Integrated assessment of yield,nitrogen use efficiency and ecosystem economic benefits of use of controlled-release and common urea in ratoon rice production

Controlled-release urea(CRU)is commonly used to improve the crop yield and nitrogen use efficiency(NUE).However,few studies have investigated the effects of CRU in the ratoon rice system.Ratoon rice is the practice of obtaining a second harvest from tillers originating from the stubble of the previously harvested main crop.In this study,a 2-year field experiment using a randomized complete block design was conducted to determine the effects of CRU on the yield,NUE,and economic benefits of ratoon rice,including the main crop,to provide a theoretical basis for fertilization of ratoon rice.The experiment included four treatments:(i)no N fertilizer(CK);(ii)traditional practice with 5 applications of urea applied at different crop growth stages by surface broadcasting(FFP);(iii)one-time basal application of CRU(BF1);and(iv)one-time basal application of CRU combined with common urea(BF2).The BF1 and BF2 treatments significantly increased the main crop yield by 17.47 and 15.99%in 2019,and by 17.91 and 16.44%in 2020,respectively,compared with FFP treatment.The BF2 treatment achieved similar yield of the ratoon crop to the FFP treatment,whereas the BF1 treatment significantly increased the yield of the ratoon crop by 14.81%in 2019 and 12.21%in 2020 compared with the FFP treatment.The BF1 and BF2 treatments significantly improved the 2-year apparent N recovery efficiency,agronomic NUE,and partial factor productivity of applied N by 11.47-16.66,27.31-44.49,and 9.23-15.60%,respectively,compared with FFP treatment.The BF1 and BF2 treatments reduced the chalky rice rate and chalkiness of main and ratoon crops relative to the FFP treatment.Furthermore,emergy analysis showed that the production efficiency of the BF treatments was higher than that of the FFP treatment.The BF treatments reduced labor input due to reduced fertilization times and improved the economic benefits of ratoon rice.Compared with the FFP treatment,the BF1 and BF2 treatments increased the net income by 14.21-16.87 and 23.76-25.96%,respectively.Overall,the one-time blending use of CRU and common urea should be encouraged to achieve high yield,high nitrogen use efficiency,and good quality of ratoon rice,which has low labor input and low apparent N loss.

Assessing the yield difference of double-cropping rice in South China driven by radiation use efficiency

Double-cropping rice in South China continues to break the total yield record,but the yield potential of singlecropping rice is not being realized.Radiation use efficiency(RUE)has been singled out as an important determinant of grain yield in many cereal species.However,there is no information on whether the yield gaps in doublecropping rice involve differences in RUE.Field experiments were performed over two years to evaluate the effects of intercepted radiation(IP)and RUE on the above-ground biomass production,crop growth rate(CGR),and harvest index(HI),in four representative rice varieties,i.e.,Xiangyaxiangzhan(XYXZ),Meixiangzhan 2(MXZ2),Nanjingxiangzhan(NJXZ),and Ruanhuayoujinsi(RHYJS),during the early and late seasons of rice cultivation in South China.The results revealed that grain yield in the early season was 8.2%higher than in the late season.The yield advantage in the early season was primarily due to higher spikelets per panicle and above-ground biomass resulting from a higher RUE.The spikelets per panicle in the early season were 6.5,8.3,6.9,and 8.5%higher in XYXZ,MXZ2,NJXZ,and RHYJS,respectively,than in the late season.The higher early season grain yield was more closely related to RUE in the middle tillering stage(R^(2)=0.34),panicle initiation(R^(2)=0.16),and maturation stage(R^(2)=0.28),and the intercepted photosynthetically active radiation(IPAR)in the maturation stage(R^(2)=0.28),while the late season grain yield was more dependent on IPAR in the middle tillering stage(R^(2)=0.31)and IPAR at panicle initiation(R^(2)=0.23).The results of this study conclusively show that higher RUE contributes to the yield progress of early season rice,while the yield improvement of late season rice is attributed to higher radiation during the early reproductive stage.Rationally allocating the RUE of double-cropping rice with high RUE varieties or adjustments of the sowing period merits further study.

