Higher Crop Growth Rate Research Articles

Screening chickpea for adaptation to water stress: Associations between yield and crop growth rate

Abstract Robust associations between yield and crop growth rate in a species-specific critical developmental window have been demonstrated in many crops. In this study we focus on genotype-driven variation in crop growth rate and its association with chickpea yield under drought. We measured crop growth rate using Normalised Difference Vegetative Index (NDVI) in 20 diverse chickpea lines, after calibration of NDVI against biomass accounting for morphological differences between Kabuli and Desi types. Crops were grown in eight environments resulting from the combination of seasons, sowing dates and water supply, returning a yield range from 152 to 366 g m −2 . For both sources of variation – environment and genotype – yield correlated with crop growth rate in the window 300 °Cd before flowering to 200 °Cd after flowering. In the range of crop growth rate from 0.07 to 0.91 g m −2 °Cd −1 , the relationship was linear with zero intercept, as with other indeterminate grain legumes. Genotype-driven associations between yield and crop growth rate were stronger under water stress than under favourable conditions. Despite this general trend, lines were identified with high crop growth rate in both favourable and stress conditions. We demonstrate that calibrated NDVI is a rapid, inexpensive screening tool to capture a physiologically meaningful link between yield and crop growth rate in chickpea.

EFFECT OF SOWING DATE AND IRRIGATION INTERVALS ON GROWTH CHARACTERS OF SOME WHEAT CULTIVARS.

The Field experiments were conducted out during the twosuccessive winter seasons of 2012/2013 and 2013/2014 at theExperimental Farm (Demo) of the Faculty of Agriculture, at FayoumUniversity , Egypt .The aim of these experiments was to evaluate growthcharacter of some wheat cultivars under different sowing dates anddifferent irrigation intervals . The experiment was laid out in split - splitplot design with four replicates and comprised of three dates of sowing,namely 1st November, 15th November and 30th November in main plotsand three irrigation intervals, namely, Irrigation every 21(I1) days,Irrigation every 28 (I2)days, Irrigation every 35( I3)days, in sub- plots andthree wheat cultivars namely, Sakha 93, Sakha 94, and Sids 12 in subsub-plots. Results showed that the Wheat cultivars significantly differedin all growth characters. Sids 12 cultivar surpassed the other varieties inall characters under this study. On the other hand, significant differenceswere observed among irrigation intervals for plant height and number ofleaf per plant at ripping stage, while dry weight per plant and leaves area/plant at two growth stages. Moreover the greatest value were obtained byirrigation every 21 days. sowing dates shown significant effect on plantheight, number of leaf per plant, dry weight per plant, leaves area /plant atflowering and ripping stages as well as crop growth rate and relativegrowth rate. Late sowing date (30th November ) gave higher values fromdry weight/plant and leaf area/plant at flowering stage and highest numberof leaves/plant at two growth stages also high crop growth rate andrelative growth rate while moderate sowing date (15th November ) gavethe highest values from plant height at two growth stages, big leaf area perplant and dry weight per plant at ripping stage only. Significantdifferences were observed among sowing dates with irrigation intervals,sowing dates with wheat varieties, irrigation intervals with wheat varietiesand sowing date x irrigation intervals x wheat variety interactions on mostgrowth traits. The results showed that early sowing date followed bymoderate sowing date under irrigation every 21 or 28 days with Sids 12variety gave the highest values for most growth characters.

Analysis of yield-attributing traits for high-yielding wheat lines in southwestern Japan

