• Authors:
    • Cui, S.
    • Chang, X.
    • Xu, B.
    • Zhu, X.
    • Luo, C.
    • Wang, S.
    • Duan, J.
    • Zhang, Z.
  • Source: Plant and Soil
  • Volume: 362
  • Issue: 1-2
  • Year: 2013
  • Summary: Few studies have investigated the effect of nitrogen (N) fertilizer on ecosystem respiration (Re) under mixed legume and grass pastures sown at different seeding ratios,and data are almost entirely lacking for alpine meadow of the Tibetan Plateau. Our aim was to test the hypothesis that although a combination of legumes with grass and N fertilizer increases Re the combination decreases Re intensity (i.e. Re per unit of aboveground biomass) due to greater increases in aboveground biomass compared to increases in Re. This hypothesis was tested using different seeding ratios of common vetch (Vicia sativa L.) and oat (Avena sativa L.) with and without N fertilizer on the Tibetan plateau in 2009 and 2010. Re was measured using a static closed opaque chamber. Re intensity was estimated as the ratio of seasonal average Re during the growing season to aboveground biomass. Compared with common vetch monoculture pasture, mixed legume-grass pastures only significantly decreased Re intensity (with a decrease of about 75 %-87 %) in the drought year 2009 due to greater increases in aboveground biomass compared to increases in Re. There were no significant differences in Re and Re intensity among different seeding ratios of oat and common vetch in either year. N fertilizer significantly decreased Re intensity for common vetch monoculture pasture by 24.5 % in 2009 and 69.5 % in 2010 although it did not significantly affect plant production and Re. From the perspective of forage yield and Re, planting mixed legume-grass pastures without N fertilizer is a preferable way to balance the twin objectives of forage production and mitigation of atmospheric greenhouse gas emissions in alpine regions.
  • Authors:
    • Xing, B. S.
    • Herbert, S.
    • Deng, X.
    • Wang, Z. Y.
    • Zheng, H.
  • Source: GEODERMA
  • Volume: 206
  • Year: 2013
  • Summary: Interest in the use of biochar to improve soil productivity has rapidly increased. Nitrogen (N) loss, retention and bioavailability in biochar-amended soils fertilized with NH4+-N and NO3--N were studied using leaching and pot experiments. NO3--N leaching from the soils fertilized with NH4+-N and NO3--N was significantly reduced by biochar addition. NH4+-N leaching from the NO3--N fertilized soil was also significantly reduced by biochar, while no significant effect was observed for the NH4+-N fertilized soil. Also lower NH4+-N and NO3--N were leached from NO3--N fertilized soil with maize (Zea mays L) grown. Mitigation of N leaching loss following biochar addition is mainly attributed to the increase in soil water holding capacity (WHC), NH4+ adsorption and enhanced N immobilization. Biochar addition stimulated maize growth, both above and below ground. Biochar also increased N utilization efficiency (NUE) of maize but decreased N accumulation efficiency (NAE), indicating that biochar addition may improve N bioavailability in agricultural soils. Therefore, reduction of N leaching, and increase of N retention and bioavailability in agricultural soils can potentially decrease the N fertilizer demand for crop growth.
  • Authors:
    • Cheng,Xiaoli
    • Yang,Yuanhe
    • Li,Ming
    • Dou,Xiaolin
    • Zhang,Quanfa
  • Source: Plant and Soil
  • Volume: 366
  • Issue: 1-2
  • Year: 2013
  • Summary: Over recent decades, a large uncultivated area has been converted to woodland and shrubland plantations to protect and restore riparian ecosystems in the Danjiangkou Reservoir area, a water source area of China's Middle Route of the South-to-North Water Transfer Project. Besides water quality, afforestation may alter soil organic carbon (SOC) dynamics and stock in terrestrial ecosystems, but its effects remain poorly quantified and understood. We investigated soil organic C and nitrogen (N) content, and delta C-13 and delta N-15 values of organic soil in plant root-spheres and open areas in an afforested, shrubland and adjacent cropped soil. Soil C and N recalcitrance indexes (RIC and RIN) were calculated as the ratio of unhydrolyzable C and N to total C and N. Afforestation significantly increased SOC levels in plant root-spheres with the largest accumulation of C in the afforested soil. Afforestation also increased belowground biomass. The C:N ratios in organic soil changed from low to high in the order the cropped, the shrubland and the afforested soil. The RIC in the afforested and shrubland were higher than that in cropped soil, but the RIN increased from the afforested to shrubland to cropped soil. The delta N-15 values of the organic soil was enriched from the afforested to shrubland to cropped soil, indicating an increased N loss from the cropped soil compared to afforested or shrubland soil. Changes in the delta C-13 ratio further revealed that the decay rate of C in the three land use types was the highest in the cropped soil. Afforestation increased the SOC stocks resulted from a combination of large C input from belowground and low C losses because of decreasing soil C decomposition. Shifts in vegetation due to land use change could alter both the quantity and quality of the soil C and thus, have potential effects on ecosystem function and recovery.
