Crop Response Research Articles

Contributions of Nano-Nitrogen Fertilizers to Sustainable Development Goals: A Comprehensive Review

Nano-nitrogen fertilizers (NNFs) have emerged as a promising technology in the field of agriculture, offering potential solutions to improve nutrient uptake efficiency, enhance crop productivity, and reduce environmental impacts. NNFs showed superior characteristics and performance on crops and, therefore, became a potential alternative to conventional nitrogen (N) fertilizers. These fertilizers enhance plant uptake while simultaneously reducing environmental losses. For example, a hydroxy appetite-based urea NNF extended the N release for 112 days, which could cover the N demand of many perennial crops, thus reducing losses. The reported NNFs in this review increased the yield by 10–80% compared to conventional fertilizers. Additionally, their small particle size increases crop acclimation and decreases the application rate. With all these beneficial traits of NNFs, they potentially contribute to achieving Sustainable Development Goals (SDGs). This review article summarizes the materials used in NNF formulation, methods of preparing NNFs, and their crop responses. Also, it highlights the limitations identified in the research studies and provides research recommendations for the future. Further, it provides a critical assessment of the current state of NNFs and their prospects for revolutionizing modern agriculture to attain SDGs.

Opening up the subsoil: Subsoiling and bio-subsoilers to remediate subsoil compaction in three fodder crop rotations on a sandy loam soil

The intensification of modern arable farming has brought on a steady increase of the risk of soil compaction, while simultaneously pushing the impact deeper into the soil profile. In the subsoil, outside the reach of regular tillage operation, it can become exceedingly difficult to deal with compacted layers. Commonly, farmers turn towards mechanical remediation strategies, like subsoiling, to deal with this issue. However, the numerous drawbacks that come with these operations have prompted the search for more sustainable alternatives, like bio-subsoilers, which are deep-rooting plant species with the capacity to penetrate compacted subsoil layers. This study aimed at investigating both mechanical and biological remediation strategies in a side-by-side comparison. The effectiveness of subsoiling and the use of two deep rooting (cover) crops (i.e. alfalfa and fodder radish) as remediation measures to alleviate subsoil compaction was assessed in terms of soil quality indicators, like penetration resistance, bulk density, porosity, plant available water capacity, air capacity and air permeability at 35 and 45 cm depth, and the above- and belowground growth of the main crop. In addition, a combination of both subsoiling and use of deep rooting (cover) crops was included to evaluate the potential role of the latter in protecting the mechanically loosened subsoil from recompaction. This complex comparison was done in three distinct maize-based fodder crop rotations (rotation 1: maize monoculture; rotation 2: maize/winter cereal rotation with fodder radish as cover crop after winter cereal; rotation 3: maize/winter cereal/alfalfa rotation). The study field (sandy loam soil) was selected based on the presence of a highly compacted layer at the interface between topsoil and subsoil (30–50 cm). The experiment demonstrated that subsoiling is an effective remediation measure to disrupt heavily compacted layers in the upper-subsoil, at least in the short-term. The crop response was however highly variable and only positive when the opportunity of reaching the subsoil proved to be advantageous for the crop (i.e. dry season). Besides its high degree of variability between years, the effects also proved to be very short-lived under a standard arable fodder crop rotation. Including deep rooting (cover) crops, like fodder radish and alfalfa, and limiting the initial subsoil disruption helped to partially stabilize the disrupted subsoil and reduce recompaction. Fodder radish and alfalfa penetrated the compacted subsoil without previous disruption by subsoiling. However, this did not lead to a significant improvement of the measured soil physical parameters.

Importance of biodiversity in rhizosphere microbes for crop response and methodsto assess the biodiversity

Microbes play a vital role in influencing the quality and health of soil and plants. Several studies had led to understanding of diversity and structure in the plant rhizosphere: linking with Soil Microbial diversity to Modern Agriculture, amrita gupta et.al (2022); Influence of long-term fertilization on soil microbial biomass, dehydrogenase activity, and bacterial and fungal community structure in a brown soil of northeast, China Peiyu Luo et.al (2013). The microbial population has many applications and advantages which are determined only through Long term fertilizer studies. Some of the methods used for assessing the biodiversity of these rhizosphere microbes are: 16s rRNA sequencing, DDGE, TDGE, SEM, etc. Some advantages of rhizosphere microbes are improved crop yield, fighting climate change with minimal soil and environmental degradation, the protection of human health for current and future generations, macro and micro-nutrient cycling for optimum agricultural growth, higher crop yield, and also prevents land degradation. In this article we will study about importance of biodiversity of rhizosphere microbes and various methods to identify the microbial population.

