Soil & Tillage Research 115–116 (2011) 56–61

Effects of conservation tillage on corn and soybean yield in the humidcontinental climate region of Northeast China

Y. Chen a, S. Liu a, H. Li a, X.F. Li a, C.Y. Song a, R.M. Cruse b, X.Y. Zhang a,*a Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin 150081, Chinab Department of Agronomy, Iowa State University, Ames, IA 500011, USA

A R T I C L E I N F O

Article history:

Received 7 March 2011

Received in revised form 15 June 2011

Accepted 25 June 2011

Keywords:

Conservation tillage

Sloping farmland

Flat farmland

Yield

Mollisols

A B S T R A C T

Soil quality and crop yield improvements through use of conservation tillage have been widely

documented in the world. As the ‘‘bread basket’’ of the northern region of Northeast China, located at

478N, China’s arable Black soils are consistently and intensively tilled and have been seriously degraded

and eroded. Wide spread adoption of conservation tillage in this area will occur only if acceptable yields

are demonstrated with its use. In this study, corn (Zea mays L.) and soybean (Glycine max Merril.) yield

with no-till (NT), reduced-till (RT) and conventional tillage (CT) were compared from 2004 to 2010 on

two separate areas, sloping and nearly flat farmland. Soybean yields increased significantly and, in

contrast, corn yields decreased significantly under NT compared to CT. The average increase of soybean

yield was 8.9% on the flat farmland and 13.8% on sloping farmland. The average corn yield decrease was

28.4% on the flat farmland and 15.7% on sloping farmland. A significant increase in soil moisture and

decrease in soil temperature was found in the early growing season for NT compared to RT and CT. NT

decreased surface runoff and increased soil water storage, which boosted soybean yield on the sloping

farmland. Our study demonstrated NT was an effective and beneficial soil tillage practice and should be

widely applied for soybean production in the northern region of Northeast China, where the sloping

farmlands are mainly distributed with soybean as the main crop.

� 2011 Elsevier B.V. All rights reserved.

Contents lists available at ScienceDirect

Soil & Tillage Research

jou r nal h o mep age: w ww.els evier . co m/lo c ate /s t i l l

1. Introduction

Conventional soil tillage (CT), such as moldboard plowing androtary plowing aggressively disturbs the surface soil layer everyyear. In the short term these systems creates a good soil physicalenvironment for crop emergence, rapid early growth, nutrientuptake, and high crop yield (Six et al., 1999). However, in the longterm the soil structure is degraded and soil organic matter (SOM)mineralization is increased, which induces SOM and nutrientcontent depletion, soil compaction and soil erosion (Triplett andDick, 2008). All of these processes degrade well-structured soiland obstruct farmland sustainability (Fernandez et al., 2009).Hence, adoption of conservation tillage practices, for exampleno-till (NT) and reduced-till (RT), has been widely accepted in thelast two decades in selected areas (Triplett and Dick, 2008;Rockstrom et al., 2009).

Abbreviations: NT, no till; RT, reduced tillage; CT, conventional tillage; SOM, soil

organic matter; P, precipitation; T, temperature.

* Corresponding author. Tel.: +86 451 86602926; fax: +86 451 86603736.

E-mail address: xyzhang1966@yahoo.com.cn (X.Y. Zhang).

0167-1987/$ – see front matter � 2011 Elsevier B.V. All rights reserved.

doi:10.1016/j.still.2011.06.007

Conservation tillage improves economic performance andenergy use efficiency, and reduces production risks (Zentneret al., 2002); it also decreases soil disturbance, improves SOMmaintenance and benefits soil quality (Zentner et al., 2004). Lafondet al. (1996) reported that conservation tillage increases pea, flaxand spring wheat grain yields. Crop grain yields in RT were similarto or greater than yields in CT (Al-Darby and Lowery, 1986).Kapusta et al. (1996) found equal maize yield under NT, RT and CTdespite the lower plant population in NT in a 20-year tillage systemexperiment. However, a 14% corn yield decrease in NT wasreported for a 20-year field experiment in north-central Indiana(West et al., 1996). Grain yield decrease for NT has also beenreported in other cooler regions (Mahli et al., 1988; Birkas et al.,1997; Canarache and Dumitru, 2008). A number of field studieshave determined the effects of varying tillage practices on factorsassociated with crop production. These studies clearly indicatethat conservation tillage compared to CT could minimize soil waterevaporation, soil erosion, and soil temperature fluctuations(Triplett and Doren, 1977; Wall and Stobbe, 1984; Dick et al.,1991; Wagger and Denton, 1992). The tillage-involved factorsinfluencing crop growth are complex, and the responses of cropyield to soil tillage systems seem different in different geographical

Table 1Precipitation and air temperature and their monthly distributions from 2004 to 2010.

