Subsequent Crop Research Articles

Применение микробных биотехнологий для устранения в почве остатков гербицидов классов имидазолинонов и сульфонилмочевин (обзор)

The review is devoted to the problems of application of modern imidazolinone and ulfonylurea herbicides, as well as to the researches in the field of microbial iotechnology for remediation of contaminated soils. Data on the traits of the influence of residual amounts of herbicides from the classes of imidazolinones and sulfonylureas on target and subsequent crops in crop rotations are given in the article. The problems of monitoring of herbicide residues due to the variety of properties of components and decomposition mechanisms in the soil are shown. Ecological aspects of the influence of imidazolinones and sulfonylureas on soil microbiota and non-target organisms are considered. The results of studies of the biodegradation pathways of herbicide components, as well as conditions that contribute to the acceleration of destructive processes, are presented. The relevance of the search for microorganisms-destructors of imidazolinones and sulfonylureas for the production of biological products is substantiated. Microorganisms of different genera, such as Rhodococcus, Rahnella, Pseudomonas, Bacillus, Methylopila, Ancylobacter, Hansschlegelia, Klebsiella, and Arthrobacter, possess destructive potential against imidazolinones and sulfonylureas. The current data on the development of biological products to eliminate residues of imidazolinones and sulfonylureas in soils to reduce the phytotoxic effect are given.

Effect of green manure incorporation on yield of subsequent groundnut crop

Field experiments were carried out during 2019 to 2021 at Oilseeds Research Station, Tindivanam to Study the effect of green manure incorporation on yield of subsequent groundnut crop. The result revealed that higher mean pod yield of (2710 kg/ha) was recorded in the treatment (M2 S3) Sunhemp incorporation with 75% RDF application. The pod yield was on par with the green manure crop daincha incorporated with 75 % RDF (M3S3). The treatment control recorded the lowest yield.

Grazing intensity and nitrogen fertilization timing to increase soil organic carbon stock and nitrogen in integrated crop-livestock systems

ABSTRACT Integrated crop-livestock systems (ICLS) foster synergistic relationships to increase nitrogen (N) cycling and soil organic carbon (SOC) accrual in agricultural setups. This study evaluated how the grazing intensity and N fertilization (rates and timing) affect both SOC and N fractions, and soil organic matter chemical composition in an ICLS managed under no-tillage in an Oxisol, six years after initiation. The ICLS was compared to a nearby pasture (PA) and a native forest (NF). The treatments consisted of two grazing intensities: Low Sward Height (LH) and High Sward Height (HH) were maintained with high and low stocking rates, respectively. The HH varied between 0.20 and 0.60 m, and LH between 0.10 and 0.30 m according to the plant forage species throughout the experiment. Fertilization using 200 kg ha -1 N-urea, not splitting up, was conducted at two timings, either at the winter pasture establishment (autumn), about 35 days after sowing or during the summer cash crop cycle (spring). Total N amount per year, including both phases, pasture and cash crop was the same for all treatments. The SOC and N contents were assessed in soil and particulate organic matter (POM), while carbon (C) and N stocks were specifically determined in the soil. Soil organic matter composition was characterized by FTIR. The combination of HH and N fertilization during the pasture phase increased the content of C from 36.1 to 39.9 ± 0.7 g C kg -1 and of N from 2.7 to 3.2 ± 0.1 g N kg -1 . The SOC stocks varied from 37.3 to 41.1 ± 0.7 Mg C ha -1 , and the N stocks from 2.1 to 3.3 ± 0.1 Mg N ha -1 at 0.0-0.10 m soil layer. The SOC content of the POM and the soil organic matter chemical composition determined by FTIR were mainly affected by the grazing intensity. The HH led to an increased in C content within the POM fraction, reaching values of 51.6 ± 1 and 49.2 g C kg -1 , respectively to N crop fertilization and N pasture fertilization. Land-use changed how organic functional groups were stored in soil organic matter fractions. The NF had a greater abundance of aliphatic and phenol in the MAOM, while pasture and ICLS systems had greater aliphatic in the POM fraction. In ICLS, SOC accrual was positively associated with more recalcitrant organic functional groups of phenol, aromatic, and carbonyl C-O. The HH increases SOC accrual, while N-fertilization on pasture ensures adequate nutrition of plants and animals during the winter ICLS phase, at the same time as providing greater residual N for subsequent cash crops through enhanced catalyzed by ruminants. Therefore, grazing and fertilization management strategies should be considered to promote sustainable agriculture intensification with ICLS.