Integration of mRNA and miRNA analysis reveals the molecular mechanisms of sugar beet (Beta vulgaris L.) response to salt stress

The continuous increase of saline-alkali areas worldwide has led to the emergence of saline-alkali conditions, which are the primary abiotic stress or hindering the growth of plants. Beet is among the main sources of sugar, and its yield and sugar content are notably affected by saline-alkali stress. Despite sugar beet being known as a salt-tolerant crop, there are few studies on the mechanisms underlying its salt tolerance, and previous studies have mainly delineated the crop’s response to stress induced by NaCl. Recently, advancements in miRNA-mRNA network analysis have led to an increased understanding of how plants, including sugar beet, respond to stress. In this study, seedlings of beet variety "N98122" were grown in the laboratory using hydroponics culture and were exposed to salt stress at 40 days of growth. According to the phenotypic adaptation of the seedlings' leaves from a state of turgidity to wilting and then back to turgidity before and after exposure, 18 different time points were selected to collect samples for analysis. Subsequently, based on the data of real-time quantitative PCR (qRT-PCR) of salt-responsive genes, the samples collected at the 0, 2.5, 7.5, and 16 h time points were subjected to further analysis with experimental materials. Next, mRNA-seq data led to the identification of 8455 differentially expressed mRNAs (DEMs) under exposure to salt stress. In addition, miRNA-seq based investigation retrieved 3558 miRNAs under exposure to salt stress, encompassing 887 known miRNAs belonging to 783 families and 2,671 novel miRNAs. With the integrated analysis of miRNA-mRNA network, 57 miRNA-target gene pairs were obtained, consisting of 55 DEMIs and 57 DEMs. Afterwards, we determined the pivotal involvement of aldh2b7, thic, and δ-oat genes in the response of sugar beet to the effect of salt stress. Subsequently, we identified the miRNAs novel-m035-5p and novel-m0365-5p regulating the aldh gene and miRNA novel-m0979-3p regulating the thic gene. The findings of miRNA and mRNA expression were validated by qRT-PCR.

Monitoring agricultural drought in Peshawar Valley, Pakistan using long -term satellite and meteorological data.

Monitoring agricultural drought across a large area is challenging, especially in regions with limited data availability, like the Peshawar Valley, which holds great agricultural significance in Pakistan. Although remote sensing provides biophysical variables such as precipitation (P), land surface temperature (LST), normalized difference vegetation index (NDVI), and relative soil moisture (RSM) to assess drought conditions at various spatiotemporal scales, these variables have limited capacity to capture the complex nature of agricultural drought and associated crop responses. Here, we developed a composite drought index named "Temperature Vegetation ET Dryness Index" (TVEDI) by modifying the Temperature Vegetation Precipitation Dryness Index (TVPDI) and integrating NDVI, LST, and remotely sensed evapotranspiration (ET) using 3D space and Euclidean distance. Several statistical techniques were employed to examine TVPDI and TVEDI trends and relationships with other commonly used drought indices such as the standardized precipitation index (SPI), standardized precipitation evapotranspiration index (SPEI), and standardized soil moisture index (SSI), as well as crop yield, to better understand how these indices captured the spatial and temporal distribution of agricultural drought in the Peshawar valley between 1986 and 2018. Results indicated that while the temporal patterns of the 3-month SPI, SPEI, and SSI generally align with those of TVEDI and TVPDI, TVEDI was more strongly correlated with these indices (e.g., correlation coefficient, r = 0.78-0.84 from TVEDI and r = 0.73-0.79 from TVPDI). Moreover, the crop yield, a measure of crop response to agricultural drought, demonstrated a significant positive correlation with TVEDI (r = 0.60-0.80), much higher than its correlation with TVPDI (r = 0.30-0.48). These outcomes indicate that the inclusion of ET in TVEDI effectively captured changes in soil moisture, crop water status, and their impact on crop yield. Overall, TVEDI exhibited enhanced capability to identify drought impacts compared to TVPDI, showing its potential for characterizing agricultural drought in regions with limited data availability.

