Field Experiment Research Articles

Soil Mulching Practices Increased Grain‐Filling Capacity of Rainfed Maize (Zea mays L.) by Improving Soil Hydrothermal Condition and Leaf Photosynthetic Potential

ABSTRACTGrain‐filling rate and duration largely affect the grain‐filling capacity, which determines the grain yield of maize (Zea mays L.). Nevertheless, there is little about the mechanism of how various soil mulching practices affect the leaf photosynthetic potential and subsequent grain‐filling capacity of maize. Field experiments were undertaken on rainfed summer maize in northwest China under flat cultivation without mulch (FNM), flat cultivation with straw mulch (FSM), flat cultivation with transparent film mulch (FTF), flat cultivation with black film mulch (FBF), ridge‐furrow cultivation with transparent film mulch (RTF) and ridge‐furrow cultivation with black film mulch (RBF) in 2021 and 2022. This study explored the impact of various soil mulching patterns on soil hydrothermal condition, leaf growth, photosynthetic potential, aboveground dry matter growth and grain‐filling process of rainfed maize. The dynamics of leaf area index (LAI) and grain‐filling were fitted with growth equations, and the relationships of grain‐filling rate, leaf area duration and LAI withering rate were quantified. The results showed that, compared with FNM, other five soil mulching practices improved soil hydrothermal condition, the maximum LAI and leaf expansion rate but reduced leaf withering rate, thereby increasing radiation interception rate (RI) at the grain‐filling stage. The soil mulching practices also increased leaf SPAD value, net photosynthetic rate, photosynthetic nitrogen use efficiency and the aboveground dry matter. Compared with FNM, other five practices extended the effective grain‐filling period and the active period of grain‐filling, increased the maximum and mean grain‐filling rates, improved the 100‐kernel weight and the average kernel per ear (KPE), thereby increasing grain yields by 9.2%, 33.7%, 38.0%, 46.3% and 58.6%, respectively. The functional relationships of grain‐filling rate and accumulated leaf area duration (y = a/(1 + b*exp(−kx))), and the functional relationships of grain‐filling rate and LAI withering rate (y = (a + cx + ex2)/(1 + bx + dx2)) were first proposed. In conclusion, various soil mulching practices improved the soil hydrothermal condition, green leaves growth process and RI, which improved the leaf photosynthetic potential and the grain‐filling capacity, thereby increasing the 100‐kernel weight, KPE and grain yield. This study can help us quantitatively describe and better understand the maize grain‐filling process under various mulching practices.

Straw return can increase maize yield by regulating soil bacteria and improving soil properties in arid and semi-arid areas

Straw return has been found to benefit soil fertility and crop yield, however, by which it affects microbial communities to mediate soil factors driving crop yields under maize continuous cropping systems in dryland areas is still unclear. To fill this gap, a 6-year field experiment was established with five straw return amounts (T0, T1, T2, T3, and T4, representing 0, 3,000, 6,000, 9,000, and 12,000kgha-1 of straw, respectively), and investigated the effects of on soil properties, enzymes, bacterial community composition and diversity, and crop yields. Our analysis showed that soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) contents significantly increased by 1-8%, 5-25%, and 2-9% under straw return treatments, respectively, compared to the T0, and soil catalase, urease, and alkaline phosphatase activities increased by at least 34.00%. Additionally, crop yield significantly increased by 4.23-12.00% under T1-T4 treatments, and showed highly significant relationships with SOC, TN, and TP. Importantly, we found straw return significantly altered the community of bacteria involved in the carbon and nitrogen cycle, and their abundance of strong responses depending on the amounts of straw return. For example, straw input increased the abundance of Proteobacteria (+2.64–5.57%), Acidobacteria (+3.82–13.83%), and Bacteroidetes (+15.37–30.49%). Similarly, the amount of straw application increased the bacterial diversity indexes (Shannon, 2.65–10.93%; Chao1, 13.47–18.50%), and had significant positive correlations with SOC, TN, and TP contents. Structural equation models (SEM) revealed that straw return management practice had positive and indirect effects on crop yields by influencing soil properties or the bacteria community. In conclusion, our findings revealed common associations and variations of bacterial community diversity with soil factors and crop yields at different straw return rates, and these findings provide insights and options for the development of better straw return strategies and sustainable agriculture in semi-arid regions.

