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Jajar legowo 4:1 cropping pattern has been adopted by rice farmers; however, there has been limited information on the comparison between internal and edge rows. In addition, the effects of timing and frequency of fertilizer applications on rice cultivated at riparian wetland also have to be understood. In this research, both single and split applications of fertilizer were employed. The single fertilizer applications were applied at 15 days after transplanting (DAT) (T1), 30 DAT (T2), 45 DAT (T3); and the split applications were 15+30 DAT (T4), 15+45 DAT (T5), 30+45 DAT (T6), and 15+30+45 DAT (T7). Results of this research indicated that crops in the edge rows produced higher leaf area index but those at internal rows produced higher dry weight biomass. Split fertilizer application to three times (T7) increased the weight of grains and number of filled spikelet but did not affect other shoot and root growth traits. Overall, fertilizer application increased leaf chlorophyll and nitrogen content. Jajar legowo 4:1 planting pattern and split fertilizer application to three times are recommended for increasing yield in rice cultivated at riparian wetlands.

IntroductionSugarcane is a long-duration and nutrient-exhaustive crop. To improve nutrient use efficiency, the 4R nutrient stewardship approach comprises applying nutrients at the right time and place with the right method and at the right proportion. Improper nutrient management in such a nutrient-exhaustive crop will result in various nutrient losses and environmental pollution.MethodsConcerning this, a field study was performed on calcareous soils of the lower Indo-Gangetic plains of India during two subsequent years at the Sugarcane Research Institute, RPCAU, India, to explore the effect of precise application of macronutrients (N and K) in different methods of applications. The application methods (broadcasting and band application) were maintained in the main plot, and split N and K applications were put in the subplots.Results and DiscussionA highly significant difference was observed in the numbers of millable cane, cane, and sugar yield under the split applications of fertilizer. The decline in millable cane numbers, cane, and sugar yield due to the broadcasting method was to the tune of 17.5 and 17.6%, 14.8 and 17.1%, and 14.7 and 15.8% in plant and ratoon crops, respectively as compared to band placement of the fertilizers. Yield increased by 16.0 and 15.1% under plant and ratoon crops, respectively, with seven split applications of N and K compared to the control (two split of N and no split application of K). Band placement of N and K fertilizers markedly improved the nitrogen uptake (284.1 and 287.3 kg ha−1, in plant and ratoon, respectively) and phosphorus uptake (34.9 and 28.3 kg ha−1 in plant and ratoon, respectively) when compared to broadcasting. Application of N and K in seven splits resulted in better availability of nutrients in the soil, thereby facilitating the higher NPK uptake by the plants and ratoon both comparing two split applications of N and no splitting of K. From this study, it was observed that the band placement coupled with seven splitting of N and K is the best fertilizer application protocol, ensuring higher growth, yield, quality, and nutrient uptake of sugarcane in the calcareous soils of the Indo-Gangetic plains.

Nitrogen use efficiency (NUE) of tef, a major staple crop in Ethiopia, is very low, either caused by untimely use of nitrogen (N) fertilizers or lack of other essential nutrients like sulphur (S). The average grain yield of this crop is low, averaging <0.8 Mg ha−1 in farmer’s fields of the semi-arid conditions. Therefore, the present study was conducted to see the effect of the timing of combined N and S fertilization on the yield, yield components, and N and S concentration in the plant parts of the crop. A factorial combination of three rates of N (0, 70, and 105 kg ha−1) with four rates of S (0, 16, 32, and 48 kg ha−1) was applied in randomized complete blocks in three replications. The experiment was carried out in the 2004 and 2005 cropping seasons in the Cambisols of the semi-arid area of Ethiopia. The crop responded significantly (P < 0.05) to both split (one-third at planting and two-thirds at late tillering) and whole (all at planting) N and S applications and years. Combined N and S fertilization increased the dry matter (DM) and grain yields on average by 1.7 and 0.3 Mg ha−1, compared with the control. Similarly, S fertilization increased the NUE of the tef crop by 36%. Nitrogen concentration of shoots was found to significantly increase with S application (P < 0.05), with strong positive interactions both in the split and whole applications. The sulphur increase in grains was significant with N rates for both applications, with significant interaction effects observed for the split application in both cropping seasons. Split application resulted in 0.9 and 0.3 Mg ha−1 significant increase in DM and grain yields, averaged for both years and treatments compared with the whole application. Similar significant increases were observed for panicle yield, NUE, and shoot and grain N and S concentrations. The average N:S ratio in grains was 10.6:1. Significant (P < 0.05) yearly variations were also observed. Dry matter and grain yields of 2005 were higher on average by 2.10 and 0.32 Mg ha−1 than those of the 2004 cropping season. The percentage of N and S concentrations of grains, averaged for both applications, were higher by 13 and 9% in 2004; even though the N and S uptakes of 2005 were higher on average by 5.0 and 0.5 kg ha−1 than those of the 2004 cropping season. This work showed that the yield response and NUE of the tef crop could be improved with split N and S fertilizer applications, with tef-producing farmers benefitting from the application of S-containing N fertilizers to soils deficient in these nutrients.

