Rice genotype and fertilizer management for improving rice productivity under saline soil conditions

Paddy and Water Environment - Soil salinity is a threat to crop production in the Senegal River Delta where salt intrusion increases soil electrical conductivity and most of farmers had abandoned...     

Impact of water management on yield and water productivity with system of rice intensification (SRI) and conventional transplanting system in rice

The system of rice intensification (SRI) reportedly enhances yield with less water requirement. This claim was investigated to determine the effects of alternative cultivation methods and water regimes on crop growth and physiological performance. Treatment combinations compared SRI with the conventional transplanting system (CTS) using standard practices, evaluating both along a continuum from continuous flooding to water applications at 1, 3, 5, or 7 days after disappearance of ponded water (DAD), subjecting plants to differing degrees of water stress while reducing total water expenditure. SRI methods gave significant changes in plants’ phenotype in terms of root growth and tillering, with improved xylem exudation and photosynthetic rates during the grain-filling stage compared to CTS. This resulted in significant increases in panicle length, more grains and more filled grains panicle^?1, greater 1,000-grain weight, and higher grain yield under SRI management. Overall, averaged across the five water regimes evaluated, SRI practice produced 49 % higher grain yield with 14 % less water than under CTS; under SRI, water productivity increased by 73 %, from 3.3 to 5.7 kg ha-mm^?1. The highest CTS grain yield and water productivity were with the 1-DAD treatment (4.35 t ha^?1 and 3.73 kg ha-mm^?1); SRI grain yield and water productivity were the greatest at 3-DAD (6.35 t ha^?1 and 6.47 kg ha-mm^?1).     

水稻强化栽培适宜密度探讨

进行水稻强化栽培不同栽植密度试验,结果表明:稀植有利于水稻个体生长优势的发挥。随着栽植密度的减少,单株分蘖数、成穗率提高,单穗总粒数增加,纹枯病减轻。不同栽植密度对强化栽培水稻的单产有明显的影响,密度过低或过高,均不利于实现高产。单产以每公顷栽植12万丛(穴)为最高,达10050kg/hm2,分别比7.5万丛/hm2、21万丛/hm2、25.5万丛/hm2增产11%、11%和19.4%,达到极显著差异水平。     

Simulation of salt and water movement and estimation of water productivity of rice crop irrigated with saline water

The HYDRUS-ID model was experimentally tested for water balance and salt build up in soil under rice crop irrigated with different salinity water (ECiw) of 0.4, 2, 4, 6, 8 and 10 dS m⁻¹ in micro-lysimeters filled with sandy loam soil. Differences of means between measured (M) and HYDRUS-1D predicted (P) values of bottom flux (Q _o) and leachate EC as tested by paired t test were not found significant at P = 0.05 and a close agreement between RMSE values showed the applicability of the HYDRUS-1D to simulate percolation and salt concentration in the micro-lysimeters under rice crop. Potential ET values of rice as obtained from CROPWAT matched well with model predicted and measured one at all ECiw treatments. The model predicted root water uptake varied from 66.1 to 652.7 mm and the maximum daily salt concentration in the root zone was 0.46, 2.3, 4.5, 6.7, 8.4 and 10.2 me cm⁻³ in 0.4, 2, 4, 6, 8 and 10 dS m⁻¹ ECiw treatments, respectively. The grain production per unit evapotranspiration ( \textWP_{\textET\texta} {\text{WP}}_{{{\text{ET}}_{\text{a}} }} ) value of 2.56 in ECiw of 0.4 dS m⁻¹ treatment declined to 1.31 with ECiw of 2 dS m⁻¹. The \textWP_{\textET\texta} {\text{WP}}_{{{\text{ET}}_{\text{a}} }} reduced to one-fifth when percolation was included in the productivity determination. Similarly, the water productivity in respect of total dry matter production (TDM) was also reduced in different treatments. Therefore, the model predicted values of water balance can be effectively utilized to calculate the water productivity of rice crop.     

