scholarly journals Effects of Mechanically Transplanting Methods and Planting Densities on Yield and Quality of Nanjing 2728 under Rice-Crayfish Continuous Production System

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 488
Author(s):  
Zhi Dou ◽  
Yangyang Li ◽  
Halun Guo ◽  
Linrong Chen ◽  
Junliang Jiang ◽  
...  

Rice–crayfish continuous production system offers high economic and ecology benefits, which developed rapidly in China. To investigate the effects of different mechanical transplanting methods and planting densities on rice yield and quality, Nanjing 2728 was used to determine rice growth performance under mechanically transplanted carpet seedling (MTCS) with equal row spacing (30 cm) at five spacings and mechanically transplanted pot seedling (MTPS) with wide and narrow rows (23 + 33 cm) at five spacings. The results showed that MTPS presented significantly higher rice yields than MTCS as more spikelets per panicle. Rice yields of both mechanical transplanting methods first increased and then reduced with decreasing planting density, and its highest value was obtained at 77.9 × 104 seedlings ha−1. Compared with MTCS at the same stage, rice tiller dynamics of MTPS first increased and then decreased. Additionally, its dry matter accumulation per stem at jointing, heading, and maturity stages, leaf area index, photosynthetic potential, crop growth rate, and net assimilation rate were all significantly higher relative to MTCS. For each mechanical transplanting method, dry matter accumulation per panicle, leaf area index, photosynthetic potential, crop growth rate, and net assimilation rate from the sowing to jointing stages declined with decreasing planting density, while dry matter accumulation per stem and net assimilation rate from the heading to maturity stages increased. Compared with MTCS, MTPS significantly improved rice milling and appearance quality, decreasing density was also beneficial to rice milling and appearance quality, while grain content of amylose and protein were not sensitive to both transplanting method and planting density. Consequently, MTPS with 13.8 cm plant spacing is a suitable mechanical transplanting method for Nanjing 2728 to obtain better yield and quality under rice–crayfish continuous production system.

1978 ◽  
Vol 90 (3) ◽  
pp. 569-577 ◽  
Author(s):  
G. O. Iremiren ◽  
G. M. Milbourn

SummaryTotal dry-matter yield of maize silage rose asymptotically as density was increased up to 17 plants/m2. Over the range 11–17 plants/m2, which is generally higher than is used in the U.K., the increase in yield was 1–1·6 t dry matter/ha which can justify the higher seed cost and although there was no adverse affect on time of maturity the risk of lodging increased at the highest density. During the harvest period whilst whole crop dry-matter percentage was rising from 23 to 28%, the ear dry-matter content rose steadily from 29 to 35%, whereas the leaf and stem dry-matter content remained essentially constant and only dried out at a later stage after a frost.Caldera 535 had a higher leaf area index and net assimilation rate than the earlier variety Julia which it outyielded by 15%. The additional yield was mainly stem tissue and the greater vegetative production caused an 11-day delay in reaching the silage stage of maturity (25% crop D.M.). NO differences occurred between density treatments and varieties in the forage quality components considered, namely percentage drymatter digestibility, modified acid-detergent fibre, crude protein and ash. Thus in U.K. conditions, total dry-matter yield exerts an overriding influence on the yields per unit area of these quality constituents. This contrasts with reports from the U.S.A. in which a reduced grain/stover ratio adversely influences silage quality.Removal of the whole ear (including husk and rachis) at an early stage in ear development resulted in a 50% reduction in the final dry-matter yield. In the earless plants, leaf area and net assimilation rate was lower, but the dry-matter content of the leaves and stem was considerably higher, and a marked purple coloration developed indicative of excess starch concentration. These results emphasize the need in maize silage not only for an adequate leaf canopy, best obtained early in the growing season by using high planting density and subsequently by using late maturing varieties, but also for sufficient sink capacity in the ear as well as in the stem fraction.


