Explore the vast range of titles available.

Melanaphis sorghi is a serious economically important pest of sorghum, Sorghum bicolor (L.), across the southern USA. Therefore, developing and refining integrated strategies that provide effective control is key to the management of this pest. The current study examined the influence of nitrogen (N) fertilization, sorghum cultivar and insecticide applications on M. sorghi and grain sorghum yield at Tifton, Georgia (31.5120° N, 83.6434° W). Field trials with three insecticide treatments (untreated control, flupyradifurone in-furrow at 117 g/ha, and flupyradifurone foliar at 73 g/ha), three nitrogen fertilization rates (25, 50 and 100 kg/ha) and two sorghum cultivars (resistant: DKS37-07 and susceptible: DKS53-53) were conducted on grain sorghum in the spring/summer of 2022 and 2023. Compared to the medium N fertilization, Low and high N fertilization supported higher aphid density and severity of infestation (cumulative insect days [CID]) on both the susceptible and resistant cultivars for both 2022 and 2023. Aphid density and severity of infestation on the susceptible sorghum cultivar (DKS53-53) were 3.4–4.8-fold greater than on the resistant cultivar (DKS37-07) for both low and high N fertilization plots in 2022. While a single foliar and in-furrow insecticide application significantly reduced infestations below the economic threshold across all treatment combinations in 2022, aphid populations were too low to warrant foliar application in 2023. Nitrogen fertilization was associated with improved yield as the high N fertilization preserved yield for both sorghum cultivars. Compared to untreated plots, in-furrow and foliar insecticide applications supported greater grain sorghum yield across all insecticide treatments only in 2022. The study suggests that manipulating N fertilization, utilizing resistant sorghum cultivars and in-furrow and foliar insecticide application can synergistically suppress aphid infestations and improve grain yield in sorghum production in southern USA.

Studies on the management of the invasive Melanaphis sorghi are essential to refining integrated pest management strategies against M. sorghi in forage sorghum in the USA. The objective of this study was to determine the impact of planting date (early planting and late planting) and in-furrow and foliar insecticide application of flupyradifurone, on M. sorghi infestation and forage sorghum yield in Tifton, Georgia and Florence, South Carolina, USA, in 2020 and 2021. Early planted sorghum supported slightly higher aphid density and severity of infestation as evident in the greater cumulative insect days values in the early planted sorghum at both Florence and Tifton in 2020 and 2021. A single foliar application reduced aphid infestations below the threshold level of 50 aphids per leaf. In contrast, in-furrow insecticidal application in selected plots at both locations significantly suppressed M. sorghi density to near-zero levels. Yield results in Florence in 2020 showed that sorghum yield was over 50% greater in early planted plots compared to late planted plots. Both insecticide treatments (foliar and in-furrow) resulted in significantly higher yield than untreated plots. These data indicate that early planting coupled with in-furrow and foliar insecticide applications can suppress M. sorghi infestations and improve silage production in forage sorghum in the USA.

Soil water uptake is a function of root growth and distribution. Therefore, restrictions on root system growth may reduce water and nutrient uptake, which results in slower plant growth. The objective of this study was to determine the effects of different irrigation strategies, nitrogen application rates, and planting methods on the winter wheat root growth. The experimental factors included two irrigation strategies (variable alternate furrow irrigation defined as partial root-zone irrigation and ordinary furrow irrigation), two planting methods (in-furrow planting and on-ridge planting), and three nitrogen (N) application rates (0, 150, and 300 kg N ha −1 ) in 2015–2016 and 2016–2017 growing seasons. Results indicated that the in-furrow planting decreased mean root length density and root mass density (8% and 10%, respectively, in the fertilized treatments) compared to that obtained in the on-ridge planting. The partial root-zone irrigation reduced root length density by about 5% and 7% in the fertilized treatments compared to that obtained in full irrigation in the first and second year, respectively; however, these reductions were not statistically significant. Furthermore, the results implied that nitrogen fertilizer application increased root length density by 48% and 24% in the first and second year, respectively. Likely, root mass density increased by 32% and 5% in the first and second year, respectively. The exponential decaying relationship between root length density and soil depth indicated that the in-furrow planting with 300 kg N ha −1 produced the highest root density at the soil surface layer and reduced deep root penetration compared to the on-ridge planting and the other N treatments. Further analysis revealed that grain yield linearly correlated with root length density and root mass density in the first year. However, a polynomial (quadratic) relationship was obtained in the second year. Consequently, increasing the main root traits, including root length and root mass, enhanced winter wheat grain yield until it reached a threshold value. Higher values negatively affected grain yield, which might be due to allocating carbon to roots instead of grains.

The deep application of liquid fertilizer in paddy fields is a fertilization technique that applies liquid fertilizer deep near the root system of paddy field crops, which can effectively improve the absorption rate of the crops and reduce the amount of fertilizer applied. In the cold regions of China, the soil return rate of the furrowing operation of the deep application of liquid fertilizer in paddy fields is low, which can easily cause the excessive liquid leakage of fertilizer and affect crop growth. Therefore, it is difficult to popularize in large areas. According to the characteristics of paddy soil in the cold regions of China and the operating requirements of a high backfill rate and low disturbance rate of the soil of the deep application of liquid fertilizer, this paper designed a bionic liquid fertilizer deep application furrow opener based on the claw-toe structure of the muskrat. In this study, an indoor soil bin test was conducted by constructing a deep application environment for the liquid fertilizer in paddy fields. The results of the soil bin test showed the effects of the key operating parameters of the bionic design of the liquid fertilizer deep application furrow opener, spraying pressure of the liquid fertilizer and operating speed on the furrowing resistance, soil disturbance rate and the leakage amount of liquid fertilizer. The bionic design of the liquid fertilizer deep application furrow opener has a low soil disturbance rate and leakage amount of fertilizer when the operating speed is 0.8 m s−1, and the spraying pressure is 0.2 MPa. This furrow opener significantly improves the operating performance of the deep application of liquid fertilizer in the cold regions of China and is suitable for the deep application of liquid fertilizer in the paddy fields of this region.