Strip clear-cutting transformations increase soil N2O emissions in abandoned Moso bamboo forests

Forest transformation can markedly impact soil greenhouse gas emissions and soil environmental factors. Due to increasing labor costs and declining bamboo prices, the abandonment of Moso bamboo forests is sharply escalating in recent years, which weakens the carbon sequestration capacity and decreases the ecological function of forests. To improve the ecological quality of abandoned Moso bamboo forests, transformations of abandoned bamboo forests have occurred. However, the impact of such transformations on N2O emissions remains elusive. To bridge the knowledge gap, we conducted a 23-month field experiment to compare the effects of various forest management practices on soil N2O emissions and soil environmental factors in abandoned Moso bamboo forests in subtropical China. These practices included uncut abandonment as a control, intensive management, three intensities (light, moderate, and heavy) of strip clear-cutting with replanting local tree species, and clear-cutting with replanting transformation. During the experimental period, the mean soil N2O flux in abandoned Moso bamboo forests was 13.2 ± 0.1 μg m-2 h-1, representing a 44% reduction compared to intensive management forests. In comparison to the uncut control, light, moderate, and heavy strip clear-cutting and clear-cutting transformations increased soil N2O emission rates by 20%, 43%, 64%, and 94%, respectively. Soil temperature (69-71%), labile C (2-6%) and N (3-8%) were the main factors that explain N2O emissions following the transformation of abandoned Moso bamboo forests. Additionally, replanting could decrease soil N2O emissions by increasing the contribution of soil moisture. Overall, the light strip clear-cutting transformation is suggested to convert abandoned Moso bamboo forests to mitigate N2O emissions.

Enhanced seed yield of full-season soybean when rotated with cereals and cover crops as compared to monoculture in a long-term experiment

Soybeans are of great importance to the global economy, but the cultivation as monoculture has shown several negative environmental implications in the long-term. Long-term studies demonstrate the cumulative effects of rotations on soil variables, but few studies have considered changes during consecutive years in a time series of soybean as a monoculture. The inclusion of cereals and cover crops in rotation with soybean increases the intensification sequence index (ISI, time with crops actively growing during the year) and increases in soybean yield are expected. In line with this, some studies suggest that only including a winter cover crop will increase ISI and raise production. However, these comparisons have not been made in the long term. The objectives of this work were to: i) compare the evolution of full-season soybean yield and production when sowed as monoculture and in cropping sequences that include cereal crops and cover crops, and ii) quantify a yield gap in full-season soybean due to monoculture by evaluating the long-term residual effect of crop sequences with different land occupation. Soybean yield time series in a 14-years period in rotation or as monoculture were studied in a long-term field experiment under no-tillage established in 2006 in the Northern Pampas region of Argentina. Rotations consisted in sequences that included soybean (S), maize (M) and wheat (W), and also incorporated wheat as a winter cover crop (CC): S-S, CC/S-CC/S, S-W/S-M, CC/S-W/S-M, M-W/S, and CC/M-W/S, with ISI values of 0.39, 0.69, 0.55, 0.64, 0.65 and 0.80, respectively. In 2021/22 season, full-season soybean was planted in all plots as a "test" crop, to evaluate the long-term residual effect of sequences with different intensification indexes. Seed yield averaged 3249 kg ha−1 among years. During the 14 years under study, seed yield in S-W/S-M surpassed S-S by 28 % in 6 out of 14 years. The differences between S-S with respect to this sequence were observed consistently from the ninth crop season (i.e. since 2017/18). The inclusion of a cover crop within a soybean monoculture (i.e. CC/S-CC/S) showed similar seed yields as in S-S in 11 out of 14 years. The analysis of the test crop showed yield-gaps when soybeans were grown as monoculture (seed yield in rotations minus seed yield in S-S) of 9, 20, 27, 21 and 31 % for CC/S-CC/S, S-W/S-M, CC/S-W/S-M, M-W/S and CC/M-W/S, respectively. In summary, soybean in rotation with cereals showed an average increase of ca. 346 kg ha−1 and including a cover crop within a soybean monoculture did not increase seed yield at the levels observed when rotated with cereals. Finally, when estimating seed yield-gaps in soybean, it is important to set in which rotation soybean is placed, since a higher maximum yield is expected to happen when soybean follows a more intensified rotation.