Advance Research on the Pre-Harvest Sprouting Trait in Vegetable Crop Seeds.

Pre-harvest sprouting (PHS), the germination of seeds on the plant prior to harvest, poses significant challenges to agriculture. It not only reduces seed and grain yield, but also impairs the commodity quality of the fruit, ultimately affecting the success of the subsequent crop cycle. A deeper understanding of PHS is essential for guiding future breeding strategies, mitigating its impact on seed production rates and the commercial quality of fruits. PHS is a complex phenomenon influenced by genetic, physiological, and environmental factors. Many of these factors exert their influence on PHS through the intricate regulation of plant hormones responsible for seed germination. While numerous genes related to PHS have been identified in food crops, the study of PHS in vegetable crops is still in its early stages. This review delves into the regulatory elements, functional genes, and recent research developments related to PHS in vegetable crops. Meanwhile, this paper presents a novel understanding of PHS, aiming to serve as a reference for the study of this trait in vegetable crops.

Nitrogen rhizodeposition from corn and soybean, and its contribution to the subsequent wheat crops

Nitrogen (N) is a key factor in the positive response of cereal crops that follow leguminous crops when compared to gramineous crops in rotations, with the nonrecyclable rhizosphere-derived N playing an important role. However, quantitative assessments of differences in the N derived from rhizodeposition (NdfR) between legumes and gramineous crops are lacking, and comparative studies on their contributions to the subsequent cereals are scarce. In this study, we conducted a meta-analysis of NdfR from leguminous and gramineous crops based on 34 observations published worldwide. In addition, pot experiments were conducted to study the differences in the NdfR amounts, distributions and subsequent effects of two major wheat (Triticum aestivum L.)-preceding crops, corn (Zea mays L.) and soybean (Glycine max L.), by the cotton wick-labelling method in the main wheat-producing areas of China. The meta-analysis results showed that the NdfR of legumes was significantly greater by 138.93% compared to gramineous crops. In our pot experiment, the NdfR values from corn and soybean were 502.32 and 944.12 mg/pot, respectively, and soybean was also significantly higher than corn, accounting for 76.91 and 84.15% of the total belowground nitrogen of the plants, respectively. Moreover, in different soil particle sizes, NdfR was mainly enriched in the large macro-aggregates (>2 mm), followed by the small macro-aggregates (2–0.25 mm). The amount and proportion of NdfR in the macro-aggregates (>0.25 mm) of soybean were 3.48 and 1.66 times higher than those of corn, respectively, indicating the high utilization potential of soybean NdfR. Regarding the N accumulation of subsequent wheat, the contribution of soybean NdfR to wheat was approximately 3 times that of corn, accounting for 8.37 and 4.04% of the total N uptake of wheat, respectively. In conclusion, soybean NdfR is superior to corn in terms of the quantity and distribution ratio of soil macro-aggregates. In future field production, legume NdfR should be included in the nitrogen pool that can be absorbed and utilized by subsequent crops, and the role and potential of leguminous plants as nitrogen source providers in crop rotation systems should be fully utilized.

