Cropping Sequence Research Articles

Impact of Long-term Application of Fertilizers and FYM on Nutrient Uptake by Soybean Crop and Properties of Black Soil

Long Term Fertilizer Experiment (LTFE) play an important role in understanding the complex interactions involving plant, soil, climate, management practices and their effect on soil productivity over a long period of time. The present investigation is a part of ongoing All India Coordinated Research Project on Long Term Fertilizer Experiment with Soybean-Wheat Cropping Sequence, which was initiated since 1972. The experiment was carried out in a randomized block design consisting of eight treatments, viz. 50% NPK, 100% NPK, 150% NPK, 100% NP, 100% N, FYM (100% NPK+FYM), 100% NPK (-S) and Control. The significant nutrient content with nutrient uptake by soybean was noted in 100% NPK+FYM treatment over the control plot. It was also observed that nutrient content with nutrient uptake increased significantly with consecutive doses of fertilizers. On the other hand, 100% N and in the control group had the lowest value. However, adding fertilizer P in addition to N (100% NP) increased nutrient content and nutrient uptake by soybean crop. The highest. Soil organic carbon content was recorded with 100% NPK dose+FYM followed by 150% NPK treatment combination which could apparently due to the synergistic contribution of integration of fertilizer and FYM application. Similarly, the available N,P, K and S content in soil were found highest with 100% NPK + FYM followed by 150% NPK fertilizer dose. However, the lowest content was noted in control where crop was grown without fertilizers. Available sulphur was significantly higher over control in all the treatments receiving single super phosphate.

Nutrient Distribution Patterns in Soil Across Various Locations in Muzaffarnagar and Ghaziabad Districts of Uttar Pradesh under a Rice-Sugarcane Cropping Sequence

A study was conducted to evaluate the macro and micronutrient levels in the soil under the sugarcane-wheat cropping sequence and its relationship with soil characteristics. Understanding the nutrient status is vital for the efficient application of fertilizers, as widespread deficiencies in both macro and micronutrients are being reported in the soils of Uttar Pradesh. The rice-sugarcane cropping sequence is a prominent practice in the northwestern plains of Uttar Pradesh and Uttarakhand, covering 10-11% of the net cultivated area in these regions. Over recent years, sugarcane and wheat yields have plateaued in these areas due to declining factor productivity. Soil samples were collected from depths of 0-15 cm, 15-30 cm, and 30-45 cm at four locations in the Muzaffarnagar and Ghaziabad districts under the rice-sugarcane sequence. The available zinc content in the surface soil (0-15 cm) ranged from 0.605 to 0.883 mg/kg, and in the sub-surface soil (30-45 cm), it varied between 0.111 to 0.629 mg/kg, with an average of 0.083 mg/kg in surface soil and 0.435 mg/kg in sub-surface soil. A correlation analysis between various soil properties across different locations at three soil depths (0-15 cm, 15-30 cm, and 30-45 cm) was also conducted. The findings indicated that the soils are generally low in nitrogen, low to medium in phosphorus and potassium, and sufficiently supplied with copper, iron, manganese, and zinc in the surface layer. Future research on nutrient distribution in these areas will help advance precision agriculture, improve fertilizer management, and boost crop productivity while minimizing environmental harm. This research will contribute to sustainable soil management, economic benefits for farmers, and provide valuable insights for regional agricultural policies, further supporting food security.

Alternative cereal crop rotations in a no‐tillage dryland under Mediterranean conditions