  • Authors:
    • Liu,Zhijuan
    • Yang,Xiaoguang
    • Chen,Fu
    • Wang,Enli
  • Source: Climatic Change
  • Volume: 117
  • Issue: 4
  • Year: 2013
  • Summary: Northeast China (NEC) is one of the major agricultural production areas in China and also an obvious region of climate warming. We were motivated to investigate the impacts of climate warming on the northern limits of maize planting. Additionally, we wanted to assess how spatial shifts in the cropping system impact the maize yields in NEC. To understand these impacts, we used the daily average air temperature data in 72 weather stations and regional experiment yield data from Jilin Province. Averaged across NEC, the annual air temperature increased by 0.38 A degrees C per decade. The annual accumulated temperature above 10 A degrees C (AAT10) followed a similar trend, increased 66 A degrees C d per decade from 1961 to 2007, which caused a northward expansion of the northern limits of maize. The warming enabled early-maturing maize hybrids to be sown in the northern areas of Heilongjiang Province where it was not suitable for growing maize before the warming. In the southern areas of Heilongjiang Province and the eastern areas of Jilin Province, the early-maturing maize hybrids could be replaced by the middle-maturing hybrids with a longer growing season. The maize in the northern areas of Liaoning Province was expected to change from middle-maturing to late-maturing hybrids. Changing the hybrids led to increase the maize yield. When the early-maturing hybrids were replaced by middle-maturing hybrids in Jilin Province, the maize yields would increase by 9.8 %. Similarly, maize yields would increase by 7.1 % when the middle-maturing hybrids were replaced by late-maturing hybrids.
  • Authors:
    • Shi,Tiezhu
    • Cui,Lijuan
    • Wang,Junjie
    • Fei,Teng
    • Chen,Yiyun
    • Wu,Guofeng
  • Source: Plant and Soil
  • Volume: 366
  • Issue: 1-2
  • Year: 2013
  • Summary: This study aimed to compare stepwise multiple linear regression (SMLR), partial least squares regression (PLSR) and support vector machine regression (SVMR) for estimating soil total nitrogen (TN) contents with laboratory visible/near-infrared reflectance (Vis/NIR) of selected coarse and heterogeneous soils. Moreover, the effects of the first (1st) vs. second (2nd) derivative of spectral reflectance and the importance wavelengths were explored. The TN contents and the Vis/NIR were measured in the laboratory. Several methods were employed for Vis/NIR data pre-processing. The SMLR, PLSR and SVMR models were calibrated and validated using independent datasets. Results showed that the SVMR and the PLSR models had similar performances, and better performances than the SMLR. The spectral bands near 1450, 1850, 2250, 2330 and 2430 nm in the PLSR model were important wavelengths. In addition, the 1st derivative was more appropriate than the 2nd derivative for spectral data pre-processing. PLSR was the most suitable method for estimating TN contents in this study. SVMR may be a promising technique, and its potential needs to be further explored. Moreover, the future studies using outdoor and airborne/satellite hyperspectral data for estimating TN content are necessary for testing the findings.
  • Authors:
    • Li, R.
    • Wang, M.
    • Jia, Z.
    • Hou, X.
    • Yang, B.
    • Han, W.
    • Nie, J.
    • Zhang, R.