Year Annual May June to August

Precipitation (mm) Mean temperature (8C) Precipitation (mm) Mean temperature (8C) Precipitation (mm) Mean temperature (8C)

2004 309 4.0 24.9 14.6 189.1 20.7

2005 569 1.9 51.2 11.6 289.6 20.6

2006 506 2.8 9.4 17.1 415.0 21.1

2007 392 3.8 124.6 14.6 177.0 22.6

2008 490 4.2 55.0 14.0 324.6 22.6

2009 478 2.6 12.6 18.2 424.7 20.1

2010 431 2.4 98.6 14.6 188.1 23.6

Y. Chen et al. / Soil & Tillage Research 115–116 (2011) 56–61 57

regions. Thus, a better understanding of conservation tillageperformance over a wide range of soil and environmentalconditions is required.

Black soil (Mollisols) of Northeast China is noted for its highSOM content and associated high crop productivity potential; itsdistribution area is known as the ‘bread basket’ of China. Itslandscape varies from rolling hills to level plains. More than 80% ofthe land has been cultivated and over 60% of the farmland slopessufficiently to impact water runoff. The dark top soil has beenseriously eroded, which has rapidly decreased soil productivitypotential (Liu et al., 2010). Conventional tillage is the main soiltillage practice used, and soil quality is declining under traditionalfarming systems. Some studies on conservation tillage in the southregion of Northeast China reported that NT and RT could improvesoil physical conditions and corn yield (Liang et al., 2009), but fewreports exist for the northern ‘bread basket’ region of NortheastChina. Large-scale adoption of conservation tillage can only beachieved by demonstrating competitive yields and improved soilquality relative to CT. It is therefore imperative to test the responseof crop yield to conservation tillage in the cooler north region.

The objective of this study was to determine for CT, RT and NTsystems (1) soybean and corn yield and (2) soil moisture andtemperature in the cool northern region of Northeast China.

2. Materials and methods

2.1. Background of the study site

The study site is located near Hailun city, Heilongjiang province,the center of the typical Mollisols zone in Northeast China. Morethan 75% of these soils are cultivated in Hailun city. This is thedominant area of corn and soybean production in China. It is in thenorth temperature zone with continental monsoon conditions(cold and arid in winter, hot and rainy in summer). Average annualprecipitation was 530 mm with 65% occurring in June to Augustwith an average precipitation of 472.3 mm from March to Octoberin 2002–2010. Annual average temperature is 1.5 8C, and annualsunshine is approximately 2600–2800 h. Average total annualsolar radiation is 4600 MJ m�2 and annual average availableaccumulated temperature (�10 8C) is 2450 8C. The soil is a typicalMollisols (Udolls) with silty clay loam texture, high clay content,high SOM content, high water holding capacity, high shrink–swelland poor drainage (details will be discussed later). The airtemperatures and precipitation during the study period arepresented in Table 1.

2.2. Experimental design

Two field experiments (the same design) were established intwo separate fields allowing comparisons of crop response totillage systems on two different slopes and soil drainage types. Onewas conducted on flat farmland, located in the Hailun AgroecologyExperimental Station (HAES) (478260N, 1268380E), Northeast

Institute of Geography and Agroecology, Chinese Academy ofSciences. Another trial was performed on farmland with a 5% slope;it is located in Guangrong village (478230N, 1268510E). The distancebetween the two fields was approximately 10 km. The sametreatments on both fields included three tillage systems: no-till(NT), reduced-till (RT) and convention tillage (CT). A randomizedcomplete block designed with three replicates of each treatmentwas used on both fields. Each plot was 8.4 m wide and 40 m long onflat farmland and 4.5 m wide and 20 m long on sloping farmlandwith soybean and corn rotation. The trials started in 2004 on theflat farmland and in 2006 on the sloping farmland. For NT only thecrop seed was harvested, and all biomass (approximate 4 t forsoybean and 10 t for corn) except harvested seeds was evenlydistributed across the plot to cover the surface. Corn or soybeanwas planted with a no-till planter on May 1 of the following year.There were no other soil tillage practices used.

