September Sowing Research Articles

Growth and yield response of Kenaf (Hibiscus cannabinus L.) seed production to different sowing times

An experiment was conducted during 2020-21 at Jute Research Substation, Jashore, to study growth and seed yield response of kenaf to different sowing times. Seeds were sown from 15 July to 1 October, an interval of 15 days, as treatment variables under RCBD design with three replications. Greater seed yield was obtained from the 1st September sowing, which was at par with 15 September and 15 August sowings values. So, maximum seed production of kenaf may be ensured with optimum seed sowing between the 1st and 15thof September. J. Bangladesh Acad. Sci. 46(2); 219-221: December 2022

The Impact of Sowing Date on Soil Mineral Nitrogen Uptake Efficiency and Fertilizer N Uptake Efficiency for Winter Oilseed Rape (Brassica napus L.) in Ireland

Nitrogen (N) application on winter oilseed rape (Brassica napus L.; WOSR) in the mild Atlantic climate of Ireland is based on a soil N Index system, which does not take into account any variations in crop N demand prior to the main spring dressing of N fertilizer. This study tests whether UK- canopy management (CM) principles for oilseed rape N fertilization are applicable for oilseed rape grown in Ireland. The tested principles included (i) final N uptake of unfertilized crops will be equivalent to the soil mineral N (SMN) and N in the crop measured at the end of winter, i.e., soil N uptake efficiency (SNUpE) = 1; and (ii) the (apparent) N fertilizer N uptake efficiency, (FNUpE) is 0.6 (60%). Three years of field trials were carried out from 2017/18 to 2019/20 on different sites based on a split-plot design. Three sowing dates (SD): mid-August (SD1), End-August (SD2) and mid-September (SD3) were set as main plots and five N application strategies namely, CM standard, CM higher yield, CM low N rate, Fix225 and zero-N were set at subplot level. Results from unfertilized plots demonstrated that the ratio of final crop N uptake at harvest to the combined post-winter SMN + crop N was 1.13 and 1.14 on the two early sowing dates but 1.68 for the latest sowing. Additionally, SMN was not systematically impacted by SD, except in site-year-2. Instead, crop N content in spring had the biggest influence when calculating soil N supply for the season. More mineralization occurred through the growing season resulting in SNUpE of above 100% on all SDs. This additional available N (AAN) was quantified as 11 kgN·ha−1 on average for SD1 and SD2 and 38.6 kgN·ha−1 for SD3. FNUpE values were calculated closest to the economical optimum N rate (Nopt) and were 0.534, 0.574 and 0.486, respectively for SD1, SD2 and SD3. The Nopts at each SD were 157 kgN·ha−1 (SD1), 148 kgN·ha−1 (SD2) and 175 kgN·ha−1 (SD3) and the respective yields at each Nopt were 4.93 t ha−1, 4.90 t·ha−1 and 4.34 t·ha−1. This study shows the UK–CM principles were applicable in the mild Irish climate; however, values of SNUpE and FNUpE differ from one site-year-SD to another. Mid-August to early September sowing dates produced higher post-winter crop N content due to SMN uptake, and this results in a lower Nopt than the later SD. Sowing later led to a higher Nopt due to a combination of lower post-winter N uptake and lower FNUpE, although the effect of these factors was partially offset by a greater AAN. Measurements of SNS post-winter, an estimate of N mineralization during the growing season, together with a consideration of the sowing date helped determine the scope for reduction in fertilizer while achieving high yield and high FNUpE. Among different N rate strategies, CM standard and CM high yield were closest to the Nopt for having lower N rates at the maximum economical yield point.