Regulation effects of water and nitrogen on yield,water,and nitrogen use efficiency of wolfberry

Wolfberry(Lycium barbarum L.)is important for health care and ecological protection.However,it faces problems of low productivity and resource utilization during planting.Exploring reasonable models for water and nitrogen management is important for solving these problems.Based on field trials in 2021 and 2022,this study analyzed the effects of controlling soil water and nitrogen application levels on wolfberry height,stem diameter,crown width,yield,and water(WUE)and nitrogen use efficiency(NUE).The upper and lower limits of soil water were controlled by the percentage of soil water content to field water capacity(θ_(f)),and four water levels,i.e.,adequate irrigation(W0,75%-85%θ_(f)),mild water deficit(W1,65%-75%θ_(f)),moderate water deficit(W2,55%-65%θ_(f)),and severe water deficit(W3,45%-55%θ_(f))were used,and three nitrogen application levels,i.e.,no nitrogen(N0,0 kg/hm^(2)),low nitrogen(N1,150 kg/hm^(2)),medium nitrogen(N2,300 kg/hm^(2)),and high nitrogen(N3,450 kg/hm^(2))were implied.The results showed that irrigation and nitrogen application significantly affected plant height,stem diameter,and crown width of wolfberry at different growth stages(P<0.01),and their maximum values were observed in W1N2,W0N2,and W1N3 treatments.Dry weight per plant and yield of wolfberry first increased and then decreased with increasing nitrogen application under the same water treatment.Dry weight per hundred grains and dry weight percentage increased with increasing nitrogen application under W0 treatment.However,under other water treatments,the values first increased and then decreased with increasing nitrogen application.Yield and its component of wolfberry first increased and then decreased as water deficit increased under the same nitrogen treatment.Irrigation water use efficiency(IWUE,8.46 kg/(hm^(2)·mm)),WUE(6.83 kg/(hm^(2)·mm)),partial factor productivity of nitrogen(PFPN,2.56 kg/kg),and NUE(14.29 kg/kg)reached their highest values in W2N2,W1N2,W1N2,and W1N1 treatments.Results of principal component analysis(PCA)showed that yield,WUE,and NUE were better in W1N2 treatment,making it a suitable water and nitrogen management mode for the irrigation area of the Yellow River in the Gansu Province,China and similar planting areas.

Effect of Slow and Controlled Release Fertilizers on the Yield and Nutrient Use Efficiency of Hot Pepper in Qiu-bei

[Objective] The aim of this study was to investigate the impacts of slow and controlled release fertilizers（SCRF）on the yield of qiubei hot pepper,its nutrient use efficiency and environment.[Method] Using Qiubei hot pepper（Capsicum frutescens L.）as the experimental material,we studied the fertilization effect and environment-protecting effect of SCRF.[Result] The result showed that SCRF could improve the agronomic characteristics of hot pepper.Compared to singly applied common fertilizers,SCRF increased economic yield by 20.90% and economic benefit by 13 234.35 Yuan/hm2,and the ratio of output to input was improved by 47.93%.In comparison with common straight fertilizers at same NPK proportion and rate,SCRF increased economic yield by 5.26% and economic benefit by 5 554.80 Yuan/hm2,and the ratio of output to input was improved by 9.91%.Under the reduced use of SCRF by 20%,SCRF increased economic yield by 12.38% and economic benefit by 9595.20 Yuan/hm2 compared with singly applied common fertilizers,and the ratio of output to input was improved by 65.95%.SCRF improved nitrogen,phosphorus and potassium use efficiencies by 12.42-17.53,3.35-5.24 and 5.37-14.02 percents respectively.[Conclusion] As the result of much reduced N and P application rates,SCRF would significantly economize fertilizer resources and minimize the pollution caused by the loss of fertilizer nutrients,which is of practical importance for environment protection.