For RT all above-ground biomass was removed manually inautumn. Corn or soybean was planted on the top of a preformed20 cm high ridge with a conventional planter on May 1. The fieldwas ridged twice at time intervals of 15 days after planting. Thefurrow was deep loosened to 25 cm by chisel plowing on June 10before the rainfall season. For CT all above-ground biomass wasremoved manually and ridged by rotary tillage in the autumn. Cornor soybean was planted on the top of ridges in these plots with aconventional planter on May 1. The field was ridged twice at timeintervals of 15 days after planting. Field management was thesame for all treatments except the soil tillage operations. Fertilizerwas applied at 20.25 kg N ha�1, 51.75 kg P ha�1 and 15 kg K ha�1

for soybean, and 138 kg N ha�1, 51.75 kg P ha�1 and 15 kg K ha�1

for corn. Weeds were controlled by herbicides of Acetochlor(1500 ml ha�1) and Thifensulfuron-methyl (120 g ha�1) one dayafter planting. The plant populations were 30 plants m�2 forsoybean and 4.8 plants m�2 for corn. The soil properties in the twostudy fields are presented in Table 2.

2.3. Measurements

Climatic data were obtained from the weather station at HAES.Thesoilwatercontentwasmeasured every15 daysdepthsof 0–5 cm,5–10 cm, 10–15 cm and 15–20 cm. All measurements were made inthe center of the ridge. All samples were dried in an oven at 105 8C toconstant weight. Soil bulk density was measured on undisturbed soilcores sampled with cylinders at the same depths as the watercontents. Soil temperature was recorded hourly at the 10-cm depthby laboratory calibrated electronic earth thermometers; hourlyrecordings were stored in a data logger. Corn and soybean yield wasdetermined by manually harvesting each plot annually, and grainyield was reported after being converted to 14% water content.

2.4. Statistical analysis

The SPSS analytical software 16.0 was used for all of thestatistical analyses. A one-way ANOVA was applied to test

Table 2Physical–chemical properties of the two fields before the experiment.

Depth (cm) SOM (g kg�1) Bulk density (g cm�3) Field capacity (%) Saturated water content (%) Wilting point (%) Clay < 0.002 mm (%)

Flat 0–20 49.1 1.25 38.5 50. 5 17.2 40.8

20–40 44.8 1.29 36.9 45.4 17.1 39.9

40–60 23.1 1.31 33.7 42. 8 17.1 40.8

Sloping 0–20 42.1 1.27 37.4 48.3 17.0 37.0

20–40 28.4 1.19 34.4 44.2 17.1 46.0

40–60 18.6 1.21 32.3 43.6 16.9 44.7

Y. Chen et al. / Soil & Tillage Research 115–116 (2011) 56–6158

treatment effects on yield at each site and means comparison usingthe Turkey test. Differences were declared significant using aprotected LSD (0.05) value.

3. Results

3.1. The responses of crop yield to conservation tillage

In this study, a positive soybean yield response occurred for NTon both flat and sloping farmland (Table 3). On the flat field,soybean yield in NT was significantly greater than RT and CT in2004, 2006 and 2008 (p < 0.05), and yield in RT and CT was similar.Significant yield difference between RT and CT was observed onlyin 2004, and no difference in the other years. On average, an 8.9%increase was found for soybean yield in NT, and only a 2.1%increase occurred in RT compared to CT. A 4.6% reduction in RTsoybean yield was found in 2006, and a 4.3% average yield increasewas observed in the other three years compared to CT. On thesloping field, the greatest soybean yield response occurred in 2008and 2010 when average yield in NT was 13.8% greater than that forCT. Soybean yield in RT was 0.9% less in 2008 and 6.4% more in2010 compared to CT yield. Our monitoring of soil erosionindicated that the soil and water loss with RT was greater than thatfor CT in 2008 but lower than CT in 2010 (Zhang et al., 2011). Thetotal precipitation from May to August was 379 mm and 287 mmin 2008 and 2010, respectively. Two events of 5-day-longcontinuous rainfall occurred in 2008, and one continuous 5-dayrainfall occurred in 2010. Although RT could greatly increase waterinfiltration in the furrow due to deep loosening in this area, it alsoraised the risk of soil erosion in the furrow when continuousrainfall happened, especially on the sloping farmland. High surfacerunoff increased the soil water stress that induced crop yieldreduction.

