Rapeseed Rotation Research Articles

Environmental parameters and management as factors affecting greenhouse gas emissions from clay soil

ABSTRACT Greenhouse gas emissions (GHG) drive climate change, with agricultural land significantly contributing, influenced by soil properties. While extensive research exists on environmental and management impacts on GHG emissions across various soils and climates, understanding key factors influencing GHG emissions from clay soil in temperate climates is limited. This study aims to investigate the combination of environmental and management factors reducing N2O, CO2, and CH4 emissions from clay soil in temperate climates. Recognising the potential of reduced tillage and legume-based crop rotations in mitigating GHG emissions, we investigate their impact on soil emissions. The conventionally managed field with spring barley, field beans, winter wheat, and winter rapeseed rotation demonstrates the lowest average N2O emission (3.7 g N2O ha−1 d− 1), while the field with winter crops in a reduced tillage rotation shows the highest N2O emission (8.5 g N2O ha−1 d− 1). A rotation with winter crops, beans twice, and barley, under conventional management, demonstrates the highest CO2 emission (140.2 kg CO2 ha−1 d− 1), while the lowest CO2 emission is observed in a rotation with winter crops, beans, and barley under reduced tillage management (100.8 kg CO2 ha−1 d− 1). CH4 assimilation ranges from 3.1 to 5.4 CH4 g ha−1 d−1 across all rotation and tillage combinations. However, ANCOVA results indicate that the volumes of GHG emissions are significantly influenced by the interaction of environmental and management factors, where precipitation is the most significant factor in the interaction with other environmental factors, soil tillage, and crop residues for N2O and CO2 emissions, while CH4 emissions are influenced by the interaction of air temperature with other environmental factors, soil tillage, and crop residues. This underscores the need to consider both management and relevant environmental factors when evaluating the impact of practices on GHG emissions from clay soil in temperate climates.

Deciphering the role of particulate organic matter in soil nitrogen transformation in rice–rapeseed and rice–wheat rotation systems

Crop rotation affects the decomposition of soil organic matter (SOM) and thereby alter the composition of SOM fractions. It remains unclear how different SOM fractions impact soil nitrogen (N) transformation in various rotation systems. The aim of this study was to ascertain the role of particulate organic matter (POM)-a labile SOM fraction-in soil N transformation under various crop rotations. A paired plot experiment was conducted under two common cropping patterns, i.e., rice–rapeseed rotation (RR) vs. rice–wheat rotation (RW). Soil chemical composition and organic matter fraction before rice transplanting were compared between RR and RW systems after four years of crop rotations (2017–2021). With the same N inputs, the rice yield and N uptake under RR were 16.4 % and 13.2 % higher than those under RW, respectively. Compared with RW, RR resulted in higher carbon (C) and N contents in soil POM, despite minimal differences in total SOM. A larger potentially mineralizable N pool and a higher N mineralization rate occurred under RR than under RW, based on the results of soil net mineralization experiment. When POM was incubated alone, its contribution to potentially mineralizable N was 65.1 % and 61.3 % in RR and RW soils, respectively. Infrared spectroscopy revealed that in contrast with RW, RR promoted the accumulation of organic matter with high bioavailability (e.g., amides, carbohydrates, polysaccharides) in soil POM. This might be responsible for the higher gross mineralization and nitrification rates but lower gross immobilization rate under RR than under RW. Consequently, RR not only increased the contents of POMC and POMN but also improved the quality of POM fraction in soils. Findings of the present study demonstrate that POM plays a distinct role in soil N mineralization in various rotation systems. The discrepancy in POM content and composition resulting from various crop rotations leads to differences in soil N mineralization, which in turn affects the N supply and rice yield.

