Determination of the Effect of the System of Rice Intensification (SRI) on Rice Yields and Water Saving in Mwea Irrigation Scheme, Kenya

Irrigated rice cultivation has long been associated with large amounts of water. Currently convectional rice production is faced with major challenges of water shortage as a result of increasing population sharing the same water resources, as well as global environmental changes. The System of Rice Intensification (SRI), as opposed to conventional rice production, involves alternate wetting and drying (AWD) of rice fields. The objective of this study was to determine the optimum drying days period of paddy fields that has a positive effect on rice yields and the corresponding water saving. The experimental design used was randomized complete block design (RCBD). Four treatments and the conventional rice irrigation method were used. The treatments were the dry days allowed after draining the paddy under SRI before flooding again. These were set as 0, 4, 8, 12 and 16 day-intervals. Yield parameters were monitored during the growth period of the crop where a number of tillers, panicles, panicle length and panicle filling were monitored. Amount of water utilized for crop growth for each treatment was measured. Average yield and corresponding water saving were determined for each treatment. The results obtained show that the 8 days drying period gave the highest yield of 7.13 tons/ha compared with the conventional method of growing rice which gave a yield of 4.87 tons/ha. This was an increase of 46.4% above the conventional method of growing rice. Water saving associated with this drying regime was 32.4%. This was taken as evidence that SRI improved yields with reduction in water use.

Long-Term No-Tillage Direct Seeding Mode for Water-Saving and Drought-Resistance Rice Production in Rice-Rapeseed Rotation System

To study the effects of long-term no-tillage direct seeding mode on rice yield and the soil physiochemical property in a rice-rapeseed rotation system, a comparative experiment with a water-saving and drought-resistance rice （WDR） variety and a double low rapeseed variety as materials was conducted under no-tillage direct seeding （NTDS） mode and conventional tillage direct seeding （CTDS） mode for four years, using the CTDS mode as the control. Compared with the CTDS mode, the actual rice yield of WDR decreased by 8.10% at the first year, whereas the plant height, spikelet number per panicle, spikelet fertility, 1000-grain weight, grain yield, actual yield, and harvest index increased with no-tillage years, which led to the actual yield increase by 6.49% at the fourth year. Correlation analysis showed that the panicle length was significantly related to the actual yield of WDR. Compared with the CTDS mode in terms of the soil properties, the pH value of the NTDS mode decreased every year, whereas the contents of soil organic matter and total N of the NTDS mode increased. In the 0-5 cm layer of the NTDS mode, the soil bulk decreased, whereas the contents of soil organic matter, total N, and available N increased. In the 5-20 cm layer of the NTDS mode, the available N and K decreased, whereas the soil bulk, contents of soil organic matter, and total N increased. In summary, the NTDS mode increased the rice yield, and could improve the paddy soil fertility of the top layer.

The supporting capability of Water and land resources for sustainable increase of yield in North China Plain

The potential of yield increase in the North China Plain is about 30 billion kg by ameliorating the low yield and medium low yield farmlands and 4 billion kg by reclaiming unused land. Water shortage will be the main limitation to the further increase of grain crop yield. The amount of water shortage is 8 200 million m3 at present, and will be 17 720 million m3 in 2 000. Yield increase can not be realized by using more water in the future. Other factors such as decrease of the area of cultivated land and the grain crop growing area, deterioration of environment and destruction of resources will also affect the development of grain production. Some suggestions have been proposed in the paper for attaining sustainable increase of yield in the plain.

Progress and Yield Bottleneck of Aerobic Rice in the North China Plain: A Case Study of Varieties Handao 297 and Handao 502

Aerobic rice has been considered a promising rice cultivation system as water scarcity is increasing in the world. This article summarizes the advances in aerobic rice management researches in the North China Plain, focusing on yield formation and its bottleneck. High-yielding and good-quality aerobic rice varieties adapted to aerobic soil conditions have been released officially and adopted by farmers in North China. The varieties Handao 502 and Handao 297 have been recognized as the most promising varieties reaching a yield level ranging 3.5-5.0 t ha-1 with 450-650 mm water input. Compared with lowland rice, water input in aerobic rice was more than 50% lower, and water productivity was 60% higher. Researches on responses of rice cultivars to nitrate nitrogen （N） and ammonium N supplied at early growth stages provided the first evidence for a preference of aerobic rice HD297 for nitrate N supply, compared with the lowland rice variety. Zinc uptake studies demonstrated that introduction of aerobic rice system on calcareous soils may increase zinc deficiency problems. Sink size was identified as the limitation of aerobic rice yield, because its spikelet number m-2 was too low （20000-24 000） compared with the lowland rice. For future research, more attention is suggested to be paid to yield formation focusing on effects of water regimes on tiller dynamics. Understanding of nutrient uptake and response to fertilization effects are also urgently required to establish optimized crop management technology. Additionally, alternative cropping systems based on aerobic rice should be established, and key sustainability and environmental impact issues in the systems need to be identified.