A negative yield response for corn to NT occurred for both flatand sloping farmland (Table 3). Corn yield was significantlydifferent among NT, RT and CT (p < 0.05), with no differencebetween RT and CT on the flat field. Corn yield in NT was greatlyreduced compared to CT. On average, a 28.4% decrease in corn yieldwas found in NT compared to CT, and only a 1.6% decrease occurredin RT corn yield. Corn yields in NT were lower than those for CT

Table 3Soybean and corn yield under different soil tillage systems.

Field crop Year Flat

NT (kg ha�1) RT (kg ha�1) C

Soybean 2004 3065a* 2857b 2

2006 2435a 2227b 2

2008 2908a 2646b 2

2010 2228a 2239a 2

Mean 2659a 2492b 2

Corn 2005 5060a 7714b 7

2007 4491a 6473b 6

2009 5029a 5848b 6

Mean 4860a 6678b 6

* Means between treatments in the same study field followed by different letters di

during the three study years of 2005, 2007 and 2009, withobserved yield reduction from 22.6% to 33.5%. An 8.4% increase inRT yield was found in 2005, and a 7.5% average yield reductionoccurred in the other two years compared to CT. A similar trendwas also observed on the sloping field for corn. NT also had thelowest corn yield, which was significantly different from CT(p < 0.05). Similar yields were observed between RT and CT. A15.7% decrease in NT yields compared to CT occurred in 2009. TheNT yield reduction on the sloping field was relatively lower thanthat observed on the flat field.

3.2. The effects of soil tillage on soil moistures and temperatures in the

plow layer

On flat farmland, independent of crop planted, two results couldbe confirmed. One was that early growing season soil watercontent was higher in NT than RT or CT in both the ridge and thefurrow (Table 4). This is primarily because the NT surface wasmulched with crop residue, which reduced evaporation in thewindy spring season (Farahani et al., 1998). Additionally,significantly higher soil water contents were observed in thefurrow of RT after June due to deep soil loosening, which markedlyincreased the rainfall infiltration, promoting greater soil waterstorage. Generally, there were significant soil water contentdifferences between NT and CT, with no differences in soil watercontent between RT and CT early in the season after planting. Nosignificant differences occurred during the middle of crop growthperiod, and then difference appeared again before harvest. Thelater differences could be explained by the different plant waterextractions under different soil tillage systems (Wagger andDenton, 1992).

Trends in soil water content as affected by tillage wereindependent of crop for the flat plot area (Table 5). The samesignificant early-season higher soil water contents were found inNT compared to RT and CT after planting. During the middle of thegrowing season, the significant differences disappeared. The highsoil water contents were not observed in the furrow of RT afterJune, even though the soil in the furrow was loosened to 20 cmearly in July. The reason was that the furrow loosening increasedsoil erosion as discussed above. The relatively higher soil water

Sloping

T (kg ha�1) NT (kg ha�1) RT (kg ha�1) CT (kg ha�1)

759c

333b

548b 2847a 2504b 2527b

122a 3393a 3145b 2956c

441b 3120a 2824b 2742c

115b

749b

497b 6822a 8008b 8096b

787b

ffer significantly at p < 0.05.

Table 4Topsoil (0–20 cm) water content for different tillage systems in the ridge and furrow positions on flat farmland from 2005 to 2010.