Effects of Annual Straw Incorporation Combined with Application of Nitrogen Fertilizer in Rice Season on Dry Matter and Nutrient Accumulation Characteristics of Subsequent Rapeseed

In the rice–rapeseed rotation system, straw incorporation plays an important role in achieving the rational utilization of resources and maintaining crop production. However, in the study of rice–rapeseed rotation, there was no study on the effect of straw and nitrogen (N) fertilizer in the rice season on the dry matter accumulation (DMA) and nutrient accumulation of subsequent rapeseed. So, this study relied on the localization experiment of rice–rapeseed rotation and annual straw incorporation (full straw returning to the field, SR; the control is full straw removal from the field, CK) with different N fertilizer application rates (N1: 0 kg ha−1, N2: 75 kg ha−1, N3: 150 kg ha−1, and N4: 225 kg ha−1) in the rice season. Based on the fourth year of experiment implementation, the effects of annual straw incorporation combined with the N fertilizer application rate in the rice season on the leaf area index (LAI), photosynthetic potential (PP), DMA and its distribution proportion and rate, and nutrient uptake and its allocation proportion in rapeseed were discussed. At the bolting stage (BS), initial flowering stage (IFS), terminal flowering stage (TFS), and mature stage (MS), the DMA of rapeseed in SR was significantly higher than that in CK by 69.90, 64.27, 62.90, and 41.27%, respectively. The accumulation of N, phosphorus (P), and potassium (K) in SR was significantly higher than that in CK at the BS, IFS, TFS, and MS. Straw treatment had a significant impact on the apparent surplus of N, P, and K in the rice, rapeseed, and annual seasons, while the application of N fertilizer in the rice season had a significant or extremely significant impact on the apparent surplus (AS) of N in the rice, rapeseed, and annual seasons, indicating that fertilization of previous crops had a certain aftereffect. Therefore, straw incorporation is a sustainable farmland management measure.

Changes in Physical and Water Retention Properties of Technosols by Agricultural Reclamation with Wheat–Rapeseed Rotation in a Post-Mining Area of Central Poland

During opencast lignite mining, the natural landscape is damaged, along with soils, and new anthropogenic landforms are created which require reclamation. Usually, the evaluation of the effects of reclamation (mostly forestry) is concerned with changes in chemical properties in the first years, mainly in the surface horizon. This study analyzed the effect of long-term agricultural reclamation (43 years) on the physical and water retention properties of Technosols. The experiment involved cultivation of winter wheat and winter oilseed rape under 3 fertilization variants. After 43 years, an Ap horizon (Ap1 and Ap2) developed in fertilized Technosols, but was not clearly formed in unfertilized minesoil. In Ap1, there was improvement in the physical quality (S), bulk density (BD), particle density (PD), structural stability index (SI), soil porosity (SP), air-filled porosity (AFP), field capacity (FC) and plant available water capacity (PAWC). In Ap2, properties were comparable to those in the surface horizon of unfertilized Technosols and to those observed before reclamation. Regardless of fertilization, there was deterioration in physical quality in parent materials. In general, the properties of fertilized Technosols have improved in the surface horizons, but increasing fertilization above plant requirements does not lead to their further enhancement.

New agri-environmental measures have a direct effect on wildlife and economy on conventional agricultural land.

The objective of this article is to evaluate economic profits along with return on investment and also the impact of newly designed agri-environmental measures (AEM) on the presence of bioindicator species-European hare and roe deer-in comparison to conventionally cultivated agricultural land. The abundance of European hare was, on average, 4.5-6.7 times higher on AEM compared to the standard agricultural regime and 3.5-6.4 times higher in the case of roe deer in 2020 and 2021. From an economic point of view, the highest incomes were found for extensive orchard alleys and standard conventional crops-wheat and rapeseed rotation. The cash flow from extensive orchard was 4.3 times larger and wheat and rapeseed were 3.5 times larger than from the clover grass mixture. Moreover, the lowest value of operational expenses was found in the case of extensive orchard alleys. The payback period ranged from 16.02 years (wheat and rapeseed rotation) to 53.6 years (clover grass mixture). It is crucial not to assess the economic parameters separately but optimize them with sustainable wildlife management and other benefits that provide ecological and efficient directions of AEM for future generations. However, the performed economic analysis highlights the significantly lower incomes of most components of AEM. We see a principal issue of AEMs usage in the lack of strong incentives for farmers to maximize conservation outcomes. Therefore, the AEMs are often placed in locations with presumed low agriculture profit, which is often related to insignificant conservation effects. Thus, the incomparable AEMs profitability compared to conventional agriculture has to be reflected by the agricultural policy at the European Union level and subsidy policy of particular member states.