Effects of Slow Release Fertilizer on the Yield and Nutrient Use Efficiency of Carnation and Its Environmental Protection Effect

[Objective] The aim was to study the effects of slow release fertilizer on the yield,economic benefit and nutrient use efficiency of carnation and environmental pollution.[Method] Taking carnation（Dianthus caryophyllus）as research object,the application effect and environmental protection effect of slow release fertilizer on carnation were discussed through field plot test.[Result] The main agronomic characters of carnation improved after the application of slow release fertilizer;compared with Conv-F treatment,the yield of carnation with slow release fertilizer increased by 18.67%-20.83%,and its economic benefit increased by 105 500 yuan/hm2,while the ratio of output to input improved by 74.29%;under the same NPK ratio and nutrient amount,the yield,economic benefit and ratio of output to input of carnation after the application of slow release fertilizer increased by 2.11%,14 800 yuan and 16.2%,respectively;besides,the application of slow release fertilizer improved the nutrient use efficiency of carnation,and N,P and K nutrient use efficiency in Opt-F-0.7% treatment increased by 13.88%,8.57% and 30.14% compared with Conv-F treatment.[Conclusion] Slow release fertilizer could not only reduce the waste of fertilizer resources and improve fertilizer use efficiency but also decrease the pollution caused by nutrient loss,which had important practical significance for protecting ecological environment and promoting the sustainable development of agriculture.

Effects of Different Tillage Techniques on Yield and Water Use Efficiency in Broomcorn Millet

[Objective] The effects of different tillage techniques on dry matter accu- mulation, soil water content, water use efficiency and yield of broomcom millet were studied. [Method] With Jinsu 9 as an experiment material, the effects of deep tillage, traditional tillage and no tillage and rotary tillage on dry matter accumulation, soil water content, water use efficiency and yield of broomcom millet were investi- gated. [Result] Dry matter accumulation rate and accumulated amount were signifi- cantly higher in the deep tillage, no tillage and rotary tillage treatments than in the conventional tillage treatment, and the highest in the deep tillage treatment. The soil water content of the deep tillage treatment at 0-100 cm was higher than those of other tillage techniques, deep tillage also exhibited the highest soil water storage, and water use efficiency values were in order of deep tillage〉rotary tillage〉no tillage〉conventional tillage. The deep tillage treatment also showed the highest grain weight per spike, 1 000-grain weight and yield, while conventional tillage exhibited the lowest values, indicating that deep tillage is most beneficial to improvement of yield and water use efficiency of broomcom millet. [Conclusion] This study provides a scientific basis for water use efficiency of broomcorh millet in its main producing areas.

Effects of Controlled-Release Nitrogen on Yield and Nitrogen Use Efficiency of Summer Maize

The field experiments were conducted in Anhui during 2016 to investigate the effects of controlled-release nitrogen （CRN） rates and mixture of controlled-re- lease nitrogen and conventional nitrogen （CN） on the yield and nitrogen efficiency of summer maize. Six treatments included CK （with no application of N）, CNIO0% splits （CN）, CRFIO0% （CRN1）, CRN60%＋CN40% （CRN2）, CRN85% （CRN3） and CRN70% （CRN4）. The results showed proper CRN increased yields and output val- ue. Compared with CN, CRN2 significantly increased by 13.74%, CRN1 increased by 4.84%, and CRN3 was equal to CN. CRN increased yield by grain number per spike of yield components. CRN2 had the highest apparent nitrogen fertilizer recov- ery efficiency and CRN1 was the second, which were significantly higher than CN. Nitrogen agronomic efficiency of CRN2 was significantly higher than CN. Nitrogen physiological efficiency of CRN2 was higher than CN. The partial productivity of CRN1 was higher than that with CN. And the effect of nitrogen fertilizer of CRN2 was the highest, which was increased 758 yuan/hm2. Considering yield, nitrogen use efficiency and economic benefit, applying the mixture of CRN and CN was the most beneficial treatment. CRN1 was the second treatment, and CRN3 didn＇t reduce yield.