Year Tillage Mean soil volumetric water content (%)

Date: 0 daysa 15 days 35 days 45 days 65 days 150 days

May June July October

Rb Fc R F R F R F R F R F

2005–2010 NT 32.1a* 32.6a 33.4a 33.7a 29.6a 31.8a 31.3a 32.2a 24.1a 29.1a 30.7a 29.3a

RT 27.2b 29.8b 28.0b 28.5b 28.0b 31.3a 29.1a 33.4a 23.8a 28.0a 26.1b 27.1b

CT 25.5c 28.8b 26.4c 26.4c 27.8b 30.3b 28.6a 31.7a 21.9b 28.3a 25.7b 28.6a

a The day after planting.b Ridge.c Furrow.* Means between treatments in the same position within a given time followed by different letters differ significantly at p < 0.05.

Table 5Topsoil (0–20 cm) water content under different tillage systems in the ridge and furrow positions on sloping farmland from 2008 to 2010.

Year Tillage Mean soil volumetric water content (%)

Date: 0 daysa 15 days 35 days 45 days 65 days 150 days

May June July October

Rb Fc R F R F R F R F R F

2008–2010 NT 36.0a* 35.4a 37.3a 33.4c 40.6a 38.3a 35.3a 35.4b 38.5a 38.2b 24.9a 24.5a

RT 28.5b 34.9b 35.9b 37.5b 39.3a 41.6a 34.0a 40.2a 36.9b 41.3a 22.2b 22.4b

CT 26.7b 36.5a 34.5c 39.2a 38.9a 43.8a 31.1b 39.1a 35.5b 42.2a 21.0b 24.1a

a The day after planting.b Ridge.c Furrow.* Means between treatments in the same location followed by different letters differ significantly at p < 0.05.

Y. Chen et al. / Soil & Tillage Research 115–116 (2011) 56–61 59

contents on sloping farmland than those on flat farmland wasunexpected. The reason remains unknown. The possible explana-tion involves the difference in physical properties between the twofields.

Normally, the soil temperature is influenced by soil moisture.The higher the soil moisture, the lower is soil temperature duringthe spring warming period, of all other factors are similar (Vyn andRaimbault, 1993). The field observations showed that NT had thelowest soil temperatures at the 10-cm depth. Because soiltemperatures were observed in only one block, i.e., no replicationsexisted, the data were not statistically analyzed. On the flatfarmland, compared to CT, the average daily soil temperatures atthe 10-cm depth in NT at the planting, seedling, jointing and grainfilling periods was 3.5 8C, 2.7 8C, 2.8 8C and 0.7 8C lower,respectively. In RT compared to CT, soil temperatures at the 10-cm depth were 0.6 8C, 1.1 8C, 0.8 8C and 0.5 8C lower for the sameidentified periods, respectively (Table 6). On the sloping farmland,compared to CT, the average daily soil temperatures at the 10-cmdepth at the planting, seedling, jointing and grain filling periods inNT were 2.9 8C, 6.1 8C, 4.3 8C and 1.9 8C lower, respectively, and inRT 0.7 8C, 2.3 8C, 1.0 8C and 1.0 8C lower, respectively (Table 7).Thus, soil temperature differences in NT and RT compared to CT

Table 6Soil temperatures at the 10 cm depth under different tillage systems on flat

farmland from 2005 to 2010.

Year Tillage Soil temperature (8C)a

Sowing

period

Seedling

period

Jointing

period

Filling

period

2005–2010 NT 6.2 12.6 16.2 20.8

RT 9.1 14.1 18.2 21.1

CT 9.6 15.3 19.0 21.5

a The mean value of the experimental years at the four measured stages.

were much larger on sloping farmland than those on the flatfarmland. NT apparently reduced the surface runoff and storedmore soil water on sloping farmland compared to that whichoccurred with CT (Zhang et al., 2011), and there was almost nosurface runoff on the flat farmland (Tables 4 and 5). For RT, becausethe field was not plowed the previous autumn, soil in the ridgeswas more compacted, which induced a lower soil temperaturecompared to that in CT.

4. Discussion

An approximate 10% increase in soybean yield and 30% decreasein corn yield in NT compared to CT were observed in the two long-term field experiments in the cool humid region of NortheastChina. By reviewing one hundred years of international field trialsaddressing crop response to NT, DeFelice et al. (2006) found thatthe average difference in soybean and corn yields between NT andCT was negligible. NT tended to have greater yields than CT in hotand wet areas, similar yields occurred in the warm and humidareas and lower NT yields were observed in the cool and semi-aridregions. NT crop yield was influenced by multiple factors includingclimate, soil characteristics, landscape, crop variety, crop rotation,

Table 7Soil temperatures at the 10 cm depth under different tillage systems on sloping

farmland from 2009 and 2010.