Impacts of long‐term fertilization on crop yield and microbial communities under rice–rapeseed rotation

AbstractSoil microbes play an integral role in agricultural production and soil fertility, while limited information is available about the effects of long‐term fertilization on rice (Oryza sativa L.)–rapeseed (Brassica napus L.) rotation yield, soil properties, and microbial communities in central China. Here, we report the response of plant–soil system to different mineral fertilizer inputs, including the balanced fertilization with N, P, and K (NPK) fertilizers and unbalanced fertilizers without one of the major nutrients (PK, NK, and NP) for 10 years. Compared with the NPK treatment, the average annual decrease rates of rice and rapeseed yield in the PK, NK, and NP treatments were 12.5%, 18.1%, 6.4% and 33.1%, 54.8%, 16.0%, respectively. Long‐term fertilization significantly changed the soil chemical properties, especially the pH and available K content. Compared with the NPK fertilization, the NK treatment increased the soil microbial composition and diversity, whereas PK and NP treatments had a reverse impact. Available K, pH, and slowly available K were closely related to alterations of the dominant bacterial community. On the contrary, the Olsen‐P, slowly available K, and pH were significantly correlated with the fungal community. Soil properties changed by fertilization had a more direct effect on crop yield than the microbial community; moreover, the bacterial group had a higher influence than the fungal group on crop yield. Therefore, a balanced nutrient input using NPK fertilization is an effective management strategy for soil biological fertility and sustainable crop yield.

Design and Test of Seedbed Preparation Machine before Transplanting of Rapeseed Combined Transplanter

In order to satisfy the soil preparation requirements of a rapeseed combined transplanter in the middle-lower Yangtze River region in China where rice–rapeseed rotation cropping system was performed, a seedbed preparation machine composed of a rotary tillage device, ditch cleaning shovel, and soil leveling auger was designed to realize the function of rotary tillage, stubble ploughing, ditching, and soil leveling. The seedbed preparation machine was designed as the two parts of the middle section and the left–right symmetrical section to realize the need for middle ditching. Based on the principle of active scraping and anti-blocking, the curves of the soil contact section, soil throwing section, and transition section of the ditch cleaning shovel were analyzed. The structure parameters of the soil leveling auger with end reversal structure were designed. In order to further improve the working performance of the seedbed preparation machine, the response surface tests were designed, selecting the forward speed(X1), the rotation speed of rotary tillage blade roller(X2), and the rotation speed of soil leveling auger(X3) as the main influencing factors, taking the soil breaking rate and the straw coverage rate and the soil flatness as the test indexes. The optimal parameter combination was obtained as a forward speed of 0.94 m/s, rotation speed of rotary blade roller of 268 rpm, and rotation speed of soil leveling auger of 204 rpm. Under the optimal parameters combination, the soil breaking rate, straw coverage rate, and soil flatness were 92.06%, 93.01%, and 8.35 mm respectively, which satisfied the agronomic requirements of rapeseed blanket seedling transplanting. This study can provide a reference for the design of a seedbed preparation machine of a rapeseed combined transplanter.

Soil development and management effects on hydraulic properties along a granitic soil toposequence in southern China

A profound understanding of the effects of natural soil development and anthropogenic land management on soil hydraulic properties is essential for soil productivity and water conservation. The objective of our research was to explore the effects of soil development on soil bulk density (BD), pore size distribution, saturated hydraulic conductivity (Ksat), and soil water retention characteristics under horseweed grass (Erigeron canadensis) and corn (Zea mays)-rapeseed (Brassica napus) rotation systems in weathered granitic soils in southern China. Pore size classes determined were macropores (effective diameter > 1000 μm), coarse mesopores (effective diameter 60–1000 μm), fine mesopores (effective diameter 10–60 μm), and micropores (effective diameter < 10 μm). Soil samples from each treatment were collected to a depth of 40 cm in 10 cm increments. The results showed that Ksat was highest in Entisols (6.08 cm h−1) and lowest in Alfisols (2.58 cm h−1), and these values were averaged across management systems and depths. The saturated water content was 12.8% higher in Alfisols than that in Entisols. With soil development, soil water retention increased for all measured soil water pressures. The highest macroporosity as well as coarse and fine mesoporosity were recorded in Entisols, while the highest microporosity was found in Alfisols. Improvement in soil physical and hydraulic properties was seen in the horseweed grass system (HG) compared with that in the corn-rapeseed rotation system (CR). The bulk density was 6% lower for the HG than that for the CR. The HG had 30% higher Ksat and 10.3% greater saturated water content than the CR. The HG also had 15.2% increased macroporosity compared with the CR, which may enhance water infiltration and reduce runoff loss.

