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The development and extension of Three Controls technology in Guangdong, China
... The overuse of N fertilizer and improper timing of application have resulted in low N use efficiency and serious environmental problems. Therefore, optimized N managements (OPT) were developed to achieve both higher yield and higher N use efficiency, such as site-specific N management [11], improved high-yielding cultivation [12], and "three controls" technology [13]. Among them, the "three controls" technology could effectively increase grain yield through increasing spikelets per panicle [14]. ...
... In this study, grain yield was greatly increased under OPT in spite of a reduction in N input, which was consistent with the results from previous studies [13,14]. Although much less N was applied at early growth stage, the number of panicles per m 2 was not decreased because of higher percentage of productive tillers under OPT [13]. ...
... In this study, grain yield was greatly increased under OPT in spite of a reduction in N input, which was consistent with the results from previous studies [13,14]. Although much less N was applied at early growth stage, the number of panicles per m 2 was not decreased because of higher percentage of productive tillers under OPT [13]. The panicle size was remarkably enlarged and filled grain rate was comparable under OPT with a considerable amount of N applied at panicle initiation stage ( Table 2). ...
Optimized nitrogen (N) management (OPT), with reduced total N input and more N applied during panicle development, has been proved to increase grain yield of rice through panicle enlargement. However, the changes in panicle architecture and source of variation are not well understood. A hybrid rice variety named Tianyou 3618 was subjected to OPT and farmer's fertilizer practice (FFP) in early cropping seasons of 2016 and 2017. With 16.7 % less N input, OPT increased panicle size by 8.6 % and 27.4 %, and grain yield by 13.8 % and 12.3 % for 2016 and 2017, respectively. OPT had greater dry matter accumulation and N uptake from panicle initiation to heading, which bolstered panicle enlargement. The number of surviving florets per branch was quite constant under different N treatments for all primary, secondary, and tertiary branches, implying that panicle size was mainly determined by the number of branches rather than the number of florets per branch. Little change was observed between OPT and FFP in differentiation, degeneration and survival of primary branches and their florets. Surviving secondary and tertiary branches and their florets were significantly more under OPT than those under FFP. The increase in surviving secondary branches under OPT resulted from both enhanced differentiation and reduced degeneration. While the increase in surviving tertiary branches under OPT was merely from enhanced differentiation though their degeneration was also dramatically increased. Among the increased differentiated florets under OPT, 32.4%–36.3 % and 61.6%–67.7 % came from secondary and tertiary branches, respectively. Among the increased surviving florets under OPT, 62.2%–65.2 % and 32.5%–37.8 % came from secondary and tertiary branches, respectively. Both secondary branches and tertiary branches were principal contributors to the increase in panicle size of OPT. To our knowledge, this is the first report on the detailed changes in panicle architecture and their involvement in panicle enlargement and yield gain under OPT.
... Meanwhile, seasonal fertilizer N input for rice growth was generally higher than 190 kg N ha − 1 . The average N recovery was lower than the global average level (Zhong et al., 2010;Deng et al., 2014). ...
... Varieties of efforts have been devoted to enhance the fertilizer N and irrigation water use efficiency in China during the past two decades. Several optimized N fertilization practices such as the balanced N fertilization, the precise and quantitative N application and the site-specific N management, etc., have been proven to increase NUE and reduce fertilizer N input in cropping systems effectively (Zhong et al., 2010;Liu et al., 2013;Ling et al., 2005). In South China, the 'three controls' technology with reduced total N input and increased panicle N application was developed and officially introduced to rice producers as optimized N management practice by the Ministry of Agriculture and Rural Affairs of China (OPTN) (http://dara.gd.gov.cn/sztjs/content/-post_3554120.html). ...
