Optimum Fertilizer Phosphorus Requirement for Maximum Productivity under Rice–Rice and Rice–Sunflower Systems in Semi-Arid Alfisols

A study was conducted at Hyderabad during 2009–11 to determine phosphorus (P) dose for rice–rice and rice–sunflower. Available P increased when 100% recommended P dose (RDP) was applied. P applied to rice gave at par yield under 100 or 75% RDP. In rice–rice, grain yield of 5668 and 5775 kg ha^?1 in kharif (5654 and 5760 kg ha^?1 in rabi) were attained with P@75 and 100% RDP. Kharif P residual effect in rabi affected rice yield. P@100/75% RDP in kharif and rabi gave grain of 5916/5973 and straw 6230/6673 kg ha^?1. P applied to sunflower revealed that yield was similar with 100 or 75% RDP. Sunflower yield was at par with P@100 or 75% RDP. 25% RDP in rice and sunflower may be reduced to attain similar yield of 100% RDP. In rice–rice, grain yield attained by 100% RDP in both seasons was 11.42t ha^?1 yr^?1, while 75% RDP gave yield of 11.45t ha^?1yr^?1.     

Effect of Sewage Sludge and Rice Straw Compost on Yield,Micronutrient Availability and Soil Quality under Rice–Wheat System

ABSTRACT

There is a need to improve the way in which crop residues and industrial organic wastes are managed and also to study their potential use in agriculture for improving soil fertility and biological activity. This study evaluated the effects of integrated use of organic (sewage sludge (SS) and rice straw compost (RSC)) and inorganic fertilizers on crop yield, soil enzymes activity, macro- and micro-nutrients availability under rice–wheat cropping system after three consecutive years of cropping in a subtropical semi-arid area. Different combinations of inorganic nitrogen and two doses of organic sources (SS and RSC) were applied to the soil. The results revealed that substitution with 50% N through RSC significantly increased the yield and biochemical properties as compared to inorganic fertilizers (NPK) alone. Micronutrients availability was found increased in treatment having substitution of 50% N through SS @10 t ha^?1. All the enzymatic activities viz. dehydrogenase, fluorescein diacetate (FDA), phosphatase, phytase, and urease) were found to be maximum by substitution of 50% N through RSC. Also, a significant positive correlation was found between soil enzymes (dehydrogenase and FDA) and organic carbon as well as crop yield. Thus, the study demonstrated that substitution of 50% inorganic nitrogen through organic sources will be a better alternative for improving soil quality and productivity.     

Screening Upland Rice Genotypes for Manganese‐use Efficiency

Manganese (Mn) deficiency in upland rice grown after common bean or soybean, which received adequate rate of liming on highly weathered Oxisols, is observed. A greenhouse experiment was conducted to evaluate Mn‐use efficiency of 10 promising upland rice genotypes. The genotypes were grown on an Oxisol at 0 mg Mn kg^?1 (natural soil Mn level) and 20 mg Mn kg^?1 of soil applied as manganese sulfate. Grain yield, panicle number, and grain harvest index (GHI) were significantly (P < 0.01) influenced by genotype. However, shoot dry weight was significantly affected by Mn as well as genotype treatments. Manganese uptake in the shoot as well as in the grain was also affected by genotype treatment. On the basis of Mn‐use efficiency (mg grain weight/mg Mn accumulated in shoot and grain), genotypes were classified as efficient and responsive (ER), efficient and nonresponsive (ENR), nonefficient and responsive (NER), and nonefficient and nonresponsive (NENR). Genotypes Carisma, CNA8540, and IR42 were classified as ER, and genotypes CNA8557 and Maravilha were classified as ENR. Genotype Caipo was in the group NER, and in the NENR group were genotypes Bonança, Canastra, Caraja, and Guarani. From a practical point of view, genotypes that produce high grain yield at a low level of Mn and respond well to Mn additions are the most desirable because they are able to express their high yield potential in a wide range of Mn availability.     

