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Cultivated peanut produces pods of varying maturity throughout most of the plant developmental stages, often leading to a considerable proportion of immature seeds at harvest. Plants originating from immature seeds not only have reduced emergence and physiological performance, but also reduced vigor of both mature and immature seeds produced in subsequent generations. Therefore, seed maturity effects on plant performance could potentially extend from physiology to the initiation and progression of reproduction. This study aimed to elucidate the impacts of seed maturity on plant performance and productivity. In this two-year experiment, season-long physiological and reproductive performance was compared among plants established from mature and immature seed of eight peanut cultivars differing in maturity potential. Our results suggest that plants produced from mature seeds had higher emergence and canopy coverage than plants produced from immature seeds over the season. Further, descendent seed quality was also affected: plants that originated from immature seeds produced mature seeds with average 9.91 % decreased mass, particularly for those formed earliest in plant development, and average 37.18 % less mature pods formed latest in plant development. At harvest, seeds were collected and tested for biochemical characteristics. Seeds that were produced by plants originating from mature seeds generally had higher carbohydrates, protein, oleic acids and lower lipid content than seeds produced by plants originating from immature seeds. Given these results, the use of mature seeds in production appears to be of utmost importance for both the performance of the subsequent plant and the resulting quality of the seed produced by these plants. • This two-year study tested peanut plant performance and the quality of their offspring seeds that formed at different time periods (represented as cohort groups) based on whether the plants and their offspring seeds originated from mature or immature seeds. • Plants produced from mature seeds had enhanced emergence and greater canopy cover than plants produced from immature seeds over the season. • Plants originating from immature vs. mature seeds produced pods/seeds differed in the numbers of mature pods, seed mass and biochemical compounds within each cohort group. • The impact of seed maturity on plant development is highly dependent to environmental influence. [ABSTRACT FROM AUTHOR]

Highlights: [•] Indian breeding lines in the field exhibited differences in nitrogen accumulation. [•] Commercial lines did not show difference in nitrogen accumulation under field drought. [•] Nitrogen fixation tolerance of commercial cultivars to soil drying was moderate. [•] Field test was reasonable screen to identify genotypes for intensive measurement. [ABSTRACT FROM AUTHOR]

Splitting N fertilizer application is recommended to increase crop N use efficiency by reducing risk of leaching. The objective of this study was to optimize the timing and rate of split N fertilizer applications to maximize tuber yield and quality of chipping potatoes grown using seepage irrigation in Florida. A two-year study was conducted on two commercial farms using cultivars Atlantic and FL1867. A factorial of two N rates applied at pre-plant (N pre-pl ) 0 or 56 kg ha −1 30 days before planting followed by four N rates applied at plant emergence (N emerg ) 0, 56, 112, or 168 kg ha −1 were randomized in a complete block design with four replicates. At tuber initiation, all treatments received an additional 56 kg ha −1 of N. All applications of N were of granular ammonium nitrate banded. Total N applied for the various treatments ranged from 56 to 280 kg ha −1 of N. Soil N was monitored in the 0–20 cm soil depth layer throughout the season. Whole plant biomass peaked at 8.5–8.7 Mg ha −1 with N emerg rates between 112–143 kg ha −1 . Plant N uptake range from 66 to 157 kg ha −1 . N uptake use efficiency decreased with increasing N rates. Potato yield ranged from 25 to 42 Mg ha −1 in both years. In 2013, application of 56 kg ha −1 of N pre-pl produced 2.5–5.1 Mg ha −1 higher yield than treatments receiving 0 N. In 2014, there was an interaction between N pre-pl and N emerg on yield. The higher 56 kg ha −1  N pre-pl resulted in higher yield only when N emerg was at or below 56 kg ha −1 . For cv. Atlantic when no N pre-pl was supplied, yield increased linearly in response to N emerg rates, while with 56 kg ha −1 of N pre-pl , yield responded quadratically to N emerg reaching a maximum at 114 kg ha −1 . For cv. FL1867 yield increased quadratically to N emerg peaking at 138 and 126 kg ha −1 of when 0 or 56 kg ha −1 of N pre-pl was applied, respectively. The study shows that while the risk of N pre-pl loss is high, N pre-pl can result in higher yield, especially when subsequent N rates are low. Application of N pre-pl was particularly effective in a dry year. By contrast, when soil mineral N from N pre-pl was largely lost to leaching in a high rainfall year, yield was increased by the N pre-pl application only when subsequent N emerg rates were less than 112 kg ha −1 . When early-season soil N was low, the N emerg had a larger impact on tuber yield due to minimum loss to leaching, maximizing yield when N emerg was 128–168 kg ha −1 . This indicates that applying N fertilizer prior to emergence is necessary to maximize tuber yield. [ABSTRACT FROM AUTHOR]

