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
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 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
[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
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
Field and glasshouse experiments were conducted to study the effect of B. japonicum inoculation and phosphorus supplementation on macronutrient uptake by soybean. The treatments consisted of B. japonicum inoculation (...Field and glasshouse experiments were conducted to study the effect of B. japonicum inoculation and phosphorus supplementation on macronutrient uptake by soybean. The treatments consisted of B. japonicum inoculation (with & without), phosphorus supplementation at the levels of 0, 20, 40 and 80 kg P·ha-1. Both treatments were replicated four times in a split plot design. The macronutrients considered were N, P, K, Ca and Mg. Results showed that inoculation with B. japonicum significantly contribute to the uptake of N, P, K, Ca and Mg in roots, shoots, pods and the whole soybean plant. Likewise, phosphorus supplementation significantly enhanced the uptake of N, P, K, Ca and Mg in roots, shoots, pods and the whole plant. The use of effective strains of rhizobia and P supplementation was an effective way of enhancing the growth of soybean, eventually the uptake of macronutrients in plant organs.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
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
The increase in the population in Egypt makes it imperative to explore promising approaches to increase food supply, including protein and oil, to meet the needs of the Egyptian people. Cotton is the principal crop of...The increase in the population in Egypt makes it imperative to explore promising approaches to increase food supply, including protein and oil, to meet the needs of the Egyptian people. Cotton is the principal crop of Egyptian agriculture, it is grown mainly for its fiber, but cottonseed products are also of economic importance. Cottonseed is presently the main source of edible oil and meal for livestock in Egypt. Economic conditions in modern agriculture demand high crop yields in order to be profitable and consequently meet the high demand for food that comes with population growth. Oil crop production can be improved by development of new high yielding varieties, and the application of appropriate agronomic practices. There is limited information about the most suitable management practice for application of N, P, K, Zn, Ca and PGRs in order to optimize the quantity and quality of oil and protein of cottonseed. In maximizing the quantity and quality of a crop’s nutritional value in terms of fatty acids and protein, field experiments were conducted to investigate the effect of nitrogen, phosphorus, potassium, foliar application of zinc and calcium, the use of plant growth retardants (Pix, Cycocel or Alar), on cottonseed, protein, oil yields, and oil properties of Egyptian cotton. From the findings of this study, it seems rational to recommend that application of N, P, K, foliar application of Zn and Ca, the use of PGRs (Pix, Cycocel or Alar), could bring about better impact on cottonseed yield, seed protein content, oil and protein yields, oil refractive index, unsaponifiable matter, and unsaturated fatty acids in comparison with the ordinary cultural practices adopted by Egyptian cotton producers.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 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
Soil nutrient heterogeneity highly correlates to plant growth and development of environmen-tal quality.In order to better understand nutrient cycling,heterogeneity’of soil nutrients and their driving mechanism in di...Soil nutrient heterogeneity highly correlates to plant growth and development of environmen-tal quality.In order to better understand nutrient cycling,heterogeneity’of soil nutrients and their driving mechanism in different land use types were summarized from 1945 to 2016.By grouping keywords indexed in the titles of articles from the data base of Web of Science,two hundred and thirty’one publications related to our topics were used for analysis.Soil sampling and statistical method were compared,and spatial dependence and the impact factors for soil organic matter(SOM),Nitrogen(N),Phosphorus(P)and Potassium(K).The results showed that soil nutrient heterogeneity was influenced by different factors at different scales.The spa-tial dependence of SOM,N and P were mainly at the moderate level(48.9-59.0%)and strong level(33.3-42.2%),while for K was at strong level(63.6-84.6%)and moderate level(15.4-36.4%).This was mainly influenced by topography,soil loss,weather condition,parent materi-al,soil type,soil texture,land use,human activities,soil moisture,mineral element,soil struc-ture,animal and plant.These impact factors were summarized separately,and the influence of factors at different spatiotemporal scales was discussed.At the end of the review,the ideas for further research were postulated.展开更多