Baseline Maps of Autumn Wheat Yield using Geographic Information Systems for The Samtskhe-Javakheti Region

In food production, not only the level of production but also its quality indicators are of great importance. The quality of wheat grains depends on the variety, climatic conditions and cultivation technology. Agro-climatic conditions affect not only wheat yield but also grain quality. In studying the timing of sowing of the wheat crop, we tried to determine the effect of sowing timing and climatic conditions on wheat yield and quality. The vegetation period of wheat was characterized by different natural-climatic conditions, which were manifested by the drought of autumn and the sharp variability of high temperatures in spring. The study used wheat varieties common in the region: Tbilisi 15, Red Doli bread of Akhaltsikhe and Sauli 9. On the content of chemicals in grains, we conducted an experimental study. Phenological observations were made during the vegetation period: emergence, recording, pruning, plant resistance to dormancy, disease resistance. As a result of the analysis of the research, we found: • Based on the data obtained from the studies, we can say that the optimal sowing date of wheat in the Samtskhe-Javakheti region is 1-15 October. • Previously, the optimal sowing dates were considered September 15-October 15. The data we obtained convinced us that wheat sown in September had significantly lower yields than wheat sown in early October (8%, 11%, and 20%). Delayed sowing after October 15 reduces crop yields by 65-75%. • It is important for farmers to reduce the optimal sowing time, which means that sowing should be carried out in a short time, 10-15 days. • Taking into account the optimal dates of wheat sowing in the Samtskhe-Javakheti region will allow us to dramatically increase the yield. In addition, the results of the experiment showed that the quality and yield of grain depend on the dates of sowing, as well as the biological characteristics of the variety, soil-climatic and agrotechnical conditions.

Assessment of production potential of long-linted Gossypium arboreum L. genotypes under different sowing times

BackgroundGossypium arboreum is one of the cultivated diploids which has inherent resistance against insect pests and diseases, can withstand moisture stress, needs less nutrients and is suitable for erratic, less rainfall and marginal soils. Due to its smaller boll size and poor locule retentivity, adoption of species by farmers is very low. So, best long-linted G. arboreum genotypes with high yielding potential and suitable sowing time will be identified for rainfed tracts of cotton cultivated areas in India.ResultsThe pooled analysis results found that the significantly highest mean seed cotton yield was recorded with Phule Dhanwanthry (1069 kg/ha) which was on par with K12 (1027 kg/ha), DLSA 17 (977 kg/ha) and PA 812 (951 kg/ha). Planting at 4 August yielded the significantly higher seed cotton yield (1345 kg/ha) in comparison with 4 September sowing (536 kg/ha). The interaction results in pooled data revealed that Genotype PA 812 planted at 4 August registered the significantly highest seed cotton yield (1487 kg/ha) which was on par with all genotypes sown on 4 August except PA 402. Amongst long-linted genotypes, PA 760 recorded the significantly highest upper half length (29.9 mm), mean length (24.9 mm) and fibre strength (27.0 g/tex) and fibre quality index (349.7); which was on par with DLSA 17, PA 812 and PA 402. The quality characters had not been influenced significantly by different times of sowing.ConclusionsThe results concluded that the significantly highest mean seed cotton yield was recorded with Phule Dhanwanthry (1069 kg/ha) which was on par with K12 (1027 kg/ha), DLSA 17 (977 kg/ha) and PA 812 (951 kg/ha). Planting at 4 August found that the significantly higher seed cotton yield (1345 kg/ha) in comparison with 4 September sowing (536 kg/ha). Amongst long-linted genotypes, PA 760 recorded the significantly higher fibre quality index (349.7)

Base-temperature, plastochron and chia (Salvia hispanica L. - Lamiaceae) yield for different sowing times

Chia is a plant whose seeds are used in cooking and is a natural source of omega-3 fatty acids, fiber and protein, as well as other important nutritional components such as antioxidants. The objective of this work was to estimate the base temperature, plastochron and chia seed yield for different sowing times in Cruz Alta, Rio Grande do Sul, Brazil. The experimental design was completely randomized and the treatments consisted of different sowing times (September, October and November). For the determination of the base temperature for node emission in the main stem of the plants, the method of least mean square error of linear regression between the number of nodes and the accumulated thermal sum was used. Regarding estimation of the plastochron at each sowing time, a simple linear regression was obtained between the number of nodes in the main stem and the accumulated thermal sum. Seed yield was measured at harvest. Sowing in times with air temperature below 19 ºC should be avoided so that the development of plants is not impaired. Plastochron ranges from 28.01 ºC to 32.26 ºC day for successive node emission in the main stem of chia plants and September sowing promotes higher seed yield.