Discussion of Fenlong Cultivation Supporting Food and Environment Safety and Broadening Survival and Development Space

A new high-efficiency farming method of global significance, Fenlong tech- nique capable of making soil fertile, increasing yield and improving ecological envi- ronment was introduced; and the Fenlong technique could deeply plough and scarify soil with a depth up to 30-50 cm, which is deeper than the depth of tractor tillage, solving the problem of difficulties in deeply ploughing and scarifying soil and keeping soil loose for muttiple seasons. The application to 20 crops in 18 provinces proved that yield could be increased by 10%-30% without increase in chemical fertilizer, quality could be improved by more than 5%, and water storage could be increased by 100%; yield could be increased for multiple seasons sustainably, and the yield of dry-land crops increased by 32.57%-38.2% from the second year to the fourth year; the net benefits of rice increased by 21.82% averagely from the first season to the sixth season; and the usage amount of chemical fertilizer decreased by 0.35-4.29 kg per 100 kg produced grain compared with conventional tillage, with an decrease amplitude of 10.81%-30.99%. It was discussed that the Fenlong technique could maximize friendly permanently-sustainable unitization of ＂natural resources＂ including soil nutrients, water, oxygen and light energy, and has good development potential in multiple fields. It was put forward that if it is popularized in 0.67x108 hm2, pro- ductivity of farmland could be newly increased by 0.1-0.13×10^8 hm2, 5.0 ×10^6 t of chemical fertilizer could be saved, the＇ storage of agricultural water could be in- creased by 3.0×10^10 m3, and increased food could feed 2,0-3.0×10^8 people.

Structural change of agricultural land use intensity and its regional disparity in China

Based on the data from the Cost-benefit Data of Farm Produce and the China Agricultural Yearbook, this paper divided the intensity of cultivated land use into labor intensity and capital intensity, and then analyzed their temporal and spatial change at both national and provincial levels between 1980 and 2006. The results showed that： （1） At the national level, labor intensity on food produce decreased from 398.5 day/ha in 1980 to 130.25 day/ha in 2006; and a continuous decrease with a steep decline between 1980 and 1986, a slower decline from 1987 to 1996, and another steep decline from 1997 to 2006. On the contrary, capital intensity shows an increasing trend since 1980. As to the internal composition of capital intensity, the proportion of seed, chemical fertilizer and pesticide input decreased from 90.36% to 73.44% and the proportion of machinery increased from 9.64% to 26.56%. The less emphasis on yield-increasing input and more emphasis on labor-saving input are the main reasons for a slow increase of yield per unit area after 1996. （2） At the provincial level, the developed areas have lower labor intensity and higher capital intensity. The less developed ones have higher labor intensity but lower capital intensity. From the viewpoint of the internal composition of capital intensity, labor-saving input accounts for more proportion in the developed areas than that of other areas. The main reason is that in these developed areas, labor input has become a constraint factor in food production as more and more labors engaged in off-farm work. Farmers increase the labor-saving input for higher labor productivity. However, in the less developed areas, the major constraint is the shortage of capital; food production is still depending on labor and yield-increasing inputs.

Experiences with Rice Grown on Permanent Raised Beds: Effect of Crop Establishment Techniques on Water Use, Productivity, Profitability and Soil Physical Properties

In recent years, conventional rice production technologies have been leading to deterioration of soil health and declining farm profitability due to high inputs of water and labor. Conservation agriculture （CA） based resource-conserving technologies i.e. zero-tillage （ZT）, raised-bed planting and direct-seeded rice （DSR） have shown promise as alternatives to conventional production technologies to overcome these problems. Present study was undertaken during 2009-2012 to establish an understanding of how permanent raised bed cropping system could be practiced to save water at the field application level to improve water productivity and also have the capability to enhance productivity, profitability and soil physical quality. The results showed that among different crop establishment techniques, conventional-tilled puddle transplanted rice （CT-TPR） required 14%-25% more water than other techniques. Compared with the CT-TPR system, zero till direct-seeded rice （ZT-DSR） consumed 6%-10%less water with almost equal system productivity and demonstrated higher water productivity. Wide raised beds saved about 15%-24% water and grain yield decrease of about 8%. Direct-seeded rice after ZT or reduced tillage or on unpuddled soil provided more net income than CT-TPR. The CT-TPR system had higher bulk density and penetration resistance due to compaction caused by the repeated wet tillage in rice. The steady-state infiltration rate and soil aggregation （〉 0.25 mm） were higher under permanent beds and ZT and lower in the CT-TPR system. Under CT-TPR, soil aggregation was static across seasons, whereas it improved under no-till and permanent beds. Similarly, mean weight diameter of aggregates was higher under ZT and permanent beds and increased over time. The study reveals that to sustain the rice productivity, CA-based planting techniques can be more viable options. However, the long-term effects of these alternative technologies need to be studied under varying agro-ecologies in western Uttar Pradesh, India.