Nitrogen Reduction Combined with Organic Materials Can Stabilize Crop Yield and Soil Nutrients in Winter Rapeseed and Maize Rotation in Yellow Soil

Objective: To investigate the effect of nitrogen reduction combined with organic materials on crop growth of winter rapeseed and maize rotation in yellow soil. Methods: A 2-year, four-season winter rapeseed and maize rotation experiment using three organic materials (biochar (B), commercial organic fertilizer (O) and straw (S), 3000 kg·hm−2) and three nitrogen application rates (100%, 85% and 70%) was carried out from 2018 to 2020 in Guizhou Province, China. By comprehensively analyzing the crop yield, biomass and nutrient absorption, soil nutrients indicators, and the efficiency of nitrogen fertilizer was calculated. Results: All organic materials could increase the yield of both crops, and 100% N + O treatment was the best, and the 2-year winter rapeseed and maize yields reached 3069 kg·hm−2, 3215 kg·hm−2 and 11,802 kg·hm−2, 11,912 kg·hm−2, respectively. When nitrogen application was reduced by 15%, the addition of the three organic materials could stabilize or increase the yield and biomass, and nitrogen, phosphorus and potassium absorption in both crops showed an increasing trend, which could improve or maintain soil nutrients. When nitrogen application was reduced by 30%, the yields of two crops with organic materials addition were lower than those of 100% N treatment. Through the interaction, it was found that nitrogen and organic material were the main reasons for the increase in yield, respectively. Conclusions: The addition of three organic materials can replace 15% of nitrogen fertilizer. It is recommended to apply 153.0 kg·hm−2 and 127.5 kg·hm−2 of nitrogen fertilizer in winter rapeseed and maize seasons, respectively, in the rotation area of Guizhou yellow soil, with the addition of 3000 kg·hm−2 organic materials, most appropriately commercial organic fertilizer.

One‐time N fertilization reduces greenhouse emissions and N leaching while maintaining high yields in a rape–rice rotation system

AbstractIn China, the rice (Oryza sativa L.)–rapeseed (Brassica napus L.) rotation system is facing great challenges, including constantly growing demand, on‐going labor shortages, and increasing environmental burdens. Thus, producing more food and higher benefits while minimizing environmental costs is required for future development. A 2‐yr field experiment comparing three nitrogen (N) fertilization treatments (non‐N treatment as control [CK], conventional urea application [CU], one‐time application of controlled‐release urea [CRU]) was performed. Results showed that the rice season dominated annual CH4 emissions (&gt;95%) and on average contributed more than 50% of the annual N2O emissions. Additionally, the main forms of mineral N leaching were different for rape and rice. Nitrate (NO3–)–N was the major component of leaching in rape season, while for rice season NO3––N and NH4+–N were equal. Relative to CU, CRU significantly increased the rapeseed yield by 10.7∼13.9% and maintained the rice productivity, reduced mineral N leaching losses by 19.6∼20.8% for the rice season, and resulted in less total methane (CH4) and nitrous oxide (N2O) emissions (TGHGs) by 12.1% across the two rotations. Furthermore, a net economic benefit (NEB) considering yields, fertilizer input, labor, and other input costs indicated CRU increased the economic return by 58.3%. However, CRU did not improve partial factor productivity of nitrogen fertilizer (PFPN) and decreased the NEB by 3.1% without considering the labor cost. It indicated a one‐time application of the CRU for rice–rapeseed rotation system was an environmentally and economically profitable technology. This paper provided a promising solution for farmers to enhance rice–rapeseed productivity and increase income while minimizing the environmental footprint.

