Effects Of Crop Rotation Research Articles

Gypsum, crop rotation, and cover crop impacts on soil organic carbon and biological dynamics in rainfed transitional no-till corn-soybean systems.

Soil organic carbon (SOC), a core soil quality indicator, is influenced by management practices. The objective of our 2012-2016 study was to elucidate the impact of gypsum, crop rotation, and cover crop on SOC and several of its biological indicators under no-till in Alabama (Shorter), Indiana (Farmland), and Ohio (Hoytville and Piketon) in the USA. A randomized complete block design in factorial arrangement with gypsum (at 0, 1.1, and 2.2 Mg/ha annually), rye (Secale cereal L.) vs no cover crop, and rotation (continuous soybean [Glycine max (L) Merr., SS] vs corn [Zea mays, L.]-soybean, both the CS and SC phases) was conducted. Composite soils were collected (0-15 cm and 15-30 cm) in 2016 to analyze microbial biomass C (SMBC), SOC, total N, active C, cold and hot-water extractable C, C and N pool indices (CPI and NPI), and C management index (CMI). Results varied for main effects of gypsum, crop rotation, and cover crop on SOC pools, total N, and SOC lability within and across the sites. Gypsum at 2.2 Mg/ha increased SMBC within sites and by 41% averaged across sites. Likewise, gypsum increased SMBC:SOC, active C, and hot-water C (as indicators of labile SOC) averaged across sites. CS rotation increased SOC, active C, CPI, and CMI compared to SS, but decreased SMBC and SMBC:SOC within and across sites. CPI had a significant relationship with NPI across all sites (R2 = 0.90). Management sensitive SOC pools that responded to the combined gypsum (2.2 Mg/ha), crop rotation (CS), and cover crop (rye) were SMBC, SMBC:SOC, active C, and CMI via SMBC. These variables can provide an early indication of management-induced changes in SOC storage and its lability. Our results show that when SOC accumulates, its lability has decreased, presumably because the SMBC has processed all readily available C into a less labile form.

Identifying rotation and tillage practices that maintain or enhance soil carbon and its relation to soil health

Physical fractions of soil organic matter (SOM) are established indicators of management-induced change and have been used to estimate the soil carbon storage capacity and storage potential. Here, we use SOM physical fractions and soil textures to identify management practices that maintain or enhance soil health and carbon storage in agricultural soils in Ontario. Metadata from the National Soil Database were used to estimate carbon storage potentials and calculate carbon deficits. A map was created showing carbon deficits in Ontario's agricultural soils and indicates that these soils have the potential to store an additional 0 to 2 kg m−2 in the top 20 cm of the soil. Tillage system generally had no effect on the size of the carbon deficit at four long-term agricultural experiments (Delhi, Elora, Ottawa, and Ridgetown). There was only a significant tillage effect at Ridgetown and only in the maize–soybean crop rotation, where the carbon deficit was 2.95 g C kg soil−1 under conventional tillage compared to 8.97 g C kg soil−1 with no tillage. A statistically significant effect of crop rotation was detected in Elora and Ridgetown. In Elora, continuous alfalfa had the smallest carbon deficit (7.25 g C kg soil−1) and maize–soybean rotation had the largest deficit (12.07 g C kg soil−1). In Ridgetown, the maize–soybean rotation had the smallest carbon deficit (2.95 g C kg soil−1). Regression analysis showed a weak negative relationship ( R2 = 0.11; P < 0.001) between carbon storage deficits and soil health scores. This suggests that increasing SOM levels alone may not improve soil health.

