosphorus(P),and potassium(K) declined with time in stem but foliar N concentration did not change. Under the I100 regime, EF increased foliar N concentration relative to the control but failed to affect N concentration in stem in September, when both N concentration and N content were increased by EF under the I80 regime. Stem-K content and concentration by EF under the I80 regime also increased in September,therefore EF-treated cuttings had a higher ratio of K content in stem to that in whole plant(%ANAR). Vector diagnosis for nutritional status indicated that EF resulted in dilution of K concentration but induced a steady-state P uptake in leaves under all irrigation regimes. Therefore, EF of N addition could promote N uptake to leaves of P. 9 euramericana cv. '74/76' cuttings, but it had a null effect on N and P reserves in stem and impaired K reserves.In conclusion, the irrigation regime of 80 % field capacity of soil moisture content was suggested for the culture of juvenile P. 9 euramericana cv. '74/76' cuttings. As the interactive meaning, EF was also suggested for its excellent promotion on both N and K uptakes.
基金Under the auspices of Science and Technology Research Projects of Education Department of Heilongjiang Province,China(No.12521010)
文摘In order to generate scientifically-based comparative information to improve fertilization efficiency and reduce nutrient loss, 610 samples of 122 soil profiles were collected at the 0–60 cm depth to compare soil nutrient contents including soil organic matter(SOM), total nitrogen(TN), total phosphorus(TP), available phosphorus(AP), and available potassium(AK) among different slope positions in a Mollisol farmland area of Northeast China. The contents of SOM and TN typically decreased with increased soil depth at back and bottom slope. Soil loss and deposition tended to decrease SOM and TN at the 0–20 cm soil depth on both the back slope and the slope bottom. The TP firstly decreased from 0–20 cm to 30–40 cm, and then not constantly increased at the back slope and the bottom slope. Due to the characteristics of soil nutrients and crop absorption, the contents of both AP and AK were typically the highest at the summit, followed by the slope bottom and the back slope in the 0–20 cm layer. Generally, in order to sustain the high soil productivity and protect the environment, attention should be paid to soil conservation on back slope; in addition, additional N and P fertilizer is necessary on the back slope.
基金project was supported by the National Natural Science Foundation of China (31170435)the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2012BAD13B07)+1 种基金the Fundamental Research Laboratory of the Central-Level Nonprofit Research Institutes, Chinathe Open Fund of the Key Laboratory of Environmental Quality in the Ministry of Agriculture and Agricultural Environment and Safety of Agricultural Products in Tianjin, China
文摘Nutrient addition can affect the structure and diversity of grassland plant communities, thus alter the grassland productivity. Studies on grassland plant community composition, structure and diversity in response to nutrient addition have an important theoretical and practical significance for the scientific management of grassland, protection of plant diversity and the recovery of degraded grassland. A randomized block design experiment was conducted with six blocks of eight treatments each: control(no nutrient addition) and K, P, N, PK, NK, NP, and NPK addition. We evaluated plant composition, height, coverage, density, and aboveground biomass to estimate primary productivity and plant diversity. Results showed that all treatments increased primary productivity significantly(P〈0.05) with the exception of the K and the NPK treatments had the greatest effect, increasing aboveground biomass 2.46 times compared with the control(P〈0.05). One-way ANOVA and factorial analysis were used for the species richness, Shannon-Wiener index, Pielou index and aboveground biomass, and the relationships between the diversity indices and aboveground biomass were determined through linear regression. We found that fertilization altered the community structure; N(but not P or K) addition increased the proportion of perennial rhizome grasses and significantly reduced that of perennial forbs(P〈0.05), thus it presented a trend of decrease in species richness, Shannon-Wiener and Pielou indexex, respectively. Only the main effects of N had significant impacts on both the diversity indices and the aboveground biomass(P〈0.05), and the interactions between N-P, N-K, P-K and N-P-K could be neglected. With fertilization, plant diversity(correlation coefficient, –0.61), species richness(–0.49), and species evenness(–0.51) were all negatively linearly correlated with primary productivity. The correlations were all significant(P〈0.01). Scientific nutrient management is an effective way to improve grassland productivity, protect the plant diversity as well as recover the degraded grassland.