水稻强化栽培体系试验初报

水稻强化栽培体系 (SystemofRiceIntensification,SRI)系20世纪80年代由HenrideLaulanie神父在马达加斯加(Madagascar)提出的一种新的栽培方法 ,其主要技术要点为少株稀植短秧龄。根据袁隆平先生介绍的资料 ,我们于2002年开展相关试验 ,以探索SRI对提高水稻产量的可能性及在本地区的应用前景。一、材料与方法水稻强化栽培体系试验的种植密度设50cm×50cm(处理① )、37.5cm×37.5cm(处理② )、25cm×25cm(处理③ )三种处理 ,均为10天秧龄 ,以25cm×25cm、30天秧龄的常规栽培法为对照 ,随机排列 ,四次重复 ,试验小区面积为1.5m×7.5m=11.…     

Water productivity and nutrient status of rice soil in response to cultivation techniques and nitrogen fertilization

Three methods of rice cultivation were compared in a field experiment at New Delhi, India during 2012 for their water use and changes in nutrient availability of soil. The experiment was laid out in a split plot design with conventional transplanting (CT), system of rice intensification (SRI), and aerobic rice (AR) cultivation technologies. Five doses of nitrogen included 100 % (120 kg N ha^?1), 125, and 150 % recommended dose of N(RDN) through urea, 75 % of RDN through urea (90 kg N ha^?1) + 25 % of RDN (30 kg ha^?1) through farm yard manure (FYM), and 100 % of RDN through FYM. Results revealed that status of available N in soil under rice at 45 and 90 days after sowing (DAS) was significantly higher in CT and SRI compared to AR method. Application of the highest dose of nitrogen through urea resulted in the highest availability of N (188.9, 174.2, and 135.2 kg ha^?1 for 45 and 90 DAS and at harvest stage, respectively). The soil under AR recorded significantly low availability of phosphorus and iron. However, availability of K in soil was not affected significantly under adopted production techniques and nitrogen management. The recorded irrigation water productivity was maximum in AR cultivation (9.16 kg ha mm^?1) followed by SRI (7.02 kg ha mm^?1) with irrigation water saving of 54 and 36 %, respectively compared to CT.     

Irrigation of paddy soil with industrial landfill leachate: impacts in rice productivity,plant nutrition,and chemical characteristics of soil

Treated industrial effluents have high levels of nutrients and dissolved organic matter. The irrigation of rice by flooding can increase nutrient uptake and grain yield. Therefore, this study evaluated the nutrient contents in the shoots and grain of the rice crop and also the chemical of the soil after irrigation of the crop with leachate of the treated industrial effluent. A greenhouse experiment was conducted using pots filled with 20 kg of soil in a randomized block design with three replications. The treatments consisted of control (irrigation with distilled water) and four concentrations of the leachate (25, 50, 75, and 100 %) for irrigation. At the end of the experiment, the nutrient contents in tissues of rice plants, sterility of spikelets, and grain mass were evaluated. Results showed that irrigation with the leachate at 25 % content increased the macro- and micronutrients’ concentrations in the shoot biomass and grain, except for potassium and iron. Irrigation with the industrial leachate decreased tillering and grain yield; however, it increased chlorophyll content, sterility of spikelets, and sodium intake at this leachate concentration. The potassium and sodium levels and the electrical conductivity values of soils irrigated with treated industrial leachate were increased. The use of the treated leachate from industrial effluents is an alternative that reuses the nutritional load, but the volume of leachate should be limited and monitored to prevent the sodicity in the soil and problemsdue to eutrophication.     

Growth behavior,productivity, leaf rolling,and soil cracks on transplanted rice in response to enforce surface drainage