Long term effects of crop rotation and fertilization on crop yield stability in southeast China

The objective of this study was to determine the effects of different fertilizer treatments and crop rotations on crop yield stability. A 9 years field experiment was conducted from 2013 to 2021 to evaluate the effects of combinations of two annual crop rotations and two methods of applying fertilizer on crop yield stability. Crop rotations were kidney bean–mustard–rice (P–B–O) and kidney bean–mustard–cowpea (P–B–V) each year. Fertilization methods were recommended fertilization (RF) and conventional fertilization (CF). The indexes Wi2 (Wricke’s ecovalance), coefficient of variation (CV), and sustainable yield index (SYI) were used to quantify the long term effects of crop rotation and fertilization on crop yield stability, and a yield change trend model was used to predict future production. For fertilization program RF, average kidney bean and mustard yields in rotation P–B–O increased respectively by 7.47% and 19.37% over P–B–V in the 9 years of the project. For CF, average kidney bean and mustard yields for P–B–O increased respectively by 14.99% and 18.33% over P–B–V. Wi2 indexes of kidney bean and mustard for P–B–O (respectively 116 and 956) were significantly less than for P–B–V (respectively 147.87 and 1259.67). SYI for kidney beans and mustard in P–B–O (respectively 0.63 and 0.57) were significantly greater than for P–B–V (respectively 0.50 and 0.42). The trends of crop average yields for RF and CF show that the average yield trends of kidney bean in P–B–O (respectively 32.41 and 32.34) were greater than in P–B–V (respectively 29.56 and 27.45). The trends of average yields of mustard for RF and CF in P–B–O (respectively 64.18 and 60.87) were greater than in P–B–V (respectively 51.74 and 51.87). The preceding results led to the conclusion that long term annual P–B–O rotation combined with RF considerably increased yield and maintained yield stability, thus establishing the sustainability of this cropping system.

A comprehensive assessment of diversified cropping systems on agro-environmental sustainability in three Mediterranean long-term field experiments

The intensification of agricultural systems has caused a noticeable impact on agro-ecosystem services. Thus, the adoption of more sustainable agricultural practices such as crop diversification and reduction of external inputs represent an alternative strategy to minimize the impacts of intensive agricultural systems to the environment. This study aimed at evaluating the effects of crop rotation, conservation tillage, and low-input strategies on soil quality and farming performance using a set of 7 indicators based on a fuzzy logic approach. Data were collected from three Mediterranean long-term field experiments (LTEs) mostly oriented on cereal-based and vegetables cropping systems, located in Spain and Italy. The selected agro-environmental indicators clearly discriminated both from a geographical point of view and between monoculture and diversification, showing their suitability for the evaluation of diversified cropping systems. Such indicators highlighted that implementing crop diversification and reducing soil disturbance and chemical inputs enhanced soil quality. In this context, the most significant effects of diversified cropping strategies were the increase of crucial variables such as soil organic carbon (SOC), total nitrogen (TN), available phosphorus (Pav), and bulk density (BD) maintaining a stability of yields in all the three LTEs. These results provide strong evidence for the benefits of crop diversification in Mediterranean areas, highlighting that diversification represents a very promising strategy for more sustainable land management. Simple and composite indicators calculated using fuzzy method can be proposed as tool to assess the effects of diversification strategies on cropping systems performance. This approach can be used to define local solutions to help the re-design of cropping system through crop diversification transition across Europe.

A modeling approach to explore the influence of different crop rotations on water-table depths and crop yields in the Pampas