Discussion on High-yield Cultivation and Assembling and Supporting Technology of Selenium-enriched Rice and Rapeseed Rotation in Taoyuan County

Taoyuan County is a large grain and rapeseed production county. Taking advantage of the resource advantage of soil rich in selenium in Taoyuan County, it promotes high-yield cultivation and assembly technology of selenium-rich rice and rapeseed rotation in one-season rice area, optimizing the aggregate structure of the soil, improving the soil ecology and reducing the content of heavy metals in the soil, laying the foundation for the continuous increase in agricultural efficiency and farmers’ income. Through rice and rapeseed rotation, the overwintering base of rice field borers are reduced, and the incidence of pests and diseases in the coming year is effectively reduced. The popularization of assembling and supporting technologies for rice-rapeseed rotation cropping and the promotion of high-quality varieties and planting techniques can increase the farmers' income significantly. This paper will describe the methods and technologies in detail from three aspects: the assembling and supporting methods of selenium-enriched rice and rapeseed rotation high-yield cultivation, main points of the supporting technology for the rice selenium-enriched cultivation and main points of supporting technology for the rapeseed selenium-enriched cultivation.

Subsoil tillage promotes root and shoot growth of rapeseed in paddy fields and dryland in Yangtze River Basin soils

Rice-winter rapeseed rotation is one of the central double-crop systems in the Yangtze River (YRB) Basin, and most soils in this region are poorly drained clay soils, which has a negative effect on rapeseed growth. A field study comprising of two different tillage depths, topsoil tillage (Top-T), and subsoil tillage (Sub-T) were conducted in the paddy field (PF) and dryland (DL) in the rapeseed season, and no-tillage (NT) in subsequent rice and soybean season. The soil properties, root-shoot growth of rapeseed, and the yield of the three crops were collected to evaluate the effects of these tillage modes. Sub-T significantly reduced soil bulk density (SBD) and penetration resistance (PR) in PF and DL, while it increased the pH in PF, the concentration of moisture and total nitrogen, organic matter, alkali-hydrolyzed nitrogen, available phosphorus, available potassium in the 10−30 cm soil layers, and the activities of catalase, sucrose, urease, and acid phosphatase in the 10−20 cm soil as compared with Top-T. Furthermore, Sub-T significantly enhanced root bleeding sap (RBS), indole acetic acid, cytokinin, zeatin, and gibberellin concentration but decreased abscisic acid concentration. A principal component analysis showed that Sub-T could improve RBS and root hormones and promote the biomass accumulation of root and shoot by reducing SBD and PR and increasing nutrients in 10−30 cm soil. Finally, Sub-T significantly increased the seed yield of rapeseed by 2–16.5 % and did not have any significant negative effect on rice and soybean yield under NT in the next season, whereas, the rapeseed yield was significantly reduced by 22.9–36.2 % under Top-T, the rice, and soybean yield were significantly reduced by 33.6–41.1 % and by 26.0–41.9 % under NT in the next season, respectively, when compared to those under conventional tillage (CT, involved moldboard plowing to 15−18 cm and rotary tillage to 10−15 cm). Consequently, favorable soil conditions provided by Sub-T lasted for the next season, as rapeseed growth and grain yield were significantly promoted, and both the rice and soybean yield can also be maintained under NT.

Boron mitigates cadmium toxicity to rapeseed (Brassica napus) shoots by relieving oxidative stress and enhancing cadmium chelation onto cell walls

In southern China, Brassica napus (rapeseed) is a widely planted oilseed crop in rice–rapeseed rotation systems with characteristically high levels of cadmium (Cd) and low levels of available boron (B). Current knowledge of the ameliorative effects of B on Cd toxicity in plants mainly concerns plant growth, Cd uptake, and Cd translocation, while little attention has been paid to the role of B on plant antioxidant enzyme systems and cell wall chelation of Cd. We explored the mechanisms whereby B improves rapeseed Cd resistance. Application of B alleviated Cd-induced oxidative stress caused by reactive oxygen species (ROS) in the shoots of Cd-treated plants, by increasing the activity of the major antioxidant enzymes, superoxide dismutase, peroxidase, and catalase. Moreover, the shoots of rapeseed plants supplied with B under Cd toxicity had higher ionic soluble pectin (ISP) content, thereby providing more Cd-binding sites in pectin, as well as higher methylesterase activity. However, no changes in covalent soluble pectin were observed. In addition, B also induced higher cellulose in Cd-toxic shoots, thus promoting Cd chelation onto cell walls. Fourier infrared spectrum analysis confirmed that the addition of B increased protein, pectin, cellulose, and carbohydrate content in the cell walls of Cd-toxic leaves. In conclusion, B can mitigate Cd phytotoxicity by alleviating oxidative stress and immobilizing Cd on the ISP and cellulose of shoot cell walls, thereby playing a potential role in improving the growth potential of crops and Cd phytoremediation. The results also provide a theoretical basis for alleviating Cd toxicity in crops and development of Cd-tolerant varieties.