As the development of city economy,Zhongdong River in Hangzhou was seriously polluted,with the worst water quality.In order to obtain the effect of water diversion and distribution from Qiantang River on the water qua...As the development of city economy,Zhongdong River in Hangzhou was seriously polluted,with the worst water quality.In order to obtain the effect of water diversion and distribution from Qiantang River on the water quality of Zhongdong River,7-year continuous monitoring was conducted,which was at the fixed stations before and after the water diversion and distribution.After the water diversion project,the dissolved oxygen concentration of the river water was one to two times higher than before,and the ammonia nitrogen and total phosphorus decreased by 60%and 65%,respectively.When increased the amount of water diversion,the dissolved oxygen concentration of the river water elevated by 13%,and the ammonia nitrogen,total phosphorus and potassium permanganate index decreased by 8%,3%and 14%,respectively.The reason for the river water pollution was contributed to the combined sewer system and riverway sludge,especially during the rainfall,the dissolved oxygen concentration of Zhongdong River sharply declined by 95%,while the ammonia nitrogen and total phosphorus increased by 90%and 87%,respectively.The research results could provide theoretic basis for sustainable improvement of Zhongdong River water quality and river management department making the related regulations and policies.展开更多
[Objectives]To study the activation effect of hydrochemical energy in regenerative agriculture on the nutrients of arsenic sandstone.[Methods]Starting from common environmental factors,moisture,it studied the mechanis...[Objectives]To study the activation effect of hydrochemical energy in regenerative agriculture on the nutrients of arsenic sandstone.[Methods]Starting from common environmental factors,moisture,it studied the mechanism of the release and activation of N,P,K nutrient elements in arsenic sandstone under different dry and wet environments.[Results]Water played a positive role in activating soil elements.Under the conditions of long-term dryness and alternating dry and wet conditions,the content of total nitrogen,available phosphorus and available potassium coexisted in the 210 d of culture and the element absorption and release,but the overall trend was increasing;under long-term flooding conditions,the content of total nitrogen and available potassium showed an overall increasing trend during the 210 d of culture,but the content of available phosphorus decreased.[Conclusions]Water plays a positive effect on activating soil elements.The research results are expected to provide a certain reference for the application research of water in regenerative agriculture.展开更多
[Objectives]This study aimed to provide a basis for the management of nitrogen,phosphorus and potassium nutrients in eum-orthic anthrosols and the fertilization of crops.[Methods]Using the indoor culture method,the co...[Objectives]This study aimed to provide a basis for the management of nitrogen,phosphorus and potassium nutrients in eum-orthic anthrosols and the fertilization of crops.[Methods]Using the indoor culture method,the contents of total nitrogen,available phosphorus and available potassium in eum-orthic anthrosols under three different moisture conditions:long-term drying,long-term logging and alternate drying and logging were analyzed and compared.[Results]The total nitrogen content was higher under the moisture condition of long-term drying.The minimum(0.60 g/kg)appeared on day 30,and the maximum(0.74 g/kg)appeared on day 120,increased by 8.8%compared with the minimum.The available phosphorus content was also higher under the moisture condition of long-term drying.The minimum(16.9 mg/kg)appeared on day 60,and the maximum(22.5 mg/kg)appeared on day 120,increased by 33.1%compared to the minimum.The available potassium content showed a downward trend under long-term logging,and was higher than those under the other two moisture conditions.The maximum(150 mg/kg)appeared on day 30,and the minimum(136 mg/kg)appeared on days 75 and 90,reduced by 9.3%compared with the maximum.[Conclusions]Water plays a positive role in activating nutrients.Different nutrients have different responses to different moisture conditions.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
Improved estimates of nutrient requirements for rice (Oryza sativa L.) in China are essential to optimize fertilization regulation for increasing grain yields and reducing the potential of environmental negative inf...Improved estimates of nutrient requirements for rice (Oryza sativa L.) in China are essential to optimize fertilization regulation for increasing grain yields and reducing the potential of environmental negative influences, especially under high-yielding intensive systems. A database involving rice grain yields, nutrient concentrations and accumulations collected from on-field station experiments in the literatures published from 2000 to 2013 in China was developed to understand the relationships between grain yields and plant nutrient uptakes, and to quantify nutrient requirements for different yield levels. Considering all data sets, rice grain yield ranged from 1.4 to 15.2 t ha^-1 with the mean value of 7.84 t ha^-1, and ca. 10.4% of yield observa- tions were higher than the yield barrier level of 10 t ha^-1. N requirement to produce one ton grain was 21.10 kg for the yield range 〈4.0 t ha^-1 with a high variation of 45.8%. Except of the yield range 〈4.0 t ha^-1, the values of N requirement, firstly increased from 18.78 kg for yield range 4.0-5.5 t ha^-1 to 20.62 kg for yield range 7.0-8.5 t ha^-1, then decreased slightly to 19.67 and 19.17 kg for the yield range 8.5-10 and 〉10 t ha^-1, respectively. Phosphorus (P) and potassium (K) requirements showed increasing trends, from 3.51 and 19.87 kg per t grain for 〈4.0 t ha^-1 yield range to 4.10 and 21.70 kg for 〉10.0 t ha^-1 range. In conclusion, nutrient requirement varied with increasement of grain yield, and N, P and K presented various response trends, increasing, declining or stagnating, which would be of great benefit for improving fertilizer strategies.展开更多