施氮量对旱直播节水抗旱稻‘八月香’产量和稻米品质的影响

为探究旱直播旱管条件下,不同施氮量对籼型特早熟节水抗旱稻‘八月香’产量和稻米品质的影响,设置4个一次性基施氮肥处理:零氮(N_(0),不施氮),低氮(N_(1),90 kg/hm^(2)),中氮(N_(2),150 kg/hm^(2)),高氮(N_(3),210 kg/hm^(2)),在生育期内测定不同处理的‘八月香’分蘖数,叶片SPAD值,干物质质量,并于成熟期考种,测定稻米品质.结果表明:‘八月香’在增施氮肥处理下产量显著增加,结实率,千粒重无显著变化,穗数,每穗粒数显著增加,分蘖数,叶片SPAD值,茎,叶,穗干物质质量也显著增加。增施氮肥导致糙米率,精米率,整精米率显著下降,垩白粒率,垩白度显著增加,蛋白质含量增加,食味值下降。150 kg/hm^(2)处理下‘八月香’产量和米质较高。

Effects of plastic sheet on water saving and yield under furrow irrigation method in semi-arid region

The increasing demand of water in the country highlights the need to introduce low-input and water saving technologies for agricultural sustainability and crop production,mainly in semi-arid region.A study was conducted to minimize deep percolation losses from the furrow bottom under two different irrigation treatments viz.(1)furrow bottom with plastic sheet(T1)and(2)furrow bottom without plastic Sheet(T0).The physical and chemical analyses of soil profile were taken at a depth of 0-80 cm before and after crop harvesting.The dry density of soil slightly increased(0.01 g/cm^(3))under both treatments,while soil pH decreased under T1.The average yield was 8332 kg/hm^(2) and 7575 kg/hm^(2),with 21.56 m^(3) and 31.09 m^(3) total volume of irrigation water applied under T1and T0,respectively.The saving percentages of water under treatments were 52.22% and 31.00% under T1 and T0 respectively as compared to the saving of water under traditional irrigation practice.Overall,better performance,in terms of crop production and water saving,was obtained with use of plastic sheet integrated with bottom of furrows.Hence,it is suggested that the furrow irrigation method with plastic sheet may be used to preventing moisture and minimize deep percolation losses from furrow bottom.

中国北方地区不同滴灌方式节水增产效应的Meta分析

为了探明中国北方地区地下滴灌(subsurface drip irrigation,SSDI)与地表滴灌(surface drip irrigation,SDI)节水增产效应的差异,该研究以SDI作为对照,采用Meta分析定量分析了不同条件下SSDI对作物产量和水分利用效率的影响。结果表明,与SDI相比,SSDI可使作物总体增产6.66%(P<0.05),水分利用效率提高9.34%(P<0.05),净效益增加6.94%(P<0.05);SSDI在西北和华北地区均能提高作物产量和水分利用效率;当年均降雨量不大于400 mm时,SSDI能显著提高作物产量;当土壤容重大于1.5 g/cm^(3),灌水施肥频率大于6次,滴灌带埋深为>15~25 cm,滴头流量介于>1.5~<2.5 L/h时,更有利于发挥SSDI优势,节水增产效果显著。研究可为中国北方地区SSDI的推广应用提供理论参考。

旱优3015在永定县种植表现及高产栽培技术

旱优3015是用沪旱7A与旱恢3015配组育成的籼型三系杂交节水抗旱稻新品种,2020年通过了国家农作物品种审定。2022年引进旱优3015在永定县坎市镇灌溉条件不保障的烟后稻区和复垦地作中稻种植,结果表现群体生长整齐、株型集散适中、分蘖力强、穗大粒多、耐旱抗倒、产量高。总结了旱优3015在永定县的种植表现和高产栽培技术。