In humid plains with shallow water-tables, vegetation and groundwater influence each other through different mechanisms. Therefore, agricultural management decisions, such as the selection of the crop rotation, can affect water-table levels and these, in turn, can affect the crop performance. In this work, we evaluated the effect of different crop rotations on water-table levels and crop yields in the Argentine Pampas, a region that shows rising water-tables in the last decades that challenge agricultural activities. For this purpose, we modeled the dynamic of water-table depth in different topographic positions with Hydrus-1D and we used empirical models to estimate the grain yield. Crop rotations evaluated were wheat/soybean (W/S), wheat/soybean – maize (W/S – M), cover crop/maize – soybean (CC/M – S) and soybean – maize (S – M), and the simulation period extended throughout 41 growing seasons. Simulated water-table levels and crop yields showed a satisfactory matching with field observations, providing enough confidence for modeling exercises. According to modeling results, the crop rotation clearly affected the water-table depth, with the most intense rotation (i.e. W/S) showing the deepest water-table (e.g. W/S = 2.40 m vs. S–M = 1.90 m in the backslope). In the shoulder, the W/S rotation deepened the water-table in such an extent that more than 76 % of the time it was located below 3.5 m. However, with the least intense crop rotation (S – M) the proportion of time that the water-table remained deeper than 3.5 m depth was reduced to only 15 %. In the footslope, the least intense rotation showed the water-table level riskily shallow (< 1 m depth), negatively affecting most crops, almost half the time (48 %), while with the W/S rotation this percentage was reduced to 14 %. Through their influence on water-table depth, crop rotations also affected grain yields as suggested by empirical models. In maize, the predicted yields were maximum in the backslope for all rotations (~11 Mg ha -1 ), while they fell more strongly in the footslope with the least intense rotation (−28 %) but in the shoulder with the most intense one (−31 %). In soybean, the topographic position for which the highest yields were predicted depended on the crop rotation, being the footslope for W/S and the backslope for the other rotations. Our work provides novel insights on the influence of agricultural management on water-table levels and crop yields, as well as new tools to help in decision-making aimed at a more efficient management of water resources. • Simulations evidenced a strong influence of crop rotation on water-table depth. • More intense crop rotations (e.g. wheat/soybean) deepened the water-table. • Waterlogging effects were higher in less intense crop rotations. • Crop rotation affected crop yields through its effect on water-table depth.

How Do Long Term Crop Rotations Influence Weed Populations: Exploring the Impacts of More than 50 Years of Crop Management in Serbia

Crop rotation is known as an eco-friendlier approach, as provides diversification in crop management systems, modifies intensive pressure on the agricultural ecosystem, utilizes various soil horizons, and prevents the establishment of specific pests and weeds. We set out here a study on the farms that have been managed over 50 years of specific continuous crop management programs. The experimental treatments were in a different management system: monoculture of maize, winter wheat, and soybean, 2-year crop rotation (winter wheat–maize) with and without chemical fertilizer, and 3-year crop rotation (winter wheat–soybean–maize) with and without chemical fertilizer and manure. We took soil samples six times from 2014 to 2017 prior to sowing and after harvesting each year. Weed seeds were extracted from soils and identified and counted by species. We, upon the data of a long term experiment of crop rotation, could conclude that crop rotations with more crops in the sequence are significantly effective in maintaining weed populations, a low-input crop production could reach a constant low population below an important damaging density, and therefore will be a more sustainable crop production while chemical fertilizers would change the soil’s chemical and structure and imbalance the plant population diversity and manures with high weed seed infestations have the potential to totally eradicate crop rotation effects, Therefore, clean manures or compost are highly recommended.

Erratum to: Improving productivity of managed potato cropping systems in Eastern Canada: Crop rotation and nitrogen source effects

Agronomy JournalVolume 114, Issue 4 p. 2618-2618 ERRATUMFree Access Erratum to: Improving productivity of managed potato cropping systems in Eastern Canada: Crop rotation and nitrogen source effects This article corrects the following: Improving Productivity of Managed Potato Cropping Systems in Eastern Canada: Crop Rotation and Nitrogen Source Effects Judith Nyiraneza, Rick D. Peters, Vernon A. Rodd, Mark G. Grimmett, Yefang Jiang, Volume 107Issue 4Agronomy Journal pages: 1447-1457 First Published online: July 1, 2015 First published: 23 August 2022 https://doi.org/10.1002/agj2.21104AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat J. Nyiraneza, R.D. Peters, V.A. Rodd, M.G. Grimmett and Y. Jiang Erratum for “Improving productivity of managed potato cropping systems in Eastern Canada: Crop rotation and nitrogen source effects” by Nyiraneza et al., Agron. J. 107:1447–1457. Under the table 3, amount of N and C in different fractions are reported in g kg−1 which is wrong. The correct unit should be mg. REFERENCE Nyiraneza, J., Peters, R. D., Rodd, V. A., Grimmett, M. G., & Jiang, Y. (2015). Improving productivity of managed potato cropping systems in Eastern Canada: Crop rotation and nitrogen source effects. Agronomy Journal, 107, 1447––1457. https://doi.org/10.2134/agronj14.0430 Volume114, Issue4July/August 2022Pages 2618-2618 ReferencesRelatedInformation