... Panicle N topdressing has greater N recovery efficiency than basal and tiller N fertilizer (Sui et al., 2013). Postponing N application and increasing the panicle N helps to prevent excessive growth of tillers and avoid waste of N nutrient by unnecessary vegetative growth (Zhong et al., 2010;Huang et al., 2017), while the biomass accumulation in grain-filling period increased (Xu et al., 2015b;Zhou et al., 2022). When more than 30% of fertilizer N was applied at PI and HD, the CGR, N uptake rate and plant N accumulation during the spikelet differentiation and grain-filling stage were substantially increased in optimized N management (Fig. 3). ...
... From China, two treatment villages, where "Three Controls Technology" (3CT) had been implemented by the extension program since 2007 (Zhong et al., 2010) and two villages with no intervention (with and without-extension program) were selected purposively to evaluate the impact of 3CT extension program on SRP PIs (Devkota et al., 2019). The China case study was used as an example of impact evaluation of extension outcomes. ...
... The 3CT program improved the overall performance of seven indicators by 27%; it increased yields, successfully reduced N fertilizer rates, reduced rice lodging rates, decreased the number of unproductive tillers, reduced nitrogen fertilizer losses, and increased NUE in Guangdong Province, China (Wang et al., 2017). It became a government-recommended technology in 2008, and the technology is welcomed by farmers as effective, reliable, cost-saving, and easy-to-use (Zhong et al., 2010). As this study showed, 25% improvement in the indicators (increasing the positive and decreasing the negative indicator (e.g., GHG emission) by 25%), the target values of 25% for the condition of China could be set as the target value. ...
Stakeholders have diverse purposes for analyzing economic, environmental and social sustainability indicators of rice production systems. Our aim was to show the added value of identifying external target values of the Sustainable Rice Platform’'s 12 performance indicators in addition to internal descriptive statistics values such as median and top decile performance for each indicator. Using household survey data from 1499 households in seven favorable rice production areas across seven countries in Asia, we identified baseline and target values appropriate to each indicator and illustrated their use for three purposes: assessing the outcomes of an extension program, comparing tradeoffs associated with two widely-used crop establishment methods, and providing individual feedback to a farmer about how to improve farm performance. We worked with our large survey data set and external reference values to calculate specific target values for each of the 12 indicators. These target values were used to evaluate the effectiveness of an extension program, showing that the extension program resulted in an improvement in scores for most indicators but did not achieve the target values for any of them. A comparison of wet-direct seeded rice (widely practice in irrigated regions of Vietnam, Thailand, and Sri Lanka) vs. puddled transplanted rice (China, Indonesia, Myanmar) indicated that there was a trade-off with wet-direct seeding having better labor productivity and greenhouse gas emission but worse pesticide use, and that both establishment methods had lower profitability than the target value. For the advice provided to an individual farmer, it was useful to be able to show both what the neighbors' average performance was and how far that was from the target values. Our illustrations demonstrate that using target values for indicators adds depth to the interpretation of indicator data.
... In all treatments, the 'three controls' technology was adopted for fertilizer management (Zhong et al., 2010). Fertilizer N was applied in the form of urea at 150 kg ha −1 for the early season and 180 kg ha −1 for the late season, with 40% as basal, 20% at midtillering (MT), 30% at panicle initiation (PI) and 10% at heading (HD). ...
... High N 2 O emissions occurred when a large amount of N fertilizer was applied to the field (Mosier and Zhu, 2000). In this research, the 'three controls' technology was adopted for fertilizer management, in which N fertilizer input was about 20% lower than farmer's fertilizer practice (Zhong et al., 2010). Further study should be carried out on safe AWD water management coupled with efficient fertilizer application to reduce CH 4 and N 2 O emissions simultaneously from rice paddies in south China. ...
