Effects of Applying Organic Fertilizer on Rice Lodging Resistance and Yield

[Objective]The aim was to provide a scientific basis for the reasonable application of organic fertilizer to improve lodging resistance and yield of rice.[Method]The application of four different kinds of organic fertilizer was applied to study their effects on rice lodging resistance and yield of late rice Yuzhengxiang that with high quality.[Result] The effect of applying organic fertilizer for improving rice lodging resistance capability was:biogas residues> chicken manure > rapeseed cake> tobac...

Changes in Grain Yield of Rice and Emission of Greenhouse Gases from Paddy Fields after Application of Organic Fertilizers Made from Maize Straw

A field experiment was conducted at the farm of Yangzhou University, Yangzhou, China, to study the effects of organic fertilizers made from maize straw on rice grain yield and the emission of greenhouse gases. Four organic fertilizer treatments were as follows： maize straw （MS）, compost made from maize straw （MC）, methane-generating maize residue （MR）, and black carbon made from maize straw （BC）. These organic fertilizers were applied separately to paddy fields before rice transplanting. No organic fertilizer was applied to the control （CK）. The effects of each organic fertilizer on rice grain yield and emission of greenhouse gases were investigated under two conditions, namely, no nitrogen （N） application （ON） and site-specific N management （SSNM）. Rice grain yields were significantly higher in the MS, MC and MR treatments than those in CK under either ON or SSNM. The MS treatment resulted in the highest grain yield and agronomic N use efficiency. However, no significant difference was observed for these parameters between the BC treatment and CK. The changes in the emissions of methane （CH4） carbon dioxide （CO2）, or nitrous oxide （N20） from the fields were similar among all organic fertilizer treatments during the entire rice growing season. The application of each organic fertilizer significantly increased the emission of each greenhouse gas （except N20 emission in the BC treatment） and global warming potential （GWP）. Emissions of all the greenhouse gases and GWP increased under the same organic fertilizer treatment in the presence of N fertilizer, whereas GWP per unit grain yield decreased. The results indicate that the application of organic fertilizer （MS, MC or MR） could increase grain yield, but also could enhance the emissions of greenhouse gases from paddy fields. High grain yield and environmental efficiency could be achieved by applying SSNM with MR.

Liquid Organic Fertilizer and Planting Space Influencing the Growth and Yield of Rice （Oryza sativa L.） in System of Rice Intensification （SRI） Methods

This research aimed to know the influence of liquid organic fertilizer and planting space to the growth and yield of rice in System of Rice Intensification （SRI） methods. The research was conducted in Palur, Sukoharjo, laid on 98 m above sea level from December 2008 to April 2009. Experimental design used was Randomized Completely Block Design with two factors of treatment. The first factor was liquid organic fertilizer; consist of control, cebreng leaf, rumen of goat, banana tree hump, and maja fruit. The second factor was planting space; consisting of 25 cm × 25 cm, 30 cm ×30 cm and 35 cm× 35 cm. There were 15 combinations of treatment and each repeated three times. Data analyzed with F test at 5% and DMRT at 5%. Research result showed that liquid organic fertilizer of maja fruit serves the best on variable of stalk length. Planting space of 35 cm × 35 cm serves the best on variable of plant height, number of total sapling, number of productive sapling, weight of dry plant, weight of rice per clump, and weight of 1,000 rice grains. There is no interaction between liquid organic fertilizer and planting space on all variables.

Coupling of reduced inorganic fertilizer with plant-based organic fertilizer as a promising fertilizer management strategy for colored rice in tropical regions