Farm-scale practical strategies to reduce carbon footprint and emergy while increasing economic benefits in crop production in the North China plain

How to achieve China's “Carbon Peak” and “Carbon Neutrality” targets in the agriculture sector is crucial but still remains challenging. This study thus aims to assess the effects of crop rotations and farm size with optimized nitrogen (N) rate on carbon footprint (CF), emergy and economic benefits to promote agricultural transformation in the North China Plain (NCP) based on 792 on-farm questionnaires. Our results showed that the CF and emergy of wheat ( Triticum aestivum Linn.)-soybean ( Glycine max (Linn.) Merr.) was 32–45% and 20–21% lower than that of wheat-maize ( Zea mays Linn.) and wheat-peanut ( Arachis hypogaea Linn.) mainly due to reduced N application by the biological nitrogen fixation (BNF) and pre-crop effects of soybean, while the farming net income (FNI) was lowest in the wheat-soybean mainly because of the low soybean yield. Furthermore, the sustainability performance index (SPI) was highest for wheat-soybean while lowest for wheat-maize. Large-size farms (LF, larger than 3.3 ha) efficiently reduced N rate without negatively influencing crop yield, thus decreasing CF and emergy compared to smallholders (SF, smaller than 3.3 ha), and the total farming profit was much higher in the LF due to the scale effect. Our results indicated that the joint application of increased soybean planting area in concert with larger farm size using optimized N rate was beneficial for reducing CF and emergy, but also increasing crop production in the NCP. However, low soybean yield was the critical factor that constrained soybean planting area in the NCP. We suggest that practical, cost-effective strategies to increase soybean yield with concurrent financial subsidies are urgently required to maximize the eco-benefits of wheat-soybean rotation in promoting agricultural green development in the NCP. • The carbon footprint (CF) and emergy was lowest in wheat-soybean. • The sustainability performance index (SPI) was highest in wheat-soybean. • Large-size farms induced lower CF and emergy compared to smallholders. • Optimizing crop rotations with larger farm size and better N managements should be beneficial for SDGs.

Effects of crop rotation on growth and physiological indexes of Panax notogingseng

Effects of crop rotation on growth and physiological indexes of Panax notogingseng

Crop Rotation and Minimal Tillage Selectively Affect Maize Growth Promotion under Late Wilt Disease Stress.

In recent years, worldwide scientific efforts towards controlling maize late wilt disease (LWD) have focused on eco-friendly approaches that minimize the environmental impact and health risks. This disease is considered to be the most severe threat to maize fields in Israel and Egypt, and a major growth restraint in India, Spain, and Portugal. Today’s most commonly used method for LWD control involving resistant maize genotypes is under constant risk from aggressive pathogen lines. Thus, this study’s objectives were to evaluate the effect of crop rotation and avoiding tillage on restraining the disease. Such an agrotechnical approach will support the continuity of soil mycorrhiza networks, which antagonize the disease’s causal agent, Magnaporthiopsis maydis. The method gained positive results in previous studies, but many knowledge gaps still need to be addressed. To this end, a dual-season study was conducted using the LWD hyper-susceptible maize hybrid, Megaton cv. The trials were performed in a greenhouse and in the field over full dual-growth seasons (wheat or clover as the winter crop followed by maize as the summer crop). In the greenhouse under LWD stress, the results clearly demonstrate the beneficial effect of maize crop rotation with clover and wheat on plant weight (1.4-fold), height (1.1–1.2-fold) and cob yield (1.8–2.4-fold), especially in the no-till soil. The clover-maize growth sequence excels in reducing disease impact (1.7-fold) and pathogen spread in the host tissues (3-fold). Even though the wheat-maize crop cycle was less effective, it still had better results than the commercial mycorrhizal preparation treatment and the uncultivated non-infected soil. The results were slightly different in the field. The clover-maize rotation also achieved the best growth promotion and disease restraint results (2.6-fold increase in healthy plants), but the maize rotation with wheat showed only minor efficiency. Interestingly, pre-cultivating the soil with clover had better results in no-till soil in both experiments. In contrast, the same procedure with wheat had a better impact when tillage was applied. It may be concluded that crop rotation and soil cultivation can be essential in reducing LWD, but other factors may affect this approach’s benefits in commercial field growth.