Combining Vermicompost with Inorganic Fertilizers Improved Rice Yield and Affected Potassium Pools under Rice-Based Cropping Systems in Inceptisols

Integrated use of inorganic fertilizer and organic manure restores soil quality and increases crop productivity. Potassium (K) pools are also affected in soil due to the rate and sources of nutrients applied. However, the integration of vermicompost and mineral fertilizers effects strongly depends on soil type, and still, no precise information is available for Inceptisols in Eastern India. Keeping this fact in view, a field experiment was conducted at the research farm of Bihar Agriculture University, Sabour, Bihar to understand the effect of soil test crop response (STCR) based balanced fertilization with or without organic manure on soil K pools and rice performance under rice-wheat and rice-maize cropping systems. This experiment included nine treatments viz., general fertilizer recommendation, farmers’ fertilizer practice, STCR with and without Integrated Plant Nutrient System (IPNS)/vermicompost for low (3 t ha−1), medium (4 t ha−1), and high target yield (5 t ha−1) and absolute control (without fertilizer application) which were replicated thrice in a randomized block design (RBD). The highest rice yield was obtained under STCR with IPNS for high target yield (2% more) than the corresponding treatment without IPNS followed by STCR with IPNS for medium target yield however treatments were statistically at par with one another. Benefit cost ratio was significantly highest under STCR with IPNS for medium target yield overall the treatments for both cropping systems. Different forms of K (water-soluble K, exchangeable K, non-exchangeable K, and mineral K) declined under farmers’ practice and absolute control whereas these forms were greater under STCR with IPNS-based treatments than the STCR without IPNS-based treatments in the corresponding target yields. The correlation study suggested that exchangeable K was the most important form, positively and highly significantly related to soil available K (R 2 = 98). Overall, this study recommended that the integrated use of vermicompost and mineral fertilizers (STCR with IPNS) for medium target yield (4 t ha−1) was more responsive toward rice yield as well as K availability for soil sustainability from Inceptisols in eastern India.

First report of severe tolpyralate sensitivity in corn (Zea mays) discovers a novel genetic factor conferring crop response to a herbicide.

Tolpyralate, a relatively new inhibitor of 4-hydroxyphenylpyruvate dioxygenase (HPPD), is registered for postemergence use in all types of corn (Zea mays L.) and has a record of excellent crop tolerance. A report of severe crop injury to sweet corn inbred (XSEN187) led to the following objectives: (i) determine whether sensitivity to tolpyralate in XSEN187 exists, and if confirmed, (ii) determine the genetic basis of tolpyralate sensitivity, and (iii) screen other corn germplasm for sensitivity to tolpyralate. Inbred XSEN187 was confirmed sensitive to tolpyralate. Inclusion of methylated seed oil or nonionic surfactant in the spray volume was necessary for severe crop injury. Tolpyralate sensitivity in XSEN187 is not conferred by alleles at Nsf1, a cytochrome P450-encoding gene (CYP81A9) conferring tolerance to many corn herbicides. Evidence suggests that tolpyralate sensitivity in XSEN187 is conferred by a single gene mapped to the Chr05: 283 240-1 222 909 bp interval. Moreover, tolpyralate sensitivity was observed in 48 other sweet corn and field corn inbreds. Severe sensitivity to tolpyralate exists in sweet corn and field corn germplasm when the herbicide is applied according to label directions. Whereas the corn response to several other herbicides, including HPPD-inhibitors, is conferred by the Nsf1 locus, corn sensitivity to tolpyralate is the result of a different locus. The use of tolpyralate should consider herbicide tolerance in inbred lines from which corn hybrids were derived, whereas alleles that render corn germplasm sensitive to tolpyralate should be eliminated from breeding populations, inbreds, and commercial cultivars. © 2023 Illinois Foundation Seeds, Inc and The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Enhancing Yield, Uptake and Nutrient Use Efficiency of Brinjal Through Soil Test Crop Response Approach