Effects of agricultural land use change on organic carbon and its labile fractions in the soil profile in an urban agricultural area

AbstractThe properties of soil organic carbon (SOC) required for carbon sequestration and nutrient availability are contradictory, and the changes in SOC caused by agricultural land use changes remain elusive. Data on the total soil organic carbon (TOC) and labile organic carbon, including easily oxidizable organic carbon (EOC), dissolved organic carbon (DOC), and microbial biomass carbon (MBC), of the soil profile were analysed for four typical agricultural land use scenarios in the Chengdu Plain, China. The impacts of agricultural land use changes on sequestration and nutrient availability of SOC were assessed in this urban agricultural area using the space‐for‐time substitution method. Conversion of land use from a traditional agricultural rotation (rice‐wheat/rapeseed rotation) to afforestation increased the MBC content and decreased the contents of EOC, DOC, and TOC due to the lower input of organic matter, improved aeration of the soil profile, and growth of aboveground biomass. Conversion of a traditional rotation to a rice–garlic rotation resulted in a significant increase in topsoil TOC, slight but insignificant decreases in subsoil TOC, and clear increases in labile organic carbon because of rice planting, rice straw mulch, and reasonable application of chemical fertilizers. In contrast, the conversion of a traditional rotation to a rice–leafy vegetable rotation decreased MBC due to the excessive use of chemical fertilizers that consequently increased EOC, DOC, and TOC. We conclude that afforestation on paddy soil has negative consequences for soil carbon sequestration and a rice–leafy vegetable rotation contributes to carbon sequestration but is detrimental to soil fertility. In addition, the MBC ratio in soil could be the optimal indicator for assessing SOC stability and soil fertility, and more attention should be paid to subsoil carbon changes.

Short‐Term Impacts of Conservation Agriculture on Soil Physical Properties and Productivity in the Midhills of Nepal

Core Ideas Aggregation and time‐to‐pond were improved under conservation agriculture.Conventional practice had a higher sorptivity rate than conservation agriculture.Maize yields were similar for conservation agriculture and conventional practice in the first year of production.Maize yields were less in conservation agriculture than in conventional practice in the second year due to patchy plant stands in conservation agriculture.There were no differences in yield between conservation agriculture and conventional practice for rapeseed or wheat. Conservation agriculture (CA) is a management system characterized by zero or minimum tillage, permanent soil cover with crop residue or plant growth, and crop rotation. This study investigated the impact of conservation tillage, crop type, and planting date on crop productivity and the soil physical properties for 2 yr following conversion to CA. After 2 yr, average mean weight diameter of dry aggregates for the 0‐ to 5‐cm and 5‐ to 10‐cm soil depths were 45 and 24% greater in the CA treatment than the conventional practice (CP) treatment, respectively. However, soil sorptivity was about three times slower in CA than in CP for rapeseed (Brassica napus L. toria) rotation treatments, but only 62% slower in CA than CP for wheat (Triticum aestivum L.) rotation treatments. Soil bulk density to a depth of 15 cm was greater in CA (1.30 g cm−3) than CP (1.24 g cm−3), but only for late‐planted treatments. Maize (Zea mays L.) yields for CA were not different from CP in the first year, but were 1.4 Mg ha−1 for CA and 5.0 Mg ha−1 for CP in the second year due to poor stand establishment under CA. There were no effects of CA on dry‐season rapeseed and wheat. Results suggest that during the transition of CP to CA, soil physical properties can be improved but yields may remain constant or decline. Achieving equivalent yield outcomes between CA and CP will largely depend on equivalent stand establishment.