Nitrogen fertilization and sowing date as wheat climate change adaptation tools under Mediterranean conditions

In the current situation, climate change has substantially disturbed precipitation occurrence in the Mediterranean region, by increasing its variability and decreasing the total annual amount, which both negatively affect rainfed crop productivity. We hypothesize that a simple cost-effective method for enhancing crop adaptation to new climate conditions would consist of modifying the crop sowing date. Traditional nitrogen (N) fertilization rates could also be adjusted to the current situation given the interdependent water/N relation in plant nutrition. Based on this hypothesis, during a 4-year field experiment with bread wheat (Triticum aestivum L., var. Pistolo), the effects of three sowing dates (October, November, February) and three N fertilization rates (54kgN ha-1, 27kgN ha-1, 0kgN ha-1) on crop development, yield, grain quality, soil N content and N use efficiency were analyzed. The results showed that water scarcity was the predominant limiting factor, because it outweighed N deficiency with half-fertilized crops being as productive as fully fertilized treatments. Nevertheless, sowing date was the most influential factor, with up to a 30% yield increase noted for the November-sown wheat compared to that sown in October, while delaying wheat sowing to February decreased crop yields. Grain protein content remained the same between the November- and October-sown crops, but increased in the February one crops. Optical sensor measurements showed that an optimal assessment of the current water/N nutritional status of crops can be achieved with these tools.

Price Sensitivity and Information Barriers to the Take-Up of Naloxone

We conducted a field experiment that randomized advertisements, advertisement content, and prices across 2,204 counties in the United States to study the impacts on online purchases of naloxone, an opioid overdose reversal drug. Advertising increased web-site users but only impacted purchases when combined with a price reduction. Messages emphasizing the discreet nature of online sales had no additional impact on purchases. Comparing counties with advertisements featuring a highly discounted price to those featuring the full price, we estimate a price elasticity of demand for online naloxone of −1.3. Price is a significant barrier to online purchases of this lifesaving medication. (JEL C93, H75, I12, I18, L65, M37)

Developing Strategies to Mitigate Squash Injury from the Soil Residual Activity of Glyphosate in Bareground Systems

Fresh market vegetables are an essential component of the human diet. Maximizing yield is critical, and to achieve this goal, fields must be weed-free when vegetable crops are planted. Historically, removing emerged weeds just before planting has been accomplished using the herbicide glyphosate. However, recent research has indicated that glyphosate applied to sandy, low-organic-matter soils just before transplanting vegetables can be injurious. Two field experiments investigated 1) the response of transplanted squash to the residual activity of glyphosate, and 2) the effects of implementing tillage, irrigation, or extending the plant-back interval after application and before planting to mitigate injury from glyphosate. Glyphosate applied at 1.3, 2.5, or 3.8 kg ae/ha 1 day before transplanting injured squash 13%, 29%, and 53%, respectively; extending the interval between application and planting to 7 days reduced injury to 1%, 11%, and 28% at the same rates. An interaction between application rate and planting interval was also observed on squash plant widths and biomass, as well as early-season and total marketable fruit numbers and weights. Total marketable fruit number was reduced 29% and 52% by glyphosate at 2.5 or 3.8 kg ae/ha, respectively, and a reduction in fruit production of 36%, 28%, and 23% was observed when glyphosate was applied 1, 4, or 7 days before transplanting, respectively. In a separate study, light tillage (5 cm deep) was the most effective cultural practice evaluated because it eliminated damage by glyphosate. Overhead irrigation of 0.6 cm was not beneficial in mitigating injury by glyphosate. Recommendations from this research will help vegetable growers avoid injury from the residual activity of glyphosate through a FIFRA 2(ee) recommendation label.