ABSTRACT Fertilizer requirement for the crop should be based on yield response to the added fertilizer nutrient, nutrient requirements of a crop, nutrient supply from indigenous sources and the fate of added fertilizers to the soil in the short and long term. Thus, the soil test crop response (STCR) approach can be adopted for calculating fertilizer requirements by crops. The field experiments were conducted at the Eastern Dry Zone of Karnataka, University of Agricultural Sciences, Bangalore, in three phases. Soil test data, yield and NPK uptake by brinjal crop were used for achieving four important basic parameters, viz. nutrient requirement, contribution of nutrients from fertilizers, soil and organic manure, to develop the targeted yield equation and these equations were validated in comparison with Low-Medium-High (LMH) approach and generally recommended dose (GRD). It was found that 1.11, 0.46, and 0.30 kg of N, P2O5, and K2O respectively were required for producing one quintal of brinjal fruit under integrated approach. The contribution of NPK from soil toward crop uptake was 26.07%, 5.94% and 36.89% respectively; from organic manure was 16.15%, 8.66% and 31.55% respectively and from fertilizers was 42.27, 11.73 and 170.84% respectively. The STCR integrated approach with FYM, at the target yields 35 and 30 t ha−1, enhanced the fruit yield to an extent of 12.90% and 9.94%, respectively, over GRD. It also exhibited higher NPK uptake and use efficiency and better profitability. Hence integrated STCR targeted yield approach could be sustainable nutrient management option(s) for improving the productivity of brinjal.

INOCULAÇÃO E APLICAÇÃO DE DIFERENTES DOSES DE Azospirillum brasilense E SUA INFLUÊNCIA NO DESENVOLVIMENTO DA CULTURA DO MILHO

Benefits in grain productivity, with low economic cost, ease of application, without causing toxic damage to the environment and with high potential for crop response, are target points in research involving the cultivation of corn. In this context, the present study aimed to evaluate the effect of inoculation of Azospirillum brasilense on the vegetative structures of the corn crop, envisioning an increase in the development of the plant. The experimental design used was completely randomized, with six treatments and four replications, totaling 24 experiments. Seeds were inoculated with A. brasilense in different doses of the commercial product (0 - 1000 mL), where the plant height (AP), ear insertion height (AIE), stem diameter (DC), total number of leaves (NTF) and number of leaves below the first ear (NFAE), were evaluated. The inoculation of corn seeds based on A. brasilense strain Ab-V5 promoted influence on some biometric variables, with an increase in the total number of leaves (NTF), plant height (AP) and height of ear insertion (AIE) for the evaluated hybrid, resulting in increments in its vegetative development. The dosage of 549 mL per hectare was considered as favorable to result in greater amounts of total leaves (NTF) in the plant, according to the adjustment of the proposed model. The results emphasized that inoculation with this strain is a valid technique and is increasingly used by farmers, and its study is a contributing factor for improvements in agronomic parameters.

Multiple cutting increases forage productivity and enhances legume pasture stability in a rainfed agroecosystem

Appropriate harvesting management is essential for sustainable forage production and improving nutritional quality. In this study, four forage crops, including Medicago sativa (Ms), Vicia sativa (Vs), Avena sativa (As), and Sorghum Sudangrass (Ss) were evaluated under two harvesting modes, i.e. single harvest and multiple cuttings. Results showed that multiple cuttings increased the forage yield of Ms., As, and Ss by 82 %–114 %, 7.5 %–51 %, and 21 %–150 % compared to the single harvest. The acid and neutral detergent fiber concentration decreased, while crude protein contents increased with multiple cuttings. Also, multiple cuttings increased the ether extract content of Ms. and Ss and reduced the ash content by 9.42 % to 33.04 % from 2015 to 2016. The variation range of legume forages' annual yield was 18.66 %–33.04 %, while that of gramineous forages was 9.42 %–25.98 %. The relative feeding value (RFV) of Ms. was higher than that of other forages under multiple cuttings. In general, multiple cuttings decreased the SOC content, but the effect was insignificant for the two leguminous forages. Correlations analysis showed a significant positive relationship of RFV and CP with precipitation while a negative relationship of ADF and NDF with temperature. Moreover, results of yield stability, contribution rate, and TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) analysis showed that the response of legume crops to multiple cutting was superior to that of gramineous crops. Overall, the cultivation of leguminous forage under multiple cuttings can provide a basis for the development of pastoral agriculture production and animal husbandry in arid regions of China.