Development of wheat cultivars that achieve high yields despite the short growing season is essential for increasing wheat production in southwestern Japan. The objectives of this study were to assess the genetic progress in grain yield and to clarify yield-attributing traits of high-yielding wheat lines in southwestern Japan. We conducted field experiments for two growing seasons (2012–2013 and 2013–2014) using three commercial wheat cultivars (Shiroganekomugi, Chikugoizumi, and Iwainodaichi) and four high-yielding wheat lines including Hakei W1380 developed in southwestern Japan. In an ancillary field experiment, we compared a commercial cultivar, Shiroganekomugi, and a high-yielding line, Hakei W1380, in the 2014–2015 season. Across the two seasons, grain yield of high-yielding lines was generally higher than commercial cultivars. Hakei W1380 achieved the highest grain yield across the two seasons, and successfully produced more than 900 g m−2 in the 2013–2014 season. Correlation analysis showed that recent yield progress of wheat lines in southwestern Japan was derived from enhanced biomass production and grain number m−2. Larger numbers of grains m−2 in high-yielding lines than in commercial cultivars were associated with higher crop growth rate at the pre-anthesis stage, and therefore higher spike dry weight m−2 at anthesis. Genotypic differences in crop growth rate from jointing to anthesis resulted mainly from differences in leaf area index. These results indicate that further improvements in grain yield in southwestern Japan could be achieved by increasing the amount of radiation intercepted at the pre-anthesis stage and grain number m−2.

POTENTIAL OF MORINGA (MORINGA OLEIFERA: MORINGACEAE) AS PLANT GROWTH REGULATOR AND BIO-PESTICIDE AGAINST WHEAT APHIDS ON WHEAT CROP (TRITICUM AESTIVUM; POACEAE)

Moringa oleifera commonly known as Moringa is a multipurpose plant. Field trials were conducted to assess the potency of Moringa leaf (MLE) and root extracts (MRE) as plant growth regulator (PGR) and a Bio-pesticide on wheat crop. At distinct crop growth stages (tillering, booting, and heading) with different concentrations (5, 10, 12.5, and 25% v/v or w/v or w/w) of MLE and MRE were applied. Results showed statistically significant increase in crop growth traits and reduction in aphid infestation (booting, milk, and heading stage). As plant growth regulator maximum leaf area duration (LAD), leaf area index (LAI), and total dry matter accumulation (TDM) were recorded at all growth stages for MLE 25%. Highest crop growth rate (CGR) (24.91 gm-2day-1) at tillering was achieved for MLE 5%, 13.04 gm-2day-1 for MRE 10% at booting stage and 8.76 gm-2day-1 for MLE 10% at heading stage. Maximum thousand grains weight (57.33g), highest number of spikes per plant (9.67plant-1) and maximum grain yield (4446Kg hac-1) were determined for MLE 25%. The heading stage of the crop was heavily infested with aphids and MLE 5% significantly reduced pest infestation compared to other concentrations of MLE and MRE and control group. Overall, MLE and MRE proved very effective as plant growth regulator and a Biopesticide against wheat aphid on wheat crop.

Growth and dry matter partitioning in selected soybean (Glycine max L.) genotypes

The experiment was conducted at the experimental site of Agronomy Department, Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Salna, Gazipur during the period from January to June 2011 to evaluate twenty selected soybean genotypes in respect of growth, dry matter production and yield. Genotypic variations in plant height, leaf area index, dry matter and its distribution, crop growth rate and seed yield were observed. The plant height ranged from 40.33 to 63.17 cm, leaf area index varied from 3.01 to 8.13 at 75 days after emergence, total dry matter ranged from 12.25 to 24.71 g per plant at 90 days after emergence (DAE). The seed yield ranged from 1745 to 3640 kg per hectare. The genotypes BGM 02093, BD 2329, BD 2340, BD 2336, Galarsum, BD 2331 and G00015 yielded 3825, 3447, 3573, 3737, 3115, 3542 and 3762 kg per hectare, respectively and gave higher than others contributed by higher crop growth rate with maximum number of filled pods. Seed yield of soybean was positively related to total dry matter at 45 DAE (Y = 632.19 + 659.31X, R2= 0.46) and 60 DAE (Y= 95.335 + 405.53X, R2 = 0.48). The filled pods per plant had good relationship with seed yield (Y = 1397 + 41.85X, R2 = 0.41) than other components.Bangladesh J. Agril. Res. 40(3): 333-345, September 2015

A functional characterisation of a wide range of cover crop species: growth and nitrogen acquisition rates, leaf traits and ecological strategies.