The accurate assessment of the spatiotemporal changes in soil nutrients influenced by agricultural production provides the basis for development of management strategies to maintain soil fertility and balance soil nut...The accurate assessment of the spatiotemporal changes in soil nutrients influenced by agricultural production provides the basis for development of management strategies to maintain soil fertility and balance soil nutrients. In this paper, we combined spatial measurements from 2 157 soil samples and geostatistical analysis to assess the spatiotemporal changes in soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP) and available potassium content (AK) from the first soil survey (in the 1980s) to the second soil survey (in the 2000s) in the Taihu region of Jiangsu Province in China. The results showed that average soil nutrients in three soil types all exhibited the increased levels in the 2000s (except for AK in the yellow brown soil). The standard deviation of soil nutrient contents increased (except for TN in the paddy soil). Agricultural production in the 20 years led to increases in SOC, TN, AP and AK by 74, 82, 89 and 65%, respectively, of the Taihu areas analyzed. From the 1980s to 2000s all the nugget/sill ratios of soil nutrients indices were between 25 and 75% (except for AK in the yellow brown soil in the 2000s), indicating moderate spatial dependence. The ratio of AP in the yellow brown soil in the 2000s was 88.74%, showing weak spatial dependence. The spatial correlation range values for SOC, TN, AP and AK in the 2000s all decreased. The main areas showing declines in SOC, TN and AP were in the northwest. For AK, the main region with declining levels was in the east and middle of western areas. Apparently, the increase in soil nutrients in the Taihu region can be mainly attributed to the large increase in fertilizer inputs, change in crop systems and enhanced residues management since the 1980s. Future emphasis should be placed on avoiding excess fertilizer inputs and balancing the effects of the fertilizers in soils.展开更多
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 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 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.
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.
文摘Field and glasshouse experiments were conducted to study the effect of B. japonicum inoculation and phosphorus supplementation on macronutrient uptake by soybean. The treatments consisted of B. japonicum inoculation (with & without), phosphorus supplementation at the levels of 0, 20, 40 and 80 kg P·ha-1. Both treatments were replicated four times in a split plot design. The macronutrients considered were N, P, K, Ca and Mg. Results showed that inoculation with B. japonicum significantly contribute to the uptake of N, P, K, Ca and Mg in roots, shoots, pods and the whole soybean plant. Likewise, phosphorus supplementation significantly enhanced the uptake of N, P, K, Ca and Mg in roots, shoots, pods and the whole plant. The use of effective strains of rhizobia and P supplementation was an effective way of enhancing the growth of soybean, eventually the uptake of macronutrients in plant organs.
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.
文摘The increase in the population in Egypt makes it imperative to explore promising approaches to increase food supply, including protein and oil, to meet the needs of the Egyptian people. Cotton is the principal crop of Egyptian agriculture, it is grown mainly for its fiber, but cottonseed products are also of economic importance. Cottonseed is presently the main source of edible oil and meal for livestock in Egypt. Economic conditions in modern agriculture demand high crop yields in order to be profitable and consequently meet the high demand for food that comes with population growth. Oil crop production can be improved by development of new high yielding varieties, and the application of appropriate agronomic practices. There is limited information about the most suitable management practice for application of N, P, K, Zn, Ca and PGRs in order to optimize the quantity and quality of oil and protein of cottonseed. In maximizing the quantity and quality of a crop’s nutritional value in terms of fatty acids and protein, field experiments were conducted to investigate the effect of nitrogen, phosphorus, potassium, foliar application of zinc and calcium, the use of plant growth retardants (Pix, Cycocel or Alar), on cottonseed, protein, oil yields, and oil properties of Egyptian cotton. From the findings of this study, it seems rational to recommend that application of N, P, K, foliar application of Zn and Ca, the use of PGRs (Pix, Cycocel or Alar), could bring about better impact on cottonseed yield, seed protein content, oil and protein yields, oil refractive index, unsaponifiable matter, and unsaturated fatty acids in comparison with the ordinary cultural practices adopted by Egyptian cotton producers.