In‐furrow starter fertilization for corn (Zea mays L.) is being preferred to alternative starter application methods by farmers in the U.S. Corn Belt. This study assessed corn grain yield, early growth (V5 to V6), and early P and K uptake responses to in‐furrow P–K starter fertilization with or without broadcast P–K fertilization for 2‐yr corn–soybean [Glycine Max (L.) Merr.] rotations. Sixteen trials were conducted on Iowa fields managed with no‐till or chisel‐plow tillage. Soil‐test P (STP) was 5 to 77 mg P kg−1 (Bray‐P1), and soil‐test K (STK) was 88 to 237 mg K kg−1 (ammonium acetate). Treatments replicated four times were a control, 3–8–15 (N–P–K) liquid starter at 5 to 7 kg P ha−1 and 10 to 14 kg K ha−1, granulated P–K fertilizer broadcast at 49 to 66 kg P ha−1 and 112 to 140 kg K ha−1, and broadcast plus starter. Nitrogen was applied across all treatments. Fertilization increased grain yield at nine sites (0.80 to 2.11 Mg ha−1). Starter fertilization produced less yield than broadcast fertilization at five sites (0.30 to 1.48 Mg ha−1 less), four of which tested low in STP (≤15 mg P kg−1). Starter fertilization in addition to broadcast fertilization did not increase yield further at any site. Starter fertilization increased corn early growth and P and K uptake more than broadcast fertilization did at most sites. In‐furrow starter P–K fertilization for corn is not an effective practice when applied in addition to 2‐yr broadcast P–K fertilization rates for corn–soybean rotations.

High residue levels provide excellent erosion control but can result in cool, wet seedbeds creating a situation where starter fertilizer may be beneficial. Research was conducted from 1999 to 2001 evaluating N rates in starter containing N, P, K, and sometimes S; and different starter fertilizer placements for continuous no-till corn (Zea mays L.). Placements consisted of direct seed contact, dribble over-the-row, and a subsurface band (5 cm below and 5 cm to the side of the seed row). Nitrogen rates for direct seed and dribble placements were 11, 22, 45, and 56 kg N ha(-1); and 34, 67, 101, and 134 kg N ha(-1) for the subsurface placement. Nitrogen was balanced at 168 kg ha(-1) on all treatments, including a no-starter check using broadcast ammonium nitrate at planting. Addition of S in starter was evaluated with subsurface placement. Starter fertilizer, regardless of placement, often increased early season dry matter production and significantly increased grain yields. Increasing N above 22 kg ha(-1) in direct seed contact did not increase yields and significantly reduced stands 2 of 3 yr. Stands were unaffected with higher N rates in dribble over-the-row and subsurface placements; however, applying N above 11 and 34 kg ha(-1), respectively, resulted in little added yield benefit. Inclusion of 11 kg S ha(-1) in a subsurface starter fertilizer sometimes increased early season dry matter production, grain yield, and nutrient uptake. Results suggest starter fertilizer is an effective, efficient way of stimulating early growth and improving yields of continuous no-till corn in Kansas.

This study was designed to evaluate the crop water stress index (CWSI) for low-energy precision application (LEPA) irrigated corn (Zea mays L.) grown on slowly-permeable Pullman clay loam soil (fine, mixed, Torrertic Paleustoll) during the 1992 growing season at Bushland, Tex. The effects of six different irrigation levels (100%, 80%, 60%, 40%, 20%, and 0% replenishment of soil water depleted from the 1.5-m soil profile depth) on corn yields and the resulting CWSI were investigated. Irrigations were applied in 25 mm increments to maintain the soil water in the 100% treatment within 60-80% of the \"plant extractable soil water\" using LEPA technology, which wets alternate furrows only. The 1992 growing season was slightly wetter than normal. Thus, irrigation water use was less than normal, but the corn dry matter and grain yield were still significantly increased by irrigation. The yield, water use, and water use efficiency of fully irrigated corn were 1.246 kg/m(2), 786 mm, and 1.34 kg/m(3), respectively. CWSI was calculated from measurements of infrared canopy temperatures, ambient air temperatures, and vapor pressure deficit values for the six irrigation levels. A \"non-water-stressed baseline\" equation for corn was developed using the diurnal infrared canopy temperature measurements as T(c) - T(a) = 1.06 - 2.56 VPD, where T(c) was the canopy temperature (degrees C), T(a) was the air temperature (degrees C) and VPD was the vapor pressure deficit (kPa). Trends in CWSI values were consistent with the soil water contents induced by the deficit irrigations. Both the dry matter and grain yields decreased with increased soil water deficit. Minimal yield reductions were observed at a threshold CWSI value of 0.33 or less for corn. The CWSI was useful for evaluating crop water stress in corn and should be a valuable tool to assist irrigation decision making together with soil water measurements and/or evapotranspiration models.