Effects of Rice Husk Ash and Bagasse Ash on Phosphorus Adsorption and Desorption in an Alkaline Soil under Wheat–Rice System

Rice husk ash (RHA) and bagasse ash (BA) are available in large quantities in South Asian countries growing rice and sugarcane. Land application of RHA and BA is likely to influence chemistry of soil phosphorus (P) and thereby P adsorption and desorption. Laboratory studies were carried out to investigate the short-term and long-term effects of RHA and BA application on P adsorption and desorption in an alkaline soil under a wheat–rice system. Addition of RHA or BA (10 Mg ha^?1) resulted in a significant decrease in P adsorption compared to the control. The decrease in P adsorption was lower when RHA and BA were applied to either rice or wheat as compared with when applied to both the crops. The BA was more effective in reducing P adsorption than RHA because of its greater P concentration. Fresh addition of RHA and BA at 1% (dry-weight basis) showed a small effect on P adsorption as compared to their long-term application. The Frendulich isotherm equation gave better fit with the experimental data than the Langmuir equation and is reliable to describe the P quantity/intensity relationships of this soil as affected by the additions of RHA and BA. The P-adsorption capacities (revealed from the Langmuir isotherms) of the unamended control, RHA, and BA (applied to both wheat and rice) were 256, 313, and 385 mg kg^?1, respectively; the corresponding bonding energies for the three treatments are 0.0085, 0.0041, and 0.0026 L kg^?1, respectively. Desorption of P was minimum in the control plots and maximum with BA followed by RHA, especially when applied to both the crops.     

Metal Contamination in Nullah Dek Water and Accumulation in Rice

A research study was carried out to determine the electrical conductivity （EC）, residual sodium carbonate （RSC）, sodium adsorption ratio （SAR）, pH and metals in metal-polluted irrigation water from a nullah and those in soils over a period of time, and the effect of metals on rice yield and metal concentrations in rice grain and straw. Two sites （I and If） were selected on the bank of Nullah Dek at Thatta Wasiran in Sheikhupura District （Pakistan）, with two rice varieties, Super Basmati and Basmati 385, at both sites. Water samples were collected during rice crop growth at 15-day intervals from August 3 to November 1, 2002. The results showed that Nullah Dek water had an EC 〉1.0 dS m^-1 and RSC of 2.78-4.11 mmolc L^-1, which was hazardous for crops, but the SAR was within the safe limit. Cu, Mn Cd and Sr were also within safe limits. The soil analysis showed that Site Ⅱ was free from salinity/sodicity, whereas Site Ⅰ was saline sodic. Among metals, Zn was sometimes deficient, Cu, Mn and Fe were adequate, and St, Ni and Cd were within safe limits in the soil at both the sites. After the rice crop harvest, concentrations of all metals tested were usually slightly increased, being higher in the upper soil layer than the lower. In addition, Basmati 385 produced higher rice grain and straw yield than Super Basmati. Chemical analysis of rice grain indicated the presence of Zn, Cu, Fe, Mn, Pb and Sr, whereas rice straw contained Zn, Cu, Fe, Mn and Sr, with Cd and Ni both being found in minute quantities.     

Senescence of Top Three Leaves in Field‐Grown Rice Plants

Abstract

The top three leaves play important roles in biomass production and grain yield of rice (Oryza sativa L.) crop since the three leaves not only assimilate majority of carbon for grain filling during ripening phase, but also provide large proportion of remobilized‐nitrogen (N) for grain development during their senescence. The objectives of this study were to (a) compare senescence of the top three leaves and (b) compare the changes in N, chlorophyll, and ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) contents of the top three leaves after their full expansion in field‐grown rice plants. When the basis of comparison among the top three leaves was plant age in terms of days after transplanting (DAT), senescence generally started earliest in ?3rd leaf, intermediate in ?2nd leaf, and latest in flag leaf. If the basis of comparison among the top three leaves was leaf age in terms of days after full leaf expansion (DAFE), it was not clear which leaf senesced earlier. Senescence rate was generally greatest in flag leaf, intermediate in ?2nd leaf, and smallest in ?3rd leaf. Ribulose‐1,5‐bisphosphate carboxylase/oxygenase content declined earlier, and at a faster rate than N and chlorophyll contents during the senescence of all top three leaves. Correlation analysis indicated a close relationship between N and chlorophyll contents. Ribulose‐1,5‐bisphosphate carboxylase/oxygenase content correlated with N content better than with chlorophyll content. The suitability of N, chlorophyll, and Rubisco contents for quantifying the leaf senescence of field‐grown rice plants is discussed.     