基金financially supported by the Indian Council of Forestry Research and Education(ICFRE),Dehradun,India
文摘The study of floral diversity in forest and its development are incomplete without taking consideration of plant-soil interactions. So with this view in mind, the present study was conducted in tropical semi-evergreen forests of the Mokukchung district, Nagaland, in eastern Himalaya. The aim of the study was to investigate the phytosociological parameters Seven sites were randomly in relation to soil properties. selected to study the soil properties at up to one meter in depth and a phytosociological study was carried out in nearby areas via the quadrate method. In the studied sites, the richness of tree species varied from 4 to 15 ha^-1, with Gmelina arborea and Duabanga grandifloras being the common species. The highest total basal area was recorded in 10 mile village (47,998.16 cm^2 ha^-1) followed by Minkong village site (32,704.66 cm^2 ha^-1). Soil physical and chemical properties-i.e, bulk density (BD), soil pH, organic carbon (OC), available nitrogen (N), available phosphorus (P), and available potassium (K) were analyzed using standard procedures. Significant differences were observed in the soil properties. The basal area of species showed significant positive correlation in terms of available K (0.754) and OM (0.302) content in soil, and the Shannon-Wiener diversity index (H) is also positively correlated with the available N content (0.402). The undisturbed nature of the sites played an important role in maintaining the soil fertility and floral diversity of the sites. Moreover, sites with maximum productivity and soil fertility are considered as potential carbon sequestration areas in the region while sites with the low soil fertility need restoration.
基金supported by the National Natural Science Foundation of China (31570634)the Project of Xinjiang Agricultural Vocational College (XJNZYKJ201712)
文摘Forest recovery may be influenced by several factors, of which fire is the most critical.However, moderate-and long-term effects of fire on forest recovery are less researched in Northwest China.Thus, the effects of different forest recovery time after fire(1917(served as the control), 1974, 1983 and 1995) and fire severities(low, moderate and high) on larch(Larix sibirica Ledeb.) forest were investigated in the Kanas National Nature Reserve(KNNR), Northwest China in 2017.This paper analyzed post-fire changes in stand density, total basal area(TBA), litter mass, soil organic carbon(SOC) and soil nutrients(total nitrogen, total phosphorus and total potassium) with one-way analyses of variance.Results indicate that litter mass, TBA, SOC and soil nutrients increased with increasing recovery time after fire and decreasing fire severity, while the stand density showed an opposite response.The effects of fire disturbance on SOC and soil nutrients decreased with increasing soil depth.Moreover, we found that the time of more than 43 a is needed to recover the litter mass, TBA, SOC and soil nutrients to the pre-fire level.In conclusion, high-severity fire caused the greatest variations in stand structure and soil of larch forest, and low-severity fire was more advantageous for post-fire forest stand structure and soil recovery in the KNNR.Therefore, low-severity fire can be an efficient management mean through reducing the accumulation of forest floor fuel of post-fire forests in the KNNR, Northwest China.
基金Financial supports from the National Basic Research Program of China(2011CB100501)the National Natural Science Foundation of China(41171239,41371247)are gratefully acknowledged
文摘In order to reveal the impact of various fertilization strategies on carbon(C) and nitrogen(N) accumulation and allocation in corn(Zea mays L.), corn was grown in the fields where continuous fertilization management had been lasted about 18 years at two sites located in Central and Northeast China(Zhengzhou and Gongzhuling), and biomass C and N contents in different organs of corn at harvest were analyzed. The fertilization treatments included non-fertilizer(control), chemical fertilizers of either nitrogen(N), or nitrogen and phosphorus(NP), or phosphorus and potassium(PK), or nitrogen, phosphorus and potassium(NPK), NPK plus manure(NPKM), 150% of the NPKM(1.5NPKM), and NPK plus straw(NPKS). The results showed that accumulated C in aboveground ranged from 2 550–5 630 kg ha^–1 in the control treatment to 9 300–9 610 kg ha^–1 in the NPKM treatment, of which 57–67% and 43–50% were allocated in the non-grain organs, respectively. Accumulated N in aboveground ranged from 44.8–55.2 kg ha^-1 in the control treatment to 211–222 kg ha^–1 in the NPKM treatment, of which 35–48% and 33–44% were allocated in the non-grain parts, respectively. C allocated to stem and leaf for the PK treatment was 65 and 49% higher than that for the NPKM treatment at the both sites, respectively, while N allocated to the organs for the PK treatment was 18 and 6% higher than that for the NPKM treatment, respectively. This study demonstrated that responses of C and N allocation in corn to fertilization strategies were different, and C allocation was more sensitive to fertilization treatments than N allocation in the area.