Intermittent and prolonged dry spell during growth of transplanted rice is an important abiotic problem in north eastern region (NER). However, the productivity of rice in the region is very low, and this is mainly associated with reduced plant population, growth, and yield attributes with lower relative water content and leaf rolling with formation of soil cracks by erratic and aberrant rainfall. Keeping this in view, a field experiment on transplanted rice was conducted during two consecutive years 2011 and 2012 at NER of India, to evaluate the imposition of forced surface drainage (SD) at various growth stages (continuous drainage, SD at tillering, SD at panicle initiation, SD at booting, SD at flowering, SD at milking, and 15 days intermittent SD) and was compared with continuous flooding on growth and yield attributes, yield, relative water content, leaf rolling, and formation of soil cracks. Results revealed that continuous flooding has significant (p < 0.05) improved the plant population, growth and yield parameters, rice grain yield (3,406.7 kg ha^?1) and straw yield (4,683.3 kg ha^?1), relative water content maintained >90 %, no leaf roll, and soil crack. However, imposition of SD at tillering has lower tillers hill^?1, but yield was compensated by improvement in yield attributes. As per the availability of water, growers of the region can utilize the water for scheduling of water and most critical stages can be avoided by moisture stress to obtain higher productivity.     

Labor requirements of system of rice intensification (SRI) in Cambodia

Local governments, NGOs, system of rice intensification (SRI) adopters, and researchers in Cambodia have extensively discussed the SRI. Agreement on the benefits, however, remains elusive. Some claim SRI increases rice yields at lower costs; others state that the evidence is still inconclusive. The adoption and impact of innovations influenced by the most practical SRI principles, which adopters can and do implement, as well as other SRI labor requirement have yet to be comprehensively investigated. This study aimed at elucidating and comparing distinct aspects of SRI labor requirements and conventional practices that can lead to more intensive SRI adoption. A household survey and field observations were conducted in three rain-fed villages in the southern part of Cambodia: two in Kampot Province and one in Kampong Speu Province. Findings showed little or no difference between SRI labor requirements and conventional practices. Laborers are in high demand when preparing land and nurseries, transplanting seedlings, and harvesting. Rice farmers alone or hired laborers have generally proved sufficient to date. Hired labor costs depend on the supply of farmer-family labor and the efficacy of the “Sharing-hand” system, not on farming techniques per se. This system helps alleviate hired labor costs, one of the highest cost factors. The findings also indicated that the degree of SRI adoption shows no correlation between the home-to-plot distance and availability of farmer-family labor or hired labor. The key factors for improving the degree of SRI adoption are farmer zeal and careful attention rather than the home-to-plot distance and availability of labor.     

水稻强化栽培体系的形成与发展

水稻矮秆品种和杂交稻及其相应的栽培技术配套使全球水稻单产稳步提高。由于这些技术基于大量化肥、除草剂、杀虫杀菌剂的应用基础上发展起来 ,加上水稻水层灌溉 ,使得近几十年来也发现水稻产量下降、病虫危害加剧、资源利用率低、环境污染、生产效益下降等不良现象 ,这严重限制了水稻可持续发展 ,并已引起国际社会的普遍关注。近十年来 ,马达加斯加在发达国家的支持下发展了一种新型的水稻强化栽培技术 ,并在生产上应用 ,取得了较好的效果 ,值得我们借鉴。本文概述了水稻强化栽培技术体系的形成与发展。一、水稻强化栽培体系起源于马达加斯…     

水稻强化栽培体系的原理及其应用效果

水稻强化栽培体系 (SystemofRiceIntensification,SRI)是1983年由Fr.HenrideLaulanie倡导和发展而成的。他在推广水稻生产技术中发现小苗移栽的水稻分蘖和产量能大幅度增加。后来进一步对小苗移栽和其他技术措施配套研究提出水稻强化栽培技术 ,于1993年发表了第一篇关于水稻强化栽培体系的论文。1990年在他的推动下在马达加斯加建立了ATS(AssociationofTefySaina)协会 ,这是一个非政府机构 ,目的是为了促进和改进水稻强化栽培体系 (SRI)。至今 ,在马达加斯加大约有10 %的水稻种植面积应用SRI技术。近年来主要技术在东南亚等产稻国…     

Assessing the acceptance of the system of rice intensification among farmers in rainfed lowland rice region of Cambodia