Influence of Sunn Hemp Biomass Incorporation on Organic Strawberry Production

Sunn hemp (Crotalaria juncea L.), a warm season leguminous cover crop, is commonly used in rotation with organic strawberry production in Florida’s subtropical environment. This study was conducted to explore the impacts of sunn hemp on growth and yield performance of the subsequent organic strawberry crop in sandy soils, taking into consideration the nutrient contribution from soil incorporation of sunn hemp biomass. Sunn hemp was seeded during the summer off-season and terminated before flowering, three weeks prior to the fall planting of two strawberry cultivars (‘Strawberry Festival’ and ‘Camino Real’). With sunn hemp residues incorporated into the soil, two application rates of nitrogen (N) through pre-plant organic fertilization for the strawberry season were used, including N at a rate of 84 kg/ha, without consideration of the N credit from sunn hemp, and N at a rate of 19.8 kg/ha, with consideration of the estimated N credit from sunn hemp. A summer fallow without cover crop and with a pre-plant organic fertilizer application at the N rate of 84 kg/ha was included as the control. Overall, the sunn hemp incorporation at three weeks after termination did not benefit the strawberry plant growth or fruit yield in this study, with rather low levels of soilborne pathogen and nematode infestations. Both sunn hemp treatments exhibited a significantly lower level of total soil N compared to the summer fallow plots at the end of the strawberry season. The reduction in the pre-plant N fertilization resulted in lower above-ground plant dry weight and accumulation of N, phosphorus (P), and potassium (K) at the end of the strawberry season, along with fewer leaves and smaller crowns of the strawberry plants during the early season. Both sunn hemp treatments decreased early fruit yields, while the sunn hemp treatment with the reduced N fertilization also led to a significant reduction in the total fruit number and weight, although no significant differences in the whole-season marketable fruit yield were observed among the nutrient management treatments. Overall, ‘Strawberry Festival’ yielded higher than ‘Camino Real’, but the effects of nutrient management did not vary with the strawberry cultivars. Further studies are needed to enhance organic strawberry nutrient management involving rotational cover crops.

Fall/winter cover crop roots change soil hydrology to control the drought status of subsequent season summer maize in Ultisol

Climate change has increased drought frequency, necessitating strategies to reduce water stress, increase water use efficiency, and improve agricultural productivity. The impacts of different fall/winter cover crops on alleviating maize drought in the subsequent season by changing soil water content remain unclear in Ultisol. Our aim was to investigate whether different fall/winter cover crops (taproot and fibrous root) can improve soil water content to attenuate subsequent season maize drought and its underlying mechanism. This research compared four fall/winter cover crops (2 rapeseed cultivars, lucerne and vetiver) and fallow control (no cover crop in winter) to investigate their root traits, root effect on subsequent season soil water content (SWC), soil drought degree (D), maize leaf and root water potential (Ψl, Ψr), maize crop water stress index (CWSI), and maize growth components (aboveground plant and root parameters) in 2019 (a dry year), 2021 (a normal wet year), and 2022 (a severe dry year). The fibrous-rooted vetiver displayed higher average root diameter and higher average root length density, leading to increased SWC (17%, 15%, 15%), and lower D values in all three years. Additionally, it exhibited a more substantial gradient between Ψl, and Ψr and lower CWSI than taproot (rapeseed cultivars and lucerne) and fallow treatment. Furthermore, the cover crop treatments enhanced the gradient between maize Ψl and Ψr to varying degrees in different drought years. Ultimately, the improvement in SWC resulting from cover crop treatments increased maize aboveground growth (plant height, stem diameter, and leaf area) and maize root development, ultimately improving maize yield. This study introduces a new perspective on investigating the role of cover crops in alleviating seasonal drought in subsequent crops, especially by changing soil water properties in the subtropical climate.