Palmer Amaranth (Amaranthus palmeri) Control in Dicamba-Tolerant Cotton (Gossypium hirsutum) when Applied with Various Dicamba + Insecticide Tank-Mixtures

Postemergence herbicide application timings for Palmer amaranth (Amaranthus palmeri) often coincide with foliar insecticide applications in cotton (Gossypium hirsutum). Combining multiple pesticides into a single application increases efficiency while reducing overall application cost. Multiple foliar insecticides are now labeled for dicamba tank-mixes. However, there is limited literature with respect to efficacy of dicamba on Palmer amaranth control when applied with insecticides. Field experiments were conducted from 2018 to 2020 to evaluate the effect of carrier volume and insecticide on the efficacy of dicamba (XtendiMaxTM with VaporGripTM) to control Palmer amaranth in XtendFlex™ cotton production systems. Dicamba was tank-mixed with acephate and dimethoate to four-leaf cotton and with thiamethoxam and sulfoxaflor just prior to bloom. Applications were made at carrier volumes of 140 and 280 L ha-1 and with a single spray droplet size of 800 µm. Palmer amaranth control 7 d after treatment was negatively impacted when applications included dimethoate; however, no corresponding response in seedcotton yield was observed relative to dicamba applied alone. However, when pooled over carrier volume, applications containing dicamba + acephate resulted in higher seedcotton yield than applications of dicamba + dimethoate. Additionally, pre-bloom applications of dicamba + thiamethoxam or sulfoxaflor increased Palmer amaranth efficacy relative to dicamba applied alone. Although certain insecticides are known to increase herbicidal crop response, the impact of insecticides on herbicide efficacy to control specific weed species is largely unknown. Therefore, we conclude that multiple dicamba + acephate, thiamethoxam, or sulfoxaflor tank-mixtures provide similar control of Palmer amaranth compared to dicamba alone.

Interactive Effect of Deficit Irrigation and Water Quality on Yield and Water Use Efficiency of Red Cabbage (Brassica oleracea var. capitate L.) under Drip Irrigation

Deficit irrigation is emerging as a promising management practice to reduce water use with marginal loss in crop yield. Further, limited studies are available on the combined effect of water deficit and water quality on the water use efficiency of leafy vegetables like red cabbage in the semi-arid climate of Kirkuk. Therefore, this study was initiated to unveil the combined effect of varying deficit irrigation levels (0.5, 0.75, 1, and 1.2 of full irrigation) and two types of water quality (fresh and saline water) on water use efficiency of red cabbage under drip irrigation with two types of emitters. The results indicated that there is a steady increase in fruit yield with an increase in the level of irrigation with saline water over the entire range of applied water. The highest water efficiency was achieved under the combined effect of fresh water and GR and Turbo emitter when the level of applied water at full irrigation was reduced by a factor of 0.5 (20.31 kg/m3)(21.96kg/m3) respectively Furthermore, crop response factor analysis revealed that the red cabbage can tolerate deficit irrigation and produce satisfactory under both fresh and saline water were GR emitter with fresh and saline water given best value (0.627) (0.703) compeer with Turbo emitter with fresh and saline water given (0.292)(0.566)respectively. Additionally, further research is proposed to study the water productivity of red cabbage with saline water and take into account the yield of the same piece of land when the experiment is repeated for several years.