... A previous study on quantification and comparison of economic and environmental indicators of SRP indicators in lowland rice production in six Asian countries indicates that significant improvement in the economic and environmental indicators is possible by promotion and widescale adoption of sustainable practices in the rice value chain and input (fertilizer, water, pesticide, seed, labor) optimization (Devkota et al., 2019a,b). Similarly, "three controls technology" (3CT; the efficient use of nutrients especially N; reduced unproductive tillers and lodging; and reduced spray of fungicide and insecticide; Zhong et al., 2010), one approach in China for sustainable rice production has proved to be effective in Guangdong Province for decreasing N fertilizer rate . The potential to reduce water and pesticide use, optimization of crop production inputs N-, P-, and K-fertilizers, seed rate, and pesticide application time and number, the option for increasing mechanization for reduced labor and child, and women empowerment for sustainably closing yield and profit gaps with reduced environmental footprint, which ultimately determines the sustainability of rice production system, could differ with establishment methods (DSR, manual PTR and MTR). ...
Sustainability of rice production systems is a prime concern for Asia to maintain food security and to support economic growth. This gain in productivity not only depends on agricultural inputs but also depends on social and environmental factors. To address these emerging issues, new resource- and capital-efficient and profitable technologies have been introduced. The conventional method of rice production (puddling and manual transplanting, PTR) is considered as highly input intensive. As an alternative, dry direct seeded rice (DSR) using seed drill has been promoted to save labor and production costs compared with PTR. Similarly, machine transplanted rice (MTR) has been also considered and promoted in many rice growing countries of South and East Asia. Economic, environmental, and social performances of DSR and MTR (alternative rice establishment technologies) were compared to the PTR using Sustainable Rice Platform (SRP) defined 12 Performance Indicators (PIs) (version 1.0) as a gauge to measure their sustainability. For that, a household survey was conducted on 652 households in Odisha India during 2016. The gaps, i.e., the target to achieve better sustainability, were computed for most of the indicators from the difference between top 10th percentile and the population mean value of the indicator. The results indicated a yield gap of 1.35 t ha-1, a profit gap of 130 ha-1), and the highest greenhouse gas (GHG) reduction potential. SRP PIs are capable for assessing the sustainability of rice establishment technologies except for a few indicators, for example food safety and workers health and safety, which are more applicable to watershed and household level indicators, respectively. The SRP PIs provide scientific evidence and practical impetus for the selection and promotion of sustainable rice production technologies.
... Ma et al., 2014) and other inputs (e.g. Heong et al., 2013) in rice cultivation recently resulted in the introduction of national best management approaches (Three Controls Technology and One Must Do Five Reductions, respectively) that aim to reduce input use (Heong et al., 2010; Zhong et al., 2010). Thus, identifying such issues are of key importance when targeting yield gaps. Table 1Common methods used to estimate yield benchmarks in rice production systems and a summary of their main limitations. ...
... We improved rice tolerance to adverse environmental factors and reduced population growth rate by increasing organic fertilizer and proportion of P and K fertilizers while reducing nitrogenous fertilizer. In fact, we were employing the "Three Controls" (control the amount of fertilizer, control the number of rice seedlings per hill and control the occurrence of pests) fertilizer application strategy, optimizing total nitrogen amount for improving nitrogen utilization efficiency, and minimizing pest population and pesticide usage (Zhong et al., 2012). Field experiment indicated that the population rice planthoppers can be strongly suppressed after rice booting stages by three control fertilizer application strategy ( (Zheng et al., 2009) ...
Ecological engineering is a relatively new concept of environmental manipulation for the benefit of man and the environment. Recently, a pioneering attempt was made in China to see if rice insect pest problems could be solved through ecological engineering. Five years of experimentation at Jinhua, Zhejiang Province in eastern China involved habitat manipulation based on growing nectar producing flowering plants (preferably sesame) combined with trap plants on the rice bounds, reducing the intensity of pesticide use and nitrogenous fertilizers, and managing the vegetation in non-rice habitats including the rice-free season. These practices increased biodiversity in the ecosystem, significantly increased biological control of rice pests, and provided biological stability in the ecosystem. Experimentation with ecological engineering in China indicated that it offers immense opportunities to rice pest management using non-chemical methods leading to economic and environmental benefits. Ecological engineering is not a “high-tech” approach so is simple and practical for rice farmers to implement. Having witnessed the benefits and utility of ecological engineering, the National Agriculture Technology Extension and Service Centre (NATESC) of Ministry of Agriculture has recommended it as the national rice pest management strategy in China.