Field experiments were conducted in 2010 and 2011 at two locations in Michigan to determine the effects of nitrogen and weed removal on glyphosate-resistant sugarbeet yield and quality. Nitrogen rates were 0, 67, 100, 134, and 67 : 67 kg N ha−1, and weeds were removed when they were < 2, 8, 15, and 30 cm tall. At the beginning of the growing season, weeds responded to N sooner than sugarbeet. Nitrogen assimilation by weeds was three times greater than sugarbeet at 0, 67, 100, and 134 kg N ha−1 and four times greater than sugarbeet with the split application of N (67 : 67 kg N ha−1) averaged over the weed removal timings. Higher N rates increased N sufficiency index values and sugarbeet canopy closure; weeds 30 cm tall had lower N sufficiency index values and a smaller sugarbeet canopy. The effect of N on root yields varied, but the highest N rates (134 kg N ha−1 or 67 : 67 kg N ha−1) were among the highest sugarbeet yields at all locations. Highest yields were achieved when weeds were controlled before reaching 2 cm tall at three of the four site-years. Delaying weed control until weeds were 8 or 15 cm tall reduced yield by 15%, whereas 30-cm-tall weeds reduced yield up to 21%. Recoverable white sucrose ha−1 (RWSH) also was reduced by 8 to 16% if weeds were 8 cm tall. These results indicate that weeds are highly competitive with sugarbeet and can assimilate large quantities of N early in the growing season, especially at larger growth stages. However, it appears that sugarbeets were able to scavenge sufficient N at the N rates used in this study to overcome N removal effects from larger weeds, resulting in no interaction between N rate and weed removal timing for sugarbeet root yield, quality, or RWSH. Nomenclature: Glyphosate; sugarbeet; Beta vulgaris L. ‘Hilleshög 9042’. En 2010 y 2011, se realizaron experimentos de campo en dos localidades en Michigan para determinar los efectos de aplicaciones de nitrógeno y la remoción de malezas en el rendimiento y la calidad de la remolacha azucarera resistente a glyphosate. Las dosis de nitrógeno fueron 0, 67, 100, 134, y 67:67 kg N ha−1, y las malezas fueron removidas cuando tuvieron una altura <2, 8, 15, y 30 cm. Al inicio de la temporada de crecimiento, las malezas respondieron al N antes que la remolacha. Al promediarse todos los momentos de remoción de malezas, la asimilación de N por las malezas fue tres veces mayor que la de la remolacha a 0, 67, 100, y 134 kg N ha−1 y cuatro veces mayor que la remolacha con la aplicación dividida de N (67:67 kg N ha−1). Las dosis más altas de N incrementaron los valores del índice de suficiencia de N y el cierre del dosel de la remolacha. Las malezas de 30 cm de altura tuvieron valores del índice de suficiencia de N más bajos y un dosel de la remolacha más pequeño. El efecto de N en los rendimientos de raíces variaron, pero las dosis más altas de N (134 kg N ha−1 ó 67:67 kg N ha−1) tuvieron los rendimientos de remolacha más altos en todas las localidades. Los rendimientos más altos fueron alcanzados cuando se controló las malezas antes de que alcanzaran 2 cm de altura, en tres de los cuatro sitios-año. El retrasar el control de malezas hasta que estas tuvieron 8 ó 15 cm de altura, redujo el rendimiento en 15%, mientras que malezas de 30 cm de altura redujeron el rendimiento en hasta 21%. Sucrose blanca recuperable ha−1 (RWSH) también se redujo entre 8 y 16% si las malezas tuvieron 8 cm de altura. Estos resultados indican que las malezas son altamente competitivas con la remolacha y pueden asimilar grandes cantidades de N temprano en la temporada de crecimiento, especialmente en estados de crecimiento más grandes. Sin embargo, parece que las remolachas fueron capaces de buscar y absorber suficiente N a las dosis de N usadas en este estudio, para compensar los efectos de la remoción de N por las malezas más grandes, lo que resultó en la ausencia de interacciones entre la dosis de N y el momento de remoción de malezas en el rendimiento, calidad y RWSH de la remolacha.

