Research on Yield and Quality of Hybrid Rice under Efficient Application Amount of Phosphorus and Potassium

[Objective] Application of P and K was not reasonable in southwest rice producing area, with no effective method for guiding application of P and K. This study aimed to conduct experiments with the same N application and different P and K application in different ecological points, to explore a scientific and efficient management method of P and K nutrients and provide guidance for application of P and K in rice production. [Method] Hybrid rice Chuanxiang9838 was used as experimental material to study the relationship among application amount of P and K, utilization rates of P and K, rice yield and rice quality in seven ecological points of four provinces （municipalities） including Sichuan, Chongqing, Yunnan and Guizhou. The application amount per hectare of P was 37.5, 75, 112.5 and 150 kg, respectively; the application amount per hectare of K was 45, 135 and 180 kg, respectively. A total of 10 treatments were set for split-plot design with three replications. [Result] Yield of Chuanxiang9838 significantly varied in different experimental locations and under different levels of P and K, interaction of ecological point and different P and K treatments varied significantly. Yield had reached the maximum in ecological point of Yunnan Binchuan and in treatment with application of N 150 kg P 75 kg K 90 kg. Efficient utilization rates of P and K varied in each ecological point, efficient application amount of P and K in Sichuan Dongpo, Sichuan Luxian, Guizhou Xiaohe and Chongqing Yongchuan was the same, while that in Sichuan Guanghan, Sichuan Zhongjiang and Yunnan Binchuan was different. The main objective of high-yield rice production was to increase the number of effective panicles per hectare and seed setting rate. Rice quality was clustered into 2 categories by locations and 6 categories by treatments. [Conclusion] Prediction models of efficient application of P and K in rice production were established, which provided guidance for high-yield rice production and rational and efficient utilization of P and K in southwest rice area.

Effect Models of Nitrogen,Phosphorus and Potassium Fertilizer Formulation in Banana

[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.

Extraction and Reaction Mechanism of Potassium from Associated Phosphorus and Potassium Ore

Potassium and phosphate were extracted at low temperature by acid hydrolysis process to decompose a new type of associated phosphorus and potassium ore. The main factors affecting the dissolution rate were investigated, such as grinding fineness, the amount of sulfuric acid and fluoride salt, reaction time and temperature, etc. Meanwhile, the effects of various factors on the formation of soluble potassium and phosphate were also discussed. The reaction products and residues were determined by X-ray diffraction（XRD）, scanning electron microscopic（SEM） analysis and other means. The results showed that the dissolution rates of potassium and phosphorus were 70wt% and 93.7wt%, respectively, under the conditions of a grain size of 95.64wt% lessthan 0.074 mm, 9.78 g·g^（-1） sulfuric acid, 0.5 g·g^（-1） ammonium fluoride, 160 ℃ and a reaction time of 2h. The thermodynamic and chemical reaction mechanism was revealed that the primary reaction could be completed spontaneously in a temperature range of 298-433 K. The increase of reaction temperature had an important influence on ion exchange reaction, which was more conducive to the spontaneous process. The research will open up a new way for efficient use of potassium ore resources.

Study on Absorption Law of Nitrogen,Phosphorus and Potassium and Proper Nitrogen Application in Chuanxiangyou 9838 under No-tillage Cultivation

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.

Transgenic approaches for improving use efficiency of nitrogen, phosphorus and potassium in crops

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.

Impact of Nitrogen, Phosphorus and Potassium on Brown Planthopper and Tolerance of Its Host Rice Plants

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.

Effect of Phosphorus and Potassium Foliar Treatment on Seed Yield and Yield Components of Red Clover （ Trifolium pratense L.） Cultivars

Proper mineral nutrition of red clover especially on the acid soils is a prerequisite for the realization of maximum potential for seed yield. The field experiment with four cultivars of red clover were established on soil having a pH （in H2O） of 4.8, in order to in conditions of dense planting （20 cm inter row） analyzes the effect of foliar application of phosphorus and potassium （PK） on yield and yield components （number of stems/m2, number of inflorescences/m2, number of inflorescences/stem, number of flowers/inflorescence, number of seeds/inflorescence and one thousand grain weight）. Regardless of foliar treatment with PK, varieties differed in the number of inflorescences/m2, number of flowers/inflorescence, number of seeds/inflorescence and seed yield. Foliar application of PK in the phase of intensive growth of red clover had a positive impact on number of stem/m2, number of inflorescences/m2 and seed yield in all varieties, as well as on the number of flowers/inflorescence, number of seeds/inflorescence in cultivar Viola.

