UF/IFAS Standardized Fertilization Recommendations for Agronomic Crops

This publication presents in abbreviated form the fertilization recommendations for agronomic crops based on soil tests performed by the UF/IFAS Extension Soil Testing Laboratory (ESTL). It contains the basic information from which ESTL soil-test reports and fertilization recommendations are generated.

Response of growth and yield of two soybean varieties to seed pre-treatment applications

Plant growth is influenced by seed quality. Seeds need to be treated to prevent pest and disease disorders or to increase seed germination. Soybean planting was carried out in this study by the treatment of varieties and seed pre-treatment application before planting. The study aimed to measure the growth and yield of soybeans by varieties and seed treatment before planting, carried out in the Village of Nggembe, District of Bolo, Bima Regency. The study used factorial randomized block design with two factors. The first factor was soybean varieties consisting of two levels, namely Devon and Dena varieties, and the second factor was the application of pre-planting seed treatments consisting of four levels namely Cruiser, Marshall, Agrisoy, and without seed treatment, each treatment was repeated three times. Observations were made on the performance of agronomic crops and soybean yields. The results showed that the treatment of soybean varieties and the application of seed treatment had a significant influence on plant height and soybean productivity, and both treatments had interactions on parameters of plant height, number of filled pods, weight of 100 seeds, and soybean productivity with the best results successively produced by a combination of Devon-Control, Devon-Marshall, Devon-Agrisoy, and Dena-Cruiser.

Differential regulation of antioxidant enzymes in Frankliniella occidentalis (Thysanoptera: Thripidae) exposed to thermal stress

Frankliniella occidentalis is an invasive insect pest that incites damage to ornamental and agronomic crops on a global scale. In this study, the effects of temperature on gene expression and enzyme activity were studied for superoxide dismutase (SOD), peroxidase (POD), and glutathione-S-transferase (GST) in F. occidentalis. SOD, POD and GST enzyme activity increased significantly at 35–37 °C but declined as the temperature increased to 41 °C. In a time course study at 35 °C, SOD, POD and GST activities were significantly elevated at 0.5, 1 and 2 h in comparison to the control at 26 °C. Expression patterns were evaluated for the three antioxidant genes under high and low temperature stress. In a time course study at –4 °C, SOD, POD and GST expression peaked at 1 h and declined at 2 h of exposure. In contrast, when transcription was monitored at 35 °C, expression was lowest at 1 h and increased at 2 h. The results provide data that will be useful in deciphering the role of antioxidant enzymes in the adaptation of F. occidentalis to climate change.

Efficacy of Synthetic Pesticides Against Thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae) on Okra Abelmoschus esculentus (L.) Moench

Okra (Abelmoschus esculentus L.) is an essential vegetable crop with good nutritional significance. Insect pests are the major threat for poor production of the okra crop. Thrips of vegetable crops are known to be serious pests on a wide range of fruit, vegetable, flower, and agronomic crops. The present field study was carried out to know the efficacy of different insecticides (acetamiprid 19% weightable water (ww), lambda 25% ww, colarphipare 32% ww, lambda 2.5% ww and abamectin 1.3% ww) against Thrips, Thrips tabaci (Lindeman) on okra crop during the year 2019, and observations against T. tabaci (Lindeman) were recorded after 24 hrs, 48 hrs, 72 hrs and 07 days of each spray in all the treatments. The pre-treatment count of thrips on okra was non-significant (P > 0.05); while the evaluated efficacy of different insecticides against thrips was significant (P < 0.01). It was noted that all the insecticides showed their highest efficacy after 7 days of spray and acetamiprid 19% weightable water (ww) was more efficient to combat the T. tabaci as compared to other pesticides that produced field efficacy of 73.92 and 74.91% against thrips after 7 days of 1st and 2nd spray respectively. Abamectin, 1.3% ww, was reasonably successful, yielding 53.81 and 56.66% field efficacy against T. tabaci (Lindeman) after 7 days of first and second spray. Also, moderately effective was colarphipare 32% ww, which developed field effectiveness of 56.41 and 61.49% against T. tabaci (Lindeman) after 7 days of first and second spray, respectively.

Effect of plant growth regulators on crop production

Plant growth regulators are the naturally extracted or synthesised compounds which are used in smaller quantity to modify the hormonal activity in agricultural and horticultural crops. Though there effect was not totally revealed there was some significant works carried out to know the effect of growth regulators on agronomic crops they are now using in wide range of crops to alter different parameters such as plant height, canopy development, effective branching, flower imitation and improving yield. They also play a key role in dryland farming as some of the plant growth regulators are used in stress tolerance of the crops. Few research works are carried to know the effect of major plant growth regulators on cereals and pulses. The plant growth regulators like auxins, gibberellins, cytokinins and ethephon are the majorly used plant growth regulators in cereals and pulses to obtain optimum plant growth and to improve the yields.