Winter wheat is a widely cultivated crop that requires high inputs of nitrogen (N) fertilization, which is often connected with N losses. The application of fertilizers with nitrification (NI) and urease inhibitors (UI) is an opportunity to eliminate the risk of N losses and improve N availability to plants. The aim of this study is to compare the effect of conventional nitrogen fertilizers with fertilizers containing nitrogen-transformation inhibitors as well as to evaluate the timing of their application on the wheat-grain yield and quality under the conditions of a three-year field experiment. The examined fertilizers with inhibitors were applied in a single dose or in a split application in combination with conventional fertilizers. The single application of urea with NI and/or UI resulted in a relatively average increase in the grain yield, while protein content and the Zeleny-test values were significantly increased compared to the split N application. The more significant effect of urea with NI and UI was found under the moisture-rich conditions compared to the drier conditions. A significant increase in the grain yield (by 6.3%) and in the Zeleny-test value (by 16.5%) was observed after inhibited urea application comparing to the control treatment (without inhibitors).

Studies were conducted in 2002 and 2003 on a golf course fairway in New Jersey to compare spring, summer, and fall treatments of bispyribac-sodium for annual bluegrass control and creeping bentgrass tolerance. Single applications at 74, 111, or 148 g ai/ha were applied in May, August, or October. Split applications of 37 followed by (fb) 37 or 74 fb 74 g/ha applied 3 wk apart were also evaluated. Summer-applied bispyribac-sodium did not reduce bentgrass quality, whereas spring and fall treatments reduced turf quality at 3 wk after treatment and fall treatments in 2002 substantially reduced bentgrass quality. Summer treatments were more effective than spring or fall treatments in reducing annual bluegrass cover. Final evaluations revealed 36, 31, 21, and 26% annual bluegrass cover averaged across nontreated, spring-treated, summer-treated, and fall-treated plots, respectively. This study demonstrates that two split applications of bispyribac-sodium at 74 g/ha in summer can effectively reduce annual bluegrass cover while minimizing creeping bentgrass injury.

Eclipta is a seed-borne summer annual that is problematic in the production of containergrown landscape plants. Halosulfuron at 70 g/ha is registered as a directed application to landscape areas but not to container-grown landscape plants. Halosulfuron was applied preemergence (PRE) to seeded eclipta and postemergence (POST) to progressively older eclipta seedlings at rates ranging from 0.18 to 100 g/ha. For halosulfuron PRE treatments, eclipta control was determined from the foliage weight of surviving seedlings. For halosulfuron POST treatments, control was determined from the weight of foliage regrowth following the removal of the treated foliage 2 wk after treatment. Nonlinear regression and log-logistic analysis indicated that the rate required for 90% control (I90) for halosulfuron PRE was 45 g/ha. For halosulfuron POST, the 190 was 60 g/ha for plants having five or fewer true leaves and 98 g/ha for plants that had lateral branching from the basal crown. Analysis estimated the 190 for flowering-sized eclipta exceeded 300 g/ha. Selective placement studies revealed that the phytotoxicity resulting from POST treatments occurs by foliar and root uptake, with foliar exposure having greater activity. For POST treatments that were limited to foliage-only contact, a split application increased control up to 25% compared with a single application of the same total dosage. However, control remained inadequate because the rate required for 75% control (15) was 157 and 121 g/ha for single and split applications, respectively. Halosulfuron sorption by a pine bark-based rooting substrate, as used in container production, was 96% of the amount applied. The propensity for surface-applied halosulfuron to be leached in this substrate was evaluated by eclipta bioassay. After 2 wk, with 23 cm of cumulative irrigation and rainfall, halosulfuron was detected 12 cm below the substrate surface. The propensity for substrate-adsorbed halosulfuron to return to the water phase may also contribute to PRE activity for eclipta control.