Climatological approaches of irrigation scheduling for growing tomato crop under drip irrigation in sub-tropical region of Punjab

A field experiment was conducted at Lovely Professional University, Phagwara, Punjab for two years (2022 and 2023) to study the response of tomato crop to drip irrigation scheduling based on climatological approach viz. Penman-Monteith, Blaney-Criddle and pan evaporation. Result revealed that, the all treatments of irrigation scheduling were found feasible for optimizing tomato yield (30.8 to 44.6 t ha-1), water saving (27 to 50.7%) and water use efficiency (1.31 to 1.61 t ha-1-cm) under drip irrigation over soil moisture depletion approach. In selected region the average daily ET0 (4.4 to 9 mm day-1) and ETC (2.5 to 10.8 mm day-1) varies with different growth stages and results varying crop water demand of tomato. This water demand can successfully meet out by applying water at 100 % ET0 based on Penman-Monteith method with significant crop yield (44.6 t ha-1) and water use efficiency (1.33 t ha-1-cm). Correlation analysis indicated that, in case of other regions where the availability of weather parameters will be limited for irrigation scheduling, the farmer could irrigate their tomato crop at 90% ET0 based on daily pan evaporation method under drip irrigation. In selected region, the Blaney-Criddle method was found ineffective and shows under and overestimated values of daily ETo during mid stage and late stage which gives more water saving (up to 51%) but reduces significant tomato yield over Pan Evaporation method.

Reduced irrigation impact on soil-applied herbicide dissipation and rotational crop response

Abstract Soil-applied herbicides are important for controlling weeds in many crops but risk damage to susceptible rotational crops if they persist. Field studies were conducted in Powell, WY, from 2015 through 2017 to evaluate the effect of reduced water availability on soil-applied herbicide dissipation. Eight soil-applied herbicides, applied to dry bean or corn, were exposed to three season-long irrigation treatments (100%, 85%, and 70% of estimated crop evapotranspiration [ETc]) by overhead sprinkler. Soil samples were collected to a depth of 10 cm from 0 to 140 d after application, and soil herbicide concentrations were quantified using gas or liquid chromatography and mass spectrometry. Herbicide concentrations were regressed over time to produce a soil half-life estimate for each herbicide and irrigation treatment. Reduced irrigation decreased dry bean yield by up to 77% and corn yield by up to 50%. After adjusting for precipitation, the lowest irrigation treatment received 78% and 76% as much water as the full irrigation treatment in 2015 and 2016, respectively. This significantly increased the soil half-life of imazethapyr but did not increase the soil half-life of atrazine, pyroxasulfone, saflufenacil, ethalfluralin, trifluralin, or pendimethalin. Reduced irrigation did not increase carryover injury to rotational crops from these herbicides 1 yr after application. Instead, carryover response was determined by the inherent persistence of individual herbicides. Imazethapyr (0.1 kg ai ha−1) injured rotational sugar beet, and isoxaflutole (0.1 kg ai ha−1) injured rotational dry bean. Pyroxasulfone (0.2 kg ai ha−1), atrazine (2.0 kg ai ha−1), saflufenacil (0.1 kg ai ha−1) + dimethenamid-P (0.6 kg ai ha−1), ethalfluralin (0.8 kg ai ha−1), trifluralin (0.6 kg ai ha−1), and pendimethalin (1.1 kg ai ha−1) did not injure rotational crops regardless of irrigation treatment. Drought stress sufficient to cause up to 77% crop yield loss did not increase soil-applied herbicide carryover.

Crop response to fertiliser nitrogen on a sodic soil in the Central Region

Crop response to fertiliser nitrogen on a sodic soil in the Central Region

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.

The Implementation of Response Surface Methodology and Artificial Neural Networks to Find the Best Germination Conditions for Lycopersicon esculetum Based on Its Phenological Development in a Greenhouse

The incorporation of biodegraded substrates during the germination of horticultural crops has shown favorable responses in different crops; however, most of these studies evaluate their effect only in the first days of seedling life, and do not follow up on the production process under greenhouse or open field conditions. The objective of this study was to evaluate the phenological development of Lycopersicon esculetum (tomato) seedlings in greenhouses that were germinated with biodegraded substrate mixed with peat moss. To find the best plant performance condition and determine whether the biodegraded substrate allows tomato plants to be obtained with the conditions for their production, the response surface methodology (RSM) and artificial neural network (ANN) were used. Three response surface models and three neural network models were developed to analyze the plant growth, the leaf length and the leaf width. The results obtained show that plant height during the first days presented statistically significant differences among the different treatments, with an initial average height of 5.3 cm. The length of the leaves at transplantation was statistically different, maintaining a length of 2.4, and the width of the leaves at transplantation measured 1.8 cm. The RSM and ANN models allowed the estimation of the optimal value of the adequate amount of degraded substrate to germinate Lycopersicon esculetum and reduce the use of peat moss. The coefficient of determination (r2) indicates that the ANNs presented a better data fit (r2 > 0.99) to predict the experimental conditions that maximize the study variables; in this sense, the plants obtained with 100% biodegraded substrate showed a better development, which suggests its use as an alternative substrate in the germination process and to reduce the use of peat moss.