ОЦЕНКА ВИДОВОГО РАЗНООБРАЗИЯ ТЛЕЙ (HEMIPTERA, APHIDIDAE) В АГРОЦЕНОЗЕ ОПЫТНОГО ПОЛЯ ВИЗР ПУШКИНСКОГО РАЙОНА САНКТ-ПЕТЕРБУРГА В 2021–2023 гг.

The research was carried out in order to analyze changes in species diversity and the dynamics of aphid abundance within the same agrocenosis under different weather conditions. The species composition and abundance of aphids were monitored using the Malaise trap at the VIZR experimental field (Pushkinsky district of St. Petersburg) during the growing season 2021-2023. During this period, 34 species of phytophages were identified, of which 20 are pests of crops, including 9 species in 2021, 11 species in 2022 and 27 species in 2023. The smallest number of individuals in the trap was observed in 2021 (36 pcs.), in 2022 and 2023 it was about the same (97 and 101 pcs., respectively). The largest number of insect species and individuals in one trap was identified in 2023, which was the result of a favorable interaction of abiotic and biotic factors. In 2021, the traps were dominated by dendrophilous aphids, among which the largest was the European birch aphid.

Chitosan-based NPK nanostructure for reducing synthetic NPK fertilizers and improving rice productivity and nutritional indices

Researchers have repeatedly emphasized how urgently we have to decrease the massive nitrogen fertilizer consumption to support agricultural productivity and maintain a sustainable ecosystem. Using chitosan (CS) as a carrier for slow release is considered a potential tool for reducing synthetic fertilizer and improving crop productivity. Therefore, two field experiments were arranged in a randomized complete block design to investigate the effects of seven treatments including synthetic fertilizer and exogenous application of chitosan-based NPK nano-structure (Ch/NPs-NPK) on growth, productivity, and nutrient uptake traits of rice as a worldwide strategy crop during 2022 and 2023 growing seasons. The experimental treatments were: T1 = full recommended synthetic NPK (recommended urea, superphosphate, potassium sulfate; control treatment), T2 = 70% of T1 + Ch/NPs-NPK 100 ppm, T3 = 70% of T1+ Ch/NPs-NPK 200 ppm, T4 = 70% of T1+ Ch/NPs-NPK 300 ppm, T5 = 30% of T1+ Ch/NPs-NPK 100 ppm, T6 = 30% of T1+ Ch/NPs-NPK 200 ppm, and T7 = 30% of T1 + Ch/NPs-NPK 300 ppm. The results revealed that T4 (i.e., 70% of recommended NPK+ Ch/NPs-NPK 300 ppm) and T1 (full recommended synthetic NPK) resulted in the highest and most significant growth and yield traits of rice as well as nutrient grain contents compared to other treatments. Therefore, combining 70% of recommended NPK with Ch/NPs-NPK 300 ppm as an exogenous application can be a smart choice for reducing synthetic NPK fertilizers by 30% in paddy fields without producing a significant decline in terms of growth, yield characteristics, or nutrient grain contents when applying the full recommended synthetic NPK.

Nutrient and energy conservation through nano-fertilizers in maize

In the current scenario, achieving food security while conserving resources and energy is a significant challenge. Maize is a widely cultivated but nutrient-exhaustive crop. The adoption of nanotechnology-based nano-fertilizers offers a pathway to achieving sustainable yields while reducing fertilizer requirements and conserving energy. A field experiment was conducted during the Kharif season of 2021 to explore nutrient and energy conservation through nano-fertilizers in maize at the University of Agricultural Sciences, GKVK, Bengaluru. The experiment involved nine treatments comprising various combinations of the recommended dose of fertilizers (RDF) with nano-urea and nano Di-Ammonium Phosphate (DAP) under a Randomized Complete Block Design (RCBD). The results indicated that Treatment T5 - 75% of the Recommended Dose of Nitrogen (RDN) + Nano-N—achieved a higher yield (10.20% higher than the conventional practice, T1-RDF + Farmyard Manure (FYM)) and improved nutrient uptake at harvest [299.22, 55.56, and 208.26 kg of nitrogen (N), phosphorus (P), and potassium (K) per hectare, respectively]. This treatment also demonstrated greater physiological efficiency (36.11, 200.66, and 52.70 kg of maize per kg of N, P, and K, respectively), higher energy output (260,851 MJ ha?¹), improved energy use efficiency (16.93), enhanced energy productivity (0.627 kg MJ?¹), and better energy profitability (15.93). Using 75% of RDN + Nano-N increases yield while reducing fertilizer use and conserving energy.

