Effects of improved field practice on crop yield,water use and profitability of irrigation in Central Chile

Summary The economic impact of improved irrigation practice was studied for a number of years in a research project carried out in Central Chile on commercial fields of eleven orchard, field, vegetable and forage crops. The cost of implementing improved irrigation practice specific to a given soil-climate and crop combination, and the benefits obtained through that technology were evaluated with respect to yield increases and savings in water and crop production costs.Semi-permanent irrigation plots were established in different locations in the Central Zone of Chile (Fig. 1). At each site, the field crops were grown in crop rotations for a number of years. Several methods of irrigation were tested, using different frequencies and depths of water application.Crop yields on plots with improved irrigation practice averaged 25% more than on plots on which irrigation was applied, according to traditional farmer practice. A significant increase in consumptive water use by the crop was found with improved irrigation practice, but the total water applied during the growing season was about half of the volume applied in traditional irrigation practice.The results suggest that in developing countries with a comparatively extensive irrigation tradition, little sophistication is needed to improve irrigation practice and obtain a significant economic impact on crop production.     

Alternative cropping strategies for assured and efficient crop production in upland rainfed rice areas of eastern India based on rainfall analysis

The productivity of rice in rainfed upland soils of eastern India is very low (<1 t/ha) and unstable because of erratic monsoon, moisture deficit during dry spells, light textured with less fertile soils and several biological constraints (weeds, pests and diseases). Keeping the urgent need of augmenting the productivity of vast rainfed upland rice ecosystem of eastern India (4.3 million ha), crop diversification technology was generated through on-farm research trials in representative upland rice soils of eastern India after analyzing agro-climatic (rainfall variability, probability and onset of effective monsoon) and edaphic (soil water retention properties) constraints and prospects. Based on rainfall analysis, direct seeded, low water requiring, rice substituted alternative upland crops namely maize, groundnut, pigeonpea, greengram and blackgram (sole or intercropping) was sown in light textured upland rice soils on 24th meteorological weeks (11–17 June) in 3 years 2000–2002 with two to three summer ploughings during pre-monsoon shower (May). Study revealed that in deficit rainfall years (2000 and 2002), when rice yield was affected adversely in light textured upland, higher rice equivalent yield and rain water use efficiency were obtained from groundnut+pigeonpea intercropping followed by sole groundnut and sole pigeonpea. Study also revealed that productivity of rice substituted crops in the same upland did not fluctuate much between rainfall excess (2001) and rainfall deficit years (2002 and 2000). Double cropping in rainfed upland rice soils was also explored through maize–horsegram/sesamum rotation with increased productivity and rainwater use efficiency. The crop diversification technology was found to be very effective for drought mitigation.     

Phenology based irrigation scheduling and determination of crop coefficient of winter maize in rice fallow of eastern India

Vast rainfed rice area (12 million ha) of eastern India remains fallow after rainy season rice due to lack of appropriate water and crop management strategies inspite of having favourable natural resources, human labourers and good market prospects. In this study, a short duration crop, maize, was tried as test crop with different levels of irrigation during winter season after rainy season rice to increase productivity and cropping intensity of rainfed rice area of the region. Maize hybrid of 120 days duration was grown with phenology based irrigation scheduling viz., one irrigation at early vegetative stage, one irrigation at tassel initiation, two irrigation at tassel initiation + grain filling, three irrigation at early vegetative + tassel initiation + grain filling and four irrigation at early vegetative + tassel initiation + silking + grain-filling stages. Study revealed that one irrigation at tassel initiation stage was more beneficial than that of at early vegetative stage. Upto three irrigation, water use efficiency (WUE) was increased linearly with increased number of irrigation. With four irrigations, the yield was higher, but WUE was lower than that of three irrigations, which might be due to increased water application resulted in increase crop water use without a corresponding increase of yield for the crop with four irrigations. The crop coefficients (K_c) at different stages of the crop were derived after computing actual water use using field water balance approach. The crop coefficients of 0.42–0.47, 0.90–0.97, 1.25–1.33, and 0.58–0.61 were derived at initial, development, mid and late season, respectively with three to four irrigation. Study showed that leaf area index (LAI) was significantly correlated with K_c values with the R² values of 0.93. When LAI exceeded 3.0, the K_c value was 1. Study revealed that the K_c values for the development and mid season stage were slightly higher to that obtained by the procedure proposed by FAO, which might be due to local advection.     