Deciphering the potassium storage phase conversion mechanism of phosphorus by combined solid-state NMR spectroscopy and density functional theory calculations

Phosphorus is the potential anode material for emerging potassium-ion batteries(PIBs)owing to the highest specific capacity and relatively low operation plateau.However,the reversible delivered capacities of phosphorus-based anodes,in reality,are far from the theoretical capacity corresponding to the formation of K3P alloy.And,their underlying potassium storage mechanisms remain poorly understood.To address this issue,for the first time,we perform high-resolution solid-state31P NMR combined with XRD measurements,and density functional theory calculations to yield a systemic quantitative understanding of(de)potassiation reaction mechanism of phosphorus anode.We explicitly reveal a previously unknown asymmetrical nanocrystalline-to-amorphous transition process via rP←→(K_(3)P_(11),K_(3)P_(7),beta-K_(4)P_(6))←→(alpha-K4P6)←→(K_(1-x)P,KP,K_(4-x)P3,K_(1+x)P)←→(amorphous K4P3,amorphous K3P)that are proceed along with the electrochemical potassiation/depotassiation processes.Additionally,the corresponding KP alloys intermediates,such as the amorphous phases of K_(4)P_(3),K_(3)P,and the nonstoichiometric phases of“K_(1-x)P”,“K_(1+x)P”,“K_(4-x)P_(3)”are experimentally detected,which indicating various complicated K-P alloy species are coexisted and evolved with the sluggish electrochemical reaction kinetics,resulting in lower capacity of phosphorus-based anodes.Our findings offer some insights into the specific multi-phase evolution mechanism of alloying anodes that may be generally involved in conversion-type electrode materials for PIBs.

Effects of Zinc on the Yield,Uptake and Distribution of Nitrogen/Phosphorus/Potassium/Zinc in Different Genotypes of Maize

[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.

Nitrogen, phosphorus and potassium recycling in an agroforestry ecosystem of Huanghuaihai Plain: with Paulownia elongata intercropped wheat and maize as an example

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.

Effects of Nitrogen-phosphorus-potassium Combined Fertilization on Rice Yield and Fertilizer Use Efficiency in Jianghan Plain

[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.

The Effect of Water and Salt Stress on Paspalum dilatatum,a Constituent of Pampas Natural Grasslands

The effects of the salt stress on plant growth are usually increased by the water stress.We studied the impact of both stresses in simultaneous pulses of drought and salinity on Paspalum dilatatum.This forage species is native to South America,spread in grasslands in many tropical,subtropical,and temperate areas of the world,and very common in grasslands of the Flooding Pampas of Argentina.Mimicking what happens in nature.We compared a pot experiment,a non-stressed control against water stress for a month(midpoint between field capacity and wilting point),and two saline stresses(moderate,6 d·Sm^(−1)and strong,12 d·Sm^(−1)),also for a month.Aerial biomass(green leaf;non-leaf green material,and dry material)and roots were harvested,weighed,and analyzed for nitrogen,phosphorus,and cations.The biomass of all components significantly decreased when both stresses were applied.Water plus strong saline stress reduced by half the total biomasses,compared to the control.The proportion of aerial biomass/root biomass ratio as well as aerial green component/dry materials ratio tend to decrease when subjected to both stresses.Nitrogen concentration in plants was not significantly affected,but phosphorus concentration increased in aerial biomass components,from 0.10 to 0.18 mg·kg^(−1)between the extreme treatments,but did not change in roots.Sodium concentration in plants increased(i.e.,in green leave sodium(Na)increased from 0.27 to 2.01 mg·kg^(−1)between the extreme treatments),whereas other cations either did not change or decreased,affecting the ratios between them.Sodium performance allows us to infer that the Na accumulation of P.dilatatum behaves in an intermediate range,compared to very tolerant to salts or non-salt tolerant species of the Paspalum genus.In agreement,when salts were applied in the form of a pulse,P.dilatatum tolerated higher salinity than that found by other authors for the same species,using continuous salinity.