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.
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>
基金the project of National Natural Science Foundation of China(41471228,41771313)China Scholarship Council(201606615020).
文摘Soil nutrient heterogeneity highly correlates to plant growth and development of environmen-tal quality.In order to better understand nutrient cycling,heterogeneity’of soil nutrients and their driving mechanism in different land use types were summarized from 1945 to 2016.By grouping keywords indexed in the titles of articles from the data base of Web of Science,two hundred and thirty’one publications related to our topics were used for analysis.Soil sampling and statistical method were compared,and spatial dependence and the impact factors for soil organic matter(SOM),Nitrogen(N),Phosphorus(P)and Potassium(K).The results showed that soil nutrient heterogeneity was influenced by different factors at different scales.The spa-tial dependence of SOM,N and P were mainly at the moderate level(48.9-59.0%)and strong level(33.3-42.2%),while for K was at strong level(63.6-84.6%)and moderate level(15.4-36.4%).This was mainly influenced by topography,soil loss,weather condition,parent materi-al,soil type,soil texture,land use,human activities,soil moisture,mineral element,soil struc-ture,animal and plant.These impact factors were summarized separately,and the influence of factors at different spatiotemporal scales was discussed.At the end of the review,the ideas for further research were postulated.
基金Supported by the National Science Foundation of China(31500394)the Foundation and Frontier Technology Research Program of Henan Province(152300410133)the Backbone Teachers Scheme of Zhongyuan University of Technology(2014 Personnel Department of Zhongyuan University of Technology 35)
文摘As the development of city economy,Zhongdong River in Hangzhou was seriously polluted,with the worst water quality.In order to obtain the effect of water diversion and distribution from Qiantang River on the water quality of Zhongdong River,7-year continuous monitoring was conducted,which was at the fixed stations before and after the water diversion and distribution.After the water diversion project,the dissolved oxygen concentration of the river water was one to two times higher than before,and the ammonia nitrogen and total phosphorus decreased by 60%and 65%,respectively.When increased the amount of water diversion,the dissolved oxygen concentration of the river water elevated by 13%,and the ammonia nitrogen,total phosphorus and potassium permanganate index decreased by 8%,3%and 14%,respectively.The reason for the river water pollution was contributed to the combined sewer system and riverway sludge,especially during the rainfall,the dissolved oxygen concentration of Zhongdong River sharply declined by 95%,while the ammonia nitrogen and total phosphorus increased by 90%and 87%,respectively.The research results could provide theoretic basis for sustainable improvement of Zhongdong River water quality and river management department making the related regulations and policies.
文摘[Objectives]To study the activation effect of hydrochemical energy in regenerative agriculture on the nutrients of arsenic sandstone.[Methods]Starting from common environmental factors,moisture,it studied the mechanism of the release and activation of N,P,K nutrient elements in arsenic sandstone under different dry and wet environments.[Results]Water played a positive role in activating soil elements.Under the conditions of long-term dryness and alternating dry and wet conditions,the content of total nitrogen,available phosphorus and available potassium coexisted in the 210 d of culture and the element absorption and release,but the overall trend was increasing;under long-term flooding conditions,the content of total nitrogen and available potassium showed an overall increasing trend during the 210 d of culture,but the content of available phosphorus decreased.[Conclusions]Water plays a positive effect on activating soil elements.The research results are expected to provide a certain reference for the application research of water in regenerative agriculture.