喷灌水肥与种植密度互作对水氮利用效率和冬小麦产量的影响

为研究豫北地区喷灌水肥一体化条件下不同种植密度和施氮频次对土壤水分、硝态氮含量及冬小麦产量的影响,开展田间试验.试验设置了2个种植密度(D1:187 kg/hm²、D2:262 kg/hm²)和3个施氮频次(F1:返青后追肥1次、F2:返青后追肥2次、F3:返青后追肥3次).试验结果表明:种植密度和施氮频次均显著影响冬小麦籽粒产量, 且两者间存在明显的互作效应.种植密度增大,冬小麦生育期0~100 cm土层土壤贮水量显著提高.主要生育期的根系生长层土壤含水量显著增加,其中孕穗期在100 cm土层深度的含水量D2较D1分别提高29.42%,3.10%和32.04%,灌浆期在80 cm土层深度的含水量D2较D1分别提高29.69%,27.52%和25.71%.当种植密度为262 kg/hm²,施氮频次为1次时,冬小麦产量较高,深层土层的土壤硝态氮当季残留较少.综合分析表明,该种植密度和施氮频次为当地冬小麦生育期的最优措施.     

Effects of winter wheat row spacing on evapotranpsiration, grain yield and water use efficiency

A field study was conducted from 2002 to 2007 to investigate the influence of row spacing of winter wheat (Triticum aestivum L.) on soil evaporation (E), evapotranspiration (ET), grain production and water use efficiency (WUE) in the North China Plain. The experiment had four row spacing treatments, 7.5 cm, 15 cm, 22.5 cm, and 30 cm, with plots randomly arranged in four replicates. Soil E was measured by micro-lysimeters in three seasons and ET was calculated from measurements of soil profile water depletion, irrigation, and rainfall. The results showed that E increased with row spacing. Compared with the 30-cm row spacing (average E = 112 mm), the reduction in seasonal E averaged 9 mm, 25 mm, and 26 mm for 22.5 cm, 15 cm, and 7.5 cm row spacings, respectively. Crop transpiration (T) increased as row spacing decreased. The seasonal rainfall interception and seasonal ET were relatively unchanged among the treatments. In three out of five seasons, the four different treatments showed similar grain yield, yield components and WUE. We conclude that for winter wheat production in the North China Plain, narrow row spacing reduced soil evaporation, but had minor improvements on grain production and WUE under irrigated conditions with adequate nutrient levels.     

滴灌水氮耦合对水氮利用及冬小麦产量的影响

以华北地区冬小麦为试验对象,参考直径20 cm标准蒸发皿的累计水面蒸发量E,通过2 a的大田试验(2012—2013),研究了大田地表滴灌条件下水氮耦合制度对作物耗水量、作物生理指标、产量、氮残留及水氮利用效率的影响,结果表明,冬小麦生育期内的耗水量、叶面积指数及产量受灌水定额的影响更为显著(P<0.05);滴灌条件下,当施氮量在120~290 kg/hm²时,水氮耦合效应对冬小麦耗水量的影响不具有统计学意义;在滴灌灌水定额为0.80E,施氮量为140~190 kg/hm²的水氮耦合模式下,冬小麦的产量较高,土壤硝态氮的当季残留较少,且进一步显著增加灌水定额和氮肥投入量将导致产量的明显下降;综合考虑冬小麦水氮利用效率和对地下水的潜在淋失风险,华北典型区滴灌水氮耦合的优化组合范围宜为灌水定额为0.80E,施氮量为140~190 kg/hm².     