We conducted interview survey with rainfed rice farmers at a commune in southern Cambodia to identify the determinants of their adoption or rejection of the system of rice intensification (SRI) for the wet season of 2014. SRI was first introduced to the commune in 2003 and spread among the farmers, but the number of farmers discontinuing the practice has increased since 2011. We classified the farmers into four categories: those who practice SRI in all their fields (OA), farmers who practice SRI in some of their fields (PA), farmers who had practiced SRI but discontinued it (DA), and farmers who have never practiced SRI (CR). Farmers in different categories of SRI adoption differed in their access to water sources. The majority of OA and PA farmers had supplementary water sources, which was, however, available to less than 50% of DA farmers and only 15% of CR farmers. Both PA and DA farmers mentioned water shortage as the reason for not practicing SRI in some (PA) or any (DA) of their fields, but they differed in the number of rice fields. All the PA farmers had more than one field, whereas a majority of DA farmers had only one field. Labor shortage and difficulty of planting in a regular grid pattern were also mentioned as the reason for not practicing SRI by the farmers, particularly by DA farmers. Water constraint and difficulties in transplanting were thus identified as two major determinants of SRI adoption/rejection at the study site.     

盐碱对水稻生产的危害及防治对策

阐述了凌海市沿海地区水稻遭受盐碱危害的状况,分析了盐碱灾害发生的原因,并提出了选种抗盐品种、培育壮秧、提高田间工程标准、科学用水、适当施肥、调节盐碱、培肥地力等防治措施。     

IT field monitoring in a Japanese system of rice intensification (J-SRI)

A demonstration study on Information Technology (IT) field monitoring was conducted in a rice field under the System of Rice Intensification (SRI) environment in Shinshiro City, Aichi Prefecture, Japan. The IT system used in this study consisted of an intelligent sensor node web-server that is equipped with in situ camera and sensor networks for agrometeorological, soil, and plant growth monitoring. Dynamic changes in soil moisture, water level, agrometeorological, and environmental conditions were measured and monitored. With this precision farming set-up, understanding and easy assessment of the salient field conditions and phenomena such as cyclic soil wetting and drying as well as critical crop growth stages were made possible. Based on the findings of the demonstration experiment, the system was effective, reliable, and efficient in monitoring soil moisture parameters and agrometeorological information in remote rice field environment. The actual field conditions were captured well by a combination of images, numerical, and graphical data sets. With this precise information, the frequency of irrigation was found to be every 7 days. The rice field was irrigated up to a moisture level of 0.592 m³/m³ (~600 mV) and allowed to be depleted to a moisture level of 0.417 m³/m³ (~400 mV). With this alternate drying and wetting method (AWD), a 25.71% of irrigation water was saved. In this study, rice production was made more scientific and more reliable. Hence, the use of IT field monitoring system represented a viable medium for the realization of better rice productivity which leads to the ethic of sustainable agriculture.     

Mitigation of greenhouse gas emission with system of rice intensification in the Indo-Gangetic Plains

System of rice intensification (SRI) is an alternate method of conventional puddled, transplanted, and continuously flooded rice cultivation for higher yield, water saving, and increased farmer’s income. The SRI may also have considerable impact on greenhouse gas emission because of difference in planting, water and nutrient management practices. A field experiment was conducted with three planting methods: conventional puddled transplanted rice (TPR), conventional SRI with 12-days-old seedling (SRI) and modified SRI with 18-days-old seedling (MSRI) to study their effect on methane and nitrous oxide emission. Seasonal integrated flux (SIF) for methane was highest in the conventional method (22.59 kg ha^?1) and lowest in MSRI (8.16 kg ha^?1). Methane emissions with SRI and MSRI decreased by 61.1 and 64 %, respectively, compared to the TPR method. Cumulative N₂O–N emission was 0.69, 0.90, and 0.89 kg ha^?1 from the TPR, SRI, and MSRI planting methods, respectively. An average of 22.5 % increase in N₂O–N emission over the TPR method was observed in the SRI and MSRI methods. The global warming potential (GWP), however, reduced by 28 % in SRI and 30 % in MSRI over the TPR method. A 36 % of water saving was observed with both SRI and MSRI methods. Grain yield in the SRI and MSRI methods decreased by 4.42 and 2.2 %, respectively, compared to the TPR method. Carbon efficiency ratio was highest in the MSRI and lowest in the TPR method. This study revealed that the SRI and MSRI methods were effective in reducing GWP and saving water without yield penalty in rice.     