Cover crops can produce ecosystem services during the fallow period, as reducing nitrate leaching and producing green manure. Crop growth rate (CGR) and crop nitrogen acquisition rate (CNR) can be used as two indicators of the ability of cover crops to produce these services in agrosystems. We used leaf functional traits to characterise the growth strategies of 36 cover crops as an approach to assess their ability to grow and acquire N rapidly. We measured specific leaf area (SLA), leaf dry matter content (LDMC), leaf nitrogen content (LNC) and leaf area (LA) and we evaluated their relevance to characterise CGR and CNR. Cover crop species were positioned along the Leaf Economics Spectrum (LES), the SLA-LDMC plane, and the CSR triangle of plant strategies. LA was positively correlated with CGR and CNR, while LDMC was negatively correlated with CNR. All cover crops could be classified as resource-acquisitive species from their relative position on the LES and the SLA-LDMC plane. Most cover crops were located along the Competition/Ruderality axis in the CSR triangle. In particular, Brassicaceae species were classified as very competitive, which was consistent with their high CGR and CNR. Leaf functional traits, especially LA and LDMC, allowed to differentiate some cover crops strategies related to their ability to grow and acquire N. LDMC was lower and LNC was higher in cover crop than in wild species, pointing to an efficient acquisitive syndrome in the former, corresponding to the high resource availability found in agrosystems. Combining several leaf traits explained approximately half of the CGR and CNR variances, which might be considered insufficient to precisely characterise and rank cover crop species for agronomic purposes. We hypothesised that may be the consequence of domestication process, which has reduced the range of plant strategies and modified the leaf trait syndrome in cultivated species.

Crescimento, índices fisiológicos e produtividade de cultivares de feijoeiro sob diferentes níveis de adubação

Conhecimentos sobre o acúmulo e a distribuição da fitomassa do feijoeiro comum, sob diferentes níveis de adubação, podem auxiliar no manejo da cultura. Este trabalho objetivou avaliar o crescimento, os índices fisiológicos e a produtividade de cultivares de feijão, sob diferentes níveis de adubação NPK. O experimento foi conduzido em um Nitossolo Vermelho distroférrico, no município de Botucatu, SP, no delineamento experimental de blocos casualizados, em parcelas subdivididas, com quatro repetições. As parcelas foram constituídas por seis tratamentos ('Pérola', sem adubação; 'Pérola', com 50% da adubação recomendada; 'Pérola', com 100% da adubação recomendada; 'IAC Alvorada', sem adubação; 'IAC Alvorada', com 50% da adubação recomendada e 'IAC Alvorada', com 100% da adubação recomendada) e, as subparcelas, por sete épocas de coletas no decorrer do ciclo. A adubação NPK aumentou os acúmulos de matéria seca, os componentes da produção e a produtividade de grãos dos cultivares Pérola e IAC Alvorada de forma semelhante. O cultivar IAC Alvorada apresentou maiores índices de área foliar e matéria seca de folhas, quando comparados com os de Pérola, sob adubação NPK recomendada, porém, sem esses índices refletirem-se em maior produtividade de grãos. O máximo acúmulo de matéria seca foi alcançado aos 80 DAE e a maior taxa de crescimento da cultura ocorreu aos 55 DAE, independentemente do tratamento.