  • Source: Transactions of the Chinese Society of Agricultural Engineering
  • Volume: 28
  • Issue: 2
  • Year: 2012
  • Summary: In order to improve rainfall utilization efficiency and increase water availability for crops in dry farming area, a field experiment was conducted in 2007-2010 at Heyang Dryland Farming Experimental Station in Shaanxi province of China to determine the effect of different ridge and furrow with mulching cultivation patterns on soil water, soil temperature, yield of spring maize, and economic returns. The ridges were covered with common plastic film in all treatments, while different furrows were mulched with common plastic film, biodegradable film, corn straw, liquid film and uncovering, respectively. The flat plot without mulch was used as the control. The results obtained in a four-year experiment showed that, at the seedling stage of maize, the average temperature in 5-25 cm soil layer under common plastic film and biodegradable film were 2.4degreesC and 2.1degreesC higher than that of the control respectively. In contrast, the temperature under corn straw covering was 1.7degreesC lower than that of the control. Besides, the different rainwater harvesting treatments could improve soil moisture in the early growth of maize. There was no difference in the soil moisture level between corn straw, liquid film, uncovering and the control during the middle and late growth of maize. However, the soil moisture of common plastic film and biodegradable film in deep soil layer were lower than that of the control. Compared with the control, the 4-year average maize yield with biodegradable film, common plastic film, and corn straw mulching significantly increased by 35.2%, 34.7% and 33.6%, and the average water use efficiency increased by 30.6%, 30.2% and 28.6%, respectively. The total net income with corn straw mulching was the highest, followed by biodegradable film mulching, and the total net income increased by 3 299 and 2 752 Yuan/hm 2 respectively, compared to the control. It was concluded that when the ridges were covered with common plastic film, the furrows was mulched with biodegradable film or straw, not only the soil water and temperature conditions were improved, but also the maize yield and net income were increased. Therefore, these two treatments are considered as efficient for maize production in Weibei Highland area.
  • Authors:
    • He, J.
    • Wang, Q.
    • Rasaily, R. G.
    • Li, H.
    • Lu, C.
  • Source: African Journal of Biotechnology
  • Volume: 11
  • Issue: 4
  • Year: 2012
  • Summary: An experiment was conducted to determine the effects of tillage on soil properties in the field of maize ( Zea mays L.) and winter wheat ( Triticum aestivum L.) annual double cropping region in North China Plain. Measurements were made following six years (2005 to 2010) of three tillage treatments; no till with controlled traffic (NTCT), no till random trafficking (NTRT) and conventional tillage (CT) on a silt loam according to the USDA texture classification system soil in Daxing district, which lies in the suburb of Beijing. Long term no till with controlled traffic significantly (P<0.05) increased macro-aggregates, infiltration rate, soil moisture, together with reductions in soil bulk density, soil compaction in different layers compared with the no till random traffic and traditional mould board tillage treatment currently used in this region. Consequently, mean winter wheat and summer maize yields for the NTCT treatment were improved by 2.8 and 7.1% when compared with the soils under no till random traffic, while huge improvement was found when it was compared with conventional ploughing management (4.2 and 12.08% for wheat and maize, respectively). The long-term experiment demonstrated that no-tillage controlled traffic with residues retained, offers a potentially significant improvement over the current farming systems in annual double cropping areas of North China Plain.
  • Authors:
    • Shirtliffe, S. J.
    • Johnson, E. N.
  • Source: Renewable Agriculture and Food Systems
  • Volume: 27
  • Issue: 1
  • Year: 2012
  • Summary: Organic farmers in western Canada rely on tillage to control weeds and incorporate crop residues that could plug mechanical weed-control implements. However, tillage significantly increases the risk of soil erosion. For farmers seeking to reduce or eliminate tillage, potential alternatives include mowing or using a roller crimper for terminating green manure crops (cover crops) or using a minimum tillage (min-till) rotary hoe for mechanically controlling weeds. Although many researchers have studied organic crop production in western Canada, few have studied no-till organic production practices. Two studies were recently conducted in Saskatchewan to determine the efficacy of the following alternatives to tillage: mowing and roller crimping for weed control, and min-till rotary hoeing weed control in field pea ( Pisum sativum L.). The first study compared mowing and roller crimping with tillage when terminating faba bean ( Vicia faba L.) and field pea green manure crops. Early termination of annual green manure crops with roller crimping or mowing resulted in less weed regrowth compared with tillage. When compared with faba bean, field pea produced greater crop biomass, suppressed weeds better and had less regrowth. Wheat yields following pea were not affected by the method of termination. Thus, this first study indicated that roller crimping and mowing are viable alternatives to tillage to terminate field pea green manure crops. The second study evaluated the tolerance and efficacy of a min-till rotary harrow in no-till field pea production. The min-till rotary hoe was able to operate in no-till cereal residues and multiple passes did not affect the level of residue cover. Field pea exhibited excellent tolerance to the min-till rotary hoe. Good weed control occurred with multiple rotary hoe passes, and pea seed yield was 87% of the yield obtained in the herbicide-treated check. Therefore, this second study demonstrated that min-till rotary hoeing effectively controls many small seeded annual weeds in the presence of crop residue and thus can reduce the need for tillage in organic-cropping systems.