Using a New Italian Ryegrass Variety having Capable Sowing in September and Sorghum-sudangrass Hybrid Variety for Year-round Cropping System in Warm Region

Using a New Italian Ryegrass Variety having Capable Sowing in September and Sorghum-sudangrass Hybrid Variety for Year-round Cropping System in Warm Region

Maize landraces management to avoid transgenic contamination, decreases yield and seed quality

Producing high-quality seeds for agroecological agriculture is needed because the plants will be exposed to a diversity of environments and management practices. Sowing times and population densities can influence the quality of seeds produced by landraces. Further, seeds for agroecological cultivation must not be contaminated by transgenes. In this context, it is necessary to know the agronomic performance of landraces outside of the recommended growing period to avoid gene flow with transgenic cultivars. Thus, the objective of this work was to determine the germination rate, vigor and sanitary quality of seeds of maize genotypes cultivated in an agroecological system at different sowing times and densities. A split-split-plot design was used in the 2016/2017 and 2017/2018 growing seasons. The physiological quality evaluation was based on germination and vigor tests, and the sanitary quality was obtained by visually examining the seeds. The results showed a significant simple effect of genotype, sowing time and density, as well as double and triple interactions among factors for all evaluated traits. The most suitable time for sowing the corn landraces evaluated in an agroecological system in western Santa Catarina is September, when the seeds exhibited the highest percentage of germination and vigor and there was a lower incidence of pathogens. At this time, a density of 55,000 plants·ha–1 had the best result for germination. Late sowing was tested to avoid gene flow from transgenic varieties that usually are sown in September, but the results indicated penalties, such as a decrease in seed yield and quality.

Crop growth and productivity of winter camelina in response to sowing date in the northwestern Corn Belt of the USA

Camelina [Camelina sativa (L.) Crantz] is a member of the Brassicaceae family, consisting of both winter and spring biotypes. In the northern Great Plains, USA, winter camelina has the potential to serve as a low-input oilseed crop for cover and/or as a source of oil used for advanced biofuels as well as human and animal consumption. Winter annual biotypes of camelina are well suited for double- or relay- cropping systems. The objective of this study was to determine optimum sowing dates for achieving the highest winter camelina seed yield as well as the delivery of several ecosystem services. The experiments were conducted in Fargo, ND in 2017–2018 and in Fargo and Prosper in 2018–2019 seasons. Six sowing dates from the end of June to mid-October were evaluated. The experimental design was a randomized complete block with four replicates at each location. A total of 700 pure live seeds m−2 were sown in each date. Fall stand counts ranged from 17 to 279 plants m−2 with greater stands at later fall sowing dates. Spring stand counts ranged from 7 to 84 plants m−2, with higher stand counts for sowing dates from the beginning to mid-September. Across plants in several sowing dates that survived the winter, seed yield ranged from 99 to 1317 kg ha-1. Results indicate that winter camelina sown before September usually does not survive the winter in this region. When winter camelina is used as a cover crop, sowing prior to mid-September was critical for biomass production and reducing soil residual nitrate. However, when winter camelina is harvested as a cash crop, the highest harvestable seed yield occurred with fall sowing in September and even as late as early October.

Effect of Planting Dates on Incidence of Legume Pod Borer (Maruca vitrata Geyer) on Cowpea (Vigna unguiculata (L.) Walp.) Varieties in Samaru Kataf, Kaduna State