Interaction of dicamba, fluthiacet-methyl, and glyphosate for control of velvetleaf (Abutilon theopharsti) in dicamba/glyphosate-resistant soybean

Velvetleaf is an economically important weed in agronomic crops in Nebraska and the United States. Dicamba applied alone usually does not provide complete velvetleaf control, particularly when velvetleaf is greater than 15 cm tall. The objectives of this experiment were to evaluate the interaction of dicamba, fluthiacet-methyl, and glyphosate applied alone or in a mixture in two- or three-way combinations for velvetleaf control in dicamba/glyphosate-resistant (DGR) soybean and to evaluate whether velvetleaf height (≤ 12 cm or ≤ 20 cm) at the time of herbicide application influences herbicide efficacy, velvetleaf density, biomass, and soybean yield. Field experiments were conducted near Clay Center, Nebraska in 2019 and 2020. The experiment was arranged in a split-plot with velvetleaf height (≤ 12 cm or ≤ 20 cm) as the main plot treatment and herbicides as sub-plot treatment. Fluthiacet provided ≥ 94% velvetleaf control 28 d after treatment (DAT) and ≥ 96% biomass reduction regardless of application rate or velvetleaf height. Velvetleaf control was 31% to 74% at 28 DAT when dicamba or glyphosate was applied alone to velvetleaf ≤ 20 cm tall compared with 47% to 100% control applied to ≤ 12 cm tall plants. Dicamba applied alone to ≤ 20 cm tall velvetleaf provided < 75% control and < 87% biomass reduction 28 DAT compared with ≥ 90% control with dicamba at 560 g ae ha−1 + fluthiacet at 7.2 g ai ha−1 or glyphosate at 1,260 g ae ha−1. Dicmaba at 280 g ae ha−1 + glyphosate at 630 g ae ha−1 applied to ≤ 20 cm tall velvetleaf resulted in 86% control 28 DAT compared with the expected 99% control. The interaction of dicamba + fluthiacet + glyphosate was additive for velvetleaf control and biomass reduction regardless of application rate and velvetleaf height.

Cultural Method Considerations for Integrated Weed Management in Agronomic Crops

This article provides growers with information on various cultural methods to increase weed control in their fields, reduce herbicide inputs, and contribute to integrated weed management. Written by Prasanna Kharel, Pratap Devkota, and Greg MacDonald, and published by the UF/IFAS Agronomy Department, May 2021.

Predictive Models for Reforestation and Agricultural Reclamation: A Clearfield County, Pennsylvania Case Study

Natural resource scientists, concerned citizens, and government officials are interested in reconstructing disturbed environments for reforestation and agricultural productivity. We examined Clearfield County in Pennsylvania, USA, to develop a predictive model to reconstruct the landscape for seven agronomic crops (corn, corn silage, oats, alfalfa hay, red clover, bluegrass, and soybeans) and thirteen woody plants (white cedar, lilac, highbush cranberry, Amur maple, gray dogwood, peashrub, white spruce, white pine, red maple, red pine, jack pine, nannyberry, and white ash). A significant predictive model (p ≤ 0.001) was generated explaining 96.94% of the variance, with percent clay, bulk density, hydraulic conductivity, available water capacity, pH, percent organic matter, percent rock fragments, slope, topographic position, and electrical conductivity explored as main effect terms, plus squared terms, and first order interaction terms. The model is not over-specified and each predictor is significant (p ≤ 0.05). The modeling effort suggests that there are at least several clusters of vegetation preference dimensions based upon the terrain of the landscape. The model provides insight into how to reconstruct the disturbed environment for vegetation in the study area.

Global insights into homoeolog gene expression in upland cotton under intraspecific hybridization

Background: Hybridization is useful to enhance yield potential of agronomic crops in the world. Cotton has genome doubling due to alloteraploidy process and hybridization process in coordinate with duplicated genome can produce more yield and adaptability. Therefore, expression of homoeolog gene pairs between hybrids and inbred parents are vital to characterize genetic source of heterosis in cotton.Results: Investigation results of homoeolog gene pairs between two contrasting hybrids and their respective inbred parents identified 36853 homoeolog genes in hybrids. It was observed both high and low hybrids had similar trends in homoeolog gene expression patterns in each tissue under study. An average of 96% of homoeolog genes had no biased expression and their expressions were derived from the equal contribution of both parents. Besides, very few homoeolog genes (An average of 1%) showed no biased or novel expression in both hybrids. The functional analysis described secondary metabolic pathways had a majority of novel biased homoeolog genes in hybrids. Conclusions: These results contribute preliminary knowledge about how hybridization affects expression patterns of homoeolog gene pairs in upland cotton hybrids. Our study also highlights the functional genomics of metabolic genes to explore the genetic mechanism of heterosis in cotton.