Rice yield and water use as affected by soil management practices

A field experiment was conducted at the Shenyang Experimental Station of Ecology, Chinese Academy of Sciences,to study the effects of soil management practices on water use and rice (Oryza sativa L.) yield in an axtuic brown soil during 2001 and 2002. A completely random experimental design with three replications was employed, having four soil management practices as treatments, namely: an undisturbed plow layer (CK), a thin plastic film (TN), a thick plastic film (TI) and subsoil compacting (CP). Results indicated no significant differences among all treatments for rice biomass and grain yields. Also, water consumption was about the same for treatments TN and CK, however the treatments TI and CP were much lower with more than 45% and 40% of the irrigation water in the treatments TI and CP, respectively,saved each year compared to CK. Therefore, water use efficiency was higher in the treatments TI and CP. These results will provide a scientific basis for the water-saving rice cultivation.     

Regionalization fro Rice Yield Estimation by Remote Sensing in Zhejiang Province

In order to provide a scientific basis for rice yield estimation and improve the acouracy of yield estimation in Zhejiang Province ,Regionalization indices for rice yield estimation by remoe sensing(RS) in the province were determined by consjdering the special features of yield estimation by RS ,and based on analysis of the natural conditions of Zhejiang Province ,The indices determined included rice cropping system ,agroclimate,landform,surface feature sturcture and rice yield level,where rice planting system was considered as the mian one ,Then reionalization fro rice yield estimation by RS was completed by spatial neighboring analysis with the Geographical Infromation System(GIS) technology combined with usig of tree algorithm The province was divided into two regions ,i.e.,the single-cropping rice region which was subdivided into 3 regions including those in mountains of northewst Zhejiang,water network area of north Zhejiang and mountains of soth Zhejiang,and double-cropping rice region which was sudivided into 5 regions including those on plain of north Zhejiang,coastal plains and hills of southeast Zhejiang,Jin-Qu Basin of middle Zhejiang,hills of east Zhejiang,and hills and mountains of northewat Zhejiang,this regionaliztion took the county borders as the region boundaries ,kept the regions connective and made the administrativ regions integrity and ,then,could meet the requirements of rice yield estimation by RS,showing that the results were quite satisfying.     

Rice genotype differences in nutrient status under excessive ferric‐iron conditions

To investigate the relationship between rice genotypic variation in tolerance to iron (Fe) toxicity and nutrient element status, 10 rice genotypes with different growing performances under Fe toxicity were grown under normal culture solution and with excessive ferrous (Fe²⁺)‐Fe concentrations of 250 and 500 mg Fe²⁺ L^‐1. A close relationship was obtained between the relative ratio of symptomatic leaf numbers to total leaf numbers (SLN/TLN) and a relative decrease in dry matter under Fe²⁺‐toxicity conditions. The genotypic variations in nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) uptake were evaluated by the relative decrease in the N, P, K, and Mg content in the plants. Remarkable genotypic variation in tolerance to excessive Fe²⁺ was observed. The results indicated that excessive Fe²⁺ reduced N, P, K, and Mg uptake. The nutrient element concentrations, however, were still higher above deficient criteria even in severely affected plants, suggesting that the retardation of growth may not be intirely due to the deficiency of these elements in plants at the seedling stage. Significant correlations were found between the genotypic variation and the decrease in N, P, K, and Mg uptake and in their tolerance to Fe²⁺ toxicity, which suggests that the ability to maintain higher nutrient element uptake under a Fe²⁺‐toxic condition contributes the tolerance to Fe²⁺ toxicity.     

Nutrient Uptake and Use Efficiency of Irrigated Rice in Response to Potassium Application

Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N,P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha^-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.     

IT—Information Technology: Simulation of Automatic Tray-unloading Operations for Rice Seedlings

In Taiwan, rice nursery centres widely adopt gantry transport systems for transferring seedling trays to/from the hardening field. To facilitate the loading and unloading procedures, a tray-unloading machine riding on top of a gantry has been developed which can orderly lay down the trays on the ground for field hardening and also pick up the trays of grown seedlings onto the loading conveyer in sequence when they are ready for transplanting. The whole system can be run automatically in an open field for seedling preparation.A simulation model for seeded tray-unloading operations by the automatic tray-unloading machine has been developed and verified with six operational conditions. Judging by the slight difference between the simulated and observed results, it was concluded that the model can accurately predict the real tray-unloading operations and, therefore, can be used as a tool for further sensitivity analysis on the maximum operation patterns.A model simulation for the total system was set up and analysed by various operation combinations. The results indicate that the system throughput can be increased from 771 to 957 trays h⁻¹ with 20 trays in a working row which represents an increase of 24·8%. Longer working rows will result in higher system throughput. The simulated results show that the system throughput changes from 771 trays h⁻¹ for 10 trays per row to 1140 trays h⁻¹ for 60 per row, with a significant increase of 48%.     