Field experiment was carried out during 2018 cropping season to evaluate the effect of planting dates on incidence of legume pod borer Maruca vitrata on cowpea (Vigna unguiculata) varieties. The treatments consist of five varieties of cowpea (local variety, SAMPEA 6, SAMPEA 7, SAMPEA 8 and SAMPEA 10) which were sown at three different dates, 7th (early), 24th (Mid) August and 7th (early) September, 2018. The experiment was laid out in a Randomized Complete Block Design (RCBD) replicated three times. The number of M. vitrata larva on flowers, damaged pods and weight of grains were determined. The result showed that first sowing nearly August had less infestation by M. vitrata than those in mid August and differs significantly (P≤0.05) from those sown in September. All varieties sown in early and mid August had less M. vitrata infestation and produced higher grain yield of 533.33kg and 395.06 kg on SAMPEA 7 and SAMPEA 8, respectively compared to those sown in early September: 256.79 and 197.53 on SAMPEA 7 and SAMPEA 10, respectively. Local variety and SAMPEA 6 were the varieties with higher mean number of M. vitrata, higher pod damage and low grain yield. Therefore, SAMPEA 7 can be utilized in breeding program for the management of pod borer.

Effect of growing environmental conditions and months of sowing on quality and yield of carrot (Daucus carota L.) cv. New Kuroda

The present investigation entitled “Effect of growing environmental conditions and months of sowing on quality and yield of carrot (Daucus carota L.) cv. New Kuroda.” was carried out at Vegetable Research Station, Rajendranagar, Sri Konda Laxman Telangana State Horticultural University, Mulugu (V & M), Siddipet Dist., Telangana State. The study was conducted with six sowing times of carrot viz., M1 Sept 2nd week, M2 Oct 2nd week, M3 Nov 2nd week, M4 Dec 2nd week, M5 Jan 2nd week, M6 Feb 2nd week having two conditions viz., C1 open condition, C2 shadenet condition (35% shade). All the parameters interms of Percentage of root forking,Percentage of root cracking, Percentage of root rotting, Core thickness, Cortex to core ratio were significantly differed among the sowing times at different conditions. The lowest percentage of root forking (4.46%) was found from the crop sown in September sowing whereas minimum root cracking (3.83%), root rotting (0.28%), core thickness (1.69cm) and maximum cortex to core ratio (1.12) were recorded in the October sowing month.

Soybean-corn succession according to seeding date

Abstract: The objective of this work was to evaluate the grain yield of soybean and corn cultivars cropped in succession, in different sowing dates. The experiment was carried out in the municipality of Dourados, in the state of Mato Grosso do Sul, Brazil, during three growing seasons, in the sowing dates: 9/15, 10/1, 10/15, and 11/1 for soybean; and 2/1, 2/15, 3/1, and 3/15 for corn. Although soybean yields are strongly affected by the crop season, sowing between late September and early October results in higher long-term yields. Planting corn in succession in mid-February provides the highest grain yield in the southern region of the state Mato Grosso do Sul; therefore, there is no need for an early soybean sowing in September, in order to ensure corn planting in January. Soybean-corn succession in which soybean is sown in early October and corn in mid-February results in higher total grain yields and reduces the climatic risk associated with these crops in the region.

Rice TKM 13: A high yielding medium duration fine grain variety

Medium duration fine grain rice culture TM 07275, a cross derivative of WGL 32100 / Swarna was released as Rice TKM 13 by State Variety Release Committee (SVRC) during 2015 as an alternate variety to BPT 5204. Rice TKM 13 is a semi-dwarf, erect, high tillering and non lodging variety and matures in 125-130 days. This variety is best suited for thaladi season (September sowing) of Cauvery delta region and samba season (August-September sowing) of other districts in Tamil Nadu. In the overall mean performance, the variety has recorded a overall mean grain yield of 5938 kg/ha in 159 locations which was 6.2 and 10.1 per cent increase over the check varieties CO (R) 49 (5592 kg/ha) and BPT 5204 (5390 kg/ha) respectively. It has medium slender fine grain with 1000 grain weight of only 13.8 g, which is lesser than all medium duration rice varieties. The rice is translucent with high milling (75.5%) and head rice yield (71.7%), which is on par with the check variety BPT 5204. Cooking quality and organoleptic characters are comparably similar to BPT 5204. It is moderately resistant to leaf folder, stem borer, GLH, blast, RTD, brown spot and sheath rot, which are its added advantages. In National trials conducted in 101 locations, TKM 13 has recorded a grain yield of 5201 kg/ha which was 11.2 per cent increase over the national check variety IR 64. Based on the superior performance, the variety was identified by Variety Identification Committee (VIC) for Central Variety Release Committee (CVRC) release in the western states viz., Gujarat and Maharashtra