Snow removal and cover crops influence soil nitrogen transfer to the subsequent corn crop

Snow removal and cover crops influence soil nitrogen transfer to the subsequent corn crop

Optimizing irrigation strategies for sustainable crop productivity and reduced groundwater consumption in a winter wheat-maize rotation system

Inefficient irrigation practices have hindered crop yields, wasted irrigation water resources, and posed threats to groundwater levels and agricultural sustainability. This study evaluated different irrigation strategies for a winter wheat-summer maize rotation system to identify sustainable practices for maintaining yields while reducing groundwater depletion. A two-year field experiment was conducted, implementing three optimized irrigation strategies during the winter wheat season: I-4 (irrigated until the soil water content (SWC) of the 40 cm soil layer reaches 60% of field capacity (FC), I-6 (irrigated until the SWC of the 60 cm soil layer reaches 80% FC), and a rainfed (R) as control. Irrigation was repeated when the SWC dropped to the specified level. No irrigation level was used during the summer maize season, except for irrigation after sowing that ensuring the normal emergence of maize. WHCNS (Water Heat Carbon Nitrogen Simulator) model was developed to simulate soil water dynamics, field water consumption, and yield of both crops. The result indicated WHCNS model accurately simulated water dynamics, consumption, and grain yield. Compared to R treatment, the I-4 treatment significantly increased annual crop yield by 19.83%–28.65% (p < 0.05), while maintaining similar crop water productivity. Furthermore, the I-4 treatment achieved comparable yields to the I-6 treatment, but with a 33.91% reduction in irrigation water use, resulting in a 33.46% increase in crop water productivity and a 90.53% increase in irrigation water productivity. From a sustainable perspective, the I-4 treatment effectively reduced field water losses and maintained relatively high soil water storage, particularly in the topsoil, which was beneficial for the early growth of subsequent crops. The R treatment greatly contributed to groundwater recharge when precipitation was sufficient, while it led to severe yield losses. Overall, under the condition of annual rotation planting systems, the I-4 treatment sustainably maintained yields with less irrigation, decreasing groundwater consumption. This approach could conserve regional water resources and groundwater table while upholding agricultural productivity and achieving system sustainable water use.

Dynamics of Yield and Chlorophyll Content of Four Kangkung (Ipomea reptans Poir) Sequences With Soilless Cultivation System Due to Direct and Residual Effects of Vermicompost Application

The applications of organic fertilizers releasing nutrients slowly not only have a direct impact on the growing crop, but also, residual effects on the subsequent crops in the conventional crop cultivation systems. Studies on the residual effects of organic fertilizer in soilless crop cultivation are quite rare. The present study, which is a pot experiment conducted in a greenhouse, describes the dynamics of yield and chlorophyll content of kangkong as direct and residual effects of vermicompost for four consecutive plantings in soilless crop cultivation, further, compared with inorganic fertilizer treatment. The experimental design used was a randomized complete block design with different levels of vermicompost rates and a control treatment using inorganic fertilizer. The vermicompost was applied only in the first crop, while, inorganic fertilizer was supplemented in each crop. Fresh weight per plant per pot increases ~35 - 54% at the second planting compared with the first planting, thereafter, gradually decreases in subsequent planting. The content of chlorophyll A was found to be relatively constant, while the chlorophyll B content was highest in the first planting and, thereafter, subsequently decreased in further planting. The higher yields were found at 400 - 500 g pot-1 vermicompost fertilizer dose, insignificantly different from the inorganic fertilizers treatment.

Comparison of nitrogen mineralisation patterns of Cichorium intybus and Medicago sativa

AbstractLittle is known about the rate of mineralisation of chicory (Cichorium intybus) residues and how this may influence the availability of nitrogen (N) for subsequent crops. An incubation study was conducted to compare the relative rates of N mineralisation and carbon dioxide production from different plant fractions of chicory and lucerne (Medicago sativa) over 112 days. Plants were separated into leaves, stems, fibrous roots (&lt;1 mm), and taproots (&gt;4 mm), which were either ground or segmented, and then mixed with soil in sealed jars. Results showed that net N mineralisation occurred from day 7 for lucerne leaves, but not until day 56 for chicory leaves. By day 112, chicory leaves only produced approximately 25% of the N mineralised by lucerne leaves. Segmented chicory taproots released 32% and 24% more of the plant N and carbon (C), respectively, than any other chicory and lucerne plant fractions despite having a C:N ratio greater than 30. The presence of a common fungal saprophyte (Rhizopus spp.) in the segmented chicory taproot treatments appeared to accelerate the net N mineralisation rate. Whilst coarse chicory roots released mineral N relatively rapidly, the lower N content observed in the chicory plant residues limited the capacity of chicory to release the same quantity of mineral N compared to lucerne. Chicory needs to be grown with a companion legume so that N mineralisation of the residues better matches the demands of N requirement for the following non‐legume cropping phase.