Effect of mixed manure on selected chemical properties, and phosphorus adsorption characteristics of Vertisols in Haramaya district, eastern Ethiopia

AbstractThe phosphorus (P) fixing behaviors of Vertisols have been identified as one of the key drivers of crop response to fertilizer application. More than 75% of applied P in tropical soil was found to be inaccessible to crops due to adsorption and precipitation reactions. A pot experiment was carried out to investigate the effect of mixed manure (MM) on P adsorption characteristics and other selected Vertisol properties. The soil was amended with 0, 5, 10, and 15 t ha−1 of MM. Changes in selected soil parameters and P adsorption characteristics were evaluated after a 30‐day incubation period. An analysis of variance was used to analyze the data. The results demonstrated a substantial drop in soil pH and an increase in soil organic carbon, total nitrogen, available P, and cation exchange capacity compared to the control. The overall quantity and efficiency of adsorbed P were drastically reduced as a result of MM rates. Moreover, the interaction effect of MM and added P concentration demonstrated a considerable increase in both the quantity and efficiency of adsorbed P. Both parameters increased with increased rates of added P concentration but decreased with increasing rates of MM. Despite the fact that all treatments fit well to both the Freundlich and Langmuir isotherms, the former was used due to its greater R2 value. When compared with the control, the Freundlich adsorption coefficient and intensity were found substantially lower. As a result, MM treatment boosted P availability by decreasing adsorption and associated Vertisols characteristics.

Plot size misperceptions and soil health: A New research agenda

Farmer misperceptions of plot size can potentially lead to greater than intended levels of fertilizer use, which can increase the threat of soil fertility decline and non responsiveness of crops to inorganic fertilizer application. In addition, due to diminishing marginal returns of fertilizer use on grain yields, overestimation of plot size can potentially decrease fertilizer profitability. In this study, we use data collected from randomly selected farmers in rural western Kenya that include both the estimated sizes of the agricultural plots as reported by the farmers and their GPS-measured sizes. We find that 65 percent of plots are overestimated by at least 20 percent. We also find that inorganic nitrogen use is strongly increasing in plot size misestimation: a 10% increase in plot misestimation was associated with a 2.6 percent increase in commercial nitrogen application. Next, we build a random forest model to examine the agronomic efficiency of the farmer intended fertilizer use rates vs. actual rates. We find that misestimation of plot sizes is associated with an average decrease in return on investment of 5% (12%) at application rates of 60 kg N/ha (120 kg N/ha). Building on this exercise, we review the literature linking soil health and plot size misperceptions and conclude by proposing a new research agenda to examine how plot size misperceptions affect soil health and farmer well-being, more broadly.

Water supply to lettuce by capillary rise of the water table

Brazil has significant potential for floodplain areas which are suitable for cultivation after the rainy season, with water supply from the water table. Short-cycle crops with shallow root systems are more suitable for these conditions. On this subject, the objective of this study was to determine the responses of the lettuce crop to rising damp rates and water table depth levels. The variables of production, gas exchange, and SEW30 values (sum of excess water above 0.30 m depth) were analyzed. A physical model of seven drainage lysimeters was used; in six, the only water supply occurred by capillary rise from the water table (0.10; 0.15; 0.20; 0.25; 0.30 and 0.35 m depth) and, in the remaining lysimeter, irrigation was performed with no water table. The water table level maintained at 0.20 m from the soil surface was able to supply the water demanded by a sandy soil. The factor-product ratio indicates this depth as the most viable option in terms of crop response. Among the analyzed cultivars and under conditions of excess water in the soil, preference should be given to the establishment of the Gloriosa cultivar, for higher yields.