Colored rice is a type of high-quality,high-added-value rice that has attracted increasing attention in recent years.The use of large amounts of inorganic nitrogen fertilizer in rice fields results in low fertilizer use efficiency and high environmental pollution.Organic fertilizer is a promising way to improve soil quality and sustain high yields.However,most studies focus on the effect of animal-based organic fertilizers.The effects of different ratios of plantbased organic fertilizer and inorganic fertilizer on the grain yield and quality of colored rice have rarely been reported.Therefore,a two-year field experiment was conducted in 2020 and 2021 to study the effects of replacing inorganic N fertilizers with plant-based organic fertilizers on the yield,nitrogen use efficiency(NUE),and anthocyanin content of two colored rice varieties in a tropical region in China.The experimental treatments included no nitrogen fertilization(T1),100% inorganic nitrogen fertilizer(T2),30%inorganic nitrogen fertilizer substitution with plant-based organic fertilizer(T3),60%inorganic nitrogen fertilizer substitution with plant-based organic fertilizer(T4),and 100% plantbased organic fertilizer(T5).The total nitrogen provided to all the treatments except T1 was the same at 120 kg ha-1.Our results showed that the T3 treatment enhanced the grain yield and anthocyanin content of colored rice by increasing nitrogen use efficiency compared with T2.On average,grain yields were increased by 9 and 8%,while the anthocyanin content increased by 16 and 10% in the two colored rice varieties under T3 across the two years,respectively,as compared with T2.Further study of the residual effect of partial substitution of inorganic fertilizers showed that the substitution of inorganic fertilizer with plant-based organic fertilizer improved the soil physiochemical properties,and thus increased the rice grain yield,in the subsequent seasons.The highest grain yield of the subsequent rice crop was observed under the T5 treatment.Our results suggested that the application of plantbased organic fertilizers can sustain the production of colored rice with high anthocyanin content in tropical regions,which is beneficial in reconciling the relationship between rice production and environmental protection.

Substitution of chemical fertilizer by Chinese milk vetch improves the sustainability of yield and accumulation of soil organic carbon in a double-rice cropping system

The double-rice cropping system is a very important intensive cropping system for food security in China. There have been few studies of the sustainability of yield and accumulation of soil organic carbon (SOC) in the double-rice cropping system following a partial substitution of chemical fertilizer by Chinese milk vetch (Mv). We conducted a 10-year (2008–2017) field experiment in Nan County, South-Central China, to examine the double-rice productivity and SOC accumulation in a paddy soil in response to different fertilization levels and Mv application (22.5 Mg ha^–1). Fertilizer and Mv were applied both individually and in combination (sole chemical fertilizers, Mv plus 100, 80, 60, 40, and 0% of the recommended dose of chemical fertilizers, labeled as F100, MF100, MF80, MF60, MF40, and MF0, respectively). It was found that the grain yields of double-rice crop in treatments receiving Mv were reduced when the dose of chemical fertilizer was reduced, while the change in SOC stock displayed a double peak curve. The MF100 produced the highest double-rice yield and SOC stock, with the value higher by 13.5 and 26.8% than that in the F100. However, the grain yields increased in the MF80 (by 8.4% compared to the F100), while the SOC stock only increased by 8.4%. Analogous to the change of grain yield, the sustainable yield index (SYI) of double rice were improved significantly in the MF100 and MF80 compared to the F100, while there was a slight increase in the MF60 and MF40. After a certain amount of Mv input (22.5 Mg ha^–1), the carbon sequestration rate was affected by the nutrient input due to the stimulation of microbial biomass. Compared with the MF0, the MF100 and MF40 resulted in a dramatically higher carbon sequestration rate (with the value higher by 71.6 and 70.1%), whereas the MF80 induced a lower carbon sequestration rate with the value lower by 70.1% compared to the MF0. Based on the above results we suggested that Mv could partially replace chemical fertilizers (e.g., 40–60%) to improve or maintain the productivity and sustainability of the double-rice cropping system in South-Central China.

Co-application of compost or inorganic NPK fertilizer with biochar influences soil quality,grain yield and net income of rice

Most agricultural soils in sub-Saharan Africa are degraded,compromising the grain yield of rice and farmers return on investment.A 3-year field study was undertaken to explore the effect of the application of compost or inorganic NPK fertilizer applied alone or in combination with biochar on soil quality,grain yield of rice and net income.The five treatments were laid out using a randomized complete block design with four replications.The treatments were applied to supply approximately 75 kg N ha–1.The best fertilizer input was compost+biochar which resulted in the greatest improvement in soil physico-chemical properties by reducing bulk density and increasing porosity and moisture retention,organic matter content,percent nitrogen,available phosphorus and cation exchange capacity.Apart from treatment with inorganic fertilizer alone,treated soils showed a decrease in pH.Bacterial and fungal counts and basal respiration decreased in soils in the following order:compost+biochar>compost only>inorganic NPK fertilizer+biochar>inorganic NPK fertilizer>control.The increase in pooled grain yield and net income in response to treatment followed the order:compost+biochar>NPK+biochar>NPK>compost>control.The findings suggest that the use of compost or NPK alone might improve soil quality and increase grain yield and net income,but it is greatly recommended to co-apply these fertilisers with biochar.