Soil biotreatment effectiveness for reducing global warming potential from main polluting tillage operations in life cycle assessment phase

In order to reduce global warming potential (GWP) due to anthropogenic and natural factors in the cultivation of winter wheat and rapeseed, proved effectiveness of soil biotreatment with different composition of bio-solutions. It was reduced greenhouse gases (GHG) through life cycle impact categories from the main polluting agricultural operations on deeply lukewarm soaked soil. According to the impact diapason evaluated the main indicators such as human toxicity air (HTA), ecotoxicity water chronic (EWC), global warming potential, ecotoxicity water acute (EWA), ozone formation (OF), human toxicity water (HTW), ecotoxicity soil chronic (ESC), human toxicity soil (HTS), terrestrial eutrophication (TE), acidification (A). Assessed researches for three seasons which carried out in production experimental areas. It was appreciated in interrelated stages according to LST EN ISO 14040:2007 standard. Mass balance for one functional unit (FU) was tonne of wheat and rapeseed. SimaPro 8.05 life cycle assessment (LCA) Software was used for comparing soil biotreatment efectiveness using different bio-solutions and its mixes with control. The aim of the assessment – to prove the soil biotreatment effectiveness for reducing main life cycle indicators from tillage operations. It was identificated that phase of field operation is one of the main factor to the global impact. Disc harrowing consists approximately 26%, ploughing – 40% of all operations. Identified effectiveness of soil biotreatment, wheat and rapeseed rotation for reduction of global warming potential. Discovered reduction interdependencies of main life cycle assessement impact categories. The largest CO2 eq reducing established from primary – disc harrowing 12–15 cm and secondary - ploughing 23–25 cm soil tillage. It was fixed till approximately 15% in mixed bacterial and non-bacterial bio-solution after first soil biotreatment. Till approximately 8% CO2 eq reduction was in mixed bio–solutions after second biotreatment. The percentage highest soil biotreatment effectiveness till approximately 30% assessed after third biotreatment compared to usual technology. Soil biotreatment effectiveness in reducing green house gases (GHG) proved first year in 86%, second year in 43%, and third year in 71% of all used bio–solutions.

Effects of irrigation management during the rice growing season on soil organic carbon pools

When addressing water shortage in rice production, we need to consider the influence of water-saving irrigation methods on soil organic carbon stocks (SOC). A typical rice–rapeseed rotation was irrigated using 3 different strategies in rice growing season over a 3 year period: continuous flooding (CF), alternate wetting and drying irrigation (AWD), and rain-fed with irrigation only during drought periods (RFL). Soil samples were separated into fractions of different stability using sequentially fractionation methods. Compared with CF, AWD had no influence on C concentrations in physicochemically protected particulate organic matter in microaggregates (iPOM) at the 0–20 cm soil depth; however, it significantly increased the iPOM percentage in the bulk soil mass at the 5–10 cm soil depth. The RFL method lowered C stocks in iPOM at 0–20 cm soil depth, in comparison with CF and AWD, which was mainly due to its significant reduction in C concentrations in iPOM and the iPOM proportion in the bulk soil mass. The different water regimes had no effect on C stocks protected in silt and clay in microaggregates and unprotected free light POM. However, when considering the whole soil profile (0–20 cm), RFL significantly decreased total SOC stock, whereas there was no difference between CF and AWD. A moderate reduction in irrigation water under AWD strategy had little impact on SOC pools, thus, it could be considered an alternative water regime in balancing saving water and maintaining SOC stability.

Effects of fertilization on crop production and nutrient-supplying capacity under rice-oilseed rape rotation system

Incredible accomplishments have been achieved in agricultural production in China, but many demanding challenges for ensuring food security and environmental sustainability remain. Field experiments were conducted from 2011–2013 at three different sites, including Honghu, Shayang, and Jingzhou in China, to determine the effects of fertilization on enhancing crop productivity and indigenous nutrient-supplying capacity (INuS) in a rice (Oryza sativa L.)-rapeseed (Brassica napus L.) rotation. Four mineral fertilizer treatments (NPK, NP, NK and PK) were applied in a randomized complete block design with three replicates. Crop yields were increased by 19–41% (rice) and 61–76% (rapeseed) during the two years of rice-rapeseed rotation under NPK fertilization compared to PK fertilization across the study sites. Yield responses to fertilization were ranked NPK > NP > NK > PK, illustrating that N deficiency was the most limiting condition in a rice-rapeseed rotation, followed by P and K deficiencies. The highest and lowest N, P and K accumulations were observed under NPK and PK fertilization, respectively. The INuS of the soil decreased to a significant extent and affected rice-rapeseed rotation productivity at each site under NP, NK, and PK fertilization when compared to NPK. Based on the study results, a balanced nutrient application using NPK fertilization is a key management strategy for enhancing rice-rapeseed productivity and environmental safety.