Influence of Liquid Biofertilizers on Growth and Yield of Sesame (Sesamum indicum L.)

A field experiment was conducted at S.V. Agricultural College Farm, Tirupati during summer, 2024 to study the influence of liquid bio fertilizers and different levels of fertilizers on growth and yield of sesame. Results revealed that the application of 100% RDF + seed treatment + soil application of liquid bio fertilizers (Azospirillum, PSB and KSB) reported higher plant height( 99 cm), leaf area index(1.72), dry matter accumulation (3341 kg ha-1), seed (945 kg ha-1) and stalk (1890 kg ha-1) yield as compared to other treatments. The grain yield of sesame with100% RDF + seed treatment + soil application of liquid bio fertilizers (Azospirillum, PSB and KSB) was enhanced by 26.5% and 24.3% when compared to the 100% RDF alone. The lowest seed yield (380 kg ha-1) and stalk yield (830 kg ha-1) was registered with absolute control.

A finite mixture distribution to model genetic architecture of image‐based oat grain morphology

AbstractThe multi‐floral oat (Avena sativa L.) inflorescence influences grain size and shape distributions, affecting the physical attributes of grain quality such as plumpness, size, and uniformity. While the grain size and shape distribution has been characterized as multi‐modal, very little is known about the genetic determinants of those distributions and their properties. The goal of this study was to model grain size and shape distribution using a finite mixture distribution approach and propose new distributional traits (i.e., emerging distributional traits) to characterize genotypes. We evaluated 47 oat genotypes in four highly replicated field experiments. Grains of three panicles per plot were individually threshed and scanned. Grain area, length, width, and roundness were obtained from each grain‐based image, while emerging distributional traits were evaluated using a finite mixture distribution approach. Finally, grain size distributions from hand‐threshed panicles (representing the full biological distribution) were compared with the grain size distributions of grains harvested with a combine harvester representing commercial harvest where small grains may be blown out. The heritability of all grain traits was high (0.89–0.94), and trait distributions differed among genotypes. Grain area and length show bi‐ and trimodal distributions, while grain width and roundness are uni‐ and bimodal. Although the full biological distribution of grains differed from the combine‐harvested grains, their genetic correlations were high, suggesting the combine‐harvested distributions can be used as a proxy for full biological distributions. This study proposes a straightforward methodological approach to model grain attributes that can aid in quality evaluations for genetic studies, breeding decisions, and industry characterization.

Water Use Efficiency Characteristics and Their Contributions to Yield in Diverse Sugarcane Genotypes with Varying Drought Resistance Levels Under Different Field Irrigation Conditions

Drought is the major abiotic constraint affecting sugarcane productivity and quality worldwide. This obstacle may be alleviated through sugarcane genotypes demonstrating good water use efficiency (WUE) performance. This study aims to investigate the WUE characteristics of various sugarcane genotypes under different soil water availability levels. Plant and ratoon field experiments were conducted using a split-plot randomized complete block design with three replications. The main plots were assigned three types of irrigation: (1) rainfed conditions (RF), (2) field capacity conditions (FC), and (3) half-available water (½ AW). The subplots consisted of six sugarcane genotypes with varying levels of drought resistance, i.e., KK3, UT13, Kps01-12, KKU99-03, KKU99-02, and UT12. Data on yield, stalk numbers, stalk diameter, height, and WUE were collected throughout the crop cycle for both plant and ratoon crops. For the plant crop, the net photosynthesis rate, transpiration rate, stomatal conductance, and leaf area index (LAI) were recorded during the crop period. In both plant and ratoon crops, the WUE in the RF treatment was lower than in the FC and ½ AW treatments during the drought stress period 4 months after planting (MAP). In the recovery phase, the WUE in the ½ AW treatment fell between the FC and RF treatments. The RF treatment exhibited the lowest WUE compared to the other two water regime treatments at the maturity stage. The drought-resistant genotypes KK3 and UT13 maintained high WUE values throughout both the drought and recovery periods and exhibited outstanding LAIs at 4 and 6 MAP. A significant relationship existed between WUE and LAI during these periods. Moreover, WUE was positively correlated with cane yields and yield components, such as stalk weight, shoot diameter, and height, during recovery and tiller number and height during ripening. Therefore, WUE and LAI are efficient parameters for supporting and maintaining growth and yield during water deficit and recovery phases under rainfed conditions.