Effects of irrigation and planting patterns on radiation use efficiency and yield of winter wheat in North China

The factor limiting the increase in winter wheat yield was not the deficiency of light radiation but the low radiation use efficiency (RUE). In 2004-2005 and 2005-2006, an experiment was conducted at the Agronomy Station of Shandong Agricultural University to study the effects of irrigation and different planting patterns on the photosynthetic active radiation (PAR) capture ratio, PAR utilization, and winter wheat yield. In this experiment, winter wheat was planted in four patterns as follows: uniform row planting (U; row spacing, 30 cm), “20 + 40” wide-narrow row planting (W), “20 + 40” furrow planting (F), and “20 + 40” bed planting (B), which are very popular in North China. The results showed that under different irrigation regimes, there was no significant difference (less than 15.93%) between any of the planting patterns with respect to the amount of PAR intercepted by the winter wheat canopies. However, significant differences were observed between different planting patterns with respect to the amount of PAR intercepted by plants that were 60-80 cm above the ground surface (53.35-225.16%). This result was mainly due to the changes in the vertical distributions of leaf area index (LAI). As a result, the effects of the planting patterns on RUE and the winter wheat yield were due the vertical distribution of PAR in the winter wheat canopies. During the late winter wheat growing season, irrespective of the applied irrigation, the RUE in case of F was higher than that in case of U, W, and B by 0.05-0.09, 0.04-0.08, and 0.02-0.12 g/mol, respectively, and the yield was higher by 238.39-693.46, 160.02-685.96, and 308.98-699.06 kg/ha, respectively. Only under the fully irrigated conditions, the RUE and winter wheat yield significantly (LSD; P < 0.05) increased in case of B. This experiment showed that in North China, where the water shortage is the highest, application of planting pattern B should be restricted. Instead, F should be used in combination with deficit irrigation to increase the RUE and grain yield of winter wheat.     

Improving water use efficiency in rice irrigation through wet-seeding

Since the early-1960's, when modern rice production technologies became available, more than 90% of the total irrigation water developed in south and southeast Asia is used for rice culture. But currently rice culture is highly inefficient in water use. As fresh water availability for agriculuture is becoming increasingly scarce, greater efficiency of water use in rice culture is deemed essential. Past experience indicates that effective implementation of water-efficient irrigation methods in rice farms within public sector irrigation systems is restricted by the difficulty of controlling water deliveries and distribution, and establishing a water charge system based on the actual amount of water used by farmers. Clearly, a rice production method that is inherently less water-requiring, or more water-efficient, would have an advantage over the traditional method in this respect. Recent studies conducted in the Philippines indicate that wet-seeded rice culture is superior to the traditional transplanted rice culture in terms of water efficiency. Other advantages of wet-seeded rice culture include its greater drought tolerance, less labor requirement for crop establishment and weed control, and higher returns from rice farming. This paper presents a comparative study of wet-seeded and transplanted rice cultures focusing on these aspects.     

灌水量对烤烟产量和水分利用效率的影响

灌水时期不当或灌水量过大会降低烟叶的产量,同时造成水分的浪费,探究烟草适宜的灌水量至关重要。在蒸渗仪中开展试验,研究了不同灌水量对土壤水分、烤烟的水分利用效率和产量的影响。结果表明：烤烟 K326各处理不同土层含水率变化规律比较一致,（0,10]cm 土层含水率受气温、日照等气候因素较大;（10,20]cm 土壤含水率变化较剧烈;（20,60]cm 土壤含水率在整个生育期变化比较平缓,尤其在成熟后期各处理均出现不同程度的回升趋势,结合烤烟成熟期生理活动减弱、需水量减少,说明成熟期采取较小的灌水量比较适宜。成熟期烤烟的干物质产量在一定范围内随灌水量的增大而增加,如果继续加大灌水量将出现“报酬递减”现象。结合烟叶产量、烟株长势、耗水量和水分利用效率的结果,表明2700～3000 m3／hm2可以作为烤烟K326适宜的灌水量。在烤烟生产中,应均衡协调产量、水分利用效率与耗水量之间的关系,在高产前提下,适当减少灌水量,可达到既高产又节水的协调统一。     