Long-term crop rotation and continuous cropping effects on soil chemical properties

Long-term crop rotation and continuous cropping effects on soil chemical properties

Response of soil organic carbon content to crop rotation and its controls: A global synthesis

Determining the effect of crop rotation (CR) on soil organic carbon (SOC) and its controls is vital for improving the potential benefits of CR in agroecosystems to achieve carbon neutrality. However, there has been no comprehensive and systematic evaluation of the response of SOC content to CR and its underlying drivers on the global level. Using 513 pairwise data from 167 studies, we conducted a global-scale meta-analysis to illuminate the changes in SOC content induced by CR and to explore the roles of climatic, edaphic, and agronomic factors in driving such changes. Results revealed that CR overall enhanced SOC content by 6.6% relative to continuous crop monoculture. SOC content under CR increased more in regions with intermediate mean annual temperature (MAT, 8–15°C) and precipitation (MAP, 600–1000 mm) than in regions with other climate types. CR had greater SOC content benefits in neutral (pH = 6–8) soils with loamy texture and medium levels of initial SOC (15–20 g kg–1) and total nitrogen (1.00–1.50 g kg–1). Also, CR performed better in the soybean-based cropping systems with more rotation cycles, longer rotation length, medium nitrogen fertilization input rate (100–200 kg N ha–1 yr–1), and the applications of no-till, straw retention, and organic fertilizers. Furthermore, the variance partitioning analysis revealed that soil (31%) and climate variables (18%) accounted for the major variations in SOC content response. Moreover, the random forest model demonstrated that soil texture, climatic factors (i.e., MAT and MAP), and initial SOC content were the predominant drivers of the response of SOC content. Overall, our findings highlight that CR is a critical practice to increase SOC content in global croplands, whereas the variations in response are governed by specific climatic, edaphic, and agronomic factors. This study helps to establish and manage site-specific CR systems that could enhance SOC in agroecosystems, ultimately facilitating carbon neutrality.

Using WaTEM/SEDEM to Model the Effects of Crop Rotation and Changes in Land Use on Sediment Transport in the Vrchlice Watershed

The Czech landscape has undergone various changes over the last 100 years and has been mainly adapted agriculturally for economic purposes. This has resulted, among other things, in reservoirs being clogged with sediment. The Vrchlice Reservoir was built in 1970 to supply drinking water for around 50,000 inhabitants, and increased sedimentation has been detected in the reservoir in recent years. Water erosion and sediment transport were modeled with WaTEM/SEDEM. Sediment volumes were measured in eight ponds across the watershed for calibration purposes. Modeled results from ponds in watersheds covered mostly with arable lands generally corresponded with the measured values. Although in forested watersheds, the measured sediment volumes greatly exceeded modeled sediment yields, indicating high uncertainty in using USLE-based models in non-agricultural watersheds. The modeled scenarios represented pre-Communist, Communist, and post-Communist eras. For these periods WaTEM/SEDEM was used to evaluate three isolated effects: the effects of various crops on arable lands, the effects of farmland fragmentation, and finally the effects of changes in land use. The change in crops proved to be an important factor causing high siltation rate (potential 23% reduction in sediment yield for historical periods), and land fragmentation played the second important role (potential 15% reduction in sediment yield can be reached by land fragmentation). Across all scenarios, the lowest sediment yield and reservoirs siltation rates were obtained from the pre-Communist and Communist crop share under current land use conditions, and current land use with farmland fragmentation implemented, as it was re-constructed for the pre-Communist era. This supports the idea that the introduction of green areas within arable lands are beneficial to the landscape and can help reduce soil erosion and reservoir siltation.