Effects of legumes and fertiliser on nitrogen balance and nitrate leaching from intact leys and after tilling for subsequent crop

Grass-legume leys combine multiple agronomic benefits, several of which are associated with symbiotic nitrogen (N) fixation. However, the best combinations of legume abundance and N fertilisation to achieve high productivity at low nitrate leaching are not yet established. Nitrate leaching risk of pure grass swards (Grs), grass-legume mixtures (Mix) and pure legume swards (Leg) at a fertiliser level of either 50, 150 or 450 kg N ha−1 yr−1 (N50, N150 and N450) was studied during two key periods: the intact ley for forage production and after tilling for subsequent winter wheat in crop rotation. The risk of nitrate leaching was determined from (i) monitoring of the nitrate concentration in the soil solution (NCSS) and (ii) the soil mineral N (SMN) content. Furthermore, the soil surface N balance was assessed by measuring N input from fertiliser and symbiosis, and N output with harvested biomass. During the period of intact plant cover, soil surface N balance of Grs swards was strongly negative at N50 and N150 with negligible NCSS and SMN. At N450, the positive N balance of Grs swards resulted in a high leaching risk after three years of cultivation (NCSS ≤ 13 mg NO3-N L−1 and SMN ≤ 20 kg N ha−1). For Mix swards, the N balance was close to zero at N50 and N150, which led to similarly low NCSS and SMN. At N450, the N balance of Mix swards was beyond zero, resulting in significantly increased NCSS and SMN (≤ 30 mg NO3-N L−1 and ≤ 35 kg N ha−1). For Leg swards, the N balance was far beyond zero at all fertilisation levels, resulting in a leaching risk even at N50 (≤ 8 mg NO3-N L−1 and ≤ 23 kg N ha−1). During the period following tilling the leys, SMN was similar or lower for Mix compared to Grs swards (≤ 43 vs. ≤ 62 kg N ha−1 at N50 and N150, 72 vs. 68 kg N ha−1 at N450), while it was significantly higher for Leg swards (SMN ≤ 95 kg N ha−1). We conclude that grass-legume mixtures combine high yields, low fertiliser requirements, and low nitrate leaching better than either pure grass or pure legume swards. This holds true both during the period with intact plant cover and after tillage for the subsequent crop.

Determining overwintering performance and economic viability of monosex tilapia fingerling production in hapa cum cage aquaculture system for Bangladesh's haor fishers

Ensuring a consistent supply of uniformly sized fingerlings for tilapia cage aquaculture in Bangladesh's poses a significant challenge. This study assessed overwintering growth performance and economic viability of monosex tilapia fingerling production in haor waters. Nine hapas, each inside a designated treatment cage, were stocked with T1 (200), T2 (250) and T3 (300) tilapia fry, averaging 1.25±0.25 g, per m³ for 90 days. The most successful treatment continued for two subsequent crops over two years for economic viability assessment. Average final body weight gain was the highest at the lowest stocking density (T1, 58.86±7.23 g), but the most desirable biomass gain (222 kg cage⁻¹) occurred at medium stocking density (T2). Beyond biomass gain, T2 exhibited superior profitability, with 26% and 30% profitability in the second and third crops respectively, over total costs. In conclusion, overwintering tilapia fingerling production in the hapa-cum-cage system at a stocking density of 250 m⁻³ proved more profitable and sustainable than other treatments, offering a viable income-generating option for resource-poor haor fishers.