Characteristics of climate resource utilization and economic benefits in new planting pattern for fresh faba bean and fresh maize in Yangtze River Delta

ABSTRACT In this research, we aimed to construct a novel planting pattern for faba bean and maize with high-efficiency utilization of climate resources for application in production. We incorporated relay intercropping in two triple-crop planting patterns, namely faba bean/maize-maize and faba bean/maize-soybean. A field experiment was conducted to compare the annual yield, utilization efficiency of climatic resources and economic benefits among these two triple-crop planting patterns and the conventional faba bean – maize double-cropping system at Nantong, Jiangsu, China, from 2016 to 2020. Compared with the conventional double-cropping system, the faba bean/maize-maize triple-crop planting pattern resulted in significantly increased annual yield by 7,392 kg hm−2 to 10,519 kg hm−2, and increased annual biomass by 5,342 kg hm−2 to 7,172 kg hm−2.The triple-crop planting patterns increased the annual economic benefit by 12,195 RMB hm−2 and 15,680 RMB hm−2, respectively. The faba bean/maize-maize triple-crop planting pattern increased the annual radiation production efficiency by 0.18 g·MJ−1 to 0.31 g·MJ−1, the annual temperature production efficiency by 2.70 kg·hm−2·°C−1 to 3.78 kg·hm−2·°C−1, and the annual precipitation production efficiency by 4.55 kg·mm−1·hm−2 to 7.20 kg·mm−1·hm−2. Considering the yields, resource-use efficiency, and economic benefits, the triple-cropping planting patterns show promise as multi-crop systems to achieve high yields and high resource-use efficiency in the Yangtze River Delta region. These results demonstrate the use of a new relay intercropping planting pattern for use in crop production and represent a theoretical contribution to the development of efficient agricultural production.

Growth and fecundity of Palmer amaranth escaping glufosinate in cotton with and without grass competition

Abstract Field experiments were conducted at Clayton and Rocky Mount, North Carolina, during the summer of 2020 to determine the growth and fecundity of Palmer amaranth plants that survived glufosinate with and without grass competition in cotton. Glufosinate (590 g ai ha-1) was applied to Palmer amaranth early postemergence (5 cm tall), mid postemergence (7 to 10 cm tall), and late postemergence (>10 cm tall) and at orthogonal combinations of those timings. Non-treated Palmer amaranth was grown in weedy, weed-free in-crop (WFIC) and weed-free fallow (WFNC) conditions for comparisons. Palmer amaranth control decreased as larger plants were treated; no plants survived the sequential glufosinate applications in both experiments. The apical and circumferential growth of Palmer amaranth surviving glufosinate treatments was reduced by more than 44% compared to the WFIC and WFNC Palmer amaranth in both experiments. The biomass of Palmer amaranth plants surviving glufosinate was reduced by more than 62% when compared with the WFIC and WFNC in all experiments. The fecundity of Palmer amaranth surviving glufosinate treatments was reduced by more than 73% compared to WFNC Palmer amaranth in all experiments. Remarkably, the plants that survived glufosinate were fecund as WFIC plants only in the Grass Competition experiment. The results prove that despite decreased vegetative growth of Palmer amaranth surviving glufosinate treatment, plants remain fecund and can be fecund as non-treated plants in cotton. These results suggest that a glufosinate-treated grass weed may not have a significant interspecific competition effect on Palmer amaranth that survives glufosinate. Glufosinate should be applied to 5 to 7 cm Palmer amaranth to cease vegetative and reproductive capacities.