Year Tillage Soil temperature (8C)a

Sowing

period

Seedling

period

Jointing

period

Filling

period

2009–2010 NT 7.1 19.6 16.7 18.4

RT 9.2 23.4 20.1 19.3

CT 9.9 25.7 21.0 20.3

a The mean value of the experimental years at the four measured stages.

Y. Chen et al. / Soil & Tillage Research 115–116 (2011) 56–6160

fertilizer application and other field management (Triplett andDick, 2008). It is quite likely that the best management practicesfor NT are different from the best management practices for CT orRT. On farm fields, practices such as timing of planting, fertilizerplacement, fertilizer rates, planting populations, and weed controlmethods would likely differ between tillage systems. In this study,common management practices, other than tillage, were used foreach system. Perhaps NT would have performed better withmanagement practices better designed for NT.

The study site in the north region of Northeast China, is a cooland humid area with an average annual air temperature of 3.1 8C,which ranged from 1.9 8C to 4.2 8C during this study with anaverage annual precipitation of 454 mm, which ranged from309 mm to 569 mm with 63.3% concentrated in June throughAugust. Heat is a dominant factor influencing agriculturalproduction in this region. While soil water is normally satisfactoryfor crop growth, precipitation is quite variable during the seasonsand years; seasonal and annual drought usually occurs. Heat is adominant factor influencing agricultural production in this region(Meng et al., 2003). Some studies indicate that the decreased NTcrop yields in cool areas result from lower early season soiltemperatures causing reduced the early crop growth and lowerfinal grain yields (Vyn and Raimbault, 1993). Many studies havereported that tillage induced soil moisture and soil temperaturedifferences affect plant heat and water stress, which has been thedominant reason of crop yield differences between tillage systemsin a variety of studies (Triplett and Dick, 2008). The soil watercontent under different soil tillage treatments were affected byrainfall, evaporation, plant uptake and soil drainage. Thesecomplex process interactions were critical in explaining resultsof this study. It seems though that the slow early plant growthcaused by lower early season soil temperature under NT was thedominant reason for reduced NT corn yield in the northern area ofNortheast China, this might be due to the fact that corn requiresmore heat than soybean. However, in opposite to corn, this lowerearly season soil temperature is beneficial for later development ofsoybean growth (Liu et al., 2005); a surprising ‘stay green’phenomenon was found in soybean with increased photosyntheticrate and duration (unpublished data), and thus an increasedsoybean yield. Detailed investigation on physiological responses ingrowth and development of each stage from corn and soybean areneeded.

Soil was another important factor influencing the response ofcrops to NT through tillage-induced differences in water infiltra-tion, drainage, thermal conduction and nutrient release (DeFeliceet al., 2006). It has been widely identified that soil with a high claycontent, high shrink–swell potential, high water holding capacity,high plasticity, low infiltration rate and poor internal drainage isnot suitable for NT production (Potter and Chichester, 1993). Thesoil in this study was a typical Mollisols, Udolls with approximately40% clay, 45% water holding capacity, 3% shrink–swell potentialand no drainage under the depth of 100 cm. Our field observationshowed lower infiltration in NT than in CT even though NT wascontinuous for 7 years. A measurement of the soil surfaceinfiltration rate at June 12, 2009 was 3.6 mm min�1 in NT and7.5 mm min�1 in CT (unpublished). All similar results wereobserved during the study years, no matter what growing seasonsand no matter what crop were. An expected high soil surfaceinfiltration rate in NT compared to CT was not found in our studyfields. This further explains the lower corn yield in NT.