  • Authors:
    • Rasaily, R. G.
    • Lu, C.
    • Li, H.
    • He, J.
    • Wang, Q.
    • Su, Y.
  • Source: Transactions of the Chinese Society of Agricultural Engineering
  • Volume: 28
  • Issue: 1
  • Year: 2012
  • Summary: In order to solve the problems of residue blocking and difficulty to open the furrow of no-till wheat planter in heavy corn residue cover fields in annual double cropping areas of the North China, a telescopic lever furrowing and anti-blocking unit was designed for no-till planter. Its key parameters were determined based on a band between orthogonal test and the structure analysis, and a telescopic lever furrowing and anti-blocking unit was used to conduct the field experiment. The field experiment showed that the telescopic lever furrowing and anti-blocking unit could solve the problem of straw blocking effectively and improve the seeding quality. Compared with the strip rotary-tilling anti-blocking unit, the telescopic lever furrowing and anti-blocking unit could reduce topsoil disturbance quantity by 21.5%; fuel consumption per unit area was reduced by 23.65% when the depth of furrow opening was 10 cm, which could reduce power consumption of tractor. Above all, the telescopic lever furrowing and anti-blocking unit has important value in extending no-tillage planter.
  • Authors:
    • Hoogmoed, W. B.
    • Oenema, O.
    • Cai D.
    • Jin, K.
    • Wu, X.
    • Zhao, Q.
    • Feng, Z.
    • Zhang, D.
    • Dai, K.
    • Wu, H.
    • Wang, X.
  • Source: Field Crops Research
  • Volume: 132
  • Year: 2012
  • Summary: Dryland farming in the dry semi-humid regions of northern China is dominated by mono-cropping systems with mainly maize ( Zea mays L.) or wheat ( Triticum aestivum), constrained by low and variable rainfall, and by improper management practices. Addressing these problems, field studies on tillage and residue management for winter wheat and spring maize were conducted at 4 sites in Linfen, Tunliu and Shouyang (Shanxi province) and Luoyang (Henan province). These studies (a.o.) explored the impacts of different tillage and residue application methods on soil physical conditions, water storage, water use, water use efficiency (WUE) and crop yields of wheat and maize. An analysis of the results of these studies is presented. Conservation tillage, comprising no-till as well as reduced tillage practices (subsoiling, deep ploughing) showed benefits which were more prominent in combination with residue application. Benefits compared to conventional tillage were found in the form of improved soil physical conditions, such as higher topsoil bulk densities but lower subsoil bulk densities. This resulted in a better water storage during the summer fallow or rainy season in winter wheat fields, and a better water conservation and soil protection in spring maize fields. Compared to conventional methods, reduced tillage gave yields around 13-16% higher in spring maize and round 9-37% higher in winter wheat. Yields under no-till were very close to those from conventional methods. Surface application of crop residue for maize was found to increase the risk for delayed seedling emergence, because of low temperatures, leading to a recommendation for incorporation of residue in combination with reduced tillage. For winter wheat, subsoiling in combination with straw mulching after harvest in summer every other two or three year, and no-till seeding is a promising practice for sandier soils and low rainfall conditions. For heavier clay loam soils, deep ploughing with straw mulching after wheat harvest in summer every other two or three year, and no-till seeding practice is recommended. For spring maize, deep ploughing with straw and fertilizers incorporation after harvest in fall, and no-till seeding practices are recommended. Subsoiling or no-till with residue mulching after harvest in fall, and no-till seeding practices in spring are also promising practices, the latter only in situations where low spring temperatures are not a problem. Continuous no-till is not recommended.