文摘The knowledge of the nutritional requirements and their relation to the physiology of marine algae growth is key to incorporate new species into aquaculture, whose dynamics tend to be largely unknown. The use of <i><span style="font-family:Verdana;">Alsidium triquetrum</span></i><span style="font-family:Verdana;"> in the pharmacological industry depends on its availability in the </span><span style="font-family:Verdana;">natural environment, occasionally scarce. As macroalgae cultivation gains</span><span style="font-family:Verdana;"> momentum worldwide, it is important to know how the effects of nutrients are modulated in the thallus during cultivation. The linking of the relative growth rates (RGR) of </span><i><span style="font-family:Verdana;">A. triquetrum</span></i><span style="font-family:Verdana;"> and their relation with the macronutrients N (nitrogen), P (phosphorus) and K (potassium) at the tissue level under culture conditions constitutes the main contribution of this article. P levels tend to decrease as the plant completes its development. Both the concentration of N and P are higher in the stipe for the month of July, N (25.31 ± 0.26) vs P (0.846 ± 0.02) period when the highest vegetative development is reached. The N and P modulate the patterns of the species’ development over the an</span><span style="font-family:Verdana;">nual cycle, unlike K, which is not considered a limiting factor. When the</span><span style="font-family:Verdana;"> tem</span><span style="font-family:Verdana;">perature and lighting are not favorable for growth, the plant simply accu</span><span style="font-family:Verdana;">mulates these compounds. As environmental conditions change, these </span><span style="font-family:Verdana;">stored</span><span style="font-family:Verdana;"> compounds are actively used in their growth. The specimens with an initial weight of 50 g present the best accumulated biomass (RGR) throughout the annual cycle.</span>
文摘Seed quality is one of the most important factors for stand establishment in cotton (Gossypium Sp.), and the use of good-quality seeds is therefore essential to obtain an optimum plant population. Conditions prevailing during seed formation can affect the quality of seed produced, and hence crop establishment in the next growing season. These conditions can affect the germination of the seeds and the ability of the seedlings to emerge from soil. Field experiments were conducted to investigate the effect of nitrogen (N), phosphorus (P), potassium (K), foliar application of zinc (Zn) and calcium (Ca), and the use of plant growth retardants (PGR) [e.g., 1, 1-dimethyl piperidinium chloride (MC);2-chloroethyl trimethyl ammonium chloride (CC);or succinic acid 2, 2-dimethyl hydrazide (SADH)], during square initiation and boll setting stage, on growth, seed yield, seed viability, and seedling vigor of Egyptian cotton (G. barbadense). Dry matter yield, total chlorophyll concentration, K, Zn and P-uptake plant-1, were increased with the addition of K, foliar application of Zn, and different concentrations of P (576-1728 g·ha-1 of P). Seed yield plant-1 and plot-1, seed weight, seed viability, seedling vigor, and cool germination test performance increased as a result of the addition of the high N-rate (142.8 kg·ha-1 N), the high P-rate (74 kg·ha-1 P2O5), K (47 kg·ha-1 K), and from application of Zn, and Ca and the PGR. From the findings of the present study, band application of such treatments showed improved cotton-seed yield and affected the quality of seed produced, and hence crop establishment in the next growing season.