Drainage, no-tillage and crop rotation decreases annual cumulative emissions of methane and nitrous oxide from a rice field in Southwest China

Permanently flooded rice fields, a special kind of all year-round flooded rice fields in China, where the crop system is summer rice (Oryza sativa ‘Q You 6′) with winter fallow, contribute to both CH4 and N2O emissions. To investigate their CH4 and N2O emissions over a whole year (November 2009 to October 2010) and responses to long-term tillage-cropping systems, four treatments after the conversion of such rice fields were examined: conventional tillage with a single summer rice and floodwater winter fallow (CTRF) or drained winter rapeseed (Brassica napus ‘W You 25′) (CTRR), no-tillage narrow- or wide-ridge with a rice and rapeseed rotation (NTNRR or NTWRR). Results showed that CTRF emitted the highest CH4 owing to permanently flooding water layer and higher soil organic carbon concentrations. Compared to CTRF, CH4 emissions under other three tillage-cropping systems were decreased not only in the winter season but also in the rice-growing season. In contrast, N2O emissions over a whole one-year rice-rapeseed rotation cycle were almost equivalent to each other under these four tillage-cropping systems. Also compared to CTRR, the two no-tillage-cropping systems tended to enhance CH4 while decrease N2O emissions, though with insignificant effects. The annual cumulative emissions of CH4 and N2O were highest under CTRF (1.07±0.20 kg CO2-eqha−1kg−1 yield) and significantly decreased under CTRR, NTNRR and NTWRR (0.59±0.10, 0.67±0.05 and 0.58±0.09 kg CO2-eqha−1kg−1 yield, respectively), indicating that the summer rice-winter rapeseed rotation system, irrespective of tillage management, rather than the summer rice-winter fallow system, had achieved the objective of higher yields with less greenhouse gas emissions. These results demonstrate that the no-tillage wide-ridge with a rice and rapeseed rotation (NTWRR) is the most efficient management in terms of decreasing CH4 and N2O emissions in Southwest China.

Effect of Conservation Agriculture Practices on Physical, Chemical and Biological Attributes of Soil Health Under Soybean–Rapeseed Rotation

A four-year field experiment was conducted with soybean–rapeseed rotation on a semiarid subtropical soil to study the influence of conservation agriculture (CA) practices vis-a-vis conventional tillage (CT) on some soil physical, chemical and biological attributes of soil health. Application of fertilizer N, P, farmyard manure (FYM) and crop residues (CR) significantly increased water-stable aggregates and had profound effect in increasing the mean weight diameter as well as the formation of macro-aggregates. After 2 years of soybean–rapeseed rotation under CA practices, the formation of macro-aggregates was the highest in both surface (84 %) and subsurface (80 %) soil layers with application of 20 kg N+60 kg P2O5 + 10 t FYM+4 t rapeseed residue ha−1 applied to soybean and 100 kg N+30 kg P2O5+3 t soybean residue ha−1 applied to rapeseed crop, respectively, and the corresponding values in CT were 83 and 77 %. The same treatment also enhanced total organic C from 4.5 g kg−1 in control to 6.4 g kg−1 in surface layer and from 3.3 to 4.4 g kg−1 in subsurface layer after 4 years in CA practices. Other soil health attributes like labile C and N fractions such as water-soluble C (38.9 mg kg−1), particulate (1483 mg kg−1) and light fraction (209 mg kg−1) organic matter, potentially mineralizable N (23.3 mg kg−1 7d−1) and microbial biomass carbon (283 mg kg−1) were also the highest under this integrated inorganic and organic treatment in conjunction with no tillage (CA practices). These results suggest that CA that integrates application of inorganic fertilizer, organic manure, retention of CR as soil cover, and minimum tillage is tremendously beneficial for soil health due to its positive effects on aggregation processes, augmenting organic matter accumulation and protecting within soil aggregates, and significantly enhancing biological pools in semiarid subtropical soils.