Effect of crop rotation and straw application in combination with mineral nitrogen fertilization on soil carbon sequestration in the Thyrow long-term experiment Thy_D5

AimsThe aim of study was to quantify the temporal change of soil organic carbon content in relation to agricultural management for a dry sandy arable soil and to derive the C sequestration potential.MethodsWe analyzed data from a long-term field experiment with three crop rotations of different cereal proportions, with two levels of straw application (removal/return) in combination with four mineral nitrogen rates (40 … 160 kg ha-1 yr-1). Treatments are arranged in a two-factorial block design with two replicates for each rotation. During the 24-year study period, grain and straw yield of two cereal test crops and soil organic carbon content in topsoil were determined annually from each plot.ResultsSoil organic carbon content was positively influenced by removing non-cereal crops from the rotation and – to a smaller extent – by straw application. Increasing mineral N-fertilization from 40 kg ha-1 yr-1 to higher rates increased grain yield of rye but not barley, increased straw yield of both cereals more, with no effect of higher straw yields on soil organic carbon content.ConclusionsDespite the overall soil organic carbon content of the sandy soil under study is comparatively low, the results indicate that agricultural management has a relevant impact on soil carbon stocks. Straw return contributes to carbon sequestration even in rotations with a low potential for reproduction of organic matter. High mineral N-fertilization is not an adequate measure to sequester carbon in these soils.

Long-term effects of crop rotation and nitrogen fertilization on phosphorus cycling and balances in loess-derived Mollisols

Developing meaningful agroecosystem soil P inventories necessitates moving beyond single measures of readily extractable inorganic P (Pi) limited to surface depths. We drew on a long-term (36 year) experimental field trial in the US Maize Belt (northwestern Illinois) to evaluate how crop rotation [maize-maize (Zea mays L.) vs maize-soybean (Glycine max L. Merr.)] and N fertilization (0 vs 269 kg N ha−1) impact P dynamics throughout the soil profile by using sequential fractionation and phosphatase activity assays, contextualized by soil P stocks and agronomic P balances. Distribution of P fractions by depth (0–15, 15–30, 30–60, 60–90 cm) indicate that management effects were limited to the surface soil layers (0–30 cm). Soil P fractions differed more by depth than by experimental treatments. Long-term N fertilization significantly decreased pH concurrently with labile organic P (Po) and phosphodiesterase activity. Soil labile inorganic P (Pi) was two-fold lower under N fertilization compared to zero N fertilization, reflecting greater yield and thus P export via grain harvest. Under N fertilization, integration of soybean elevated soil phosphodiesterase activity and decreased water-extractable Po. Higher stocks of soil Po than labile Pi at surface depths (0–30 cm) corroborated a hypothesized appreciable pool size of soil Po relative to the labile Pi pool to which most agronomic assessments are limited. Large negative agronomic balances over the 36-year period (−426 to −945 kg P ha−1) are suggestive of legacy P from pre-experiment manure application and high native P stocks, with net P export equivalent to 11–35% of soil P stocks at 0–90 cm depth at the initiation of the experiment. These results contribute to a better understanding how N fertilization and rotation practices influence soil P cycling and stocks, thereby informing P budgets for comprehensive agroecosystem P management.