• Most sesame roots were present between 20 to 50 cm deep, and root diameter did not exceed 2 mm. • There was evidence of a lag in senescence between below- and aboveground parts of the plant. • Genotypic differences between non-dehiscent cultivars did not translate into strong rooting architectural differences. This study described sesame's rooting behavior and the relationship between above- and belowground biomass in architecture and senescence dynamics. Six non-dehiscent sesame cultivars, branched and non-branched, were grown for two years in North Central Florida's sandy soils in 2013 and 2014. The root systems were imaged in situ with a minirhizotron camera 5 times in 2013 and 7 times in 2014. Total root length, surface area and diameter were measured for each image, and roots were separated between alive, dying and dead. Leaf area index was recorded 5 times both years. Results showed that averaged maximum root diameter for all cultivars was <2 mm. Most roots were present between 20 to 50 cm deep, and a multivariate approach, namely a canonical discriminant analysis, showed that some cultivars tended to have more roots in the soil mid-depth ranges than others. However, these observations were not stable throughout the season. Leaf area index showed differences between cultivars, but these did not translate into contrasting yields. Results also highlighted a lag between leaf area index and total root length senescence, the former declining about 2 weeks before the latter. This study is among the first to describe sesame rooting characteristics in details. [ABSTRACT FROM AUTHOR]

Land use conversion of row crops to bioenergy cropping systems in the southeastern United States (U.S.) creates concerns associated with water use and NO 3 -N leaching. Production of energy from biomass is associated with large amounts of byproducts generated during biofuel processing. Biochar and vinasse are two nutrient rich byproducts that could be land-applied to bioenergy crops to reduce reliance on synthetic fertilizer. However, effects on water dynamics of applying these byproducts to support biomass production is poorly understood, particularly when bioenergy crops replace traditional row crops. Thus, this study aimed to compare a cotton ( Gossypium hirsutum L.)-peanut ( Arachis hypogaea L.) rotation to sweet sorghum [ Sorghum bicolor (L.) Moench] receiving annual applications of biochar and vinasse, on biomass yield, crop evapotranspiration, water use efficiency (WUE), NO 3 -N leaching, and soil volumetric water content. A field study was conducted from 2013 to 2015 to assess the following treatments: cotton + 150 kg N ha −1 (COT), peanut + 30 kg N ha −1 (PEA), and sweet sorghum receiving one of the following i) 30 kg N ha −1 (S30); ii) 30 kg N ha −1 + biochar (S30B); iii) 30 kg N ha −1 + vinasse (S30V); and iv) 150 kg N ha −1 (S150). Similar aboveground dry matter yields were obtained in 2013 and 2015 for cotton and all sweet sorghum treatments and were on average 19 Mg ha −1 for both years. S30 and S150 achieved similar yields. Sweet sorghum and COT exhibited the highest WUE (∼5 g kg −1 ). S30B increased soil moisture retention at 0–0.2 m depth 36, 29, and 24% in 2013, 2014, and 2015, respectively. Biochar incorporated at 0.15 m soil depth increased soil moisture retention down to 0.4 m. Low N rate application combined with biochar in S30B could represent an alternative management practice to minimize N leaching, recycle nutrients, and increase soil water retention if sweet sorghum were to be widely adopted by farmers in the southeastern U.S. [ABSTRACT FROM AUTHOR]

• Peanut is said to provide N credits to future crops in the southeastern USA but evidence is lacking to support this claim. • We evaluated wheat performance following peanut, cotton, and fallow in a conservation tillage cropping system. • Peanut residues contained up to 93 kg N ha-1, but available N at wheat planting was usually not affected by cropping history. • Peanut did not provide detectible N credits to wheat, but there were cases of lower yield after cotton relative to peanut. Agricultural extension services in many peanut (Arachis hypogaea L.)-producing regions recommend that farmers reduce nitrogen (N) fertilization rates, or apply N credits, to crops planted after peanut but do not typically specify how peanut residue management or planting schedules of subsequent crops affect the magnitude of peanut N credits. The objective of this study was to quantify peanut N credits to winter wheat (Triticum aestivum L.) in a conservation tillage cropping system in different subtropical growing environments. A five site-year study was conducted in Florida, USA beginning in 2016. A split-plot experimental design was arranged in which summer crop [peanut, cotton (Gossypium hirsutum L.), and weed-free fallow] was the main plot factor, while N rate (0, 34, 67, and 101 kg N ha−1) to winter wheat was the split plot factor. Peanut and cotton were planted under strip-tillage, while winter wheat was drilled into peanut and cotton residues and weed-free fallow plots without tillage. Although peanut residues accumulated 54–93 kg N ha−1, plant available N at winter wheat planting in the 0–15 cm soil depth range of former peanut plots was only higher than in former cotton or fallow plots for one site-year. A previous peanut crop did not affect winter wheat grain yield, but there were cases of lower grain yield, grain N removal, and agronomic efficiency following cotton relative to peanut depending on site. Nonlinear regression procedures predicted that N rates required to optimize grain yields following peanut would exceed 94 kg N ha−1, further indicating the absence of detectible peanut N credits in this study. These results suggest that assuming peanut provides N credits to subsequent crops in the southeastern USA is not justified and, if assumed, will reduce the productivity of subsequent crops. [ABSTRACT FROM AUTHOR]