Context or problem: Compound fertilizers containing nitrogen (N), phosphorus (P), and potassium (K) are often applied to rice (Oryza sativa L.) in Asia, but the fixed P:K ratio of these fertilizers can restrict the adjustment of P and K rates to match crop needs.
Objective or research question: We hypothesized that site-specific nutrient management (SSNM) using a locally available NPK fertilizer could increase rice yield and then that soil properties could be used to better adjust nutrient inputs to match crop needs.
Methods: Yield responses to added N, P, and K in on-farm nutrient omission plot technique (NOPT) trials across Indonesia were used to develop an SSNM practice, which was evaluated relative to farmer’s fertilizer practice (FFP) in 528 on-farm trials with lowland rice. Relationships of soil properties with yield responses were then examined across 38 additional trials on diverse soils.
Results: An SSNM practice with one NPK fertilizer supplying all P and K increased yield by 0.4 Mg ha− 1 and increased gross return above fertilizer cost by 173 USD ha− 1 compared to FFP. The SSNM practice used less N and P but slightly more K than FFP. Median relative yields — defined as the ratio of yield in a nutrient omission plot and yield in a full-fertilizer plot — were 0.75 without added N, 0.94 without added P, and 0.94 without added K for 252 NOPT trials. Based on NOPT trials, the SSNM practice could be improved by applying more K at some locations because the P:K ratio of 0.52 (P2O5:K2O = 1) for the NPK fertilizer was higher than the estimated optimum to meet crop needs. Higher K requirement was associated with soil pH < 5.5, soil K saturation < 1.8 %,
and soil base saturation < 40 %.
Conclusions: Farmer’s P use for rice can often be reduced with an upper limit for the P rate set to match the net
removal of P by the crop. An NPK fertilizer with P:K ratio = 0.44–0.52 would meet P and K requirements at many
locations, and a mid-season topdressing of additional K could be targeted to locations requiring more K. Higher K use could target areas with soil pH < 5.5, which could be approximated from soil maps and verified with soil test kits.
Implications or significance: The examination of associations between crop response to a nutrient and soil properties, other than soil nutrient status, merits use elsewhere to identify soil characteristics helpful in fine-tuning SSNM.
Rice–fish co-cultures have been practiced for over 2000 years, and they have tremendous potential in terms of increasing food security and economic benefits. However, little research has been conducted into achieving stable yields and high lodging resistance with regard to rice while simultaneously promoting the harmonious and healthy growth of fish in rice–fish co-culture paddy fields. We conducted a field study aimed at selecting suitable rice varieties for rice–fish co-culture systems (encompassing both ratoon and main crop). This selection process was grounded in an evaluation of lodging resistance and grain yield among 33 rice varieties used throughout the studied region. The results revealed a range of lodging indices of the main crop for the second internode, spanning from 62.43 to 138.75, and the annual grain yield (main crop and ratoon crop) ranged from 7.17 to 13.10 t ha⁻¹ within rice–fish co-culture systems. We found that the use of rice–fish co-culture farming could improve the milling quality, nutrient quality, and appearance quality of rice, though the improvement gained through co-culturing varied across rice varieties. Moreover, the lodging index of the three basal internodes of rice plants was significantly and positively correlated with the plant height and the culm fresh weight, but it was negatively correlated with the bending strength of the rice basal internodes. Additionally, the 33 tested rice varieties were clustered in accordance with their lodging resistance (i.e., high resistance with lodging indices 62.43–75.42; medium resistance with lodging indices 80.57–104.62; and low resistance with lodging indices 113.02–138.75) according to the hierarchical cluster analysis. The 33 rice varieties were also clustered in accordance with the annual (main crop and ratoon crop) grain yield (i.e., high yield with 11.17–13.10 t ha⁻¹; medium yield with 10.15–10.83 t ha⁻¹; and low yield with 7.16–9.88 t ha⁻¹). In all, 11 rice varieties were identified by a comprehensive evaluation as suitable varieties for grain production in the rice–fish co-culture system. These varieties displayed favorable traits, including a high annual rice yield, strong lodging resistance, and good grain quality. This is the first study to systematically evaluate rice varieties based on grain yield, lodging resistance, and grain quality in rice–fish co-culture systems.