Increasing soil microbial biomass nitrogen in crop rotation systems by improving nitrogen resources under nitrogen application

Soil microbial biomass nitrogen (MBN) contains the largest proportion of biologically active nitrogen (N) in soil, and is considered as a crucial participant in soil N cycling. Agronomic management practices such as crop rotation and mono-cropping systems, dramatically affect MBN in agroecosystems. However, the influence of crop rotation and mono-cropping in agroecosystems on MBN remains unclear. A meta-analysis based on 203 published studies was conducted to quantify the effect of crop rotation and mono-cropping systems on MBN under synthetic N fertilizer application. The analysis showed that crop rotation significantly stimulated the response ratio (RR) of MBN to N fertilization and this parameter reached the highest levels in upland-fallow rotations. Upland mono-cropping did not change the RR of MBN to N application, however, the RR of MBN to N application in paddy mono-cropping increased. The difference between crop rotation and mono-cropping systems appeared to be due to the various cropping management scenarios, and the pattern, rate and duration of N addition. Crop rotation systems led to a more positive effect on soil total N (TN) and a smaller reduction in soil pH than mono-cropping systems. The RR of MBN to N application was positively correlated with the RR of mineral N only in crop rotation systems and with the RR of soil pH only in mono-cropping systems. Combining the results of Random Forest (RF) model and structural equation model showed that the predominant driving factors of MBN changes in crop rotation systems were soil mineral N and TN, while in mono-cropping systems the main driving factor was soil pH. Overall, our study indicates that crop rotation can be an effective way to enhance MBN by improving soil N resources, which promote the resistance of MBN to low pH induced by intensive synthetic N fertilizer application.

Effects of Crop Rotation on Maize Soil Fertility in Alluvial Soil

Crop rotation is a method for crop production diversification and soil fertility improvement. However, the effectiveness of crop rotation in improving soil quality may vary depending on soil types, climate, crops, and farming practices. This study was conducted to evaluate the influence of crop rotation on alluvial soil quality properties. Four crop rotation systems have been investigated, namely, maize-maize-maize (MMM), maize-mungbean-maize (MBM), maize-sesame-maize (MSM), and mungbean-chili-maize (BCM). The research was laid out in randomized complete block design with four replicates, and each plot area was 36 m2. The quality of the topsoil layer (0-20 cm) was assessed. Seven soil physicochemical parameters were selected: soil pH, electrical conductivity (EC), total nitrogen (Ntot), available phosphorus (Pavail), soil organic carbon (SOC), bulk density (BD), and cation exchange capacity (CEC). They were measured after the completion of the 1-year experiment. The results indicated that crop rotation did not affect the soil pH, EC, BD, and CEC but improved the SOC, Ntot, and Pavail. The SOC and Ntot contents in the MBM and BCM crop rotation systems were higher than those in MSM. Our results show that crop rotation systems improved maize soil fertility and are a beneficial option for a sustainable agriculture in alluvial soil.

Combining randomized field experiments with observational satellite data to assess the benefits of crop rotations on yields

With climate change threatening agricultural productivity and global food demand increasing, it is important to better understand which farm management practices will maximize crop yields in various climatic conditions. To assess the effectiveness of agricultural practices, researchers often turn to randomized field experiments, which are reliable for identifying causal effects but are often limited in scope and therefore lack external validity. Recently, researchers have also leveraged large observational datasets from satellites and other sources, which can lead to conclusions biased by confounding variables or systematic measurement errors. Because experimental and observational datasets have complementary strengths, in this paper we propose a method that uses a combination of experimental and observational data in the same analysis. As a case study, we focus on the causal effect of crop rotation on corn (maize) and soybean yields in the Midwestern United States. We find that, in terms of root mean squared error, our hybrid method performs 13% better than using experimental data alone and 26% better than using the observational data alone in the task of predicting the effect of rotation on corn yield at held-out experimental sites. Further, the causal estimates based on our method suggest that benefits of crop rotations on corn yield are lower in years and locations with high temperatures whereas the benefits of crop rotations on soybean yield are higher in years and locations with high temperatures. In particular, we estimated that the benefit of rotation on corn yields (and soybean yields) was 0.85 t ha−1 (0.24 t ha−1) on average for the top quintile of temperatures, 1.03 t ha−1 (0.21 t ha−1) on average for the whole dataset, and 1.19 t ha−1 (0.16 t ha−1) on average for the bottom quintile of temperatures. This association between temperatures and rotation benefits is consistent with the hypothesis that the benefit of the corn-soybean rotation on soybean yield is largely driven by pest pressure reductions while the benefit of the corn-soybean rotation on corn yields is largely driven by nitrogen availability.

