Influence of Integrated Agronomic and Weed Management Practices on Soybean Canopy Development and Yield

The role of weed suppression by the cultivated crop is often overlooked in annual row cropping systems. Agronomic practices such as planting time, row spacing, tillage and herbicide selection may influence the time of crop canopy closure. The objective of this research was to evaluate the influence of the aforementioned agronomic practices and their interaction with the adoption of an effective preemergence (PRE) soil residual herbicide program on soybean canopy closure and yield. A field experiment was conducted in 2019 and 2020 at Arlington, WI as a 2×2×2×2 factorial in a randomized complete block design, including early (late-April) and standard (late-May) planting time, narrow (38 cm) and wide (76 cm) row spacing, conventional tillage and no-till, and soil-applied PRE herbicide (yes and no; flumioxazin 150 g ai ha−1 + metribuzin 449 g ai ha−1 + pyroxasulfone 190 g ai ha-1). All plots were maintained weed-free throughout the growing season. In both years, early planted soybeans reached 90% green canopy cover (T90) before (7 to 9 d difference) and yielded more (188 to 902 kg ha−1 difference) than the standard planted soybeans. Narrow-row soybeans reached T90 earlier than wide-row soybeans (4 to 7 d difference), but yield was similar between row spacing treatments. Conventional tillage had a higher yield when compared to a no-till system (377 kg ha−1 difference). The PRE herbicide slightly delayed T90 (4 d or less) but had no impact on yield. All practices investigated herein influenced the time of soybean canopy closure but only planting time and tillage impacted yield. Planting soybeans earlier and reducing their row spacing expedites the time to canopy closure. The potential delay in canopy development and yield loss if soybeans are allowed to compete with weeds early in the season would likely outweigh the slight delay in canopy development by an effective PRE herbicide.

Light Quality Environment and Photomorphological Responses of Young Olive Trees

Tree densities have increased greatly in olive orchards over the last few decades. In many annual crop species, increased density reduces the horizontal red/far-red (R/FR) and blue/green (B/G) ratios during canopy development even before direct shading occurs, and such changes are known to alter plant morphology. This study with olive trees evaluated: (1) whether the leaf area index (LAI) of neighboring trees modifies the light quality environment prior to a tree being directly shaded and (2) the potential morphological responses of three olive cultivars to changes in light quality. Increasing LAI using different spatial arrangements of potted, three-year-old trees reduced the horizontal R/FR ratio more than that of the B/G ratio. Cultivar-specific responses to low R/FR ratio were observed for individual leaf area and aboveground/belowground biomass ratio using laterally positioned FR mirrors or green fences. No statistically significant responses were detected in response to green vegetation fences that reduced both horizontal R/FR and B/G ratios, but a cluster analysis grouped together the overall morphological responses to both FR mirrors and green fences. These results in olive trees suggest that cultivar differences in response to light quality may be relevant for understanding adaptation to dense orchards and identifying cultivars best suited to them.

Quantitative Survey of ‘Montmorency’ Tart Cherry Orchard Design in Utah

‘Montmorency’ tart cherry trees (Prunus cerasus L.) are grown commercially in the United States in low-density systems. Commercial tart cherry orchard design has not changed significantly over the past 50 years, but there is some variation from farm to farm in management strategies, including tree spacing, training, and pruning, and the resulting orchard production and turnover. Canopy dimensions and dynamics are important considerations for evaluating and improving orchard management strategies but are not well documented for tart cherry systems. Current orchard design and canopy management strategies were surveyed along a gradient of orchard age across five commercial farming operations in Utah. Trunk cross-sectional area and various canopy dimensions, including spread and volume, were quantified to capture tree size and canopy architecture. The survey indicated a surprising lack of deviation in orchard design in the region over the last several decades with higher variation among blocks within a farm than across farms. As a result, the survey revealed trends in tree growth and canopy structure across the range in orchard ages despite differences in management approaches of the surveyed farms. These trends were useful in illustrating canopy development and space fill. Tree age between 11 and 15 years after planting was determined to represent a transition between establishment and mature growth, where canopies filled available row space and began experiencing senescing canopy structure. Based on the distribution of ages captured in the survey, a significant number of orchards in Utah are at an age range of 11–15 years, perhaps contributing to superior yields per land area reported for the region. The confluence of space-fill and canopy development described in this study highlights a critical period for tart cherry orchard management at the transition of canopy establishment and maturity. These baseline dynamics will provide benchmarks for evaluating strategies for refining and improving orchard management systems for tart cherry in the Intermountain West region.