English

Crop growth rate (CGR) response of three warm season C 4 -grasses (cereals) namely: corn ( Zea mays L., cv. Hybrid-5393 VT3), grain sorghum ( Sorghum bicolor L. Moench, cv. Hybrid-84G62 PAT), and foxtail millets ( Setaria italica , cv. German Strain R) grown in pure and mixed stands under low and high water levels was investigated at one month interval namely: 30, 60 and 90 days after emergence (DAE), in pot experiment at Dryland Agriculture Institute, West Texas AM but the CGR was reduced by 42% in the three crops mixed stand than the average of two crops mixed stand at 90 DAE. Corn mixed stand in two crops (average of corn + sorghum and corn + millets) had 78, 75 and 74% higher CGR than the mixed stand of sorghum and millets at 30, 60 and 90 DAE, respectively. Corn and millets mixed stand had 16, 9 and 38% higher CGR than the corn and sorghum mixed stand at 30, 60 and 90 DAE, respectively. Corn had higher CGR under high water at 30 DAE. There was no difference in the CGR of sorghum under low and high water levels at different growth stages. Millets had higher CGR under high water level at 30 DAE, but had lower CGR under high water level at 90 DAE. Among the three crops, corn plants had the higher CGR due to the highest total dry matter accumulation in both shoots and roots and was considered the best competitor in all the mixed stands. Grain sorghum ranked second, while foxtail millets ranked in the bottom in terms of competitiveness in the mixed stands. Keywords: Zea mays , Sorghum bicolor , Setaria italica , competition, water levels, crop growth rate. African Journal of Biotechnology , Vol 13(30) 3036-3051

Crop growth rate differs in warm season C4-grasses grown in pure and mixed stands

Crop growth rate (CGR) response of three warm season C 4 -grasses (cereals) namely: corn ( Zea mays L., cv. Hybrid-5393 VT3), grain sorghum ( Sorghum bicolor L. Moench, cv. Hybrid-84G62 PAT), and foxtail millets ( Setaria italica , cv. German Strain R) grown in pure and mixed stands under low and high water levels was investigated at one month interval namely: 30, 60 and 90 days after emergence (DAE), in pot experiment at Dryland Agriculture Institute, West Texas AM but the CGR was reduced by 42% in the three crops mixed stand than the average of two crops mixed stand at 90 DAE. Corn mixed stand in two crops (average of corn + sorghum and corn + millets) had 78, 75 and 74% higher CGR than the mixed stand of sorghum and millets at 30, 60 and 90 DAE, respectively. Corn and millets mixed stand had 16, 9 and 38% higher CGR than the corn and sorghum mixed stand at 30, 60 and 90 DAE, respectively. Corn had higher CGR under high water at 30 DAE. There was no difference in the CGR of sorghum under low and high water levels at different growth stages. Millets had higher CGR under high water level at 30 DAE, but had lower CGR under high water level at 90 DAE. Among the three crops, corn plants had the higher CGR due to the highest total dry matter accumulation in both shoots and roots and was considered the best competitor in all the mixed stands. Grain sorghum ranked second, while foxtail millets ranked in the bottom in terms of competitiveness in the mixed stands. Keywords: Zea mays , Sorghum bicolor , Setaria italica , competition, water levels, crop growth rate. African Journal of Biotechnology , Vol 13(30) 3036-3051

Physiological Attributes of Transplant <i>Aman</i> Rice (Cv. Brri Dhan52) as Affected by Tiller Seedlings and Urea Super Granules

The experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, Bangladesh to investigate the effect of age of tiller seedlings, number of tiller seedlings hill-1 and application of urea super granules (USG) on some physiological attributes of transplant Aman rice cv. BRRI dhan52. The experiment consisted of two ages of tiller seedlings viz. 25- and 35-day old, three levels of tiller seedlings hill-1 viz.1, 3 and 5 seedlings hill-1 and three USG levels viz. 0, 1.8g and 2.7g USG per four hills in every alternate row. The experiment was laid out in a randomized complete block design with three replications. The effect of age of tiller seedlings, number of tiller seedlings hill-1 and USG application were significant on crop growth rate (CGR), relative growth rate (RGR), net assimilation rate (NAR) and leaf area index (LAI). The highest CGR and RGR were found by transplanting 35-day old tiller seedlings during the period at 15-30 and 60-75 DAT when 5 tiller seedlings hill-1 were transplanted. The highest NAR was observed at 60-75 DAT with transplanting 5 tiller seedlings hill-1 and the lowest one was recorded at 30-45 DAT. The highest LAI was found at 35-day old tiller seedlings during the period at 60 and 75 DAT when 5 tiller seedlings hill-1 were transplanted. CGR and RGR were found highest by applying 1.8 g USG at 45-60 and 60-75 DAT while NAR was the highest with application of 2.7g USG at 60-75 DAT and lowest one was found in control (0 g USG) at 45-60 and 60-75 DAT. The highest LAI was found by applying 1.8g USG at 15, 30, 45 and 60 DAT and the lowest one was found at 60 DAT in control and at 15, 30 and 45 DAT when 2.7g USG was applied. The highest LAI and CGR were found in older tiller seedlings (35- day old) by transplanting five tiller seedlings hill-1 fertilized with 1.8g USG whereas the highest RGR and NAR were obtained in younger tiller seedlings (25-day old) by transplanting single tiller seedling hill-1 fertilized with 1.8g USG per four hills of every alternate row.DOI: http://dx.doi.org/10.3329/pa.v24i1-2.19094 Progress. Agric. 24(1&2): 17 - 27, 2013