The Effect of Nutrient Management and Crop Rotation on Weed Dynamics in Rice under Dry Zone (DL1B) of Sri Lanka

The Integrated weed management (IWM) is widely used to manage we eds in diverse cropping systems. Crop rotation and diverse n utrient management strategies are essential components in IWM. However, the effect of crop rotation and nutrient management systems on weed dynamics in Sri Lankan rice-based cropping systems is scarce. Therefore, an experiment was conducted to identify weed density, biomass, and abundance of two different nutrient management systems (Synthetic; SNM and Integrated; INM) and under rice monoculture and rice-maize rotation during four seasons within the farm premises of the Faculty of Agriculture, Rajarata University of Sri Lanka. Rice variety Bg300 and maize hybrid Pacific-998 were cultivated. Growing maize in the Yala season increased weed density and weed biomass compared to growing rice in both crop rotation cycles. During the first cycle, weed den sity was high under INM in the Rice crop phase. However, in the second cycle, both crop phases (rice and maize) had low weed density under INM compared to SNM. A higher density of sedges was reported with the crop rotation in the Yala season s, and grasses were dominant in the mono-cropping in both seasons. Grass biomass did not change with the nutrient manageme nt systems, while the biomass of sedges increased with synthetic fertilizer only. High weed density and biomass in maize during the first cycle were substantially reduced in the second cyc le for both nutrient management systems. Overall, reducing chemical fertilizer by 50% and incorporating organic matter, INM, substantially supported weed management in both rice and maize crops.

Soil microbial communities following 20\xa0years of fertilization and crop rotation practices in the Czech Republic

BackgroundAlthough fertilization and crop rotation practices are commonly used worldwide in agriculture to maximize crop yields, their long-term effect on the structures of soil microorganisms is still poorly understood. This study investigated the long-term impact of fertilization and crop rotation on soil microbial diversity and the microbial community structure in four different locations with three soil types. Since 1996, manure (MF; 330 kg N/ha), sewage sludge (SF; 330 and SF3x; 990 kg N/ha), and NPK (NPK; 330 kg N/ha) fertilizers were periodically applied to the soils classified as chernozem, luvisol and cambisol, which are among the most abundant or fertile soils used for agricultural purposes in the world. In these soils, potato (Solanum tuberosum L.), winter wheat (Triticum aestivum L.), and spring barley (Hordeum vulgare L.) were rotated every three years.ResultsSoil chemistry, which was significantly associated with location, fertilization, crop rotation, and the interaction of fertilization and location, was the dominant driver of soil microbial communities, both prokaryotic and fungal. A direct effect of long-term crop rotation and fertilization on the structure of their communities was confirmed, although there was no evidence of their influence on microbial diversity. Fungal and bacterial communities responded differently to fertilization treatments; prokaryotic communities were only significantly different from the control soil (CF) in soils treated with MF and SF3x, while fungal communities differed across all treatments. Indicator genera were identified for different treatments. These taxa were either specific for their decomposition activities or fungal plant pathogens. Sequential rotation of the three crops restricted the growth of several of the indicator plant pathogens.ConclusionsLong-term fertilization and crop rotation significantly altered microbial community structure in the soil. While fertilization affected soil microorganisms mainly through changes in nutrient profile, crop rotations lead to the attraction and repulsion of specific plant pathogens. Such changes in soil microbial communities need to be considered when planning soil management.