The landscape influences soil moisture and temperature andimpacts crop response to NT. The different trial areas had differentamounts of surface runoff (Lal, 1998). Our field monitoring showed11.5% of rainfall ran off the CT area and only 1.9% ran off the NT areaon sloping plots, and no surface runoff occurred on flat plots (Zhanget al., 2011). Although NT had a lower soil infiltration rate than CT,

its soil surface was covered by residual that reduced the surfacesplash erosion and slowed surface runoff. While CT was ridged,rainfall easily collected in furrows and that increased surfacerunoff (Liu et al., 2010). This explains the larger difference in soilmoisture between NT and CT on the sloping farmland than that onthe flat farmland. This could explain why a greater soybean yielddifferential (13.8%) occurred on the sloping farmland than that onthe flat farmland (8.9%) under NT. This may also explain the lowerrelative corn yield reduction (15.7%) on the sloping farmland thanthat (28.4%) on the flat farmland under NT. A higher yield andvariable relative yields in NT compared to CT was found for bothsoybean and corn, respectively, for the sloping study site.Therefore, compared to flat farmland, sloping, better drainedfarmland seems more suitable for the NT practice than flat areas forthese types of soil and this location.

The type of crop also impacted the response to soil tillage. Acorn-soybean rotation was used in this study. The different cropshad completely opposite responses to NT compared to the othermore intensive tillage systems. NT significantly increased soybeanyield compared to CT, whereas corn yield fell significantly underNT, independent of soil slope. Corn needs more water andnutrients, especially nitrogen, compared to soybean (Meng et al.,2003). Many studies have demonstrated that less N release andgreater water availability in NT induces N deficiencies, and 30%more N should be applied with corn production in NT compared toCT (Al-Darby and Lowery, 1986). Accordingly, nitrogen and waterstress was the third reason for corn yield reduction under NT. Forsoybean, symbiotic nitrogen fixation could partly eliminate thenitrogen stress resulting in a relatively high yield (Dickey et al.,1994).

In conclusions, significant increase of soybean yield anddecrease of corn yield under NT compared to CT was clearlyshown in the cool humid region of Northeast China. There weremultiple effects of climate, soil properties, landscape, crop type,and crop rotation. NT significantly reduced surface runoff andstored more water in soil than CT on sloping arable farmland.Hence, it seems NT is more effective and beneficial on the moreeroded sloping farmland, especially for soybean, than it is on flatfarmland in the north region of Northeast China.

Acknowledgements

The authors sincerely thank the support of the National High-tech R&D Program of China (2008AA10z212) and the NationalKey Technology R&D Program (2009BADB3B04 and 2007BAD89B05-12).

References

Al-Darby, A.M., Lowery, B., 1986. Evaluation of corn growth and productivity withthree conservation tillage systems. Agron. J. 78, 901–907.

Birkas, M., Nyarai, F., Szalai, T., 1997. Experiments with direct drilling in Hungaryimpact on soil condition, weed infestation and crop yield. In: PNA Bibl. Frag-menta Agron., vol. 2. pp. 79–82.

Canarache, A., Dumitru, E., 2008. No-till and minimum tillage in Romania. In:Goddard, T., Zoebisch, M., Gan, Y., Ellis, W., Watson, A., Sombatpanit, S.(Eds.), No-Till Farming Systems. WASWC, Thailand, p. 331345.

Dick, W.A., McCoy, E.L., Edwards, W.M., Lal, R., 1991. Continuous application of no-tillage to Ohio soils. Agron. J. 83, 65–73.

DeFelice, M.S., Carter, P.R., Mitchell, S.B., 2006. Influence of tillage on corn andsoybean yield in the United States and Canada. Available from:<www.plantmanagementnetwork.org/cm>.

Dickey, E.C., Pasha, J.P., Grisso, R.D., 1994. Long-term tillage effects on grain yieldand soil properties in a soybean/grain sorghum rotation. J. Prod. Agric. 7,465–470.

Farahani, H.J., Peterson, G.A., Westfall, D.G., 1998. Dryland crop ping intensifica-tion: a fundamental solution to efficient use of precipitation. Adv. Agron. 64,197–223.

Fernandez, U.O., Virto, I., Bescansa, P., Imaz, M.J., Enrique, A., Karlen, D.L., 2009. No-tillage improvement of soil physical quality in calcareous, degradation-prone,semiarid soils. Soil Till. Res. 106, 29–35.

Y. Chen et al. / Soil & Tillage Research 115–116 (2011) 56–61 61

Kapusta, G., Krausz, R.F., Matthews, J.L., 1996. Corn yield is equal in conventional,reduced, and no tillage after 20 years. Agron. J. 88, 812–817.