AbstractCereal crops are frequently rotated with broadleaf crops to achieve the benefits associated with crop diversification. However, broadleaf crops often fail in Mediterranean drylands due to their lower adaptation to drought. Alternative cereal crops such as triticale (×Triticosecale Wittmack) and oat (Avena sativa L.) can help diversify drylands in the Ebro valley, dominated by barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) cultivation. A 6‐year field experiment was conducted with five crop sequences under no‐tillage: triticale–wheat–barley (TWB), oat–wheat–barley (OWB), fallow–wheat–barley, monocrop wheat, and monocrop barley. Wheat and barley grain yield, N use efficiency, and water use efficiency responses were evaluated, and economic analyses of the whole sequences were performed. Oat increased subsequent wheat yields by 15% and barley yields by 12% (p < 0.001) compared to monocropping. Similar water and N availability at sowing suggest additional synergies in an OWB rotation (possibly pest reduction), contributing to the yield increase of both crops. However, this rotation was less profitable than a TWB rotation (p = 0.002) due to the limited adaptation of oat to Mediterranean settings. Long fallowing lacked consistent benefits in water and N availability for subsequent crops. This practice protects farmers from economic losses in low‐yielding seasons, but there is an associated opportunity cost in favorable years. The introduction of alternative cereal crops has demonstrated benefits for wheat and barley production, although greater understanding of the synergistic mechanisms involved is essential to ascertain whether resource efficiency is maintained beyond the studied timeframe.

Enhancing crop productivity and nitrogen use efficiency by application of pine oleoresin coated urea in maize-wheat cropping sequence in vertisols

Enhancing crop productivity and nitrogen use efficiency by application of pine oleoresin coated urea in maize-wheat cropping sequence in vertisols

EFFECT OF IRRIGATION METHODS AND NUTRIENT MANAGEMENT PRACTICES ON PRODUCTION AND ECONOMICS OF POTATO UNDER DIFFERENT PRECEDING CROP SEQUENCES IN CENTRAL INDIA

A field experiment was conducted at ICAR-Central Potato Research Institute-RS, Gwalior, in split-plot design: 3 irrigation methods (main plots) and 5 fertilizer doses in various crop sequences (sub-plots), with four replications. Results revealed that the highest total tuber number (604 thousand/ha) was recorded with dhaincha - potato (75% RDF NPK) which was significantly higher than all other treatments except green gram - potato (75% RDF NPK). Drip irrigation resulted in highest total tuber yield (35.8 t/ha), significantly surpassing other methods. Dhaincha - potato (75% RDF NPK) combination yielded (37.5 t/ha) highest, significantly outperforming others except fallow - potato (50% RDF NPK/ha + 15 t FYM) sequence. Drip irrigation x fallow - potato (50% RDF NPK/ha + 15 t FYM) combination recorded the highest total tuber yield at 40.3 t/ha. Drip irrigation resulted in water-use efficiency of 137 kg/ha-mm and harvest index of 72%, significantly surpassing other methods. Fallow – potato {FYM 7.5 t/ha + crop residue 7.5 t/ha + biofertilizers (Azotobacter and PSB)} sequence recorded highest harvest index 73%, significantly surpassing other treatments. Drip irrigation resulted in highest WUE (137 kg/ha-mm), significantly surpassing other methods. Combination of drip irrigation x fallow – potato (FYM 7.5 t/ha + 50% RDF NPK) sequence recorded highest WUE (155 kg tuber/ha-mm), significantly outperforming other treatments. Dhaincha – potato (75% RDF NPK) sequence resulted in the highest nitrogen content (216 kg/ha), significantly surpassing others. Dhaincha - potato (75% RDF NPK) sequence significantly out performed in tuber nitrogen uptake (77 kg/ha) to other sequences. Combination of drip irrigation x dhaincha - potato (75% RDF NPK) sequence recorded highest N uptake (83 kg/ha). Benefit : cost was highest with drip irrigation (3.1) among irrigation methods and it was highest with dhaincha - potato (75% RDF NPK) sequence (2.99) among crop sequences.

Evaluation of Alternative Break Crops in Rotation with Bread Wheat (triticum aestivum l.) in South-Eastern Ethiopia