新开垦重盐碱地种植水稻技术

本文阐述了新开垦重盐碱地种稻获得高产应抓住的几项关键技术,包括建立健全排灌系统,灌水泡田洗盐,选择抗盐品种,培育壮秧,施肥、灌溉等技术。     

Effect of saline soil on grain quality of rices differing in salinity tolerance

Four varieties of rice, differing in salinity tolerance and grown in saline soil (electrical conductivity 5–6 dS/m) at Sadhoke, Punjab, Pakistan, had lighter grain and higher Na content than control samples. Grains of three out of the four rices grown on saline soils had higher brown rice protein (higher nutritional value), less translucent grain, lower starch and amylose content, and lower K than their control samples, but these differences were not related to salinity tolerance. Alkali spreading value and gel consistency were not affected by culture in saline soil. Cooked rice Instron hardness increased in saline culture in two higher-protein samples of the four rices. Amylograph peak viscosity was suppressed by saline culture.     

The impact of on-farm water saving irrigation techniques on rice productivity and profitability in Zhanghe Irrigation System,Hubei, China

To optimize the use of limited water resources, surface irrigation systems in parts of China have introduced a new water saving irrigation method for rice termed alternate wetting and drying (AWD). The basic feature of this method is to irrigate so that the soil alternates between periods of standing water and damp or dry soil conditions from 30 days after crop establishment up to harvesting. However, many Chinese rice farmers still practice the continuous irrigation method with late- season drying of the soil.A comparative assessment of these two methods of on-farm water management for rice was conducted at two sites within the Zhanghe Irrigation System (ZIS) in Hubei province of China for the 1999 and 2000 rice crops. The objective was to evaluate the impact of AWD on crop management practices and the profitability of rice production. In conjunction with irrigation district officials, two sites within ZIS were selected for study, one where AWD was supposed to be widely practiced (Tuanlin, TL) and one where it had not been introduced (Lengshui, LS). It was found that farmers at both sites do not practice a pure form of either AWD or continuous flooding. However, farmers in TL did tend to let the soil dry more frequently than their counterparts in LS.Because most farmers practice neither pure AWD nor pure continuous flooding, an AWD score was developed that measures the frequency with which farmers allow their soil to dry. This AWD score was not significantly correlated with yield after controlling for site and year effects and input use. AWD scores were also not correlated with input use. We conclude that AWD saves water at the farm level without adversely affecting yields or farm profitability.     

Effects on rice plant morphology and physiology of water and associated management practices of the system of rice intensification and their implications for crop performance

Field experiments were conducted in Bhubaneswar, Orissa, India, during the dry season (January–May) in 2008 and 2009 to investigate whether practices of the System of Rice Intensification (SRI), including alternate wetting and drying (AWD) during the vegetative stage of plant growth, could improve rice plants’ morphology and physiology and what would be their impact on resulting crop performance, compared with currently recommended scientific management practices (SMP), including continuous flooding (CF) of paddies. With SRI practices, grain yield was increased by 48% in these trials at the same time, there was an average water saving of 22% compared with inundated SMP rice. Water productivity with AWD-SRI management practices was almost doubled (0.68 g l⁻¹) compared to CF-SMP (0.36 g l⁻¹). Significant improvements were observed in the morphology of SRI plants in terms of root growth, plant/culm height, tiller number per hill, tiller perimeter, leaf size and number, leaf area index (LAI), specific leaf weight (SLW), and open canopy structure. These phenotypic improvements of the AWD-SRI crop were accompanied by physiological changes: greater xylem exudation rate, crop growth rate, mean leaf elongation rate (LER), and higher light interception by the canopy compared to rice plants grown under CF-SMP. SRI plants showed delayed leaf senescence and greater light utilization, and they maintained higher photosynthetic rates during reproductive and grain-filling stages. This was responsible for improvement in yield-contributing characteristics and higher grain yield than from flooded rice with SMP. We conclude that SRI practices with AWD improve rice plants’ morphology, and this benefits physiological processes that result in higher grain yield and water productivity.