Improvement of soil fertility and rice yield after long-term application of cow manure combined with inorganic fertilizers

Fertilization is an effective technique to improve soil fertility and increase crop yield.The long-term effects of different fertilizers on soil considerably vary.Over 38 consecutive years of different fertilization positioning experiments in a double cropping rice field of Qiyang Red Soil Experimental Station,seven different fertilization treatments including CK(no fertilization),NPK(nitrogen,phosphorus,and potassium fertilizer),M(cow manure),NPKM(nitrogen,phosphorus,and potassium with cow manure),NPM(nitrogen and phosphorus with cow manure),NKM(nitrogen and potassium with cow manure),and PKM(phosphorus and potassium with cow manure)were applied to study the effects on rice yield,soil fertility,and nutrient apparent balance in a paddy field.The results showed that the annual average yields of rice in NPKM,NPM,NKM,PKM,M,NPK and CK treatments ranged from 6214 to 11562 kg ha-1.Yields under long-term organic and inorganic treatments(NPKM,NPM,NKM and PKM)were 22.58,15.35,10.53 and 4.41%,respectively,greater than under the NPK treatment.Soil organic carbon(SOC),total nitrogen(TN),available nitrogen(AN)and available potassium(AK)concentration with long-term organic and inorganic treatment(NPKM,NPM,NKM and PKM)were significantly higher than in inorganic fertilizer(NPK)treatments.Soil total phosphorus(TP)and available phosphorus(AP)contentration with organic fertilizer combined with inorganic N and P fertilizer treatment(NPKM,NPM and PKM)were significantly higher than with inorganic fertilizer alone(NPK treatments).The average annual rice yield(11562 kg ha-1),SOC(20.88 g kg-1),TN(2.30 g kg-1),TP(0.95 g kg-1),TK(22.50 g kg-1)and AP(38.94 mg kg-1)concentrations were the highest in the NPKM treatment.The soil AN concentration(152.40 mg kg-1)and AK contentration(151.00 mg kg-1)were the highest in the NKM treatment.N and P application led to a surplus of nitrogen and phosphorus in the soil,but NPKM treatment effectively reduced the surplus compared with other treatments.Soils under all treatments were deficient in potassium.Correlation analysis showed that SOC,TN,AN,TP,and AP contentration was significantly correlated with rice yield;the correlation coefficients were 0.428,0.496,0.518,0.501,and 0.438,respectively.This study showed that the combined application of N,P,and K with cow manure had important effects on rice yield and soil fertility,but balanced application of N,P,and K with cow manure was required.

Effects of Organic Manure Application with Chemical Fertilizers on Nutrient Absorption and Yield of Rice in Hunan of Southern China

To evaluate the effect of organic manure application with chemical fertilizers on rice yield and soil fertility under long-term double-rice cropping system, a six year field experiment was conducted continually in the paddy soil derived from Quaternary red clay in Hunan Province of southern China. Four different treatments, i.e., no nitrogen with chemical P and K （PK）, swine manure only （M）, N, P and K chemical fertilizers only （NPK）, and half chemical fertilizers combined with half swine manure （NPKM） with four replications were included. Each N, P and K application rate was the same at all the treatments （except the N application rate at PK） and N application rate was 150 kg N ha^-1. All fertilizers were applied to soil tillage layer with once application as baseal fertilizers. The nutrients uptake rate, grain yield, nitrogen use efficiency, and soil organic matter content at each treatment were investigated. The NPKM treatment achieved the highest mean annual yield of 12.2 t ha^-1 （68% higher than that of PK）. Higher dry matter accumulation and nutrients absorption were observed during the middle-late growth period in the NPKM treatment, with higher panicle number per unit and filled-grain number per panicle. Its average nitrogen use efficiency was 36.3% and soil organic matter increased by 18.5% during the experimental period in the NPKM treatment, which were significantly higher than those in the NPK treatment. Organic manure application with chemical fertilizers increased the yield and nitrogen use efficiency of rice, reduced the risk of environmental pollution and improved soil fertility greatly. It could be a good practical technique that protects the environment and raises the rice yield in this region.