Improving both grain yield and resource use efficiencies simultaneously is a major challenge in rice production. However, few studies have focused on integrating dense planting with delayed and reduced nitrogen application to enhance grain yield, nitrogen use efficiency (NUE) and radiation use efficiency (RUE) in rice (Oryza sativa L.) in the double rice cropping system in South China. A high-yielding indica hybrid rice cultivar (Yliangyou 143) was grown in field experiments in Guangxi, South China, with three cultivation managements: farmers’ practice (FP), dense planting with equal N input and delayed N application (DPEN) and dense planting with reduced N input and delayed N application (DPRN). The grain yields of DPRN reached 10.6 and 9.78 t ha–1 in the early and late cropping seasons, respectively, which were significantly higher than the corresponding yields of FP by 23.9–29.9%. The grain yields in DPEN and DPRN were comparable. NUE in DPRN reached 65.2–72.9 kg kg–1, which was 61.2–74.1% higher than that in FP and 24.6–30.2% higher than that in DPEN. RUE in DPRN achieved 1.60–1.80 g MJ–1, which was 28.6–37.9% higher than that in FP. The productive tiller percentage in DPRN was 7.9–36.2% higher than that in DPEN. Increases in crop growth rate, leaf area duration, N uptake from panicle initiation to heading and enhancement of the apparent transformation ratio of dry weight from stems and leaf sheaths to panicles all contributed to higher grain yield and higher resource use efficiencies in DPRN. Correlation analysis revealed that the agronomic and physiological traits mentioned above were significantly and positively correlated with grain yield. Comparison trials carried out in Guangdong in 2018 and 2019 also showed that DPRN performed better than DPEN. We conclude that DPRN is a feasible approach for simultaneously increasing grain yield, NUE and RUE in the double rice cropping system in South China.
Despite the overuse of fertilizer in China, yields have stagnated while environmental pollution has risen. To increase sustainable production, the “Three Controls” Technology (3CT) was adopted in Guangdong Province as an agricultural best management practice for rice production. Its goal is to reduce the fertilizer use of farmers while decreasing the number of unproductive tillers and controlling pests and diseases. The objective of this study was to determine the farmers’ perception of 3CT focusing on three different impact factors: economic, social, and environmental. Using a digital survey questionnaire application, 142 farmers from six villages in Guangdong Province were interviewed to evaluate perceived changes in their farming and livelihood since adopting 3CT. Results showed that the farmers were highly satisfied with 3CT. They perceived positive livelihood changes and increased agronomic performance with reduced fertilizer use. Farmers who had adopted 3CT for the longest perceived significantly higher levels of change, more benefits, and improved agricultural efficiency. The study showed that 3CT is highly appreciated by farmers due to its effectiveness, ease of use, and compatibility. Our model highlighted the relevance of including social and environmental impact analysis for sustainability research in agriculture. Ultimately, 3CT has the potential of being implemented in other regions of China.