Crop Classification and Growth Monitoring in Coal Mining Subsidence Water Areas Based on Sentinel Satellite

In high groundwater level mining areas, subsidence resulting from mining can lead to waterlogging in farmland, causing damage to crops and affecting their growth and development, thereby affecting regional food security. Therefore, it is necessary to restore agricultural production in the coal mining subsidence water areas in the densely populated eastern plains. This study focuses on the Yongcheng coal mining subsidence water areas. It utilizes Sentinel-1 and Sentinel-2 data from May to October in the years 2019 to 2022 to monitor the growth and development of crops. The results demonstrated that (1) the accuracy of aquatic crops categorization was improved by adjusting the elevation of the study region with Mining Subsidence Prediction Software (MSPS 1.0). The order of accuracy for classifying aquatic crops using different machine learning techniques is Random Forest (RF) &gt; Classification and Regression Trees (CART) ≥ Support Vector Machine (SVM). Using the RF method, the obtained classification results can be used for subsequent crop growth monitoring. (2) During the early stages of crop growth, when vegetation cover is low, the Radar Vegetation Index (RVI) is sensitive to the volume scattering of crops, making it suitable for tracking the early growth processes of crops. The peak RVI values for crops from May to July are ranked in the following order: rice (2.595), euryale (2.590), corn (2.535), and lotus (2.483). (3) The order of crops showing improved growth conditions during the mid-growth stage is as follows: rice (47.4%), euryale (43.4%), lotus (27.6%), and corn (4.01%). This study demonstrates that in the Yongcheng coal subsidence water areas, the agricultural reclamation results for the grain-focused model with rice as the main crop and the medicinal herb-focused model with euryale as the main crop are significant. This study can serve as a reference for agricultural management and land reclamation efforts in other coal subsidence water areas.

Cover crop residue quality regulates litter decomposition dynamics and soil carbon mineralization kinetics in semi-arid cropping systems

Cover crop residue addition provides several soil health benefits and serves as a precursor for storing soil organic carbon (SOC). However, information on residue decomposition dynamics and its contribution to soil carbon (C) and nitrogen (N) cycling in arid and semi-arid environments is limited. This study evaluated cover crop residue decomposition in field conditions and C mineralization kinetics in laboratory conditions. For the field experiment, approximately 20 g of Austrian winter pea (Pisum sativum subsp. arvense L.), turnip (Brassica rapa subsp. rapa L.), and triticale (×Triticosecale Wittmack) cover crop residues were kept in litter bags and placed on the soil surface before subsequent forage sorghum (Sorghum bicolor L. Moench) planting in ongoing cover crops study plots. Litter bags were collected every other week (12 destructive samplings) to evaluate the remaining dry matter and C and N contents. The decomposition data were plotted with first order kinetics and exponential models to describe the model fit. To study C mineralization kinetics, a 10-week incubation was set up in a laboratory with Austrian winter pea, turnip, and triticale cover crops and native grass, wheat, and sorghum residues. Carbon mineralization rates were evaluated with three statistical models (first order kinetics and single and double exponential). The exponential model best described the cover crop residue decomposition kinetics in the field. After 98 days, the residue decomposition was higher with Austrian winter pea (47 %), followed by turnip and triticale with ∼40 % biomass decomposition. Residue types and quality both affected the decomposition rates. The C mineralization rate correlated with initial N content (r = 0.87, P < 0.05), C: N ratio (r = −0.88, P < 0.05), and lignin: N (r = −0.87, P < 0.05). While the single exponential model explained field decomposition dynamics, the double exponential decay model best fitted the observed C mineralization trend among the three models. The decay models from our study can be applied to estimate the decomposition dynamics of other winter cover crop residues in similar agroecosystems. This study demonstrated that selecting suitable cover crops and mixtures is critical for maximizing soil C sequestration and N availability in subsequent crops in cover crop-integrated semi-arid cropping systems.