Design and Testing of an Offset Straw-Returning Machine for Green Manures in Orchards

In order to solve the problems of traditional orchard-specific green manure crushing and returning machines, such as the single operation effect, root system damage, unsustainable green manure growth, and low utilization rate, an offset crushing–furrowing–burying–straw-returning machine was designed for green manures in orchards. Based on quadratic regression combination experiments, the Discrete Element Method (EDEM) was used to construct a discrete element model simulating the deep furrowing and burying processes of the furrowing and soil-covering device, where the advance speed, plow-shaped furrowing blade rotation speed, and furrowing depth were considered as experimental factors and the coverage rate was taken as an evaluation index, and then simulation analyses were carried out to obtain experimental data; Design-Expert was used to perform ANOVA and RSM analyses, thus finding that its optimal working parameter portfolio consists of the advance speed of 42 m/min, the furrowing blade rotation speed of 300 r/min, and the furrowing depth of 190 mm, and that the coverage rate is 95.82% when this parameter portfolio is applied. Field experiments were conducted to validate the optimal parameter portfolio. The experimental results show that with an average coverage rate of 90.87% (4.95% away from the optimal value based on the simulation experiments on average), an average crushing length qualification rate of 91.24%, and an average root system damage rate of 5.6%, this device is applicable for its operation conditions. The development of this machine and the construction of its parameter model can provide a certain reference value for developing and optimizing related machines including green manure-returning machines.

Oxyfluorfen use in Combination with Clomazone or Quinclorac

Abstract Oxyfluorfen, a Herbicide Resistance Action Committee (HRAC)/Weed Science Society of America (WSSA) Group 14 herbicide that inhibits protoporphyrinogen IX oxidase, has shown significant potential in controlling barnyardgrass. Despite its current lack of labeling for use in midsouthern U.S. rice due to the potential for crop injury, the introduction of a trait in rice that confers resistance to oxyfluorfen could provide producers with an effective alternative site of action for weed control. Field experiments were conducted during the 2021 and 2022 growing seasons near Stuttgart, AR, and near Lonoke, AR, to determine the optimum rates of clomazone (280 or 336 g ha-1) and oxyfluorfen (673 or 840 g ha-1) to use in sequential preemergence (PRE) and postemergence (POST) applications on a silt loam soil and to assess the efficacy of oxyfluorfen when combined with clomazone and quinclorac PRE, followed by oxyfluorfen POST. No differences in barnyardgrass control were observed among treatments 14 days after emergence (DAE) in three site years, as all control was ≥90%. By 35 days after the postemergence application (DAPOST), all barnyardgrass control was ≥94% for herbicide treatments in all site years. All herbicide treatments resulted in lower barnyardgrass seed production than the nontreated in 2021. Contrasts revealed that oxyfluorfen applied PRE on a silt loam soil resulting in barnyardgrass control similar to clomazone or quinclorac alone at 14 DAE. Although oxyfluorfen combined with clomazone or quinclorac did not increase barnyardgrass control, an additional site of action for control of this weed could help reduce the evolution of resistance. Mixing oxyfluorfen with clomazone in a dry-seeded rice production system in the midsouthern U.S. would effectively control barnyardgrass and reduce the risk for resistance to both herbicides, further highlighting the potential of oxyfluorfen in rice production.

No-Tillage Treatment with Total Green Manure Mulching Reduces Soil Respiration by Regulating Soil Water Content Affecting Heterotrophic Respiration