Effects of Integrated Organic and Inorganic Fertilizers on Yield and Growth Parameters of Rice Varieties

We investigated the effects of integrated organic and inorganic fertilizers on the growth and yield of indica rice variety Manawthukha and japonica rice variety Genkitsukushi.In a split-plot design,the two rice varieties were assigned as main plot factors,and the integrated treatments were the subplot factors,including no-N fertilizer(N0),50%chemical fertilizer(CF)(CF50),100%CF(CF100),50%CF+50%poultry manure(PM)(CF50PM50),50%CF+50%cow manure(CM)(CF50CM50),and 50%CF+50%compost(CP)(CF50CP50).CF100 was equivalent to N at 85 kg/hm2.Manure was applied based on the estimated mineralizable nitrogen(EMN)level,which is dependent on total N(%)of each manure type.Manawthukha rice plants were taller with higher tiller number and dry matter content.However,higher soil-plant analysis development(SPAD)values were measured in Genkitsukushi throughout the crop growth period,resulting in higher seed-setting rate(%)and greater yield.At the same N level,CF50PM50 application in both rice varieties resulted in higher SPAD values,plant height and tiller number than CF100.CF50PM50 containing total N more than 4%supplied synchronized N for the demands of the rice plants,resulting in maximum dry matter,yield and yield components.CF50CM50 and CF50CP50 treatments containing total N less than 4%resulted in lower yields which were similar to CF100.These results indicated that integrating organic and inorganic fertilizers enhanced growth parameters and yields of Manawthukha and Genkitsukushi,while reducing the dose of chemical fertilizer.

Carbon sequestration rate,nitrogen use efficiency and rice yield responses to long-term substitution of chemical fertilizer by organic manure in a rice–rice cropping system

Combined application of chemical fertilizers with organic amendments was recommended as a strategy for improving yield,soil carbon storage,and nutrient use efficiency.However,how the long-term substitution of chemical fertilizer with organic manure affects rice yield,carbon sequestration rate(CSR),and nitrogen use efficiency(NUE)while ensuring environmental safety remains unclear.This study assessed the long-term effect of substituting chemical fertilizer with organic manure on rice yield,CSR,and NUE.It also determined the optimum substitution ratio in the acidic soil of southern China.The treatments were:(i)NPK0,unfertilized control;(ii)NPK1,100%chemical nitrogen,phosphorus,and potassium fertilizer;(iii)NPKM1,70%chemical NPK fertilizer and 30%organic manure;(iv)NPKM2,50%chemical NPK fertilizer and 50%organic manure;and(v)NPKM3,30%chemical NPK fertilizer and 70%organic manure.Milk vetch and pig manure were sources of manure for early and late rice seasons,respectively.The result showed that SOC content was higher in NPKM1,NPKM2,and NPKM3 treatments than in NPK0 and NPK1 treatments.The carbon sequestration rate increased by 140,160,and 280%under NPKM1,NPKM2,and NPKM3 treatments,respectively,compared to NPK1 treatment.Grain yield was 86.1,93.1,93.6,and 96.5%higher under NPK1,NPKM1,NPKM2,and NPKM3 treatments,respectively,compared to NPK0 treatment.The NUE in NPKM1,NPKM2,and NPKM3 treatments was higher as compared to NPK1 treatment for both rice seasons.Redundancy analysis revealed close positive relationships of CSR with C input,total N,soil C:N ratio,catalase,and humic acids,whereas NUE was closely related to grain yield,grain N content,and phenol oxidase.Furthermore,CSR and NUE negatively correlated with humin acid and soil C:P and N:P ratios.The technique for order of preference by similarity to ideal solution(TOPSIS)showed that NPKM3 treatment was the optimum strategy for improving CSR and NUE.Therefore,substituting 70%of chemical fertilizer with organic manure could be the best management option for increasing CSR and NUE in the paddy fields of southern China.