Field experiments were conducted in 1999 and 2000 to evaluate reduced-rate split-applied treatments of imazamethabenz and ICIA 0604 for wild oat control in hard red spring wheat. Single herbicide treatments were applied at standard timing to wild oat at the two- to four-leaf stage. The first split-applied treatments were made when most of the wild oat had emerged but prior to the two-leaf stage. The second split-applied treatments were made after the surviving wild oat had visibly recovered and prior to the two-leaf stage of late-emerging wild oat. Split applications of imazamethabenz or ICIA 0604 allowed the herbicide rate to be reduced by half while maintaining or improving wild oat control. Both imazamethabenz and ICIA 0604 were most effective with methylated vegetable oil adjuvants. Wheat yield and net returns were greatest for half-rate split applications of imazamethabenz and ICIA 0604 in both years, likely because of less early-season wild oat competition and reduced wheat injury caused by ICIA 0604.

Split application of herbicides for wild oat control may minimize wild oat competition with wheat while reducing the number of wild oat seeds returned to the soil. Field experiments were conducted in 2000 and 2001 to evaluate the effects of CGA-184927, fenoxaprop-P, flucarbazone, and ICIA 0604 at labeled and reduced rates on wild oat control, wild oat seed rain, and wheat yield. Each herbicide was applied once at 25, 33, and 100% of the labeled rate at the two-leaf stage of wild oat or split applied at 50 and 66% of the full rate as two equal applications. Excellent full-season wild oat control was obtained with CGA-184927, flucarbazone, and ICIA 0604 applied twice at reduced rates. ICIA 0604 or CGA-184927 split applied at 25 and 33% rates (totaled 50 and 66% of the full rate) provided wild oat control equal to one application of labeled rates. Wild oat seed rain was similar among all herbicide treatments, except plots treated with fenoxaprop-P once at 25 and 33% rates where seed rain was higher and equal to 47% of untreated plots. Wheat yields and net returns were highest and similar after treatment with CGA-184927 or ICIA 0604 applied either once at the labeled rate or split applied at 25 or 33% rates.

A field experiment was conducted in China during winter season of 2001–2002 to study the response of time of nitrogen application on two cultivars (Xiumei 3 and 92-11) of barley. Apart from basal dose of 40 kg N/ha, 110 kg N/ha was applied at tillering (T 1) or in two equal splits at tillering and boot stages (T 2) or at boot stage (T 3). Cultivar 92-11 attained significantly lower plant height at boot stage and number of spikes/plant but took significantly more number of days to heading, registered significantly more chlorophyll content in leaves at different growth stages, produced significantly more number of grains/spike, grain weight/spike, single grain weight, N concentration at boot stage and consequently produced significantly higher grain yield (3764 kg/ha) than cultivar Xiumei 3 (3201 kg/ha). Application of nitrogen at boot stage significantly reduced the plant height at both stages, dry matter accumulation, days taken to heading, leaf chlorophyll content at boot stage, grains per spike, grain weight per spike and individual grain weight but recorded significantly higher chlorophyll content in leaves at heading stage and higher N content as compared to its application at tillering. Split application of nitrogen at tillering and boot stages also recorded significantly better growth and yield attributes, N concentration and grain yield than its application at boot stage alone but was at par with nitrogen applied at tillering except grain weight per spike. Consequently application of nitrogen at tillering or its split application at tillering and boot stages produced statistically similar (4052 and 3816 kg/ha, respectively) but significantly higher grain yield than its application at boot stage (2500 kg/ha).