Effects of Potassium Fertilizing Rates on Yield, Fiber Quality and Potassium Use Efficiency of Three Hybrid Cotton Cultivars

The effects of potassium （K） application rates on the yield, fiber quality and K fertilizer use efficiency of three hybrid cotton varieties （Jin102, Xiangzamian8, Siyang328） were studied in field experiment. Fertilizer rates of K2O 135 and 270 kg/hm2, representing 1x and 2x recommended K rates, were applied, no application of k fertilizer as the CK. The results show that the lint yield increased 39.13%-57.48%with potassium application, highly significantly. Al yield components of the three hy-brid cotton varieties increased with the increase of K application amounts. The bol number per plant, single bol weight and lint percentage were increased by 14.24%-40.29%, 3.59%-15.51% and 0.16%-4.89%, respectively, and the fiber length and specific strength also increased with the increasing K application amounts, showing no significant influence on Micronaire. When the K application amounts increased from 135 to 270 kg/hm2, the partial factor productivity （PFPk） reduced by 45.93%-48.01%, and the agronomic efficiency （AEk） reduced by 37.1%-42.9%. The PFPk and KE （K efficiency coefficients） of S328 were the highest among the three varieties, which also showed the strongest resistance to low potassium stress, and with no potassi-um fertilizer application （K0）, the lint yield of S328 was 5.54% and 11.19% higher than that of X8 and J102. The AEk of J102 was the highest, and its reward of K fertilizer was the greatest among the three varieties.

Analysis of High Yield and Efficiency Technique in Hybrid Rice Zhongzheyou No.1

To understand the high yield and efficiency technique in hybrid rice Zhongzheyou No. 1, we conducted the correlation analysis, regression analysis and path analysis of hybrid rice Zhongzheyou No. 1 based on the data of its ear, grain and weight at different yield levels. From this study, we put forward the high yield and efficiency technique in Zhongzheyou No. 1 .. on the basis of certain effective ear number, filled grains per ear should be mainly targeted with a consideration to 1 000-grain weight.

Effects of Different Management Modes on Yield and Nutrient Efficiency of Ginger

In order to establish high-yield and high-efficient cultivation technology for ginger in the central region of Shandong Province, the effects of different manage-ment modes on yield of ginger, nutrient efficiency and soil nitrate were carried out by field experiment. Four management modes were farmer convention mode, high yield and high efficiency mode, super high yield mode and super high yield and high efficiency mode, in which farmer convention mode was local farmers ’ conven-tional cropping methods, the other three management modes were optimized combi-nations of al management measures under a certain goal of increasing yield and efficiency. The results were as fol ows： ginger yield and nitrogen fertilizer efficiency under such three optimized management measures combinations as high yield and high efficiency mode, super high yield mode and super high yield and high efficien-cy mode were al higher than these of farmer convention mode, moreover, com-pared with farmer convention mode, the yield increased by 11.85%, 25.75% and 23.34%, respectively, and nitrogen fertilizer efficiency increased by 47.94%, 11.24%and 33.14%, respectively. Thereinto, the yield under super high yield mode were the greatest,and nitrogen fertilizer efficiency under high yield and high efficiency mode was the highest.

Strategies for Jointly Enhancing Water Use Efficiency and Yield of Crops in the North China Plain

The North China Plain （NCP） is one of the most important agricultural re- gions in China, but it is experiencing a serious water-resource crisis due to exces- sive exploitation of groundwater reserves. Improving water-use efficiency （WUE） of crops is thought to have good potential for conserving groundwater and in maintain- ing high crop production in the region, In this paper, firstly, strategies for improving WUE of crop cultivars in the NCP were discussed. According to studies on key factors affecting cultivar WUE, stomatal conductance, which has large genotypic variability and differs among cultivars in response to drought, is an important physio- logical trait associating closely with the performance of cultivars in WUE and yield. Higher WUE and higher yield may be obtained through strategies of cultivar adop- tion with appropriate stomatal characteristics suitable to different conditions of water availability. Secondly, irrigation scheduling in the North China Plain was further dis- cussed. The irrigation frequency currently employed in this area could be reduced by at least one application （from four to three applications） to obtain higher produc- tion and also higher WUE. Finally, straw mulching and the use of early vigor culti- vats were suggested as two practices that had the potential to be effective in in- creasing crop WUE.