Combined Effect of Organic Manures and Inorganic Fertilizers on the Growth and Yield of Hybrid Rice (Palethwe-1)

We investigated the effect of combining organic and inorganic fertilizers on the growth and yield of hybrid rice (Palethwe-1) in the dry and wet seasons of 2015. Four quantities of inorganic fertilizer were used in the main plot [0%, 50%, 75%, and 100% nitrogen, phosphorus, and potassium (NPK)] based on the recommended amounts of 150 kg N ha-1, 70 kg P2O5 ha-1, and 120 kg K2O ha-1, while different organic manures were applied to subplots [no organic manure (O0), cow manure (Oc), poultry manure (Op), and vermicompost (Ov);all at 5 t·ha-1] as part of a split-plot experimental design with three replicates. In both seasons, significant differences in growth parameters including number of tillers hill-1, soil-plant analysis development (SPAD) values, total dry matter, yield, and yield components were observed in plants supplied with different inorganic fertilizers. The 100% NPK (I100) fertilizer produced the maximum yield but similar yields were achieved in plots supplied with 50% NPK (I50) and 75% NPK (I75). Significant differences in growth and yield parameters were also found in crops supplied with organic manures. Although identical quantities were supplied, Op produced the best growth parameters in both seasons including total dry matter, yield, and yield components. Oc also performed well. Combining inorganic and organic fertilizers demonstrated that I50 together with Op (5 t·ha-1) provided similar growth, total dry matter, and yield parameters to I100 in both seasons. Oc (5 t·ha-1) plus I75 also achieved similar yields to I100. This study demonstrates that the combined application of inorganic fertilizers and organic manures has the potential to reduce chemical fertilizer usage without decreasing the yield of hybrid rice, and can enhance the growth, yield, and yield components of Palethwe-1.

Organic Manures and Crop Residues as Fertilizer Substitutes: Impact on Nitrous Oxide Emission, Plant Growth and Grain Yield in Pre-Monsoon Rice Cropping System

It has been previously argued that application of organic residues added in soils has a great impact on soil quality, grain productivity as well as greenhouse gas emissions. Substitution of chemical fertilizers has become a common practice in agricultural systems which consequently affect the greenhouse gas emissions from agricultural fields. To observe the effects of organic manures and crop residues amendments, five fertilizer treatments including conventional inorganic nitrogen fertilizer—NPK, cow manure, rice straw, poultry manure and sugarcane bagasse were applied in the field for two consecutive pre-monsoon rice seasons. Addition of rice straw, poultry manure and sugarcane bagasse decreased the cumulative N2O emissions by 14% and 31%, and by 1% and 7% and 5% and 3% in 2012 and 2013 respectively when compared with conventional fertilizer treatment (NPK) in both the seasons. Yield differences were not significant (p > 0.005) amongst the treatments, however, a slight increase was observed due to rice straw amendment over control. Soil organic carbon decreased by 11% - 17% under the application of organic residues which might have contributed to lower N2O emissions from the plots. Results of carbon equivalent emission (CEE) and carbon efficiency ratio (CER) indicated that incorporation of rice straw during pre-monsoon rice season had the potential to reduce the N2O emissions and yield scaled emissions of rice production at lower level than the conventional farmers’ practice of using chemical fertilizers (NPK).

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：

Low N apparent surplus with higher rice yield under long-term fertilizer postponing in the rice-wheat cropping system

Nitrogen(N)fertilization increases rice yield,but inappropriate N fertilizer application increases N loss and the risk of environmental pollution.Short-term fertilizer postponing(FP)generally reduces N apparent surplus and increases rice yields,but the effects of long-term FP on N surplus and rice yields remain unknown.Our study was the first to investigate the impacts of long-term FP(11 years)on N apparent surplus and rice yields.FP effects in the short term(≤6 years)did not affect rice yields,whereas FP effects in the long term(>6 years)increased rice yields by 13.9%compared with conventional fertilization(CF).FP did not affect panicles per unit area,1000-kernel weight,and filled-kernel rate,but spikelets per panicle increased over time due to spikelet formation stimulation.FP also reduced the N apparent surplus over time more strongly than CF owing to higher N accumulation and N utilization efficiency.FP effects in the long term also significantly increased soil organic matter,total N,and NH4_(+)^(-)N content.Our results were supported by a pot experiment,showing that rice yields in soils with a history of FP were significantly higher than those for soils without a history of FP,indicating that FP increased rice yields more strongly in later years mainly because of soil quality improvement.Our findings suggest that longterm FP can reduce N loss while increasing rice yields by improving soil quality.