Effect of Transplanting Dates and Plant Population on Growth Parameters of Potato (Solanum Tuberosum L.) Raised from True Potato Seed (Tps)

ABSTRACT A field experiment was conducted during the rabi season of 2007- 2008 and 2008-2009 at Paschim Medinipore, West Bengal to study the effect of transplanting dates and plant population on growth parameters of potato raised from TPS. Dry matter accumulation per plant was more in early transplanted (December 3) and sparsely populated (60 cm x 15 cm) crop. The highest leaf area index was observed in early transplanted crop with closer spacing (40 cm x 10 cm) at 60 days after transplanting. The highest crop growth rate, tuber bulking rate and tuber growth rate values were also recorded in early and closely transplanted TPS crop between 45- 60 days after transplanting during both the years under investigation

Yield comparison between dry seeded and transplanted rice in southern China

Field experiments were conducted at the Experimental Farm of Guangxi University, Guangxi province, southern China in early and late rice-growing seasons in 2012 to compare grain yield and yield attributes between dry seeded and transplanted rice. A hybrid rice cultivar Guiliangyou 2 was grown under dry seeding (DS) and dry transplanting (DT) in each season. Grain yield, yield components, tillering process, biomass production, growth duration, crop growth rate (CGR), leaf area index (LAI), leaf area duration (LAD) and net assimilation rate (NAR) were determined for each establishment method. DS produced higher and equal grain yield than DT in early and late seasons, respectively. The higher grain yield under DS in early season was attributed to improvement in both sink and source. For source, DS had significantly higher panicles/m2 than DT, which resulted in larger sink size (spikelets/m2). High tillering capacity was responsible for high panicles/m2 under DS. For the source, DS produced significantly higher biomass than DT during reproductive and grain-filling phases. High CGR was responsible for high biomass production under DS. High CGR under DS was attributed to high LAI, LAD and NAR during reproductive phase and to high LAI and LAD during grain-filling stage. No yield superiority observed under DS in late season might be associated with temperature. Mean temperature was lower in late season than in early season by 5.8°C during grain-filling phase. Our results suggest that multi-year and multi-location field experiments should be conducted in future to determine the yield stability of dry seeded rice.

Crescimento, acúmulo de nutrientes e fixação biológica de nitrogênio de Flemingia macrophylla