Effects of the nutrient supply and sowing time on the yield and the phytopathological traits of winter oilseed rape (Brassica napus var. napus f. biennis L.) on chernozem soil

We have studied the fertilizer response of oilseed rape on the chernozem soil in Eastern Hungary in a three-year experiment (years of 2009/2010, 2010/2011, 2011/2012) in two sowing times (end of August, middle of September). Our research results proved that oilseed rape has high fertilizer (N+PK) demand. In the experiments, N = 210 kg ha-1 +PK proved to be the optimal fertilizer dose. The yield increasing effect of fertilization was 800 to 1300 kg ha-1, depending on the cropyear. The maximum yield (5000 kg ha-1) was obtained in the cropyear of the less infection. The excellent natural nutrient providing ability of chernozem soil was confirmed by the high yield level (3000-4200 kg ha-1) of the control treatment (N = 0 kg ha-1 +PK). According to our studies, as an effect of the increasing N doses, the specific fertilization yield surplus of oilseed rape declined (from 19-27 kg/1 kg NPK to 11-12 kg/1 kg NPK). On the other hand, fertilization improved the water utilization efficiency (WUE) of oilseed rape in the experimental years (from 4-8 kg/1 mm precipitation + irrigation water to 11-14 kg/1 mm precipitation + irrigation water). The results of our studies confirmed that the hybrid rape had of excellent adaptation to the sowing time; due to this fact, the yield decrease was minimal (0-270 kg ha-1) in the middle September sowing time compared to the late August one. According to the results of the Pearson’s correlation analysis, strong correlation (0.6*-0.9**) was found between the spring precipitation and temperature and the most important diseases (Sclerotinia, Alternaria, Peronospora, Phoma) of oilseed rape.

Estimation of Planting Dates for Roselle (<i>Hibiscus sabdariffa</i> L.) in the Humid Tropical Environment of Owerri, South-eastern Nigeria.

In order to fill the gap existing between the production and consumption of roselle in the humid tropical areas of Nigeria, this experiment was carried out in Owerri between May and December, 2012 to evaluate the effects of planting dates and accessions on the growth and performance of roselle (Hibiscus sabdariffa). Six planting dates including planting at monthly intervals from May to October and two accessions (Purple calyx and Green calyx) were evaluated. The experiment was laid out as a 2 x 6 factorial in Randomized Complete Block (RCB) with three replications. Results revealed that all roselle crops planted in May through August flowered within the same period (26 – 29th September) which coincided with the period of short days in the northern hemisphere. Consequently, roselle planted in May produced flower buds significantly (138 days after planting) compared to other dates. July sown roselle in addition to producing flower bud relatively earlier (80.2 days after planting), had comparably higher number of flower buds/plant and calyx length. Roselle sown in September and October however did not flower. For use as vegetables in soup making, green calyx roselle should be sown in May and harvested not later than 8 weeks after planting. Planting in July appears to favour early flowering and is appropriate for purple calyx roselle.Keywords: Roselle, Accession, Planting Date, Month, Calyx Length

Autumn terms of sowing of turf grasses and legumes and their initial development

The most frequent way to establish turfgrass in the climatic conditions of the Czech Republic is sowing during spring period. The seedlings are endangered by lack of soil moisture and by high temperatures if irrigation is no available. One of the possibilities how to increase probability of successful turfgrass establishment in warm areas which suffer by low amount of precipitation is autumn term of sowing.Eight grass species and subspecies and two legumes were sown in three autumn terms (September, October and November) during 2009 and 2010. The shortest time for seedling emergence was found in average of all terms atMedicago lupulinaandTrifolium repens(9 days).Lolium perenne(14)and Festuca arundinacea(17) were the fastest emerged grasses. On the other hand the longest emergence time was realised atPoa pratensis(23),Festuca rubra ssp. trichophyla(22)andFestuca ovina(21). Plants sown in September emerged in 10 days, in October 12 and in November in 29 days. September term was suitable for all used species but November term underwent most successfullyFestuca rubrassp.commutata(23% soil cover in April next year)andLolium perenne(19%). November term was not acceptable for legumes.