Nutrient Accumulation and Utilization in Rice Under Film‐Mulched and Flooded Cultivation

Abstract

In recent years, plastic film mulched cultivation has been widely used in China as a strategy to reduce irrigation water consumption and increase water use efficiency (WUE). Experiments were conducted to study nitrogen (N), phosphorus (P), and potassium (K) accumulation and utilization in flooded rice comparing plastic film mulched (PFM) and conventionally flooded cultivation (CFC) in two successive years. In comparison with the plants under CFC, the plants under PFM had significantly higher N concentration at booting stage and lower K and P concentrations at heading and maturity stages and N concentrations after booting stage. More N accumulation was found in PMC‐treated plants than in CFC‐treated plants before booting, while thereafter CFC showed a significant increase in nutrient accumulation. N, P, and K accumulation ratios were significantly larger for PFM than for CFC at early stage (before booting), but the trend was just opposite after booting. The PFM‐treated plants substantially showed smaller nutrient accumulation rate through the whole growing process relative to the CFC‐treated plants. Although PFM‐treated plants had significantly higher physiological efficiency (PE) of all three nutrients than the CFC‐treated plants, its fertilizer recovery efficiency (RE) and agronomic nutrient utilization efficiency (AE) was markedly lower due to lower biomass and grain yield. In addition, the PFM‐treated plants had lower P/N and K/N in terms of nutrient accumulation, suggesting the importance to improve the P and K availability in rice film‐mulched cultivation.     

Effects of Different Lead Compounds on Growth and Heavy Metal Uptake of Wetland Rice

Effects of different lead compounds, PbCl₂, Pb(NO₃)₂ and Pb(OAc)₂, on the rice growth and uptake of lead and some microelements by wetland rice were studied. The results showed that the seed germination, rice seedling growth, chlorophyl content, grain yield and uptake of Pb, Cu, Zn, Fe and Mn by rice plant were affected by the chemical forms of Pb compounds added in soil to a certain degree. The germination rate and the amount of chlorophyl decreased remarkably with increasing Pb concentration, the root extension was restrained obviously by the presence of Pb, and the effect of PbCl₂ was more evident than that of Pb(NO₃)₂ or Pb(OAc)₂.     

欢迎订阅2019年《中国水稻科学》、《Rice Science》

正《中国水稻科学》(ISSN 1001-7216,CN 33-1146/S)为中国水稻研究所主办的全国性学术期刊,主要报道以水稻为研究对象的未经发表的原始论文。所设栏目包括研究报告、研究简报、研究快报、研究简讯、实验技术、学术专论、文献综述等。读者对象为国内外从事水稻科研、教学、生产和管理的有关人员。同时,还办有《Rice Science》。《中国水稻科学》为中文核心期刊、中国科学引文索引数据库核心期刊,中国科技核心期刊,也是国内外30多种数     

Are Pseudokirchneriella subcapitata and Chlorella vulgaris Affected by Environmental Samples from a Rice Field?

Rice fields represent important production rates in Portugal. However, the intensive soil management and the exploitation of agrochemicals may pose a threat to nontarget organisms. Hence, the present work regards the toxicity screening of surface waters and sediment elutriates collected during the drainage of fields in the vicinity of a rice paddy (Quinta do Seminário, Soure, Portugal): 1. in River Pranto (RP), the river from which the field irrigation water is canalized; 2. inside the rice paddy, from the main drainage channel – Vala de Enxugo (VE). For that purpose, it was used a combination of physico-chemical analyses and bioassays with two green algae species – Pseudokirchneriella subcapitata and Chlorella vulgaris. The chemical screening showed an apparent absence of xenobiotics in sediment samples, while no pesticides were found within the chemical contaminants detected in water samples. The nutrient load reflected low levels of inorganic contamination. Bioassays revealed that P. subcapitata was more sensitive to the overall physico-chemical conditions in natural samples than C. vulgaris, being its growth inhibited under water samples from both sites. On a whole, water samples, mainly those from the main irrigation/drainage channel of the rice fields (VE), were more deleterious to microalgae than those from RP or any of the elutriates.     