Green manure is widely applied in agricultural production due to its beneficial soil modification and fertilization effects. However, the mechanisms underlying the effects of green manure return methods on soil respiration (Rs) and its components remain unclear. This study aimed to investigate the effects of green manure return methods on Rs in maize fields by quantifying Rs levels. A field experiment was conducted from 2021 to 2023 in the inland river oasis irrigation area of Gansu, with five treatment conditions: tillage with a full quantity of green manure incorporated into the soil (TG), no tillage with a full quantity of green manure mulched on the soil surface (NTG), tillage with roots incorporated into the soil and above-ground green manure removed (T), no tillage with above-ground manure removed (NT), and conventional tillage and leisure (CT). The results showed that, compared with CT, the NTG treatment increased the maize grain yield while reducing the soil heterotrophic respiration rate (Rh) by 8.5–9.8% and Rs by 6.7–8.7%, but did not significantly affect the soil autotrophic respiration rate (Ra), and decreased the carbon emission efficiency (CEE) by 20.8–25.6%. The increase in the soil water content (SWC) significantly reduced Rh during all growth periods, which was the primary factor in the reduction of Rs. Additionally, the net ecosystem productivity carbon sequestration (NEP-C) of the farmland ecosystem was positive under this system, indicating that the soil acts as a carbon “sink”. Therefore, a no-tillage treatment with a full quantity of green manure mulched on the soil surface can be used as a reasonable green manure return method to reduce carbon emissions from farmland in arid oasis irrigation regions.

Synergistic effect of pyridate-based herbicide mixtures for controlling multiple herbicide-resistant kochia

Abstract Multiple herbicide classes resistant (MHCR) kochia poses a serious concern for producers in the Central Great Plains, including western Kansas. Greenhouse and field experiments were conducted at Kansas State University Research and Extension Centers near Hays and Garden City, KS to evaluate pyridate-based postemergence (POST) herbicide mixtures for controlling MHCR kochia. One previously confirmed MHCR population (resistant to atrazine, glyphosate, dicamba, and fluroxypyr) and a susceptible (SUS) kochia population were tested in a greenhouse study. The kochia population at Hays field site was resistant to atrazine, dicamba, and glyphosate while kochia population at Garden City site was resistant to atrazine and glyphosate. Colby’s analysis revealed synergistic interactions when pyridate was mixed with atrazine, dicamba, dichlorprop-p, fluroxypyr, glyphosate, or halauxifen/fluroxypyr and resulted in ≥94% control and shoot dry biomass reduction of MHCR kochia in a greenhouse study. Similarly, synergistic interactions were observed for MHCR kochia control in fallow field studies at both sites when pyridate was mixed with glyphosate or atrazine. Kochia control was increased from 26% to 90% with the application of glyphosate + pyridate and from 28% to 95% with atrazine + pyridate at both sites as compared to separate applications of glyphosate or atrazine. This is the first report for such a strong synergistic effect for both glyphosate and atrazine mixtures with pyridate on a weed resistant to both. All other pyridate-based herbicide mixtures showed an additive interaction and resulted in better control of MHCR kochia (87 to 100%) as compared to their individual applications (23 to 92%) across both sites except 2,4-D. These results suggest that pyridate can play a crucial role in various POST herbicide mixtures for effective control of MHCR kochia.

Evaluation of IPM Module for the Management of Key Insect Pests in Chilli

Chilli is a crop cultivated in tropical and subtropical regions of India, and the crop is attacked by a multitude of pests at different crop stages. The present study revealed that field experiments were laid out with three treatments, viz., IPM module, farmer practice, and untreated control, at Kuttiyagoundanur village of Kolathur block of Salem District, Tamil Nadu. The results of the IPM capsule for the management practices of major pests and diseases, including viral diseases in chillies. The pre-treatment count on thrips/leaf was non-significant in all treatments, and it ranged from 7.20 to 8.40 thrips/leaf. Among the three treatments, farmers practice of chemical control recorded less infestation of 2.93 thrips/leaf, followed by the IPM module recording 3.60 thrips/leaf. Before adoption of treatment, the mite/leaf count was between 17.09 and 19.23 mite/leaf. The IPM module recorded less infestation of 5.32 mites/leaf, followed by farmers practice recording 12.90 mites/leaf. The pre-treatment count of Helicoverpa armigera larvae was between 3.20 and 3.72 larvae/plant. Among the treatments, chemical control recorded less infestation of fruit borer and fruit damage (0.17 larvae/plant) and 1.40 percent, followed by the IPM module, which is 1.17 larvae/plant and 4.91 percent. The leaf curl infection was low in farmers practices. 10.82 percent, followed by the IPM module recorded 15.26 percent. Maximum fruit yield of 11200 kg/ha with a comfortable B:C ratio of 2.96 was obtained in the IPM module, followed by farmer practice with a B:C ratio of 2.91.