Crop rotation could be a possible intervention to resolve multifaceted problems of monoculture. In recent years, there is a concern about soil depletion caused by intensive farming. In crop rotation legume crops, which capture atmospheric nitrogen and “fix” it into forms available to plants will increase soil fertility. Faba bean (Vicia faba L.), rapeseed (Brassica napus L.), oat (Avena sativum L.) and vicia (Vicia dasycarpa Ten.) forage mixture were considered as a break/precursor crops. The result showed that most profitable cropping sequence was faba bean grown in a 3 year cycle with 2 crops of wheat (Amanuel et al., 1994). Thus, searching for promising and alternative break crops for wheat based rotation could increase productivity and maximize profit. Adaptaion trial around Bekoji showed that sweet lupine seems an option in tolerating acidity where faba bean is found susceptible. Thus, the objectives of this study was to evaluate alternative break crops on yield and yield components of the succeeding wheat and soil fertility maintenance in the rotation scheme. Thus, this study was executed for three consecutive years from 2017- 2019 main cropping seasons at Kulumsa, Bekoji and Asasa Arsi zone, South-Eastern Ethiopia to evaluate advantage of alternative break crops on yield and yield components of the succeeding wheat and its effect on soil fertility maintenance in the rotation scheme. The experiment was laid out in randomized block design with five replications. The treatment include: wheat-sweet lupine-wheat-wheatwheat in year one (2017), sweet lupine-wheat-wheat faba bean-Ethiopian mustard in year two (2018) and wheat-wheat-wheat-wheat-wheat in the third year (2019). These leguminous crops have improved physico-chemical properties of soil. Plant nutrients of soil on which legumes were grown were increased. This improvement of soil properties by leguminous crops has resulted in higher yield of wheat than plots on which wheat was grown after wheat. Although non-significant, the third year Bekoji and Asasa combined analysis of variance revealed that the highest wheat grain yield (4197kg/ha) was obtained at sweet lupine-wheat-wheat followed by wheat-faba bean-wheat (4003kg/ha). However, plant height was significantly (P<0.05) affected by rotational crops effect. The tallest plant height of wheat (105.0cm) was recoded from wheat-Ethioian mustard-wheat treatment. From this study, sweet lupine-wheat-wheat followed by wheat-faba bean-wheat with proper agronomic packages could be forwarded as a temporary recommendation in Asasa, Bokoji and Kulumsa areas and in areas with similar agro ecologies.

Effect of 32 years of manuring and fertilization on carbon budgeting and carbon pools under sorghum-wheat cropping sequence in Vertisol of Central India

Effect of 32 years of manuring and fertilization on carbon budgeting and carbon pools under sorghum-wheat cropping sequence in Vertisol of Central India

Soil Water Balance and Productivity of Different Maize-Based Crop Sequences Compared to Rice–Wheat System under Contrasting Irrigation Regimes in North–West India

Soil Water Balance and Productivity of Different Maize-Based Crop Sequences Compared to Rice–Wheat System under Contrasting Irrigation Regimes in North–West India

Associations Among Cultivar Cropping Sequence, 2,4-Diacetlyphloroglucinol-Producing Pseudomonad Populations, and Take-All Disease of Winter Wheat in Oregon.

Take-all of wheat (Triticum aestivum L.), caused by Gaeumannomyces tritici (syn. G. graminis var. tritici), is perhaps the most important soil-borne disease of wheat globally and can cause substantial yield losses under several cropping scenarios in Oregon. Though resistance to take-all has not been identified in hexaploid wheat, continuous cropping of wheat for several years can reduce take-all severity through the development of suppressive soils, a process called "take-all decline" (TAD). Extensive work has shown that TAD is driven primarily by members of the Pseudomonas fluorescens complex that produce 2,4-diacetlyphloroglucinol (DAPG), an antibiotic that is associated with antagonism and induced host resistance against multiple pathogens. Field experiments were conducted to determine the influence of agronomically relevant first year wheat cultivars on take-all levels and ability to accumulate DAPG-producing pseudomonads within their rhizospheres in second-year field trials and in greenhouse trials. One first year wheat cultivar consistently resulted in less take-all in second-year wheat and accumulated significantly more DAPG-producing pseudomonads than other cultivars, suggesting a potential mechanism for take-all reduction associated with that cultivar. An intermediate level of take-all suppression in other other cultivars was not clearly associated with population size of DAPG-producing pseudomonads, however. The first year cultivar effect on take-all dominated in subsequent plantings, and its impact was not specific to the first year cultivar. Our results confirm that wheat cultivars may be used to suppress take-all when deployed appropriately over cropping seasons, an approach that is cost effective, sustainable, and currently being utilized by some wheat growers in Oregon to reduce take-all.