Grazing cover crops: How does it influence soils and crops?

AbstractGrazing cover crops (CCs) can potentially generate economic benefits, but how this practice affects soils and crop production compared with non‐grazed CCs is not well understood. We reviewed all published literature up to June 30, 2023, on grazing CCs to evaluate how this practice impacts soils and crop production and discuss potential factors that may influence grazing CC effects. The emerging literature indicates that 18%–92% of CC biomass was removed when grazed. Grazing CCs increased soil bulk density and penetration resistance (compaction indicators) in 54% of cases (six of 11 studies). However, the increase in soil compaction as measured by penetration resistance generally remained below the root‐growth threshold level (&lt;2 MPa). Grazing CCs had small and mixed effects on soil C concentration, wet aggregate stability, water infiltration, water retention, and soil microbial biomass. In addition, grazing did not affect subsequent crop yields in 61% of cases (eight of 13 studies) or had variable effects. Grazing at high stocking rates or when soils are wet can result in soil compaction and potentially reduce subsequent crop yields. Additional long‐term (&gt;5 years) data are needed to better discern CC grazing implications for different climates, stocking rates, soil types, CC grazing infrastructure, and CC management practices. Particularly, data on CC grazing from water‐limited regions (i.e., semi‐arid regions) are scant. Success with CCs in water‐limited regions depends on timely precipitation input unless irrigated. Overall, grazing of CCs under proper management has small or no effects on soils and crop yields.

Adding a diversity of legumes to a crop decision-support system: Maintaining satisfactory accuracy while keeping the model simple

In a context of economic and environmental concerns in agriculture, legumes appear to be suitable alternative crops to diversify current cropping systems and reduce their dependence on synthetic nitrogen (N) fertiliser and protein from imported soya bean. However, legume-based cropping systems may increase N losses through nitrate leaching if the N available from legumes does not coincide with subsequent crop requirements. To help agricultural advisers manage N in these systems, we adapted the decision-support system Syst’N®, designed to assess N losses in cropping systems, to simulate three annual and one perennial legume crops: pea, faba bean, soya bean and lucerne. To this end, we adapted and simplified existing submodels of legume functioning to include them in Syst’N, to keep the latter simple. We adapted the submodels “BNF” (i.e. biological N fixation) from the STICS model and “dormancy” from the CropSyst model. We also added the ability to enter the flowering date to improve predictions (improvement in N fixation’s rRMSE from 57% to 41% and EF from 0.57 to 0.77). The equations and associated parameter set developed for the four legume crops yielded satisfying predictions of crop biomass (rMBE = 9%, EF = 0.82, rRMSE = 39%) and N content (rMBE = 5%, EF = 0.76, rRMSE = 37%). These performances support the philosophy of Syst’N® that requires minimising the number of additional parameters for users when representing new crops or processes.

Influence of organic amendments and different levels of nitrogen on production potential, economics and energetics of rice (Oryza sativa)–wheat (Triticum aestivum) cropping system

A field experiment was conducted during 2018–19 and 2019–20 at the Punjab Agricultural University, Ludhiana and Research Station, Dyal Bharang, Amritsar, to study the influence of organic amendments and nitrogen levels on rice (Oryza sativa L.)-wheat (Triticum aestivum L.) cropping system. In rice, main plot treatments were green manuring (GM), farmyard manure (FYM), poultry manure (PM) and control (NA). Nitrogen levels in sub-plots comprised control (N1), 50 kg N/ha (N2),75 kg N/ha (N3) and 100 kg N/ha (N4). In wheat, residual effect of organic amendments and nitrogen levels applied to preceding rice was evaluated. The statistically highest grain yield of rice was obtained with PM (8.29 t/ha), followed by GM (8.02 t/ha) which was at par with FYM (7.90 t/ha). The lowest rice grain yield was obtained with NA (5.16 t/ha) and its subsequent wheat crop recorded significantly higher grain yield with PM (6.14 t/ha), followed by FYM (5.88 t/ha) and GM (5.72 t/ha). Treatment N4 recorded significantly higher yield than N2 and was at par with N3. Maximum rice-equivalent yield (14.7 t/ha) was recorded with PM, while the highest energy-use efficiency of rice was recorded with green-manure (16.2) as compared to the other treatments. Treatment with the application of PM and N4 recorded significantly the highest economic parameters and system productivity for both rice and wheat crops compared to rest of the treatments.