Optimized agronomic management improves nitrogen (N) use efficiency in crop production. However, limited information exists about the effect of improved agronomic practices on the N surplus in double rice cropping system. In this study, we conducted field experiments to evaluate the N surplus for the prevailing farmers’ practices (FP), optimized N management (OPTN) and optimized N and water management (OPTNW) during 2016–2017 in Guangdong province, South China. Grain yield, recovery efficiency (REN), partial factor productivity (PFPN) and agronomic efficiency (AE) of applied N in OPTN and OPTNW were substantially higher than FP. The yearly N surplus and environmental N loss in OPTN were 29.4% and 26.2% lower than FP, respectively. The N surplus in OPTNW was 32.1% lower than FP. Annual N losses resulting from runoff and leaching in OPTNW were reduced by 45.0% and 17.4%, respectively, compared with OPTN. Pooled data of 22 on-farm field trials from six sites in 2014–2017 showed that N input in OPTN and OPTNW was 16.2%–33.8% lower than FP. The tradable N output in OPTN and OPTNW was 9.9% and 9.0% greater than FP, respectively. The N efficiency of cropping systems (NUEc) in OPTN and OPTNW was increased by 39.8% and 42.0%, respectively, compared with FP. N surplus notably increased with the increasing fertilizer N input, and decreased with the increasing tradable N output and NUEc. These results suggest that through optimized N and irrigation management, N surplus and environmental risk can be practically reduced in a double rice cropping system without yield penalty.
Overuse of nitrogen fertilizer represents a considerable environmental problem globally, but especially in China. Recently, a recent approach on an experimental scale based on the diffusion of the so-called Three-Control Technology (TCT) successfully alleviated the overuse of nitrogen fertilizer in southern China villages in the Guangdong Province, serving as a reference point for other rice-producing countries tackling similar challenges. Here, we assessed the correlation between rice yields and reduction in the use of nitrogen fertilizer following the introduction of TCT. Our study was based on the collection of primary data from 248 households randomly selected from four rice-growing areas of Guangdong Province, China. Our results show that TCT significantly improved the efficiency in the use of nitrogen. Crucially, participating farmers, including both full adopters and partial adopters, were found to fundamentally change their application practices of nitrogen fertilizer, resulting in major improvements in the local soil and water systems.
Nitrogen non-point pollution and greenhouse gas (GHG) emission are major challenges in rice production. This study examined options for both economic and environmental sustainability through optimizing water and N management. Field experiments were conducted to examine the crop yields, N use efficiency (NUE), greenhouse gas emissions, N losses under different N and water management. There were four treatments: zero N input with farmer's water management (N0), farmer's N and water management (FP), optimized N management with farmer's water management (OPTN) and optimized N management with alternate wetting and drying irrigation (OPTN + AWD). Grain yields in OPTN and OPTN + AWD treatments increased by 13.0–17.3% compared with FP. Ammonia volatilization (AV) was the primary pathway for N loss for all treatments and accounted for over 50% of the total losses. N losses mainly occurred before mid-tillering. N losses through AV, leaching and surface runoff in OPTN were reduced by 18.9–51.6% compared with FP. OPTN + AWD further reduced N losses from surface runoff and leaching by 39.1% and 6.2% in early rice season, and by 46.7% and 23.5% in late rice season, respectively, compared with OPTN. The CH4 emissions in OPTN + AWD were 20.4–45.4% lower than in OPTN and FP. Total global warming potential of CH4 and N2O was the lowest in OPTN + AWD. On-farm comparison confirmed that N loss through runoff in OPTN + AWD was reduced by over 40% as compared with FP. OPTN and OPTN + AWD significantly increased grain yield by 6.7–13.9%. These results indicated that optimizing water and N management can be a simple and effective approach for enhancing yield with reduced environmental footprints.
Tillering plays an important role in determining rice grain yield. Several models have been developed to predict tiller production in irrigated rice. In this paper we tested three models using data drawn from a wide range of plant densities and N inputs in two field experiments conducted at the International Rice Research Institute, Philippines during the 1997 and 1998 dry seasons. Two rice cultivars (IR64 and IR72) were used in the experiments. Plant samples were taken at intervals to determine number of tillers, leaf area index (LAI), biomass, relative growth rate (RGR) and leaf N concentration. The models were parameterized using an iteration procedure of the simplex method. Previous models (TIL and SINK) using the original values of parameters for IR64 failed to predict the number of tillers of IR64 in 1997. However, when re-parameterized, both models described the 1997 data well for both cultivars. The two models also predicted fairly well the number of tillers of different transplanting spacing and N input treatments of IR72 in 1998 using IR72 parameters derived from the 1997 experiment. A simple RGR model was comparable with the TIL and SINK models in descriptive and predictive ability. It appears that all three models could be used for predicting tiller production of irrigated rice.