Flemingia macrophylla é uma leguminosa arbustiva asiática, pouco conhecida no Brasil. Este trabalho objetivou avaliar a produção de massa seca, o acúmulo de nutrientes e a fixação biológica de nitrogênio (N2) de flemingia. Conduziram-se dois experimentos de campo, entre dezembro de 2006 e dezembro de 2007, em Seropédica, RJ, e em Avelar, RJ. O delineamento experimental utilizado em ambos os experimentos foi de blocos casualizados, com quatro repetições, e os tratamentos foram as diferentes épocas de amostragens. A área foliar, a produção de matéria seca e o acúmulo de nutrientes da parte aérea foram determinados em 12 coletas mensais. A contribuição da fixação biológica de N2 foi estimada pelo método da abundância natural de 15N. A massa seca da parte aérea atingiu 4,0 Mg ha-1 em Seropédica e 2,3 Mg ha-1 em Avelar, aos 360 dias após transplante (DAT). O menor crescimento em Avelar foi associado ao inverno mais frio e seco, em relação a Seropédica. A taxa de crescimento da cultura atingiu valor máximo aos 165 DAT, na primeira floração. O acúmulo de N, P, K, Ca e Mg na parte aérea foi de, respectivamente, 74, 5, 33, 25 e 8 kg ha-1 aos 360 DAT. A percentagem de N, proveniente da fixação biológica de N2 em flemingia, foi de aproximadamente 76%, o que propiciou 57 kg ha-1 de N oriundo da fixação biológica, na parte aérea, aos 360 DAT. Os resultados indicam que flemingia é uma espécie que pode contribuir com quantidades significativas de biomassa e nutrientes, especialmente N, sendo promissora para uso como adubo verde e em cultivos em aleias, em sistemas de produção.

How does soil fertility affect yam growth?

Yams (Dioscorea spp.) are known to be very demanding in terms of soil fertility. The influence of deleterious soil fertility on the growth of yams, however, has not yet been studied. A field study was carried out in Côte d'Ivoire, in a fertile forest site and in a low fertility savanna site, submitted to identical climatic conditions, to determine how soil fertility affects Leaf Area Index, Leaf Area Ratio, Crop Growth Rate, Tuber Bulking Rate, Radiation Interception, Radiation Use Efficiency and final tuber yields in D. alata and D. rotundata, grown in the presence of adequate fertilizers. While germination and establishment of both species were not affected by the site, growth parameters of D. alata were superior to those of D. rotundata. This resulted in higher yields of D. alata, when compared to D. rotundata. Only the radiation use efficiency was higher in D. rotundata than in D. alata. Both species reached higher Crop growth rate and Tuber bulking rate and produced higher fresh tuber yields at the forest site than at the savanna site, reflecting the known demand of yams for high fertility soil. Correlation analyses showed significant relationships between the mean Leaf Area Index measured over the entire growth period, Tuber Growth Rate calculated between tuber initiation and harvest, and fresh tuber yields, suggesting that the development of leaf area is determining the growth rate of the tuber which itself determines the fresh tuber yield. The decrease in D. alata tuber yields at the savanna site was explained by a decrease in Leaf Area Index, while the decrease in D. rotundata tuber yields at this site was explained by a decrease in Radiation Use Efficiency. Both effects might have been the consequence of a suboptimal nitrogen and potassium nutrition at the savanna site.

Field appraisal of seed priming to improve the growth, yield, and quality of direct seeded rice

Poor crop stand and high weed infestation are the major constraints of direct seeded rice. Seed priming has the potential to improve the seedling emergence and crop stand. This study was conducted to evaluate the on-farm assessment of direct seeded rice by employing different priming techniques such as on-farm priming, hydropriming, hardening, and osmohardening with CaCl_2 and KCl. Untreated seeds were taken as control. Among all the seed priming techniques, osmohardening with CaCl_2 improved the stand establishment, allometric response, agronomic traits, yield, and quality of harvested paddy compared with other priming techniques, and non-primed control in direct seeded culture. Improved crop stand as indicated by lower values of time to emergence and higher values for emergence index and final emergence, higher crop growth rate, and improved plant height, tiller numbers, and straw and kernel yield with high harvest index were recorded from osmohardening with CaCl_2. In addition, seed priming treatments also improved the kernel quality. Osmohardening with CaCl_2 was the best way to reduce sterile spikelets, abortive and chalky kernels, and improve kernel length. However, none of the seed priming techniques could improve the number of kernels per branch, 1000-kernel weight, kernel width, and kernel water absorption ratio. Moreover, improved phosphorus, calcium, and potassium contents were also observed from osmohardening with CaCl_2 followed by KCl. Osmohardening with CaCl_2 can therefore be employed for better crop stand, growth, yield, and quality in direct seeded rice.