Rapid-screening Bioassay Assessing Potential Allelopathic Influence on Spinach by Aqueous Extract from Fresh, Whole-plant Sorghum-sudangrass Tissue

Cover crops are defined as crops grown primarily for agroecosystem improvement rather than for market or sale. The use of cover crops to decrease the negative effects of weeds and improve soil and ecosystem health is increasing, but unanticipated allelopathic responses to those cover crops by subsequent crops is sometimes a problem. Allelopathy is broadly defined as the biochemical interactions between all types of plants, including microorganisms. Because allelopathic effects include both inhibitory and stimulatory responses and may be species- and cultivar-specific, a method of rapidly screening donor and recipient crops for allelopathic interactions is needed. The objective of this research was to evaluate a growth chamber bioassay for rapidly screening spinach (Spinacia oleracea L.) cultivars for allelopathic interactions with an aqueous extract from fresh whole-plant tissue of sorghum-sudangrass [Sorghum bicolor (L.) Moench; SSG] cultivars. The bioassay exposed the seed of 10 spinach cultivars to the aqueous extract of three cultivars of SSG during the imbibition and germination processes and evaluated the consequent root and stem development. Compared with the control, the extract from all three SSG cultivars decreased the root length of all spinach cultivars. A subsequent field screen where spinach cultivars were planted into decomposing SSG residue resulted in a similar pattern of growth suppression. These results demonstrate that the growth chamber bioassay is suitable for predicting allelopathic interactions between cultivars of SSG and cultivars of spinach and can be used by growers for making cultivar selection decisions when spinach follows SSG in a cropping sequence. This rapid-screening growth chamber bioassay protocol eliminates many of the environmental and other challenges frequently associated with field trials and may be adaptable for predicting allelopathic interactions among other cover crops, weeds, and subsequent market crops.

Satellite imagery and modeling contribute understanding cover crop effect on nitrogen dynamics and water availability

Cover crops (CCs) can affect the cropping systems’ N dynamics and soil water content (SWC), but optimizing their potential effects requires knowledge of their growth pattern, N accumulation, and mineralization. For this purpose, a 3-year field experiment was initiated in northeast Italy involving a maize-soybean rotation. The objectives of this study were to (i) evaluate the use of time series vegetation indices (VIs) obtained from the Sentinel-2 satellite for monitoring the growth of CCs and estimating their biomass and N uptake at termination; (ii) investigate the effects of different CCs on cash crop yield and SWC; and (iii) use the simulation model CC-NCALC to predict the nitrogen contribution of CCs to subsequent cash crops. Three CC systems were tested: a fixed treatment with triticale; a 3-year succession of rye, crimson clover, and mustard; and a control with no CCs. Satellite imagery revealed that rye and triticale grew faster during the winter season than clover but slower compared to mustard, which suffered a frost winterkilling. Both grasses and mustard produced greater biomass at termination compared to clover, but none of the CC species affected SWC or yield and N uptake of the cash crop. A net N mineralization of all the CC residues was estimated by the model (except for the N immobilization after triticale roots residues). During the subsequent cash crop season, the estimated clover and mustard N released was around 33%, and the triticale around 3% of their total N uptake, with a release peak 2 months after their termination. The use of remote sensing imagery and a prediction model of CC residue decomposition showed potential to be used as instruments for optimizing the CCs utilization and enhancing cropping water and N fertilization management efficiency; however, it must be further analyzed with other CCs species, environmental conditions, and cropping systems.