Effect of Different Fertilization Methods on Grain Yield and Nitrogen Agronomy Efficiency of TwoLine Super Hybrid Rice

ln order to explore the effect of broadcast application of urea （BR-U） and surface concentrated-fertilization on grain yield and nitrogen agronomy efficiency of two-line super hybrid rice, this experiment was conducted with super hybrid rice Y-Liangyou 1 and Liangyou 0293 to determine til ering dynamics, SPAD, LAl and dry matter accumulation. lts total N application was 180 kg/hm2 and different application rate and topdressing methods were set respectively. The results showed that grain yield and nitrogen agronomy efficiency were significantly improved with the T3 and T4 nitrogenous fertilizer application model. The improving of grain yield and nitrogen agronomy efficiency was benefited from rational postponing N application. However, neither single application of base fertilizer （T2） nor single application of topdressing fertilizer （T5 and T6） can coordinate the relationship between source and sink. Both grain yield and nitrogen agronomy efficiency were insignificantly under the broadcast application of urea and surface concentrated fertilization.

Straw return and appropriate tillage method improve grain yield and nitrogen efficiency of winter wheat

Straw return is an important management tool for tackling and promoting soil nutrient conservation and improving crop yield in Huang-Huai-Hai Plain, China. Although the incorporation of maize straw with deep plowing and rotary tillage practices are widespread in the region, only few studies have focused on rotation tillage. To determine the effects of maize straw return on the nitrogen （N） efficiency and grain yield of winter wheat （Triticum aestivum L.）, we conducted experiments in this region for 3 years. Five treatments were tested： （i） rotary tillage without straw return （RT）; （ii） deep plowing tillage without straw return （DT）; （iii） rotary tillage with total straw return （RS）; （iv） deep plowing tillage with total straw return （DS）; （v） rotary tillage of 2 years and deep plowing tillage in the 3rd year with total straw return （TS）. Treatments with straw return increased kernels no. ear-1, thousand-kernel weight （TKW）, grain yields, ratio of dry matter accumulation post-anthesis, and nitrogen （N） efficiency whereas reduced the ears no. ha-1 in the 2011-2012 and 2012-2013 growing seasons. Compared with the rotary tillage, deep plowing tillage significantly increased the grain yield, yield components, total dry matter accumulation, and N efficiency in 2013-2014. RS had significantly higher straw N distribution, soil inorganic nitrogen content, and soil enzymes activities in the 0-10 cm soil layer compared with the DS and TS. However, significantly lower values were ob- served in the 10-20 and 20-30 cm soil layers. TS obtained approximately equal grain yield as DS, and it also reduced the resource costs. Therefore, we conclude that TS is the most economical method for increasing grain yield and N efficiency of winter wheat in Huang-Huai-Hai Plain.

Optimizing integrative cultivation management improves grain quality while increasing yield and nitrogen use efficiency in rice

A major challenge in rice(Oryza sativa L.)production is to cope with increasing grain yield and fertilizer use efficiency without compromising grain quality.This study was designed to determine if optimizing integrative cultivation management in rice could improve grain quality while increase yield and nitrogen use efficiency(NUE).An indica-japonica hybrid rice cultivar and a japonica rice cultivar were grown in the field,with five cultivation managements including no N application(0 N),local farmer's practice(LFP),and three optimizi ng in teg rati ve cultivati on managements,reducing N rate and increasi ng plant density(ND),ND+alternate wetting and moderate soil drying irrigation(NDW),and NDW+applying rapeseed cake fertilizer(NDWR).The results showed that the optimizi ng integrative cultivati on man ageme nts could not only in crease grain yield,but also enhance NUE compared to LFP.Compared to LFP,NDWR sign ifica ntly in creased brow n,milled,head milled rice rate,ratio of the kern el le ngth to breadth and breakdown value of starch,whereas decreased amylose content,gel consiste ncy,prolamin con tent,setback value,perce ntage of chalky kern els,and chalki ness.The three optimizing in tegrative cultivation managements increased con tents of total protei ns,albumin and glutelin,activities of the key enzymes involved in the sucrose-starch con version in grains,root oxidati on activity,and malic and succinic acid concentrations in root exudates during the grain-filling period.The results suggested that optimizing integrative cultivation managements could improve grain quality meanwhile increase grain yield and NUE by enhancing physiological activities of rice plants.