文摘[Objectives]This study aimed to provide a basis for the management of nitrogen,phosphorus and potassium nutrients in eum-orthic anthrosols and the fertilization of crops.[Methods]Using the indoor culture method,the contents of total nitrogen,available phosphorus and available potassium in eum-orthic anthrosols under three different moisture conditions:long-term drying,long-term logging and alternate drying and logging were analyzed and compared.[Results]The total nitrogen content was higher under the moisture condition of long-term drying.The minimum(0.60 g/kg)appeared on day 30,and the maximum(0.74 g/kg)appeared on day 120,increased by 8.8%compared with the minimum.The available phosphorus content was also higher under the moisture condition of long-term drying.The minimum(16.9 mg/kg)appeared on day 60,and the maximum(22.5 mg/kg)appeared on day 120,increased by 33.1%compared to the minimum.The available potassium content showed a downward trend under long-term logging,and was higher than those under the other two moisture conditions.The maximum(150 mg/kg)appeared on day 30,and the minimum(136 mg/kg)appeared on days 75 and 90,reduced by 9.3%compared with the maximum.[Conclusions]Water plays a positive role in activating nutrients.Different nutrients have different responses to different moisture conditions.
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.
基金supported by the Key Technologies R&D Program of China during the 12th Five-Year Plan period(2011BAD11B05)
文摘Improved estimates of nutrient requirements for rice (Oryza sativa L.) in China are essential to optimize fertilization regulation for increasing grain yields and reducing the potential of environmental negative influences, especially under high-yielding intensive systems. A database involving rice grain yields, nutrient concentrations and accumulations collected from on-field station experiments in the literatures published from 2000 to 2013 in China was developed to understand the relationships between grain yields and plant nutrient uptakes, and to quantify nutrient requirements for different yield levels. Considering all data sets, rice grain yield ranged from 1.4 to 15.2 t ha^-1 with the mean value of 7.84 t ha^-1, and ca. 10.4% of yield observa- tions were higher than the yield barrier level of 10 t ha^-1. N requirement to produce one ton grain was 21.10 kg for the yield range 〈4.0 t ha^-1 with a high variation of 45.8%. Except of the yield range 〈4.0 t ha^-1, the values of N requirement, firstly increased from 18.78 kg for yield range 4.0-5.5 t ha^-1 to 20.62 kg for yield range 7.0-8.5 t ha^-1, then decreased slightly to 19.67 and 19.17 kg for the yield range 8.5-10 and 〉10 t ha^-1, respectively. Phosphorus (P) and potassium (K) requirements showed increasing trends, from 3.51 and 19.87 kg per t grain for 〈4.0 t ha^-1 yield range to 4.10 and 21.70 kg for 〉10.0 t ha^-1 range. In conclusion, nutrient requirement varied with increasement of grain yield, and N, P and K presented various response trends, increasing, declining or stagnating, which would be of great benefit for improving fertilizer strategies.
基金the funding support from the New Century Exceptional Talent Program of China(NCET-08-0797)the National High-Tech Research and Development Program of China(2013AA100404)+2 种基金the National Basic Research Program of China(2009CB118608)the CSIRO-Chinese Ministry of Education(MOE)PhD Research Fellowship Programthe Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘The accurate assessment of the spatiotemporal changes in soil nutrients influenced by agricultural production provides the basis for development of management strategies to maintain soil fertility and balance soil nutrients. In this paper, we combined spatial measurements from 2 157 soil samples and geostatistical analysis to assess the spatiotemporal changes in soil organic carbon (SOC), total nitrogen (TN), available phosphorus (AP) and available potassium content (AK) from the first soil survey (in the 1980s) to the second soil survey (in the 2000s) in the Taihu region of Jiangsu Province in China. The results showed that average soil nutrients in three soil types all exhibited the increased levels in the 2000s (except for AK in the yellow brown soil). The standard deviation of soil nutrient contents increased (except for TN in the paddy soil). Agricultural production in the 20 years led to increases in SOC, TN, AP and AK by 74, 82, 89 and 65%, respectively, of the Taihu areas analyzed. From the 1980s to 2000s all the nugget/sill ratios of soil nutrients indices were between 25 and 75% (except for AK in the yellow brown soil in the 2000s), indicating moderate spatial dependence. The ratio of AP in the yellow brown soil in the 2000s was 88.74%, showing weak spatial dependence. The spatial correlation range values for SOC, TN, AP and AK in the 2000s all decreased. The main areas showing declines in SOC, TN and AP were in the northwest. For AK, the main region with declining levels was in the east and middle of western areas. Apparently, the increase in soil nutrients in the Taihu region can be mainly attributed to the large increase in fertilizer inputs, change in crop systems and enhanced residues management since the 1980s. Future emphasis should be placed on avoiding excess fertilizer inputs and balancing the effects of the fertilizers in soils.