Impact of mechanical weed control on soil N dynamics, soil moisture, and crop yield in an organic cropping sequence

Mechanical weed control is a major element of weed suppression in organic farming systems. In addition to the direct effect on weed growth, mechanical weeding, such as harrowing or hoeing, is known to induce side effects on several soil- and crop-related properties. In this study, we investigated the impact of mechanical weeding on soil mineral nitrogen (SMN), soil moisture, and crop yield in an organic crop rotation of grass-clover (Lolium multiflorumLam., Trifolium pratense L.), silage maize (Zea mays L.) and winter barley (Hordeum vulgare L.). The experiment was conducted in two consecutive years (2021, 2022), where each crop was grown in each year on a Plaggic Anthrosol with sandy loam in North-West Germany. Two weed control treatments (mechanical: harrowing, hoeing; chemical: herbicide application) were implemented in a randomized block design with four replications. Greater net nitrogen (N) mineralization in maize compared to winter barley were attributed to the incorporation of grass-clover residues before sowing of maize and greater mineralization potential during the maize growing season. Higher weed growth in maize after mechanical weeding resulted in a reduction of up to 47% in SMN content in the topsoil. In barley, no differences in weed suppression were observed between the treatments and only small effects on SMN were determined after mechanical weeding. The soil water content in the mechanically weeded plots was significantly higher at several events in both years and for both crops, which was attributed to increased water infiltration by disrupting the soil crust. Neither crop yield nor N uptake in harvest products was affected by the different treatments.

Influence of Crop Diversification in Potato-Based Cropping Sequence on Growth, Productivity and Economics of Potato in Red and Lateritic Soil of West Bengal

Influence of Crop Diversification in Potato-Based Cropping Sequence on Growth, Productivity and Economics of Potato in Red and Lateritic Soil of West Bengal

A comparative analysis of soil organic carbon stock and soil aggregation in two crop sequences in the Rolling Pampa (Argentina)

Understanding how farming practices affect soil organic carbon (SOC) accumulation is essential for sustainable agriculture. Agronomic decisions, such as crop sequence, significantly influence various soil properties. However, the overall benefits of crop rotation on soil structure and SOC storage remain uncertain. We compared the effects of soybean (Glycine max L.) monocropping with a three-year crop rotation comprising wheat (Triticum aestivum L.)/soybean double crop, maize (Zea mays L.), and soybean on the vertical distribution of SOC up to one metre depth. Additionally, we examined carbon accumulation as particulate organic matter-carbon (POM-C), soil aggregation, and structural stability in the topsoil. Compared to monocropping, crop rotation increased SOC concentrations (19 vs. 16 gC kg soil⁻¹), stock (12 vs. 10.7 MgC ha⁻¹), and POM-C content (6 vs. 3.2 gC kg soil⁻¹) in the first 5 cm of soil. At 20–65 cm depth, rotation showed a marginal increment of SOC stock with respect to soybean monocropping. The increased surface SOC content in the rotation positively affected the POM-C content and macro-aggregation. However, soil structural stability showed a tendency to be higher in the monocropping, especially at a depth of 5–20 cm. Overall, crop rotation demonstrated potential for enhanced carbon sequestration in temperate agroecosystems within three years, despite not significantly improving soil structural stability.

Root parameters and water productivity of rice and wheat in a rice‒wheat cropping system as influenced by enriched compost and crop establishment methods