Effect of Straw Incorporation on 15N‐Labeled Ammonium Nitrogen Uptake and Rice Growth

Abstract

A greenhouse experiment was conducted to determine the effect of rice straw residue on growth and uptake of added ¹⁵N‐labeled ammonium nitrogen (NH₄‐N) (3% ¹⁵N abundance at the rate of 150 kg N ha^?) by rice in Crowley silt loam soil (Typic Albaqualfs). Higher rates of rice straw addition had an adverse affect on plant growth from the first to sixth week. After 6 weeks, the high rice straw treatment had a positive effect on plant growth (P<0.05). The ¹⁵N‐labeled ammonium or fertilizer nitrogen (N) uptake by rice was significantly lower (P<0.05) in the high rice straw treatment as compared to lower rice straw treatments. Greater plant growth was recorded under alternate flooding and draining condition as compared to continuously flooded treatment (P<0.01).     

Effects of Different Organic Materials on Crop Production under a Rice–Corn Cropping Sequence

Soil organic matter (SOM) is an important index of soil quality because of its relationship with crop yield. The application of organic matter to soil is a significant method for increasing SOM. Different organic materials have varying effects in increasing SOM. This study investigates the effects of combining different sources of organic matter (i.e., compost, leguminous green manure, and peat) with a chemical nitrogen (N) fertilizer on the growth and N accumulation in corn and rice plants. This study examines seven treatments, including a no-fertilization check and a conventional chemical fertilizer treatment. Shoots of corn and rice were sampled at the tasseling (panicle initiation for rice) and maturity stages. The biomass yield was measured and the total N was analyzed. At the maturity stage, the soil samples were collected to determine the chemical properties. The results showed that a small percentage of the N in the compost and peat, after their application, was available to the crop during the growth season; the production of biomass and N absorption among rice and corn plants was minimal compared to that treated with chemical N fertilizer. The application of compost and peat resulted in SOM accumulation, particularly with peat. However, the application of compost combined with chemical fertilizer not only produced sufficient nutrients for crop growth but also resulted in an accumulation of SOM, which is vital for enhancing the soil quality. Most of the N in green manure (GM) was mineralized shortly after application, causing excessive growth of rice and corn plants during the early stage, but reducing their reproductive growth and grain yield.     

Effect of Amorphous Silicon Dioxide on Cadmium Behavior in the Soil–Rice Plant System

The effect of amorphous silicon dioxide (SiO₂) on cadmium behavior in the soil–plant system was studied in a field experiment on a flooded paddy soil slightly contaminated by cadmium. The application of amorphous SiO₂ results in a 1.3- to 1.8-fold smaller cadmium accumulation in the aboveground organs of rice and a 1.8- to 2.6-fold decrease in the content of its available compounds, which can be explained by metal sorption on the surface of applied silicon dioxide and by the reaction of monosilicic acid, which forms in the SiO₂ solution, with cadmium. The decrease in cadmium availability is most intensive in the first 2 weeks after SiO₂ application. Amorphous silicon causes a 26.6% increase in rice productivity in the first season and 72.9% in the second. The data obtained testify to the fact that the application rates of traditional mineral fertilizers can be decreased without risk to rice productivity if silicon compounds are used. They should become an integral and important part of implementing the 4R-STRATEGY for fertilizer application and plant nutrition optimization.     

Efficient Management of Nitrogen Fertilizers for Flooded Rice in Relation to Nitrogen Transformations in Flooded Soils

Recent progresses in efficient management of nitrogen fertilizers for flooded rice in relation to nitrogen transformations in flooded soil were reviewed.Considerable progress has been achieved in the investigation on the mechanism of ammonia loss and the factors affecting it .However,little progress has been obtained in the investigations on nitrification-denitrification loss owing to the lack of method for estimating the fluxes of gaseous N products.Thus,so far the management practices developed or under investigation primarily for reducing ammonia loss are feasible or promising,while those for reducing nitrification-denitrification loss seem obscure,except the point deep placement. In addition,it was emphasized that the prediction of soil N supply and the recommendation of the optimal rate of N application based on it are only semi-quantitative.The priorities in research for improving the prediction are indicated.