Effect of Reducing Chemical Fertilizer on Rice Yield,Output Value,Content of Soil Carbon and Nitrogen after Utilizing the Milk Vetch

A located field experiment was carried out to study the effects of different amount of chemical fertilizer usage on rice yield,economic benefits of rice,soil carbon（C） and total nitrogen（TN） under ploughing back of Chinese milk vetch for 5consecutive years.Six treatments were included in the experiment,they are CK（unfertilized）,CF（100% chemical fertilizer with the amount of N,P2O5,K2 O being150,75,120 kg/hm^2respectively）,A1（22 500 kg/hm^2 Chinese milk vetch and 100%chemical fertilizer）,A2（Chinese milk vetch and 80% nitrogen and potassium fertilizer and 100% phosphate fertilizer）,A3（Chinese milk vetch and 60% nitrogen and potassium fertilizer and 100% phosphate fertilizer）,A4（Chinese milk vetch and 40% nitrogen and potassium fertilizer and 100% phosphate fertilizer）.The results were as follows：application of fertilizer could increase the yield of rice,while Chinese milk vetch combined with fertilizer application had a much more increase effect in rice yield.Under the condition of milk vetch application with 22 500 kg/hm^2,the early rice yield of the treatment A1 was significantly increased by 7.7% compared with that of CF.And the yield of treatment A3 was basically identical to or slight increase in comparison with that of CF.Decreasing amount of fertilizers cloud improve output value of rice in the case of the utilization of Chinese milk vetch.The treatment A1 increased output value of rice by 5.92% in comparison of CF,and treatment A2 was by 4.08% in the next.Treatment A4 showed much better effect in increasing soil organic carbon and total nitrogen in the paddy soil than those of treatments applying mineral fertilizer only.There was a significant reduction on soil organic carbon and TN in treatment A2 in comparison with that of CF.In general,amount of application of milk vetch with 22 500 kg/hm^2 could replace chemical fertilizer partially,it also could improve rice yield,decrease the production cost,and raise the utilization efficiency of nutrients.

Effects of FCMP Compound Fertilizer on Development and Yield of Early Rice

[Objective] The aim was to explore effects of FCMP compound fertilizer on growth, development and yield of early rice. [Method] Based on lower-graded phos- phate resource, effects of FCMP compound fertilizers on yield and growth of early rice in a field were researched. [Result] FCMP compound fertilizers 0, 1 and 2 en- hanced rice yield, increasing by 21.86%, 20.25% and 13.46%, compared with the rice applied with conventional fertilizer; number of productive ears and grain number per ear in unit area were improved by FCMP compound fertilizer, for example, the two factors achieved the highest with FCMP compound fertilizer 1, increasing by 11.70% and 19.63%. Furthermore, FCMP compound fertilizer promoted plant height and tiller number, maintained high photosynthetic efficiency, enhanced lodging-resis- tance and guaranteed stable and high yield. [Conclusion] The research is of theoret- ical and practical significance for further exploration of production techniques and application of FCMP compound fertilizer.

Effects of different types of slow-and controlled-release fertilizers on rice yield

This experiment explored the effects of single application of seven types of slow-and controlled-release fertilizers on rice yield and various population characteristics.Based on a study of the nitrogen(N)release characteristics of these fertilizers,pot experiments were conducted in 2018 and 2019 with split fertilization(CK,urea applied split equally at basal and panicle initiation stages,respectively)as control,which assessed the effects on SPAD value,yield and yield components,dynamic changes of rice tillers and dry matter accumulation.The results showed that the N release characteristics of different types of slow-and controlled-release fertilizers were significantly different.Polymer-coated urea(PCU)showed a controlledrelease mode and provided sustained release throughout the whole growth stages.Sulfur-coated urea(SCU)exhibited a slow-release mode,providing insufficient release at the middle and late stages.Urease inhibitor urea(AHA)and ureaformaldehyde(UF)yielded a rapid-release mode,with an explosive N release at the early stage and no release at the middle and late stages.These results showed that PCU delayed the peak seedling stage.Compared with CK,dry matter accumulation and SPAD showed no significant differences,and due to the continuous release of N throughout the growth stages,rice yield,spikelets per panicle,seed setting rate,and 1000-grain weight were all increased.Owing to the lack of N supply at the late stage and the low number of spikelets,SCU led to a reduction of rice yield,which is nevertheless not statistically significant.AHA and UF were susceptible to environmental factors and had varying effects on rice yield.The results of this experiment indicated that given a fixed amount of N applied in a pot,the stronger the N supply capacity and the longer the effective duration time of the fertilizer,the higher the dry matter accumulation at the late growth stage,and the higher the rice yield.