Modeling the role of irrigation in winter wheat yield,crop water productivity,and production in China

Irrigation plays an important role in increasing food production in China. The impact of irrigation on crop yield (Y), crop water productivity (CWP), and production has not been quantified systematically across regions covering the whole country. In this study, a GIS-based EPIC model (GEPIC) was applied to simulate Y and CWP for winter wheat (Triticum aestivum L.) in China at a grid resolution of 5 arc-minutes and to analyze the impacts of reducing irrigation water on wheat production. The findings show that irrigation is especially important in improving CWP of winter wheat in the North China Plain (NCP), the “bread basket” of China. On average, the provincial aggregate CWP was 56% higher under the irrigated than that under the rainfed conditions. The intensification of water stress and the associated increase in environmental problems in much of the NCP require critical thoughts about reducing water allocation for irrigated winter wheat. Two scenarios for irrigation reduction in the NCP provinces are presented: reducing irrigation depth (S1), and replacing irrigated winter wheat by rainfed winter wheat (S2). The simulation results show that S1 and S2 have similar effects on wheat production when the reduction in irrigation water supply is below 20% of the current level. Above this percentage, S2 appears to be a better scenario since it leads to less reduction in wheat production with the same amount of water saving.     

Forage sorghum yield and water use efficiency under variable irrigation

The response of forage sorghum [Sorghum bicolor (L.) Moench] to three irrigation treatments in a semiarid environment was studied in the field for two seasons. Treatments were light frequent, moderate less frequent, and heavy infrequent irrigation, where irriga-tion water at 8 mm day^–1 was delivered every 7, 10, and 13 days, respectively. These irrigation regimes meant heavier water inputs with increasing irrigation frequency. Plant heights and leaf area indices of forage sorghum were higher in the frequently watered plots than in plots where irrigation water was delivered less frequently. Averaged over the two seasons, maximum dry matter (DM) yields were 16.3, 11.8, and 10.5 tonnes ha^–1 for frequent, intermediate, and infrequent irrigation regimes, respectively. Light, frequent irrigation resulted in a significantly higher water use efficiency (WUE) compared to the other two regimes, thus increasing the return from irrigation. These results suggest that in such semiarid environments, DM yields and WUE of forage sorghum could be increased by combining light irrigation with a short interval. Received: 6 February 1997     

Effects of arrangement of surge-rootirrigation emitters on growth,yield andwater use efficiency of apple trees

Six-year old apple trees were selected for field experiment. The objective of this study was to obtain the reasonable arrangement of surge-root irrigation emitters in apple orchards. There were three factors: the buried depth H( 25,40,55 cm),the horizontal distance L( 30,40,60 cm) between the emitters and the trunk of the experimental tree,and the number of the irrigation emitters N( 1,2,4). The effect of the arrangement of surge-root irrigation emitters on the growth,yield and irrigation water use efficiency( IWUE) of apple trees were studied in Northern Shaanxi where the irrigation quota takes 60%-75% of the field water capacity. The results showed that the arrangement of emitters for surge-root irrigation had a significant effect on apple tree yield and IWUE,especially,the yield and IWUE reached 28 388. 17 kg/hm2 and 16. 83 kg/m3 in treatment T3,respectively. At the same L and N levels( T1,T2,and T3),the yield and IWUE in treatment T3 were the highest,and the yields in treatments T1 and T2 were decreased by 26.22% and 31.48%,while IWUE is reduced by14.02% and 18.12% compared with T3,respectively. At the same H and N levels( T3,T4,and T5),the yield and IWUE of apple trees were decreased with increasing L level. Especially,when L was 30 cm( T3),the yield and IWUE were the highest. The same L and H levels( T3,T6,and T7) could promote the growth of apple trees when N was 2( T3). Compared with treatment T3,it was found that the increment of new shoots was decreased by 8.07%-18.71%,and the fruit diameter was decreased by 5.41%-9.11%. Therefore,two emitters should be arranged symmetrically on both sides of an apple tree,each was buried at a 40 cm depth and 30 cm away from the trunk of the tree to effectively improve the yield and IWUE of the apple tree in mountainous areas in Northern Shaanxi.     