分根区交替灌溉在农业生产中的应用研究进展

在全球水资源日益紧缺的背景下,如何提高农业用水利用效率,对于农业可持续发展具有重要意义。分根区交替灌溉作为一种具有较好前景的高效节水灌溉技术,被认为是未来最具发展潜力的灌溉技术之一。目前,各国科技工作者围绕分根区交替灌溉对作物生长、生理的影响方面开展了大量研究,并对其节水机制进行了解析,亟待总结梳理。本文回顾了分根区交替灌溉技术的发展历程,综述了分根区交替灌溉对作物生长发育、产量及品质的影响,归纳了该技术影响作物水分利用效率的生理机制,并对分根区交替灌溉在未来的研究方向进行了展望,以期为作物分根区交替灌溉节水灌溉机理研究和节水灌溉技术的革新提供参考。

不同灌溉用水量对水稻产量和水分利用效率的影响

节水灌溉是提高水分利用效率和水稻高效生产的重要措施。以华南地区种植面积较广的水稻品种粤禾丝苗为材料,盆栽试验比较了4种不同灌溉用水量处理对水稻产量、生物量和水分籽粒生产效率的影响。结果表明,随着灌溉用水量的减少,水稻每穗粒数逐渐下降,结实率逐渐增加,而水稻产量先增加后减少。与CK(长期淹水灌溉,水量38.6 L/盆)相比,T2处理(长期淹水灌溉用水量的88.6%)的水稻产量增加14.55%,T4处理(长期淹水灌溉用水量的36.8%)的水稻产量减少45.28%,但T3处理(长期淹水灌溉用水量的62.4%)无明显差异,表明减少37.6%的灌溉用水量不影响水稻产量。与CK相比,T4处理的生物量显著减少50.84%,T2和T3处理无显著差异。4个处理中T3处理的水分籽粒生产效率最高,比CK显著增加62.38%。综上所述,在本试验条件下,T3处理(减少37.6%的灌溉用水量)水稻不减产,水分籽粒生产效率最高。

节水灌溉条件下小麦新品系‘石17T5252’丰产性和品质分析

为了推荐节水小麦新品种用于缓解河北省农业用水压力,探究节水小麦新品系‘石17T5252’的节水丰产特性。本实验检测了新选育小麦品系‘石17T5252’和河北省节水对照品种‘石麦22’全生育期不灌水(W0)、灌拔节水(W1)、灌拔节和灌浆水(W2)的产量、形态、灌浆和品质性状,并对拔节期、抽穗期和灌浆中期叶片的荧光参数进行检测。结果表明,W1和W2处理下‘石17T5252’产量显著高于‘石麦22’,分别增产10.32%和7.56%;其中W1通过增加千粒重增加产量,W2通过增加穗粒数和千粒重增加产量。W1和W2较W0的株高没有增加,但‘石麦22’的穗长和‘石17T5252’的穗粒数较W0显著增加,分别增加了0.72~0.84 cm和1.33~5.03粒;W2较W1显著增加‘石麦22’籽粒的长度和宽度,分别增加0.36 mm和0.32 mm,‘石17T5252’增加了0.31 mm的籽粒宽度。荧光参数检测仅在W0处理下发现‘石麦22’抽穗期的Fv/Fm显著高于‘石17T5252’。除容重外在3种灌溉制度下‘石17T5252’蛋白含量、湿面筋含量和面筋指数显著优于‘石麦22’。说明‘石17T5252’在节水灌溉条件下产量与品质得到同步提升,有望成为河北节水灌溉的小麦主栽品种。

不同灌溉量处理对节水抗旱稻产量形成及氮素吸收的影响

为了阐明节水抗旱稻在不同灌溉量条件下产量形成特点及氮素吸收规律,设置100%(0.63 L/kg)、80%(0.51 L/kg)、60%(0.38 L/kg)、40%(0.26 L/kg)和20%(0.14 L/kg)5个灌溉量处理,采用单因素方差分析不同灌溉量处理对节水抗旱稻品种(旱优73、WDR129)和传统水稻品种(H优518、扬粳4038)这4个供试水稻品种的产量构成因子、成熟期根系伤流速率、成熟期干重及氮素积累量的影响。结果表明,随着灌溉量的减少,4个供试品种的产量、产量构成因子、根系伤流液速率及干重均呈现下降趋势,且传统水稻品种H优518与扬粳4038的下降幅度大于节水抗旱稻品种旱优73和WDR129;低灌溉量处理对节水抗旱稻品种旱优73和WDR129影响较小,且氮素积累量高于传统水稻品种H优518和扬粳4038。研究显示,节水抗旱稻品种旱优73和WDR129通过维持较高的根系伤流液速率,保证了在低灌溉量条件下仍有较高的氮素积累量及产量。