Lafond, G.P., Boyetchko, S.M., Brandt, S.A., Clayton, G.W., Entz, M.H., 1996. Influenceof changing tillage practices on crop production. Can. J. Plant Sci. 76, 641–649.

Lal, R., 1998. Soil erosion impact on agronomic productivity and environmentalquality. Crit. Rev. Plant Sci. 17, 319–464.

Liang, A.Z., Yang, X.M., Zhang, X.P., Neil, M., Shen, Y., Li, W.F., 2009. Soil organiccarbon changes in particle-size fractions following cultivation of Black soils inChina. Soil Till. Res. 105, 21–26.

Liu, X.B., Jin, J.S.J., Herbert, Zhang, Q.Y., Wang, G.H., 2005. Yield components, drymatter, LAI and LAD of soybeans in Northeast China. Field Crops Res. 93, 85–93.

Liu, X.B., Zhang, X.Y., Wang, Y.X., Sui, Y.Y., Zhang, S.L., Herbert, S.J., Ding, G., 2010. Soildegradation: a problem threatening the sustainable development of agriculturein Northeast China. Plant Soil Environ. 56, 87–97.

Mahli, S.S., Mumey, G., O’Sullivan, P.A., Harker, K.N., 1988. An economic compari-son of barley production under zero and conventional tillage. Soil Till. Res. 11,159–166.

Meng, K., Zhang, X.Y., Sui, Y.Y., Zhao, J., 2003. Black soil water characteristic inHailun, Heilongjiang. Chin. J. Soil Sci. 34, 11–14 (in Chinese).

Potter, K.N., Chichester, F.W., 1993. Physical and chemical properties of a Vertisolwith continuous controlled-traffic, no-till management. Trans. ASAE 36, 95–99.

Rockstrom, L., Kaumbutho, P., Mwalley, J., Nzabi, A.W., Temesgen, M., Mawenya, L.,Barron, J., Mutua, J., Damgaard, L.S., 2009. Conservation farming strategies inEast and Southern Africa: yields and rain water productivity from on-farmaction research. Soil Till. Res. 103, 23–32.

Six, J., Elliott, E.T., Paustain, K., 1999. Aggregate and soil organic matter dynamicsunder conventional and no-tillage systems. Soil Sci. Soc. Am. J. 63, 1350–1358.

Triplett, G.B., Doren, D.M., 1977. Agriculture without tillage. Sci. Am. 236, 28–33.Triplett, G.B., Dick, W.A., 2008. No-tillage crop production: a revolution in agricul-

ture. Agron. J. 100, 153–165.Vyn, T.J., Raimbault, B.A., 1993. Long-term effect of five tillage systems on corn

response and soil structure. Agron. J. 85, 1074–1079.Wagger, M.G., Denton, H.P., 1992. Crop and tillage rotations: grain yield, residue

cover, and soil water. Soil Sci. Soc. Am. J. 56, 1233–1237.Wall, D.A., Stobbe, E.H., 1984. The effect of tillage on soil temperature and corn (Zea

mays L.) growth in Manitoba. Can. J. Plant Sci. 64, 59–67.West, T.D., Griffith, D.R., Steinhardt, G.C., Kladivko, E.J., Parsons, S.D., 1996. Effect of

tillage and rotation on agronomic performance of corn and soybean: twenty-year study on dark silty clay loam soil. J. Prod. Agric. 9, 241–248.

Zentner, R.P., Lafond, G.P., Derksen, D.A., Campbell, C.A., 2002. Tillage method andcrop diversification: effect on economic returns and riskiness of croppingsystems in a Thin Black Chernozem of the Canadian Prairies. Soil Till. Res.67, 9–21.

Zentner, R.P., Lafond, G.P., Derksen, D.A., Nagy, C.N., Wall, D.D., May, W.E., 2004.Effects of tillage method and crop rotations on non-renewable energy useefficiency for a thin Black Chernozem in the Canadian Prairies. Soil Till. Res.77, 125–136.

Zhang, S.L., Zhang, X.Y., Huffman, T., Liu, X.B., Yang, J.Y., 2011. Soil loss, crop growth,and economic margins under different management systems on a sloping fieldin the Black soil area of Northeast China. J. Sustain. Agric. 35 (3), 293–311.