Effect of irrigation and nitrogen on yield,yield components and water use efficiency of barley in Saudi Arabia

Water use efficiency and yield of barley were determined in a field experiment using different irrigation waters with and without nitrogen fertilizer on a sandy to loamy sand soil during 1994–1995 and 1995–1996. Depending upon different fertilizer treatments, the overall mean crop yield ranges for two crop seasons were: greenmatter from 19.48–55.0 Mg ha⁻¹ (well water) and 21.92–66.5 Mg ha⁻¹ (aquaculture effluent); drymatter from 6.86–20.69 Mg ha⁻¹ (well water) and 7.87–20.90 Mg ha⁻¹ (aquaculture effluent); biomass from 4.12–21.31 Mg ha⁻¹ (well water) and 8.10–19.94 Mg ha⁻¹ (aquaculture effluent) and grain yield from 2.12–5.50 Mg ha⁻¹ (well water) and 3.25–7.25 Mg ha⁻¹ (aquaculture effluent). The WUE for grain yield was 3.37–8.74 kg ha⁻¹ mm⁻¹ (well water) and 5.17–11.53 kg ha⁻¹ mm⁻¹ (aquaculture effluent). The WUE for total biomass ranged between 6.55–33.88 kg⁻¹ ha⁻¹ mm⁻¹ (well water) and 12.88–31.70 kg ha⁻¹ mm⁻¹ (aquaculture effluent). The WUE for drymatter was 10.91–32.90 kg ha⁻¹ mm⁻¹ (well water) and 12.51–33.22 kg ha⁻¹ mm⁻¹ (aquaculture effluent). It was found that grain yield and WUE obtained in T-4 and T-5 irrigated with well water and receiving 75 and 100% nitrogen requirements were comparable with T-4 and T-5 irrigated with aquaculture effluent and receiving 0 and 25% nitrogen requirements. In conclusion, application of 100 to 150 kg N ha⁻¹ for well water and up to 50 kg N ha⁻¹ for aquaculture effluent irrigation containing 40 Mg N l⁻¹ would be sufficient to obtain optimum grain yield and higher WUE of barley in Saudi Arabia.     

控制灌溉增氧对超级稻生理生化特性及水分利用效率的影响

为了提升超级稻灌溉用水的利用效率,采用控制灌溉技术与增氧灌溉技术相结合的灌溉方式进行试验.以超级稻“陵两优268”为研究对象,设置4组处理:控制灌溉机械增氧(JX)、控制灌溉超微泡增氧(WP)、控制灌溉(CK)、淹水灌溉(YS),探究控制灌溉条件下增氧对超级稻返青期后的各生育期生理生化特性指标及产量的影响.试验表明,叶片叶绿素含量,在水稻分蘖期、拔节孕穗期、抽穗开花期差异并不明显,但乳熟期最大提升了38.2%.净光合速率、蒸腾速率、气孔导度均有显著提升,其中在抽穗开花期,早稻分别提升了44.9%,18.5%,25.0%;晚稻分别提升了14.3%,11.5%,22.2%.根系活力,在抽穗开花期,对比YS组最大提升了44.6%,对比CK组最大提升了11.5%.同时,对土壤氧化还原电位进行定期监测,得知控制灌溉条件下增氧处理后,其各时期基本均处于氧化态,而淹水灌溉下基本处于还原态.在全生育期耗水量上,控制灌溉条件下3组处理的节水效率显著提高,控制灌溉增氧条件下全生育期最大有效节水达18.5%.     