Influence of Organic and Inorganic Nitrogen on Grain Yield andYield Components of Hybrid Rice in Northwestern Pakistan

Field experiments were conducted to assess the impact of various organic sources, inorganicnitrogen （N） and the different combinations of inorganic N （urea） ＋ organic source on the yieldcomponents （YC） and grain yield （GY） of hybrid rice （Oryza sativa L., Pukhraj） under rice-wheat system.The experiments were conducted at Batkhela （Malakand）, Northwestern Pakistan, in 2011 and 2012.Our results revealed that YC and GY ranked first for the hybrid rice when applied with sole inorganic N（urea）, followed by the application of N in mixture （urea ＋ organic sources）, while the control plots （no Napplied） ranked in the bottom. Among the six organic sources （three animal manures： poultry, sheepand cattle; three crop residues： onion, berseem and wheat）, application of N in the form of poultrymanure was superior in terms of higher YC and GY. When applying 120 kg/hm2 N source, 75% N fromurea ＋ 25% N from organic source resulted in higher YC and GY in 2011, while applying 50% N fromurea ＋ 50% N from organic sources caused higher YC and GY in 2012. Therefore, the combinedapplication of N sources in the form of urea ＋ organic source can produce good performances in termsof higher YC and GY of rice under rice-wheat cropping system.

Effects of Film-Degraded Rice Controlled Release Fertilizer on the Nitrogen Uptake and Yield of the Hybrid Rice

Field experiment was carried out to nitrogen release characteristics of rice controlled release fertilizer (RCRF) coated with natural and half natural high molecular materials, and to thereof effects on the nitrogen uptake and yield of early and late hybrid rice from 1999 to 2000, with urea as control.In experimental fields regardless of early and late seasons, the amount of N in the plants increased exponentially at the early growth stage (y=abx) and nonlinearly at the middle and late growth stages (y=a+bx+cx2).Rice controlled release fertilizer lengthened the exponential phase and increased the parameter -b/c during the nonlinear phase. Although the N amount of plants was less in rice controlled release fertilizer plots man in urea plots within 20 days after transplanting, at the heading and maturity stages, the N amount of plants in rice controlled release fertilizer plots was above two times greater than in the urea plots due to the higher N recovery, and the high absorption density of N in the nonlinear phase.Tillers pattern and achievement of the maximum tillering stage varied with fertilizer types. The maximum tillering stage in the urea plots occurred a week earlier than in the rice controlled release fertilizer plots. Yield sink size and potential sink size of the plants reflected the N absorption pattern and the amount of N in the plants. The yields of early and late rice with 90 kg N ha-1 of rice controlled release fertilizer were respectively increased by 832.7 kg ha-1 and 412.8 kg ha-1 than those with 90 kg N ha-1 of urea, almost equivalent to the yield of early and late hybrid rice with 180 kg N ha-1 of urea.

Effects of Silicon Fertilizer on Rice Blast (Magnaporthe oryzae) Green Control, Rice Growth and Yield

Three doses of silicon fertilizer and seven dominant rice varieties were selected to study the effects of silicon fertilizer on rice blast(Magnaporthe oryzae)green control,rice growth and yield.The results showed application of silicon fertilizer had certain control effect on panicle blast,and was beneficial for rice growth and yield.However,application effect varied among different varieties,and application of silicon fertilizer at the dose of 225 kg/hm2 received the best effect.Applying silicon fertilizer to control rice blast is safe and environmental-friendly,which is beneficial to the production of green food production.