Delayed sowing can increase lodging resistance while maintaining grain yield and nitrogen use efficiency in winter wheat

Lodging resistance of winter wheat(Trnticum aestivum L.) can be increased by late sowing.However, whether grain yield and nitrogen use efficiency(NUE) can be maintained with delayed sowing remains unknown. During the 2013-2014 and 2014-2015 growing seasons, two winter wheat cultivars were sown on three dates(early sowing on October 1, normal so,wing on October8, and late sowing on October 15) to investigate the responses of lodging resistance, grain yield,and NUE to sowing date. No significant differences in lodging resistance, grain yield, or NUE between early and normal sowing were observed. Averaging over the two cultivars and years,postponing the sowing date significantly increased lodging resistance by 53.6% and 49.6%compared with that following early and normal sowing, respectively. Lodging resistance was improved mainly through a reduction in the culm height at the center of gravity and an increase in the tensile strength of the base internode. Late sowing resulted in similar grain yield as well as kernel weight and number of kernels per square meter, compared to early and normal sowing.Averaging over the two cultivars and years, delayed sowing resulted in a reduction in nitrogen uptake efficiency(UPE) by 11.0% and 9.9% compared to early and normal sowing, respectively,owing to reduced root length density and dry matter accumulation before anthesis. An average increase in nitrogen utilization efficiency(UTE) of 12.9% and 11.2% compared to early and normal sowing, respectively, was observed with late sowing owing to a reduction in the grain nitrogen concentration. The increase in UTE offset the reduction in UPE, resulting in equal NUEs among all sowing dates. Thus, sowing later than normal could increase lodging resistance while maintaining grain yield and NUE.

Response of yield,quality,water and nitrogen use efficiency of tomato to different levels of water and nitrogen under drip irrigation in Northwestern China

The objective of this study was to investigate the effects of applying different amounts of water and nitrogen on yield, fruit quality, water use efficiency （WUE）, irrigation water use efficiency （IWUE） and nitrogen use efficiency （NUE） of drip-irrigated greenhouse tomatoes in northwestern China. The plants were irrigated every seven days at various proportions of 20-cm pan evaporation （Ep）. The experiment consisted of three irrigation levels （11, 50% Ep; 12, 75% Ep; and 13, 100% Ep） and three N application levels （N1, 150 kg N ha^-1; N2, 250 kg N ha^-1;and N3, 350 kg N ha^-1）. Tomato yield increased with the amount of applied irrigation water in 12 and then decreased in 13. WUE and IWUE were the highest in Ii. WUE was 16.5% lower in 12 than that in I1, but yield was 26.6% higher in 12 than that in I1. Tomato yield, WUE, and IWUE were significantly higher in N2 than that in N1 and N3. NUIE decreased with increasing N levels but NUE increased with increase the amount of water applied. Increasing both water and N levels increased the foliar net photosynthetic rate. I1 and 12 treatments significantly increased the contents of total soluble solids （TSS）, vitamin C （VC）, lycopene, soluble sugars （SS）, and organic acids （OA） and the sugar：acid ratio in the fruit and decreased the nitrate content. TSS, VC, lycopene, and SS contents were the highest in N2. The harvest index （HI） was the highest in 12N2. 12N2 provided the optimal combination of tomato yield, fruit quality, and WUE. The irrigation and fertilisation regime of 75% Ep and 250 kg N ha^-1 was the best strategy of water and N management for the production of drip-irrigated greenhouse tomato.

Effects of Real-Time and Site-Specific Nitrogen Managements on Rice Yield and Nitrogen Use Efficiency

Using hybrid rice Shanyou63, the agronomic and economic characters of different nitrogen(N) managements were evaluated. The results showed that the grain yield of the control(N omission plots) ranged from 6.8 to 7.4 t ha-1, indicating the high indigenous N supplyof the soil. Compared with farmers fertilizer practice (FFP, 240 kg N ha-1), the modifiedFFP (70% N of FFP), real-time N management (RTNM, applying N based on values ofchlorophyll meter) and site-specific N management (SSNM, applying nitrogen based on thetiming, amount of N and values of chlorophyll meter) increased the grain yield by 9.2-10.3%, 3.3-7.0% and 8.9-9.3%, and agronomic N efficiency (the increase in grain yieldper unit N applied) by 110.5-135.6%, 204.3-297.0% and 200.9-276.4%, respectively. Theresults suggested that RTNM and SSNM have great potential for improving N use efficiencywithout sacrificing the grain yield. In addition, RTNM and SSNM also decreased chalkygrain percentage and chalkiness to improve grain appearance quality.