Food security worldwide is largely dependent on the rice–wheat cropping sequence (RWCS) Hence, a field study was carried out during 2018–19 and 2019–20 at ICAR-IARI, New Delhi, to determine the effect of various enriched organic sources and crop establishment methods on the root parameters, water productivity and yield of rice, its carryover effect on the succeeding wheat crop and the overall efficiency of system. A split plot design was used which involved two main plot treatments, viz., aerobic rice (AR) and conventional transplanted (CT) rice, and five subplot treatments, viz., T1: control (without fertilizer), T2: 100 % RDF (100 % fertilization by using inorganic sources), T3: 50 % phosphorus was applied by using P-enriched compost + 50 % P was applied by using DAP, T4: 50 % N was applied by using N-enriched compost + 50 % nitrogen was applied by using DAP and urea, and T5: 100 % organic fertilizer was applied (100 % fertilization by using N-enriched compost and P-enriched compost). After rice, wheat was grown in all the plots under uniform management practices. Among the nutrient sources, T4 had greater effects on root activity, system economic water productivity and system water productivity than did the other treatments. CT rice can be recommended under irrigated conditions with the integration of enriched compost and inorganic fertilizers. However, under rainfed conditions with less available water, aerobic rice can also be produced by combining enriched compost and inorganic fertilizer.

Rotation with Soybean Improved Weed Control and Foxtail Millet Yield

Foxtail millet is an important characteristic grain crop in northern China. However, weeds compete seriously with foxtail millet and have long been a biological factor that has plagued foxtail millet production. Rotation requires determining the species and sequence of crops, and reasonable rotation has many benefits for agriculture, including reducing the damage by weeds. In order to clarify the combination effects of foxtail millet–soybean rotation sequence and herbicide on weed control and crop yield, fixed-position experiments were designed in three growing seasons. Foxtail millet and soybean were planted following the sequence below in successive years (FFF, foxtail millet–wheat–foxtail millet–wheat–foxtail millet; SFF: soybean–wheat–foxtail millet–wheat–foxtail millet; SSF, soybean–wheat–soybean–wheat–foxtail millet; SSS, soybean–wheat–soybean–wheat–soybean), and weed density, biodiversity, weed seedbank, and crop yield were examined and analyzed. The results showed that the average weed density of SFF and SSF was reduced by 61.7% and 66.3% compared with FFF in the three years and by 16.5% and 26.6% compared with SSS, separately. Foxtail millet–soybean rotation (SFF and SSF) increased the species richness and the Margalef species richness index of the weed community and reduced the Simpson index compared with the continuous foxtail millet and the continuous soybean cropping (FFF and SSS). The weed seedbank of SFF and SSF was 45.7% and 55.8% smaller than that of FFF and increased by 92.7% and 56.7% compared with SSS, respectively. The weed density in the FFF treatment was significantly correlated with the 0–5 cm grass seedbank size, while there was no significant correlation in the other three treatments. Benefiting from the lower weed damage intensity, the yield of foxtail millet in SFF and SSF increased by 54.05% and 221.81% compared with FFF, respectively. The research results revealed that both SFF and SSF can effectively reduce the damage of weeds and help improve biodiversity. SSF has a higher weed control effect and higher foxtail millet yield than SFF. This study contributes to the understanding of crop–weed interactions in foxtail millet–soybean rotation and can be applied to areas with similar environments.

Determination of threshold crop water stress index for sub-surface drip irrigated maize-wheat cropping sequence in semi-arid region of Punjab

A thorough understanding of how crops respond to water stress is essential for effective irrigation management under changing climate conditions and declining water resources. Amongst the various methods of irrigation, crop water stress index (CWSI)-based irrigation is popular due to its non-invasive techniques that require less data and can precisely indicate the severity of crop water deficiency. The present study focuses on establishing the upper- and lower-baselines of canopy-air temperature difference (Tc-Ta) for the estimation of the CWSI and to determine the CWSI threshold for maize and wheat crops. The upper- and lower-baseline of (Tc-Ta) was established using the relationship between (Tc-Ta) and vapor pressure deficit (VPD) for different irrigation treatments such as 60 %ETc, 70 %ETc, 80 %ETc, 90 %ETc, and 100 %ETc with irrigation interval of 1-day, 2-days, and 3-days. The study showed that the baselines varied with the growth stages of the crop and with irrigation treatments and reached the maximum in Anthesis and Silking growth stage for wheat and maize, respectively. The threshold of CWSI was estimated by developing a relationship between the normalized values of grain yield (GY) and irrigation water productivity (WPI). For the Rabi wheat, a quadratic correlation was identified between CWSI and WPI (r2 = 0.89), and GY (r2 = 0.93). Similarly, for Kharif maize, a quadratic relationship was noted between CWSI and both WPI (r2 = 0.75) and GY (r2 = 0.85). From the study, it was found that the CWSI thresholds of Rabi wheat and Kharif maize are 0.29 and 0.31, respectively. Based on the study, it can be concluded that by utilizing the thresholds for a winter wheat-summer maize cropping system, high GY and WPI can be achieved.