Accumulated heat unit and phenology of diverse maize varieties as affected by planting dates under Rampur condition, Nepal

Accumulated heat unit and phenology of a full season open pollinated and three specialty corn (Zea mays L.) cultivars (Hybrid, QPM and Pop) were studied by growing them on three different planting dates (September 1, October 1 and November 1) in RCB design at Rampur Chitwan, Nepal during the winter season of 2009-10. The results indicated that the number of days required to attain different phenological stages were short for the early winter and gradually long for late winter plantings. For all the phenological studies, plants of normal sowing condition (September 1) recorded comparatively higher heat units than the late planting (October 1 and November 1) for all cultivars. Both early and late plantings recorded the higher helio-thermal units at advanced growth phases than at the early stages. The pheno-thermal indices at the earlier growth stages were significantly higher for early planting than the late plantings. The heat use efficiency (HUE) was found to be higher under normal planting as compared to the late plantings. Popular maize variety Rampur Composite was found to be the most suitable to produce stable HUE than the other varieties tested. The specialty corn cultivars could not show stable yield in late planting conditions suggesting their planting could be better for September sowing during early winter seasons. DOI: http://dx.doi.org/10.3126/ajn.v2i0.7526 Agronomy Journal of Nepal (Agron JN) Vol. 2: 2011 pp.111-120

Effect of planting time and spacing on growth characteristics of yellow lantern chilli (Capsicum chinense)

Yellow lantern chilli [(Capsicum chinense (Jacq.)], the world’s hottest chilli is mostly grown in the north eastern part of India. The crop is cultivated by traditional ways since time immemorial. However, very little research towards scientific cultivation has been conducted in the past and until now scientific package of practices is not available. In the present investigation, the effect of various planting time and spacing on the growth characteristics of the hottest chilli, yellow rantern chilli (bhoot jolokia) was studied in north-eastern hill region of India. Seeds of the variety local cultivar, bor Bhoot of bhoot jolokia were planted in four different dates i e September 15 (P1), October 15 (P2), January 15 (P3) and February 15 (P4) with three spacings viz. 75cm × 75cm (S1), 90cm × 90cm (S2) and 105cm × 105cm (S3). The results revealed that the growth parameters and yield attributing characters were significantly influenced by different planting dates and spacings. Sowing in September 15 (P1) and with a spacing 105cm × 105cm (S3) were recorded the highest plant height, number of primary branches, number of fruits/plant, fruit weight and fruit yield/plant. In case of phyllochron index September 15 sowing showed maximum days to phyllochron but closest spacing 75cm × 75cm showed maximum phyllochron. Among all the treatments, the crop sown in September with a spacing of 105cm × 105cm showed better performance for all the parameters studied and can be considered basis for studying the effects of other agronomic practices.

Complex evaluation of agrotechnical factors in rape seed

A polifactorial field trial with rape was carried out in the crop-years of 2007/2008 and 2008/2009 at the Látókép Research Centre of University of Debrecen, 15 km away from Debrecen. The soil type of the research area was a calcaric chernozem, with a levelled and homogeneous surface. Our investigations on the dynamics of lodging proved that rape can easily be lodged under unfavourable weather conditions, which results in a significant crop failure: In crop-year 2009 yields were 1.0-1.5 t ha-1 higher than in 2008, when the weather conditions were more unfavourable. In both crop-years the influence of sowing time on the crop yield of rape was examined in three soil cultivation systems, with ploughing, loosening or disking. Different sowing time influenced the yield of rape in both crop-years significantly. In the crop-year of 2007/2008 – due to mild winter – we got the highest yield in the first sowing time (at the end of August) with loosening (3930 kg ha-1) and disking (3727 kg ha-1), while in case of ploughing we experienced the highest yield (3770 kg ha-1) in the second sowing time. There were no significant differences between the first and second sowing time (the end of August and the beginning of September), and in the third sowing time (end of September) also a moderate crop failure (-6.7%) cold be obtained, due to the favourable weather in winter and the water supply of the crop-year 2007/2008. In 2008/2009 all the three cultivation systems showed the best yield-results in the second sowing time (ploughing: 4886 kg ha-1, loosening: 5186 kg ha-1, disking: 5090 kg ha-1), and the first sowing time hardly differed from this (-4.1%), while the late September sowing time resulted in a significant crop failure of -11.1%.