Effects of Tillage Methods on Soil Available Phosphorus and Available Potassium in the Loess Plateau

In order to find out the effects of long-term no-tillage operation on soil available phosphorus and available potassium in the loess plateau, a suitable high-yield and high-efficiency tillage technology system was established. In the Changwu loess plateau agri-ecological experiment station of the Northwest A&F University of Changwu County, Shaanxi Province, the no-tillage experimental field for three consecutive years was selected. In September 2015, no-tillage, tillage, and rotary tillage were carried out before winter wheat was sowed. After the harvest of winter wheat in 2016, the contents of available phosphorus and available potassium in 0-30 cm soil layer under three tillage methods were analyzed. The results showed that in the 0-30 cm soil layer, the soil available phosphorus and available potassium decreased with the increase of the soil depth in the three tillage methods. The content of available phosphorus and available potassium in 10-20 cm soil layer and 20-30 cm soil layer decreased by 16.07%, 32.74%, 15.54% and 27.08%, respectively, and there were significant differences ( P <0.05). Under different tillage methods, the soil available phosphorus content in the 0-10 cm soil layer significantly reduced by 11.31% compared with no-tillage. The soil available potassium content under tillage and rotary tillage significantly reduced by 6.16% and 4.97%, respectively ( P <0.05). Compared with no-tillage, the soil available phosphorus content in the 20-30 cm soil layer significantly reduced by 18.12%. The soil available potassium content under tillage and rotary tillage methods significantly reduced by 17.17% and 9.22%, respectively ( P <0.05). Therefore, in the long-term no-tillage dry loess plateau, it is necessary to conduct proper tillage or rotary tillage.

Model for Quantitative Evaluation and Prediction of the Concentration of Phosphorus Removed during Pyro-Hydro Beneficiation of Haematite

This paper presents a model derived for quantitative evaluation and prediction of the concentration of phosphorus removed during pyro-hydro beneficiation of iron oxide ore. Potassium hydroxide was used as the leaching solution and the reaction vessel containing the solution and ore was heated at a temperature of 600℃ for 10 minutes. The results of the investigation indicates that the model;P = (e0.7827) S predicts the concentration of phosphorus removed, based on the concentration of sulphur simultaneously removed. It was observed that the validity of the model is rooted in the expression lnP = lnN + lnS where both sides of the expression are approximately equal to 4. The maximum deviation of the model-predicted concentration of removed phosphorus from the corresponding concentration obtained from the experiment was less than 3%. The concentrations of phosphorus removed per unit mass-input of iron oxide ore as obtained from experiment and derived model are 0.8917 and 1.0354 mg/kg g-1 respectively. Similarly, the concentrations of phosphorus removed per unit concentration of removed sulphur as obtained from experiment and derived model are 1.8838 and 2.1874 mg/kg (mg/kg)-1 respectively. This implies that the concentration of phosphorus removed is approximately equal to the concentration of simultaneously removed sulphur during the beneficiation process.

Macronutrients Uptake in Soybean as Affected by <i>Bradyrhizobium japonicum</i>Inoculation and Phosphorus (P) Supplements

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.

Effects of different ration of NPK fertilizer on the grain yield and protein content in forage rice

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：

Polysaccharide,proline,and anti-oxidation enzyme activities of Thailand rosewood(Dalbergia cochinchinensis)seedlings exposed to exponential fertilization

Thailand rosewood(Dalbergia cochinchinensis)is a vulnerable high value tree species in subtropical and tropical Southeast Asia.The demand for the rehabilitation of the natural habitat of the species requires high-quality seedlings.However,current fertilizer regimes tend to deliver a coarse rate of fertilizers that result in a low uptake efficiency and a high risk of nutrient excess.Exponential fertilization is an effective approach to promote seedling quality through identifying an optimum dose out of a range of applications.In this study,Thailand rosewood seedlings were cultured in a mixed substrate of perlite,vermiculite,and peat(2:2:3,v/v/v)and received exponential fertilization from 0(control),through 100,200,300,400,and 600 mg nitrogen(N)per plant over a four-month cultural rotation.Height,diameter,and shoot biomass increased with fertilizer rate and were maximized at 300 mg N per plant.This application also reduced nutrient deficiencies and avoided excess supply compared to higher rates.Polysaccharide,proline,and anti-oxidation enzyme activities tended to be greater in unfertilized controls or in over-fertilized high dosages,with lower activities around 100–300 mg N plant(-1).Application of 300 mg N per plant was identified as the optimum dosage as it maximized nutrient reserves,polysaccharide and proline contents,and anti-oxidants without causing any symptoms from excess fertilizer toxicity.Future work is required to identify the effects of N-fixation on the formation of nutritional reserves in Thailand rosewood seedlings subjected to exponential fertilization.

Interactive effects of irrigation and exponential fertilization on nutritional characteristics in Populus 3 euramericana cv. ‘74/76' cuttings in an open-air nursery in Beijing, China

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.

Soil Nutrient Variance by Slope Position in a Mollisol Farmland Area of Northeast China

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.

Responses of plant diversity and primary productivity to nutrient addition in a Stipa baicalensis grassland, China

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.