Spring wheat nitrogen-use indicators responses to cropping sequence and nitrogen fertilization

ABSTRACT Spring wheat (Triticum aestivum L.) nitrogen-use efficiency (NUE) and recovery with nitrogen (N) fertilization rates in crop rotations need further exploration. The effect of cropping sequence and N fertilization rate were evaluated on spring wheat N concentration and uptake, N harvest index (NHI), N-use efficiency (NUE), and N recovery index (NRI) from 2012 to 2019 in the northern Great Plains, USA. Cropping sequences were conventional till spring wheat-fallow (CTWF), no-till spring wheat-fallow (NTWF), no-till spring wheat-pea (Pisum sativum L.) (NTWP), and no-till continuous spring wheat (NTCW), and N fertilization rates to spring wheat were 0, 50, 100, and 150 kg N ha−1. Straw N concentration and N uptake were greater for CTWF than NTWP and NTCW in 4 out of 8 years and increased with increased N fertilization rate. Grain N concentration and NHI varied with treatments and years. Grain N uptake was greater for CTWF and NTWF than NTWP and NTCW at most N fertilization rates and years. In contrast, NUE was greater for NTCW than CTWF and NTWF at all N fertilization rates in most years. The NRI was greater for NTWP or NTCW than CTWF or NTWF in most years. Increasing N fertilization rate increased grain N uptake for most cropping sequences in all years but had a variable effect on NUE and NRI. Although spring wheat N concentration and N uptake were superior for CTWF and NTWF, and NUE for NTCW, NTWP with 50 to 100 kg N ha−1 can be used to sustain grain yield, N uptake, NUE, and NRI.

Potassium release behaviour and fixation potential of Vertisol under continuous sorghum-wheat cropping sequence

Potassium release behaviour and fixation potential of Vertisol under continuous sorghum-wheat cropping sequence

Integrated plant nutrient supply modules for enhancing crop growth, productivity and nutrient balance in maize - chickpea cropping sequence

A long-term field study was conducted to evaluate integrated plant nutrient supply (IPNS) system in maizechickpea cropping sequence. In this study, twelve IPNS modules of Soil Test Crop Response (STCR) based fertilizers, recommended dose of fertilizers (RDF), farmyard manure (FYM), poultry manure (PM), urban compost (UC), maize residue (MR) and Gliricidia loppings (GL) were investigated. Results indicated that plant height, dry biomass, yield parameters (cob length and girth, grains/cob and 1000-grains weight) and yields (grain and stover) of maize significantly (p=0.05) improved with IPNS module (75% NPK +5 t FYM) and increased 31.8 and 23.8% grain yield over the RDF and 100% NPK of STCR, respectively. In chickpea, the higher plant height, dry biomass, pods/ plant and yields (grain and straw) were obtained with the residual fertility of FYM @ 25 t/ha every year and followed by IPNS module (75%NPK +5 t FYM). However, residual fertility of PM and UC based IPNS modules also considerably improved the crop growth and yields of chickpea. Substantially higher system productivity was also noticed with 75% NPK +5 t FYM and followed 75% NPK +1 t PM based IPNS modules which was 1.86 and 0.99 t/ ha higher than RDF. A positive nutrient balance was recorded with addition of higher level FYM only (25 t/ha) Whereas, a negative nutrient balance was noticed for N and K in all plots excluding higher level of organic manures. However, there has been substantial build-up of N, P and K in plots receiving 25 t FYM every year. The additional supply of nutrients (organic + inorganic) is crucial for positive nutrients balance. Thus, STCR based fertilizers (75% NPK) along 25% nutrients through organic manures (FYM and PM) sustained the crop yield while the addition of FYM (25 t/ha) is essential for a positive balance of nutrients in the soil.