Physiological and genetic drivers underpinning canopy development are associated with durum wheat yield in rainfed environments

Durum wheat (Triticum turgidum L. ssp. Durum) is largely grown in rainfed production systems around the world. New cultivars with improved adaptation to water-limited environments are required to sustain productivity in the face of climate change. Physiological traits related to canopy development underpin the production of biomass and yield, as they interact with solar radiation and affect the timing of water use throughout the growing season. Despite their importance, there is limited research on the relationship between canopy development and yield in durum wheat, in particular studies exploring temporal canopy dynamics under field conditions. This study reports the genetic dissection of canopy development in a durum wheat nested-association mapping population evaluated for longitudinal normalized difference vegetation index (NDVI) measurements. Association mapping was performed to identify quantitative trait loci (QTL) for time-point NDVI and spline-smoothed NDVI trajectory traits. Yield effects associated with QTL for canopy development were explored using data from four rainfed field trials. Four QTL were associated with yield in specific environments, and notably, were not associated with a yield penalty in any environment. Alleles associated with slow canopy closure increased yield. This was likely due to a combined effect of optimised timing of water-use and pleiotropic effects on yield component traits, including spike number and spike length. Overall, this study suggests that slower canopy closure is beneficial for durum wheat production in rainfed environments. Selection for traits or loci associated with canopy development may indirectly improve yield and support selection for more resilient and productive cultivars in water limited environments.

Arbuscular Mycorrhizal Fungus Stimulates Young Field-Grown Nectarine Trees

Although mycorrhizae applications have been widely used to improve the establishment and growth of agricultural crops, there have been no studies on their application in field-grown nectarine trees. In this work, a commercial arbuscular mycorrhizal fungus (AMF; Glomus iranicum var. tenuihypharum) was applied by means of fertigation to inoculate young “Flariba” nectarine trees grown in south-eastern Spain to evaluate its effect on plant water status, and vegetative and reproductive growth. Using minirhizotrons to measure the root dynamics over a complete growing season, revealed that AMF substantially increased root growth (51% increase compared with untreated trees), while no changes in plant water status or canopy development were noted. The productive response improved in inoculated trees, as demonstrated by a significantly higher yield, fruit size, number of fruits per tree and greater crop load efficiency values than in untreated trees. Given that the same amount of irrigation solution was applied in both treatments, the irrigation water use efficiency increased by 19.5% in AMF compared with untreated trees. The findings of this study suggest that a simple inoculation of AMF can be considered a good practice in semi-arid agro-systems to firmly establish efficient young nectarine trees and enhance their adaptation to field conditions.

Respons fisiologis dan agronomis bibit kopi pada kerapatan naungan yang berbeda

AbstrakTanaman kopi seringkali dibudidayakan di areal hutan, dimana terdapat tanaman tahunan seperti pepohonan yang terus tumbuh sehingga menurunkan intensitas cahaya yang jatuh ke tanaman kopi. Hal ini menjadi masalah bagi pertumbuhan dan perkembangan tanaman kopi yang dinaungi pohon tersebut. Penelitian ini bertujuan untuk menguji fisiologis dan agronomis dua kultivar kopi dalam intensitas naungan yang berbeda untuk mendapatkan informasi kultivar kopi yang terbaik. Percobaan dilaksanakan dari bulan Maret hingga Juni 2020 di Kebun Percobaan Ciparanje, Fakultas Pertanian, Universitas Padjadjaran, Jatinangor, Sumedang, Jawa Barat. Percobaan menggunakan Rancangan Petak Terbagi (Split plot) dengan dua faktor dan diulang sebanyak tiga kali. Taraf dari main plot adalah tanpa naungan, naungan paranet 50%, 60%, 70%, dan 80%, sedangkan taraf dari sub plot adalah kultivar Lini S 795 dan Sigararutang. Hasil penelitian menunjukkan tidak terdapat pengaruh interaksi antara naungan dan kultivar. Penggunaan naungan 70% memberikan pengaruh terbaik terhadap tinggi bibit kopi dan suhu daun, serta kultivar Lini S 975 memberikan pengaruh terbaik terhadap tinggi bibit kopi, luas daun, indeks klorofil, klorofil fluoresens dan suhu daun.Kata Kunci: Kopi, Lini S 795, Klorofil fluorescence, Sigararutang AbstractCultivation of coffee tree in forest areas, where the wooden trees grew previously, it will be causing in decreasing of light intensity that is falling into the ground as long as trees canopy development leading to shade of coffee trees, this is affecting coffee tree growth and development. The objective of this study was to evaluate physiologically and agronomically of two coffee seedling cultivars under net shading densities. The experiment was conducted at Ciparanje Experimental Station, Faculty of Agriculture, Padjadjaran University, Jatinangor, Sumedang, West Java, from March to June 2020. Experimental design used in this research was split plot with two factors and three replications. The main plot was the shading densities which consisted of five levels, namely without shade 0%, net shade 50%, 60%, 70%, and 80%. The subplot was the coffee cultivars, consisted of two levels, namely Lini S 795 cultivar and Sigararutang. All parameters was not indicated any interaction. The results showed that the 70% shade gave the best effect on plant height and leaf temperature. Lini S 795 cultivar gave the best effect on plant height, leaf area, chlorophyll index, chlorophyll fluorescence, and leaf temperature.Keywords: Coffee, Chlorophyll fluorescence, Lini S 795, Net shading, Sigararutang

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.