不同水量交替灌溉对木薯产量和水分利用的影响

为探讨作物旱后复水的补偿效应,采用不同水量交替灌溉方式研究木薯的生长、产量及水分利用效率的变化规律,设计了5种水分处理模式,分别为3种常规灌水处理(T1,T2和T3处理的灌水定额分别为10,20,30 mm)和2种交替灌水处理(T4处理:即对灌水定额10和20 mm进行轮回交替;T5处理:即对灌水定额10和30 mm进行轮回交替).结果表明:与T2处理相比,T5处理的总叶面积、总干物质质量、产量和水分利用效率分别显著增加31.1%,20.3%,64.6%和114.0%.与T3处理相比,T5处理节水33.3%,其总干物质质量下降较小,而根系干物质质量、水分利用效率和产量分别显著增加11.2%,119.0%和13.3%.因此,T5处理是有利于木薯产量和水分利用效率提高的最佳灌溉模式.     

Effect of field levelling quality on irrigation efficiency and crop yield

Proper land levelling in areas irrigated by canals is an essential pre-requisite for judicious use of scarce irrigation water. The concept of land levelling index, which is different from land uniformity coefficient used hitherto, has been adopted to evaluate quantitatively the precision or quality of land levelling work. Using this concept the quality of land levelling work being done in newly canal commanded areas has been assessed and it is demonstrated that the prevalent deficiency in levelling quality ranges from 21.4 to 42.2%. Field investigations have been carried out to assess quantitatively the effect of land levelling quality on irrigation and water-use efficiencies and crop yield. The study comprised five levelling indices viz., 1.2, 2.0, 2.5, 3.0 and 3.7 cm and two irrigation treatments, i.e., fixed depth and complete irrigation. The results show that irrigation application, distribution, and water-use efficiency are appreciably reduced with increase in levelling index or deterioration in levelling quality. The wheat grain yield is also similarly reduced and it is significantly less for levelling index values higher than 2.5 cm. The fixed irrigation depth treatment gives better results from the point of water economy than does the complete irrigation treatment. From this study, it can be inferred that to obtain reasonably high yield and judicious use of water at a reasonable cost the field levelling index should not have a value greater than 3.0 cm.     

控制灌溉条件下增氧对超级稻根系生长及水分利用效率的影响

以超级稻“陵两优268”为试验材料,采用控制灌溉与增氧灌溉技术相结合,设置4组处理,分别为机械控制灌溉增氧(JX)、超微泡控制灌溉增氧(WP)、控制灌溉(CK)、淹水灌溉(YS),研究控制灌溉条件下增氧对水稻根系生长特征及水分利用效率的影响.结果表明:控制灌溉条件下增氧与淹水灌溉条件相比,有效节约用水最大达15.3%,有利于促进根系生长,增大了水稻的根部干物质质量,降低了水稻的茎叶干物质质量;提高了水稻根体积、根粗及干物质的质量,能显著增强水稻的根系活力,延缓水稻根系的衰老;产量上,控制灌溉增氧处理基本与淹灌处理接近,但结实率、千粒重、水分利用效率都优于淹灌处理.     