Crop Diversification and Fertilization Strategies in a Rainfed System with Drought Periods

Crop diversification and the reduction of nitrogen (N) inputs are key issues in the EU for more sustainable agriculture. An experiment was set up in a semiarid rainfed Mediterranean system. Our hypothesis was that these challenges could be addressed by introducing new crops and using pig slurries (PSs). The experimental factors were N fertilization at sowing (with or without PS) combined (according to a split-block design) with N fertilization as topdressing (the control, two N mineral rates, and two N rates from PS). Barley, rapeseed, and pea performances were evaluated in two different crop sequences: (i) barley–rapeseed or rapeseed–barley after a fallow season, and (ii) barley–pea or pea–barley after a fallow season followed by a non-fertilized barley crop. The results of the four-year study demonstrated that under a spring drought risk, barley performed better than peas in terms of relative crop yield maintenance. After fallow, N can be saved while maintaining the yields and total biomass of barley and rapeseed. In the second crop sequence, maximum pea and barley yields were associated with a minimum topdressing of 60 or 120 kg mineral N ha−1, respectively. However, slurry fertilization at sowing also allowed the highest yields for barley. Rapeseed and peas can be introduced to reduce N fertilization inputs. However, the obtained yield plateau for pea and rapeseed (3 and 4 Mg ha−1, respectively) and the effect of a yield spring drought on pea yields (50% reduction) might be a constraint for the success of EU policies on crop diversification.

Agronomic performance of novel, nitrogen-rich biobased fertilizers across European field trial sites

Context or problemSubstituting mineral fertilizers with novel biobased fertilizers (BBFs) produced from various organic waste and side streams could contribute to a reduction in the environmental and climate impacts of fertilizer production and use and the recycling of otherwise potentially wasted nutrients. For the substitution to be beneficial for farmers, the environment, and food security, the BBFs need to be effective, reliable and safe. However, the agronomic performance of novel, nitrogen (N) rich BBFs has not yet been well studied. Objectives or research questionThe main objective of this study was to determine the agronomic efficiency of N in a relevant range of commercially available BBFs. We hypothesised that they can function as effective substitutes for mineral N fertilizers, independent of the agricultural and geographic settings. MethodsField trials (fully randomized block design) were conducted at four field sites across Europe covering different climates, soil types, and crop sequences. In total 18 BBFs were tested, 7 of which were common BBFs tested at all sites, while the other 11 (2–3 per site) were local BBFs at individual sites. The design included 4–5 increasing levels of mineral N reference. Trials with BBF application were conducted over 2 years, and the agronomic performance (crop yield and N offtake) was determined to estimate 1st year mineral N fertilizer replacement value (NFRV) in both years, while residual NFRV was estimated only in the 2nd year. ResultsThe BBFs showed an average N fertilizer replacement value (NFRV) of 70 % across sites and years, with variations in the agronomic performance between the trial sites and years. Compared with the mineral N fertilizer reference applied at the same total N level, no consistent ranking of BBF and no significant differences in yields were found. The BBFs tended to have a higher NFRV when incorporated compared to surface application. Of the 18 BBFs tested, 8 had a NFRV above 75 %, 6 were in the range 60–75 % and 4 were in the low range of 10–60 %. The residual effect of BBFs in the year after application was not significantly higher for any of the BBFs than that of the mineral N fertilizer. ConclusionsGenerally, the BBFs performed similar to the mineral reference applied at the same total N level. The performance of BBFs was not significantly affected by climate or soil type. The BBFs appeared to have higher agronomic performance when incorporated into the soil compared to surface application. The second year residual effect of BBF was not significantly higher than that of the mineral reference fertilizer. Implications or significanceIn general, most of the investigated BBFs can be considered reasonably effective substitutes for mineral N fertilizers. The results suggest that soil incorporation of BBFs will result in better agronomic performance than surface application.