Author(s):  
A. Reshma ◽  
P. Latha ◽  
V. Umamahesh ◽  
R. P. Vasanthi ◽  
P. Sudhakar

Groundnut is grown during July to October in kharif season, however area under early kharif (sowing in May) is increasing in Andhra Pradsh, where ever irrigation facilities exists. Hence to identify suitable variety for the situation, fourteen pre release and two released groundnut genotypes were evaluated during early kharif 2013 for growth, physiological traits and yield attributes. At harvest genotypes TCGS-1375 (41.331 g plant-1), TCGS-1342(41.059 g plant-1) significantly recorded higher total dry matter compared to all other cultivars and checks followed by TCGS-1330 (36.667 g plant-1), TCGS-1349 (36.433 g plant-1). TCGS-1342 recorded significantly higher Crop Growth Rate (CGR) value of 33.848 g m-2 day-1, where as TCGS-1346 (0.1265 g dm-2 day-1) and TCGS-1330 (0.1262 g dm-2 day-1) recorded significantly higher Net Assimilation Rate (NAR) values at 45-60 DAS. Cultivar, TCGS-1330 recorded significantly higher pod yield 4210.44 Kg ha-1 compared to other entries and checks. The results revealed that pre release genotypes, TCGS-1342, TCGS-1375, TCGS-1330, TCGS-1346 recorded high physiological efficiency in terms of growth and physiological traits viz. total dry matter (TDM), crop growth rate (CGR), net assimilation rate (NAR) and leaf area index (LAI) and also recorded high pod yield.


1994 ◽  
Vol 45 (7) ◽  
pp. 1347 ◽  
Author(s):  
EL Armstrong ◽  
JS Pate

Biological yield and photosynthetic performance of six field pea genotypes of contrasting foliar morphology and growth habit were studied in a water-limited field environment at Wongan Hills, Western Australia. Dundale and Wirrega were tall, indeterminate, scrambling and conventionally leaved; Dinkum, L82 and L80 (semi-leafless) and Progreta (tare-leaved) were semi-dwarf and more erect. Green area index (green leaf area per unit of ground area), green area duration (time integral of green area), crop growth rate (rate of dry matter accumulation per unit ground area) during early spring, net photosynthetic rate (CO2 exchange rate per unit green area or unit green weight) and net assimilation rate (rate of dry matter accumulation per unit green area) all influenced crop productivity. Shoot and root biomass was highest in Wirrega, due mainly to superior green area index, extended green area duration and maintenance of high growth rate during pod fill. Inverse relationships amongst genotypes were evident between green area index and net assimilation rate, and between green area index and CO2 exchange rate of green area. Total net photosynthesis of the tendrils of semi-leafless types was similar to that of leaflets of conventional types, due mainly to larger biomass of tendrils compensating for poor photosynthetic rates. The poor growth of semi-leafless and tare-leaved types was attributed to lower vigour, green area, ground cover and photosynthate production. Future selection of such types for water-limited environments should concentrate on increasing shoot height, node number per plant, stipule and tendril size and photosynthetic efficiency of green area.


2013 ◽  
Vol 409-410 ◽  
pp. 314-317
Author(s):  
Heng Jia Zhang

An experiment was conducted to determine the effect of limited water supply on plant height, leaf area, dry matter and net assimilation rate (NAR) of spring maize. The results indicated that limited water supply had little effect on plant height of maize at six-leaf, twelve-leaf, heading and early grain filling except the end of filling. Leaf growth and leaf area expansion were effectively increased at middle and late maize growth stages under limited water supply and the maximum leaf area was maintained at early grain filling to middle filling. In addition, dry matter accumulation of maize in reproductive organs may be promoted by limited water supply. Finally, limited water supply also had great effect on net assimilation rate of maize and the maximum was maintained at six-leaf to twelve-leaf, followed by heading to silking.


Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 751-757 ◽  
Author(s):  
David T. Patterson ◽  
Maxine T. Highsmith ◽  
Elizabeth P. Flint

Cotton, spurred anoda, and velvetleaf were grown in controlled-environment chambers at day/night temperatures of 32/23 or 26/17 C and CO2concentrations of 350 or 700 ppm. After 5 weeks, CO2enrichment to 700 ppm increased dry matter accumulation by 38, 26, and 29% in cotton, spurred anoda, and velvetleaf, respectively, at 26/17 C and by 61, 41, and 29% at 32/23 C. Increases in leaf weight accounted for over 80% of the increase in total plant weight in cotton and spurred anoda in both temperature regimes. Leaf area was not increased by CO2enrichment. The observed increases in dry matter production with CO2enrichment were caused by increased net assimilation rate. In a second experiment, plants were grown at 350 ppm CO2and 29/23 C day/night for 17 days before exposure to 700 ppm CO2at 26/17 C for 1 week. Short-term exposure to high CO2significantly increased net assimilation rate, dry matter production, total dry weight, leaf dry weight, and specific leaf weight in comparison with plants maintained at 350 ppm CO2at 26/17 C. Increases in leaf weight in response to short-term CO2enrichment accounted for 100, 87, and 68% of the observed increase in total plant dry weight of cotton, spurred anoda, and velvetleaf, respectively. Comparisons among the species showed that CO2enrichment decreased the weed/crop ratio for total dry weight, possibly indicating a potential competitive advantage for cotton under elevated CO2, even at suboptimum temperatures.


1987 ◽  
Vol 108 (1) ◽  
pp. 245-247 ◽  
Author(s):  
S. Singh ◽  
P. N. Gururaja Rao

In sugar cane, investigations made earlier (Singh & Gururaja Rao, 1985) have shown that high-yielding varieties have higher net assimilation rate than low-yielding types. Similarly, differences in progeny means for relative growth rate and net assimilation rate have been reported by George (1965). In other crops also, varietal differences in leaf area index and net assimilation rate have been reported (Watson, 1947). It appears that in this crop, limited attempts have been made to study all the growth characteristics. This paper describes the differences in most of the growth characteristics in six sugar-cane varieties.


2015 ◽  
Vol 28 (2) ◽  
pp. 155-175
Author(s):  
Witold Drezner

The correlation between the net assimilation rate and the degree of plant tillering are investigated for several varieties of simple winter wheat. The net assimilation rate (E, NAR, An) of the studied varieties for different degrees of tillering, individual shoots and individual plants is described according to the units mg/cm<sup>2</sup> • 24 h. Index of efficiency of assimilation surface (F, LAR, I<sub>S</sub>) is determined in units cm<sup>2</sup>/mg. The tillering ability of vegetative shoots in plaints is a very important factor which increases the total assimilate stirfaice value and the assimilation effectivity of the plant's biomass.


1972 ◽  
Vol 12 (55) ◽  
pp. 216 ◽  
Author(s):  
DW Turner

The quantitative aspects of banana plant growth (omitting roots) at Alstonville, New South Wales, are described. Dry matter distribution, leaf area index (L), net assimilation rate (E), leaf area ratio (F) and relative growth rates (R), were measured. For a spring planting, only 1695 kg ha-l dry matter were produced in the first twelve months but 6780 kg were produced in the first half of the second year as the bunch and first ratoon crop developed. The plant crop was characterized by early leaf growth (high F) whereas in the ratoon crops, corm growth was a feature of early growth stages. Leaf area index was less than 1 for the first twelve months but reached 5 after 18 months. Plants were 3.1 m X 1.9 m apart. Net assimilation rate was affected by internal and external factors. The main internal control was the growth of suckers, which tended to increase E. Removal of the suckers in autumn or winter caused a sudden drop i i ~ E and absolute growth rate but when they were removed in early summer E was increased. The external controls affecting E were solar radiation, temperature and soil moisture, although the amount of variation explained in correlations was low. - R appeared to be constant in the plant crop within morphologically defined growth stages. This was not so in moon crops and R was probably a resultant of ontogenetic and climatic drifts. Desuckering in autumn and winter decreased R. Early summer desuckering increased R.


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