News Update on Growth and Yield : Nov 2021

Forest Dynamics, Growth, and Yield

The introduction points out the very specific system characteristics of trees and forest stands which determine the approach and methods to analyse and model forest stand dynamics, growth and yield. Like other disciplines, forest science looks with an ever-increasing spatial and temporal resolution on the functions and structures of woodlands, forest stands, trees, tree organs, plant cells…. This makes it necessary to discuss concepts for bridging the growing gap between an increasing amount of knowledge on structures and processes on temporarily and spatially highly resolved scales (chemical, biochemical, molecular-biological processes), and an information deficit on more strongly aggregated system levels (stand, ecosystem, landscape scale). The reconciliation between progressing reductionism on the one hand and the demand for holistic system knowledge for forest ecosystem management on the other is a general challenge to forest science and other “green sciences”. [1]

Salinity Effects on Seedling Growth and Yield Components of Rice

Flood irrigation practices that are commonly used in California during the early stages of rice (Oryza sativa L.) establishment may contribute to salinity damage and eventually decrease yield. Knowledge of salinity effects on rice seedling growth and yield components would improve management practices in fields and increase our understanding of salt tolerance mechanisms in rice. Salinity sensitivity of rice was studied to determine salinity effects on seedlings and yield components. Plants of rice cultivar M-202 were grown in a greenhouse in sand and irrigated with nutrient solutions of control and treatments amended with NaCl and CaCl2 (2:1 molar concentration) at 1.9, 3.4, 4.5, 6.1, 7.9, and 11.5 dS m−1 electrical conductivity. Shoot dry weights of seedlings were measured at five harvests in the first month after seeding. Seedling growth was significantly reduced by salinity at the lowest salinity treatment, 1.9 dS m−1. At 1.9 and 3.4 dS m−1, significant reduction of seedling growth occurred at longer cumulative thermal time than at higher salt levels. Seedling survival was significantly reduced when salinity was 3.40 dS m−1 and higher. Highly significant linear responses of grain weight per plant, grain weight per panicle, spikelet number per panicle, and tiller number per plant to salinity were observed. There was a common lowest salt level for fertility and pollen germination beyond which they were significantly reduced by salinity. Harvest index was significantly decreased when salinity was at 3.40 dS m−1 and higher. Tiller number per plant and spikelet number per panicle contributed the most variation in grain weight per plant under salinity. Reductions in seedling survival, tiller number per plant, and spikelet number per panicle were the major causes of yield loss in M-202 under salinity. The compensation between spikelets and other yield components was confounded with salinity effects, but was believed to be minor relative to the reduction of spikelets due to salinity and, therefore, not sufficient to offset yield loss even at moderate salt levels.[2]

Radiation absorption, growth and yield of cereals

Analysis of measurements of absorbed radiation and leaf area indices of wheat and barley crops showed that throughout most of growth the fraction of absorbed solar radiation could be described by a simple exponential equation.

For several of these crops grown under a wide range of weather and husbandry at Sutton Bonington and Rothamsted, 2-weekly values of crop growth rate (C) were closely related to radiation absorbed until ear emergence and about 3·0 g of dry matter (D.M.) were produced by each MJ of photosynthetically active radiation (PAR) absorbed. Final crop weight was closelyrelated to total PAR absorbed during growth (SA); on average about 2·2 g D.M. were produced per MJ absorbed, equivalent to a growth efficiency (Eg) of approximately 3·9%. Unfertilized and drought-stressed crops had a smaller Eg.

The fraction of total crop D.M. harvested as grain (harvest index) varied more for wheat than for barley. Calculations of a maximum realizable grain yield made using the largest values of Eg and SA for the crops measured and assuming a harvestindex of 0.53 (achieved in an experimental crop) showed a grain D.M. yield of 10·3 t D.M./ha to be possible. To achieve such a yield would require full crop cover from the beginning of April until the end of July in a typical English growing season.[3]

Plant Row Spacing Effect on Growth and Yield of Green Pepper (Capsicum annuum L.) in Western Kenya

Green pepper production based on the package of recommendations developed has not given the desired growth and yield performances in the world and specifically Kenya. Information is required with which to evolve the agronomic practices that will be adopted to maximize yield in green pepper production. Great attention should be paid when selecting the most appropriate spacing where there are very few reports and limited information regarding plant spacing in cultivation of the crop under the agro-climatic conditions of Kenya. Therefore, a field study was carried out at the Alupe Research Station, Busia County, to evaluate the growth and yield responses of green pepper under three row plant spacings namely: 50×40 cm, 40×40 cm and 30×40 cm during the long and short rainy seasons of 2015. The experiment was set up in a randomized complete block design with three replicates. The treatment effects were measured on plant growth for 12 weeks and ripe fruit yield parameters which were later cleaned statistically analyzed. The plant spacing had significant variation in almost all the growth and yield components except the fruit length. In both seasons, the number of branches per plant, stem girth and number of fruits per plant were found to be significantly increased with the increasing of plant spacing but the plant height, number of leaves per plant, fruit breadth and yield per plant were found to be significantly increased with the decreasing plant spacing. The highest yield per plant of 555.1 g and 551.8 g were realized during the short and long rainy seasons respectively in the 40 by 40 cm spacing treatment. Considering the yield of fruits per plant, the 40 by 40 cm plant spacing appeared to be the most recommendable for the cultivation of green pepper. [4]

Growth and Yield of Maize (Zea mays L.) as Influenced by Integrated Weed Management under Temperate Conditions of North Western Himalayas

A field experiment was conducted at Experimental Station of CSIR-IIIM, Srinagar, J&K, India during kharif 2013 and 2014. The experiment was laid in a randomized block design with 4 weed management practices viz., W0=  No weeding, W1 = Hand weeding 20 and 50 days after sowing, W2 = atrazine @ 1.0 kg a.i ha-1 PRE + hand weeding 20 days after sowing and W3 = atrazine @ 1.0 kg a.i ha-1 PRE + Isoproturon @ 1.0  kg a.i ha-1 POST. The results revealed that weed management practices W2 at par with W3 significantly improved plant height, number of functional leaves, leaf area index and dry matter production at different growth stages as compared to W0, whereas W2 took significantly more number of days for the crop to reach different phenological stages over rest of the treatments including control during both years of study. Similarly, W2 being at par with W3 recorded significant improvement in all yield contributing characters over W1 and W0. Both grain and stover yields were also significantly higher with W2 over W1 and W0. Significantly higher biological yield and harvest index was recorded with W3 as compared to the rest of treatments during both the years of experimentation. [5]

Reference

[1] Pretzsch, H., 2009. Forest dynamics, growth, and yield. In Forest dynamics, growth and yield (pp. 1-39). Springer, Berlin, Heidelberg.

[2] Zeng, L. and Shannon, M.C., 2000. Salinity effects on seedling growth and yield components of rice. Crop science, 40(4), pp.996-1003.

[3] Gallagher, J.N. and Biscoe, P.V., 1978. Radiation absorption, growth and yield of cereals. The Journal of Agricultural Science, 91(1), pp.47-60.

[4] Edgar, O.N., Gweyi-Onyango, J.P. and Korir, N.K., 2017. Plant row spacing effect on growth and yield of green pepper (Capsicum annuum L.) in Western Kenya. Archives of Current Research International, pp.1-9.

[5] Rasool, S. and Khan, M., 2016. Growth and yield of maize (Zea mays L.) as influenced by integrated weed management under temperate conditions of North Western Himalayas. Journal of Experimental Agriculture International, pp.1-9.

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