Effects of rainfall harvesting and mulching technologies on water use efficiency and crop yield in the semi-arid Loess Plateau, China

In semi-arid areas, crop growth is greatly limited by water. Amount of available water in soil can be increased by surface mulching and other soil management practices. Field experiments were conducted in 2005 and 2006 at Gaolan, Gansu, China, to determine the influence of ridge and furrow rainfall harvesting system (RFRHS), surface mulching and supplementary irrigation (SI) in various combinations on rainwater harvesting, amount of moisture in soil, water use efficiency (WUE), biomass yield of sweet sorghum (Sorghum bicolour L.) and seed yield of maize (Zea mays L.). In conventional fields without RFRHS, gravel-sand mulching produced higher biomass yield than plastic-mulching or straw-mulching. In plastic-mulched fields, an increasing amount of supplemental irrigation was needed to improve crop yield. There was no effect of RFRHS without plastic-covered ridge on rainwater harvesting when natural precipitation was less than 5 mm per event. This was due to little runoff of rainwater from frequent low precipitation showers, and most of the harvested rainwater gathered at the soil surface is lost to evaporation. In the RFRHS, crop yield and WUE were higher with plastic-covered ridges than bare ridges, and also higher with gravel-sand-mulched furrows than bare furrows in most cases, or straw-mulched furrows in some cases. This was most likely due to decreased evaporation with plastic or gravel-sand mulch. In the RFRHS with plastic-covered ridges and gravel-sand-mulched furrows, application of 30 mm supplemental irrigation produced the highest yield and WUE for sweet sorghum and maize in most cases. In conclusion, the findings suggested the integrated use of RFRHS, mulching and supplementary irrigation to improve rainwater availability for high sustainable crop yield. However, the high additional costs of supplemental irrigation and construction of RFRHS for rainwater harvesting need to be considered before using these practices on a commercial scale.     

痕量灌溉对温室种植球茎茴香产量、干物质分配和水分利用率的影响(英文)

痕量灌溉是基于土壤毛细管力原理和膜过滤技术而发明的一种新的灌溉技术.以滴灌为对照处理,研究了温室条件下,痕量灌溉对球茎茴香（Foeniculum vulgare Mill. subsp. vulgare var. dulce (Mill.) Batt.）产量、干物质分配和水分利用率的影响.结果表明,痕量灌溉条件下球茎茴香球茎和地上部分（茎和叶）的鲜重和干物质重量显著高于滴灌条件下栽培的球茎茴香,且痕量灌溉的总耗水量显著低于滴灌.试验条件下采用痕量灌溉的水分利用率是滴灌的2.3倍.     

Effects of conservation tillage practices on winter wheat water-use efficiency and crop yield on the Loess Plateau,China

In the semi-humid to arid loess plateau areas of North China, water is the limiting factor for rain-fed crop yields. Conservation tillage has been proposed to improve soil and water conservation in these areas. From 1999 to 2005, we conducted a field experiment on winter wheat (Triticum aestivum L.) to investigate the effects of conservation tillage on soil water conservation, crop yield, and water-use efficiency. The field experiment was conducted using reduced tillage (RT), no tillage with mulching (NT), subsoil tillage with mulching (ST), and conventional tillage (CT). NT and ST improved water conversation, with the average soil water storage in 0–200 cm soil depth over the six years increased 25.24 mm at the end of summer fallow periods, whereas RT soil water storage decreased 12 mm, compared to CT. At wheat planting times, the available soil water on NT and ST plots was significantly higher than those using CT and RT. The winter wheat yields were also significantly affected by the tillage methods. The average winter wheat yields over 6 years on NT or ST plots were significantly higher than that in CT or RT plots. CT and RT yields did not vary significantly between them. In each study year, NT and ST water-use efficiency (WUE) was higher than that of CT and RT. In the dry growing seasons of 1999–2000, 2004–2005 and the low-rainfall fallow season of 2002, the WUE of NT and ST was significantly higher than that of CT and RT, but did not vary significantly in the other years. For all years, CT and RT showed no WUE advantage. In relation to CT, the economic benefit of RT, NT, and ST increased 62, 1754, and 1467 yuan ha⁻¹, respectively, and the output/input ratio of conservation tillage was higher than that of CT. The overall results showed that NT and ST are the optimum tillage systems for increasing water storage and wheat yields, enhancing WUE and saving energy on the Loess Plateau.