Fertilizer K and P requirements for rice (Oryza sativa L.) can be determined with site-specific nutrient management (SSNM) using estimated target yield, nutrient balances, and
yield gains from added nutrient. We used the QUEFTS (QUantitative Evaluation of the Fertility of Tropical Soils) model with
>8000 plot-level observations to estimate the relationship between grain yield and nutrient accumulation in above-ground dry
matter of irrigated rice with harvest index ≥ 0.4. Predicted reciprocal internal efficiencies (RIEs) at 60–70% of yield potential
corresponded to plant accumulation of 14.6kgN, 2.7kg P, and 15.9kgK per tonne of grain yield. These RIEs enable determination
of plant requirements for K and P and net output of K and P in harvested grain and removed crop residues at a target yield.
Yield gains for nutrient applied to irrigated rice averaged 12% for K and 9% for P for 525 to 531 observations. For fields
without certain yield gain, fertilizer K and P requirements can be determined by a partial maintenance approach (i.e., fertilizer
input < output in nutrient balance), which considers nutrient supply mediated through soil processes and balances trade-offs
between financial loss with full maintenance rates and risk of excessive nutrient depletion without nutrient application.
When yield gains to an added nutrient are certain, partial maintenance plus yield gain can be used to determine fertilizer
requirements. The SSNM-based approach and algorithms enable rapid development of field-specific K and P management.
KeywordsField-specific nutrient management-Nutrient balance-SSNM-Rice-Wheat-Maize
Studies on tillering of the rice plant show that a tiller primordium is always present at each node of the culm (10). Whether the primordllun develops into a tiller depends on such factors as the nutritional status of the plant, the supply of carbohydrates, and the light and temperature conditions (2,3,5,6,7,8,9,11,12,13,14,15,17).
Relative tillering rate (RTR) increases linearly as leaf nitrogen concentration (NLV) increases in rice (Oryza sativa L.) plants. Leaf area index (LAI) has a negative effect on the emergence and survival of tillers. The objectives of this paper were to quantify the interactive effect of NLV and LAI on tillering in irrigated rice. Field experiments were conducted at Philippine Rice Research Institute (PRRI) and International Rice Research Institute (IRRI), Philippines during the dry seasons of 1995 and 1998. Two indica cultivars, IR72 and IR68284H, were subjected to various nitrogen (N) treatments. Number of tillers (including main stems), leaf area, and tissue N concentration were measured. The NLV explained a large part of variation in number of tillers m among treatments. However, the residual, defined as the difference between observed and estimated number of tillers m, was negatively correlated with LAI (P 0.05). The critical NLV and critical LAI for tillering to stop were interrelated; higher NLV was needed to prevent tillers from dying when LAI was high, and vice versa. Use of stem or shoot N concentration instead of NLV gave similar results. Results suggest that LAI, in addition to NLV, should be considered in predicting tillers in rice crop.
A field study was conducted at the International Rice Research Institute (IRRI), Philippines during the dry seasons of 1997 and 1998 under irrigated conditions. The objectives of this study were to quantify the critical leaf area index (LAIc) at which tillering stops based on the relationship between tillering rate and LAI, and to determine the effect of nitrogen (N) on LAIc in irrigated rice (Oryza
sativa L.) crop. Results showed that the relative tillering rate (RTR) decreased exponentially as LAI increased at a given N input level. The coefficient of determination for the equation quantifying the RTR-LAI relationship ranged from 0·87 to 0·99. The relationship between RTR and LAI was affected by N input level, but not by planting density. The N input level had a significant effect on LAIc with a high N input level causing an increase in LAIc. Tillering stopped at LAI of 3·36 to 4·11 when N was not limiting. Under N limited conditions LAIc reduced to as low as 0·98. Transplanting spacing and number of seedlings per hill had little effect on LAIc. Results from this study suggest that LAI and plant N status are two major factors that influence tiller production in rice crops. The possibility that LAI influences tillering by changing light intensity and/or light quality at the base of the canopy where tiller buds and young tillers are located is discussed.