Crop growth and nitrogen turnover under increased temperatures and low autumn and winter light intensity

The rise in mean annual temperatures under the projected climate change will affect both soil organic matter turnover and cropping patterns in agriculture. Nitrogen (N) mineralization may be higher during autumn and winter and may increase the risk of nitrate leaching. Our study tested whether a soil cover of winter wheat or a ryegrass catch crop would be able to take up the extra N mineralized during autumn and winter under the low light conditions in Northern Europe, both at current average temperatures ( T 0) and at 4 °C ( T +4) and 8 °C ( T +8) above average. The crops were grown in pots in growth chambers from mid-September to February. Two sowing times were included for winter wheat, with an early sowing in September representing current practice and a late sowing in October to reflect possible future cropping conditions. Biomass yield and soil inorganic N were determined from replicate pots in November, December and February. Reference pots with bare soil were included. N mineralization clearly increased with higher temperatures with, respectively, 22% and 80% more N mineralized in bare soil at T +4 and T +8 than at T 0 after 136 days. The ryegrass catch crop emptied the soil of inorganic N very efficiently during both autumn and winter months at all temperatures. The early-sown wheat crop left negligible amounts of inorganic N in the soil at the last harvest in February at T +4 and T +8, whereas it was unable to take up all mineralized N at T 0. The prolonged period without a crop before the late sowing of wheat caused generally higher levels of inorganic N to accumulate in soil. Despite the higher mineralization under the raised temperatures, at T +8 the late-sown winter wheat was able to reduce soil inorganic N to a lower level than late-sown wheat at the two lower temperatures. The results indicate that even at the low light intensity during autumn and winter, accelerated N mineralization caused by raised temperatures can potentially be offset by crop N uptake. However, sowing should take place sufficiently early in the autumn to give the crop time to capture the additional N mineralized during autumn, and this may collide with the projected need for later sowing of winter cereals under a warmer climate.

Desempenho de quatro genótipos de soja-hortaliça em dois anos agrícolas

Com o objetivo de avaliar o desempenho de quatro genótipos de soja-hortaliça, em dois anos agrícolas, foi instalado um ensaio, em área da UNESPFCAV, Campus de Jaboticabal-SP. O delineamento experimental adotado foi de blocos casualizados, com quatro genótipos e cinco repetições, para cada ano agrícola. Cada parcela experimental foi constituída por quatro linhas de plantio, com 3 m de comprimento, dispostas no espaçamento de 0,10 m entre plantas e 0,60 m nas entrelinhas, sendo consideradas para avaliação 20 plantas por parcela, das duas linhas centrais. As sementes foram semeadas em bandejas de poliestireno expandido de 128 células, contendo substrato Plantmax Hortaliças®. O transplante ocorreu dez dias após a semeadura, sendo que o solo já estava devidamente preparado, conforme recomendações para a cultura. A colheita foi realizada quando as vagens estavam em estádio reprodutivo R6. Avaliaram-se os genótipos: JLM003; JLM010; JLM018 e CNPSoI quanto às características: altura de inserção da primeira vagem, número médio de vagens por planta, número médio de sementes por vagem, produção de vagens por planta, massa fresca de 100 sementes e produtividade estimada de grãos imaturos. De acordo com os resultados obtidos, concluiu-se que, dentre os genótipos avaliados, JLM003, JLM010 e CNPSoI foram os mais produtivos, e quando semeados em dezembro apresentam produtividades maiores do que quando semeados em setembro.