节水灌溉对块根作物和土壤微生物影响的研究进展

我国是人均水资源匮乏的国家,节水灌溉对于绿色农业和经济社会的可持续发展具有重要现实意义。本文围绕节水灌溉对块根作物产量与品质、农田土壤微生物的影响,阐述当前研究进展,并提出亟待解决的关键问题,以期为块根作物增产提质和水资源高效利用提供理论依据。

水氮胁迫对春小麦产量与水分利用效率的影响

针对干旱地区水资源有限、小麦生产水肥投入过高和水分利用效率低的问题,探讨水氮亏缺对小麦水分利用效率的影响,为建立小麦水分高效利用理论提供一定的依据。2022年在甘肃省武威市设置试验,选定永良4号(YL4)和陇春41号(LC41)两个品种的春小麦作为研究对象,每个品种设置4个处理,包括两个水分处理即充分灌溉W_(1)处理(预测作物需水量)和调亏灌溉W_(2)处理(在拔节-孕穗期和灌浆-成熟期灌溉预测作物需水量的65%,其余生育期灌溉量为充分灌溉处理预测作物需水量的100%),两个氮肥处理即N_(1)处理(当地传统施氮量,220 kg/hm^(2))和N_(2)处理(减量施氮,110 kg/hm^(2)),重点研究节水减氮对于小麦耗水特性、水分利用效率的影响。研究结果表明,春小麦耗水量因水分亏缺和氮素亏缺而显著降低,减量施氮对耗水量的影响不显著,但降低了籽粒产量和水分利用效率。春小麦的水分利用效率受产量和耗水量调控且相关性呈抛物线关系,因此在干旱灌区可通过一定的水氮调控保持产量的同时提高水分利用效率。

冬小麦-夏玉米周年“四密一稀”浅埋滴灌水肥药一体化绿色生产技术

本研究针对黄淮海冬小麦-夏玉米两熟区面临的出苗质量、播种—出苗期水分供应、灌溉施肥及时性及技术粗放等问题,并就进一步提高光温水肥资源利用效率是实现该区域粮食单产提升和绿色发展的重要途径等,从2018年起开展了一系列创新研究。通过实施冬小麦“四密一稀”条带种植配套卫星导航播种技术、冬小麦-夏玉米周年浅埋滴灌水肥药一体化技术等关键核心技术,结合配套现代化农机与信息技术装备,形成了一套集成的“冬小麦-夏玉米周年‘四密一稀’浅埋滴灌水肥药一体化绿色生产技术”。2010—2023年田间示范表明,该技术有效解决了上述生产难题,达到了小麦玉米周年增产和水肥资源高效利用的目标。与农民传统相比,小麦增产9%~17%,玉米增产12%~14%,周年节水450~750 m^(3)/hm^(2),节肥20%,节约人工成本2250~3000元/hm^(2)。该技术为黄淮海区冬小麦-夏玉米周年绿色高产提供了新的可行性方案。

水电站经济运行指标实时数字化研究

在传统的水电优化调度工作中,因水电站特性和管理单位的不同,存在对电站的水电经济运行管理评价方法和标准不统一的情况。该文通过介绍水电站经济运行实时数字化研究,按水电优化调度提高发电效益的两种主要途径,分别建立数学计算模型,对单电厂、梯级多厂和电网整体综合的经济运行指标进行数字化处理,分别以小时、日、月、年为阶段自动计算,实时展示优化调度结果,为综合评价水电优化调度成果提供更科学、合理、客观的数据量化指标依据,指导电网和水电厂优化调度工作。

考虑降雨预报的灌溉模式对水稻产量及需水量的影响

以早稻和晚稻为试验材料,在考虑降雨预报的前提下,研究了智能灌溉和传统淹水灌溉2种模式对水稻的产量指标以及作物需水量的影响。结果表明:智能灌溉模式能够使早稻、晚稻分别节约灌溉水量83.9、119.2 t/hm^(2),减少排水量193.8、35.6 t/hm^(2);智能灌溉模式在降雨频繁时充分满足作物在关键期的需水量,在缺少降雨时可在不影响产量、保证作物的关键期需水的情况下适当降低作物的需水量;智能灌溉模式可使早稻和晚稻的理论产量分别提高284.52、508.84 kg/hm^(2)。综上,在水稻种植过程中,考虑降雨预报的智能灌溉模式能够提高灌溉效率;优化作物的关键期需水量,降低水资源的消耗,减少环境污染,以及实现水稻增产,具有一定的环境和经济效益。