Adaptability of four cassava (Manihot esculenta crantz) cultivars in swampy inland valley ecology

Cassava is a popular dry season crop grown to utilize residual soil moisture in inland valleys. Trials to evaluate growth rates of four cultivars (TMS 4(2) 1425, TMS 91/02324, TMS 91/02327 and Isunikankiyan) were conducted along the toposequence in a 4 x 4 Latin square design. Effects of toposequence position, site, year and their interactions as well as of cultivar were significant for Leaf area index (LAI), net assimilation rate (NAR), crop growth rate (CGR), tuberous root bulking rate (TRBR), relative growth rate (RGR) and root yield. LAI, NAR, CGR, TRBR and RGR correlated positively with yield. TMS 91/02324 and TMS 91/02327 with the highest growth indices produced the highest yields. The deep water table site at Alabata had the highest growth indices and yield in valley bottom and the lowest in the fringe, while the shallow water table site at Ibadan recorded higher yield and growth indices in the fringe than the other positions. The shallowest water table depths at Ibadan and Alabata were and below mound surface in valley bottom and fringe, respectively. Valley fringe at Ibadan and valley bottom at Alabata had similar water table depth and they produced the highest growth indices and yield. Shallow water table of below mound surface reduced LAI, TRBR, CGR, RGR and yield, but increased NAR. Drought stress and high radiation, temperature andevaporation reduced yield and growth indices, while well distributed rainfall increased them. Cassava cultivars with high root yields in swampy inland valley are early maturing and maintain high LAI, TRBR, CGR, RGR and NAR under excess soil moisture and drought stress. Keywords: Growth indices, Cassava cultivars, Root yield, Groundwater table depth, Inland valley ecology, Drought stress

Growth of marandu palisadegrass subjected to strategies of intermittent stocking

Grazing strategies alter sward leaf area patterns of growth, affecting herbage accumulation and utilisation. The objective of this experiment was to evaluate the growth of marandu palisadegrass (Brachiaria brizantha cv. Marandu) swards subjected to strategies of intermittent stocking. The experiment was carried out in Piracicaba, São Paulo, Brazil, from October/2004 to September/2005. Swards were grazed at 95 and 100% canopy light interception (LI) to post-grazing heights of 10 and 15 cm, following a 2 × 2 factorial arrangement with four replications in a randomised complete block design. The response variables evaluated were: crop growth rate, relative growth rate, net assimilation rate, leaf area ratio and leaf weight ratio. In early and late spring, the highest crop growth rate was recorded for treatment 95/15 (11.2 and 10.1 g m-2 day-1, respectively), along with high values of net assimilation rate (4.4 and 6.9 g m-2 day-1, respectively), leaf area ratio (0.0095 and 0.0103 m-2 g-1, respectively) and leaf weight ratio (0.56 and 0.56 g g-1, respectively). To compensate reductions in net assimilation rate plants made some morphological and physiological adjustments increasing leaf area and leaf weight ratio. Relative growth rate and net assimilation rate were 26 and 50% higher, respectively, on swards grazed at 95% than at 100% LI. In early spring treatments 100/10 and 95/15 resulted in the highest relative growth rate (0.086 and 0.059 g m-2 day-1, respectively). Treatment 95/15 resulted in the most favourable pattern of growth (crop growth rate, relative growth rate, net assimilation rate), particularly during the transition period between winter and spring.

Performance of a High-Yielding Modern Rice Cultivar Takanari and Several Old and New Cultivars Grown with and without Chemical Fertilizer in a Submerged Paddy Field