Irrigated rice in China accounts for nearly 30% of global rice production and about 7% of global nitrogen (N) consumption. The low agronomic N use efficiency (AEN, kg grain yield increase per kg N applied) of this system has become a threat to the environment. The objective of this study was to determine the possibility to improve the AEN of irrigated rice in China by comparing the farmers’ N-fertilizer practices with other N management strategies such as real-time N management (RTNM) and fixed-time adjustable-dose N management (FTNM). Field experiments were conducted in farmers’ fields in four major rice-growing provinces in China in 2001 and 2002. The same experiment was repeated at the International Rice Research Institute (IRRI) farm in the dry seasons of 2002 and 2003. Agronomic N use efficiency was determined by the “difference method” using an N-omission plot. Maximum yield was achieved mostly at 60–120 kg N ha−1, which was significantly lower than the 180–240 kg N ha−1 applied in farmers’ practices at the Chinese sites. With the modified farmers’ fertilizer practice, a 30% reduction in total N rate during the early vegetative stage did not reduce yield but slightly increased yield and doubled AEN compared with the farmers’ practice at the Chinese sites. The total N rate in RTNM and FTNM ranged from 30 to 120 kg ha−1 at the Chinese sites, but their yields were similar to or higher than that of the farmers’ practice. Compared with the modified farmers’ practice, RTNM and FTNM further increased AEN at the Chinese sites. Overall, FTNM performed better than RTNM at the Chinese sites because the total N rate of FTNM was closer to the optimal level than RTNM. A quantum leap in AEN is possible in the intensive rice-growing areas in China by simply reducing the current N rate and by allocating less N at the early vegetative stage.
Relationship between productive tiller percentage and biomass accumulation in rice (Oryza sativa L.): a simulation approach
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Zhong XH, Peng SB, Sheehy JE, Liu HX. 2001. Relationship between productive tiller percentage and biomass accumulation in rice (Oryza sativa L.): a simulation approach. Chinese
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Application of the 'three controls' nutrient management technology of rice at Qujiang county of north Guangdong
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Rice Research Institute, Guangdong Academy of Agricultural Sciences
- Authors
Authors' addresses: Xuhua Zhong, Nongrong Huang, and Ka Tian, Rice Research Institute,
Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China; Shaobing
Peng, Roland J. Buresh, and Grant Singleton, International Rice Research Institute,
DAPO Box 7777, Metro Manila, Philippines. Email: xzhong8@163.com.
Agriculture and nitrogen cycle: assessing the impacts of fertilizer use on food production and the environment
- R J Buresh
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Buresh RJ, Peng SB, Huang JL, Yang JC, Wang GH, Zhong XH, Zou YB. 2004. Rice systems
in China with high nitrogen inputs. In: Mosier AR, Syers JK, Freney JR, editors. Agriculture and nitrogen cycle: assessing the impacts of fertilizer use on food production and
the environment. Washington, D.C. (USA): Island Press. p 143-153.
Application of 'three controls' technology at Leizhou of Guangdong province
- H R Wu
- W C Ding
- T Y Cai
- N R Huang
- X H Zhong
Wu HR, Ding WC, Cai TY, Huang NR, Zhong XH. 2008. Application of 'three controls' technology at Leizhou of Guangdong province. Guangdong Agric. Sci. 2008(12):79-80,86.
Nitrogen consumption of double-season hybrid rice and influence factors in South China
- X H Zhong
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Zhong XH, Huang NR, Zheng HB. 2007b. Nitrogen consumption of double-season hybrid rice
and influence factors in South China. Plant Nutr. Fert. Sci. 13:569-576.
Application of the 'three controls' nutrient management technology of rice at Xinhui county
- Y X Dai
- N R Huang
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