Yield potential and nitrogen use efficiency of China's super rice

In 1996, a mega project that aimed to develop rice varieties with super-high yield potential （super rice） was launched by the Ministry of Agriculture （MOA） in China using a combination of the ideotype approach and intersubspecific heterosis. Significant progress has been made in the last two decades, with a large number of super rice varieties being approved by the MOA and the national average grain yield being increased from 6.21 t ha^-1 in 1996 to 6.89 t ha^-1 in 2015. The increase in yield potential of super rice was mainly due to the larger sink size which resulted from larger panicles. Moreover, higher photosynthetic capacity and improved root physiological traits before heading contributed to the increase in sink size. However, the poor grain filling of the later-flowering inferior spikelets and the quickly decreased root activity of super rice during grain filling period restrict the achievement of high yield potential of super rice. Furthermore, it is widely accepted that the high yield potential of super rice requires a large amount of N fertilizer input, which has resulted in an increase in N consumption and a decrease in nitrogen use efficiency （NUE）, although it remains unclear whether super rice per se is responsible for the latter. In the present paper, we review the history and success of China＇s Super Rice Breeding Pro- gram, summarize the advances in agronomic and physiological mechanisms underlying the high yield potential of super rice, and examine NUE differences between super rice and ordinary rice varieties. We also provide a brief introduction to the Green Super Rice Project, which aims to diversify breeding targets beyond yield improvement alone to address global concerns around resource use and environmental change. It is hoped that this review will facilitate further improvement of rice production into the future.

Effects of Different Tillage Systems on Soil Properties,Root Growth,Grain Yield,and Water Use Efficiency of Winter Wheat (Triticum aestivum L.) in Arid Northwest China

Studies on root development, soil physical properties, grain yield, and water-use efficiency are important for identifying suitable soil management practices for sustainable crop production. A field experiment was conducted from 2006 through 2008 in arid northwestern China to determine the effects of four tillage systems on soil properties, root development, water-use efficiency, and grain yield of winter wheat （Triticum aestivum L.）. The cultivar Fan 13 was grown under four tillage systems：conventional tillage （CT） without wheat stubble, no-tillage without wheat stubble mulching （NT）, no-tillage with wheat stubble standing （NTSS）, and no-tillage with wheat stubble mulching （NTS）. The soil bulk density （BD） under CT system increased gradually from sowing to harvest, but that in NT, NTSS, and NTS systems had little change. Compared to the CT system, the NTSS and NTS systems improved total soil water storage （0-150 cm） by 6.1-9.6 and 10.5- 15.3% before sowing, and by 2.2-8.9 and 13.0-15.1% after harvest, respectively. The NTSS and NTS systems also increased mean dry root weight density （DRWD） as compared to CT system. The NTS system significantly improved water-use efficiency by 17.2-17.5% and crop yield by 15.6-16.8%, and the NTSS system improved that by 7.8-9.6 and 7.0-12.8%, respectively, compared with the CT system. Our results suggested that Chinese farmers should consider adopting conservation tillage practices in arid northwestern China because of benefits to soil bulk density, water storage, root system, and winter wheat yield.

Effects of single basal application of coated compound fertilizer on yield and nitrogen use efficiency in double-cropped rice

Fertilizer plays an important role in increasing rice yield. More than half of all fertilizer applied to the field is not taken up, resulting in environmental damage and substantial economic losses. To address these concerns, a low-cost, coated compound fertilizer named "Xiang Nong Da"(XND), requiring only a single basal application, was studied. A two-year field experiment was conducted to test the effects of XND application on rice yield and nitrogen fertilizer use efficiency. An ordinary uncoated compound fertilizer(UNCF), with 20% more nutrients and split application was selected as the control. The yield of XND-treated rice was only 3.1% lower than that of the control, an insignificant difference. There were no significant differences between N use efficiency indices of the two fertilizer treatments except for N partial factor productivity(PFP_N). PFP_Nof XND treatment was 19.7%–23.2% higher than the control, a significant difference. This result indicates that a 20% decrease in N application rate is possible with XND without yield reduction and with savings in both labor and time.