A high nitrogen-uptake capacity and effective use of absorbed nitrogen for dry matter and grain production are required to improve the production cost and environmental pollution. We characterized grain yield, dry matter production and nitrogen accumulation in six rice cultivars: Sekitori (released in 1848) and Aikoku (1882), referred to as SA cultivars hereafter; Koshihikari (1956); Nipponbare (1963) and Asanohikari (1987), referred to as NA cultivars hereafter; and Takanari (in 1990) as a high-yielding modern cultivar. The plants were grown with and without chemical fertilizer in a submerged paddy field. When plants were supplied with manure and chemical fertilizer, Takanari consistently produced the heaviest grain and dry matter, followed by the NA cultivars, and the SA cultivars the lightest. Dry matter production before heading was greater in Takanari and the NA cultivars due to the longer duration of vegetative growth. Dry matter production after heading was greatest in Takanari, with a larger crop growth rate (CGR), and smallest in the SA cultivars with a shorter ripening time. Greater dry matter production during ripening was accompanied by the greater accumulation of nitrogen by Takanari and NA cultivars. These plants developed a larger amount of roots. The smaller light extinction coefficient of the canopy was also attributed to the higher CGR in Takanari. When plants were grown without chemical fertilizer, Takanari also produced heavier grain and dry matter, followed by the NA cultivars. The heavier grain in these cultivars resulted from the greater dry matter production before heading, which was due to the longer period of vegetative growth. The greater dry matter production and nitrogen accumulation by Takanari and NA cultivars were evident when plants were grown with chemical fertilizer. Koshihikari was characterized by a higher CGR and greater nitrogen accumulation during ripening in the absence of chemical fertilizer which should be noted in efforts to decrease rates of nitrogen application.

Growth and yield of maize as influenced by sowing date and poultry manure application.

Two fields experiments were conducted in 2004 and 2005 at Evboneka in Edo State, Nigeria to determine optimum sowing date and poultry manure requirement of maize (Zea mays) for the forest ultisol location. We examined the biomass production and yield, besides growth parameters under three sowing dates (April 7, May 7 and June 7) and four levels of poultry manure (0, 2.5, 5.0 and 7.5 tonnes per hectare (tha-1)) in factorial arrangement fitted into randomized complete block design with three replications. Plant heights, leaf area index (LAI), days to 50% flowering and biomass were significantly affected by sowing date and poultry manure application. The plant height values ranged from 3.9 to 10.80 centimetre (cm) at two weeks after sowing (WAS) to 48.3 cm at six WAS, respectively for the three sowing dates and four levels of poultry manure combinations. Days to 50% flowering was increased when sowing was delayed and with increased in applied poultry level and it vary from 50 to 73 days after sowing. The corresponding value of biomass was 3.32 to 8.80 t ha-1 at final harvest. These parameters resulted in higher crop growth rate for April 7 sown plants treated with poultry manure giving higher grain yield and 1000-grain weight. The maximum grain yield of 5.77 t ha-1 and 1000-grain weight were obtained from April 7 sown plants treated with 5.0 t ha-1 of poultry manure indicating that the best sowing date and poultry level for growth and yield of maize in the rainforest ultisol.

Response of growth of Genotypes of maize (Zea mays L.) under different spaces

A field study was conducted during Autumn season 1999 and Spring season 2000 at experimental farm department of Field Crop Sciences, College of Agriculture, Abu-Ghraib. بحث مستل من رسالة ماجستیر للباحث الثانی The objective of the study was to investigate response of growth of Genotypes of maize (Bohoth 106, IPA 3001) to densities with different spaces (80 cm  20 cm, 100 cm  16 cm ,40 cm  40 cm , 80 cm 10 cm, 80 cm 15 cm and 80 cm  30 cm). The experiment was laid out in randomized complete block design (RCBD) with three replications. The result obtained could summarized as following: All treatments caused significant effect on all studied characteristics. The density (125000 plant .ha-1) which planted with spaces 80 cm  10 cm gave the highest value of leaf area index (5.40, 5.90), weight of dry matter (19.76, 30.29 t. ha-1) respectively in Autumn and Summer seasons. There fore we get high crop growth rate (32.69, 60.52) respectively in both seasons then other treatments. Genotype bohoth 106 gave high value of leaf area index (3.59, 4.69) respectively in Autumn and Spring seasons. The interaction between genotypes and spacing was significant. The genotypes bohoth with space 80 cm  10 cm gave high value in weight dry matter (20.41, 31.30) and crop growth rate (37.70, 68.21 gm. m-2. day-1) in both seasons.