Sowing

About: Sowing is a research topic. Over the lifetime, 33888 publications have been published within this topic receiving 273438 citations. The topic is also known as: seeding.

Seed priming techniques in field crops-A review

Abstract: Germination and seedling emergence are the critical stages in the plant life cycle. Insufficient seedling emergence and inappropriate stand establishment are the main constraints in the production of crops which receiving less rainfall. Farmers do not have sufficient resources to meet the requirement of seedbed preparation for sowing and they are at more risk as compared to progressive farmers. On the other hand good establishment increases competitiveness against weeds, increases tolerance to drought period, increase yield and avoids the time consuming need for re-sowing that is costly too. It is well accepted fact that priming improves germination, reduces seedling emergence time and improves stand establishment. A method to improve the rate and uniformity of germination is the priming or physiological advancement of the seed lot. The general purpose of seed priming is to partially hydrate the seed to a point where germination processes are begun, but they would exhibit rapid germination when re-imbibed under normal or stress conditions. A lot of work has been done on seed priming and results of these studies indicate well the importance of priming to get a good crop stand in many crops of tropical region such as rice, maize, sorghum and pigeon pea.

Deep floodwater protects high-nitrogen rice crops from low-temperature damage

Abstract: A field experiment was conducted to investigate the interaction of nitrogen (N) status, sowing date, and water depth on rice yield in the Murray Valley, New South Wales, where low minimum temperatures often lead to pollen sterility and low yield in high N status crops. The experiment combined 4 N rates (0, 75, 125, 250 kg N/ha) applied as urea just before permanent flood; 3 cultivars (Jarrah, early maturing; Amaroo and Doongara, midseason); 2 sowing dates (26 September, 31 October 1991); and 2 water depths (5, 20 cm) at the microspore stage. The early-sown crops and the later sown Jarrah crop encountered minimum air temperatures of 19¦C at the cold-sensitive microspore stage, compared with 15¦C for the other 2 later sown crops. Total dry matter production was little affected by either water depth or sowing date, but increased from 16 to 22 t/ha with N application. Shallow water depth and delayed sowing date affected yield through reduced harvest index. Grain yield response to N fertiliser was dependent on sowing date, water depth, and variety. For the early-sown crops grown in deep water, yields of Amaroo and Jarrah-increased from 7 to 13 t/ha with increasing N supply, while the yield response of Doongara plateaued at 9 t/ha. With shallow water, the yields of all varieties decreased from 7 to 3 t/ha with increasing N. For the later sowing date, Jarrah growing in deep water yielded up to 13 t/ha at high N, but yields of Amaroo and Doongara decreased from 7 to 2 t/ha with increasing N supply. For the later sowing date, yields of all varieties growing in shallow water decreased to <2 t/ha with applied N. In the deep water crops, developing microspores were submerged or partially submerged and so avoided low air minimum temperatures. In the early-sown crops, the microspore stage occurred during a period of relatively warm nights. Harvest index was successfully modelled using panicle temperature and N content at early pollen microspore. The experiment shows that high N applications can lead to high rice yields provided the microspores are protected from low temperatures by the use of deep water at the stage of microspore development. As a result, recommendations for N fertiliser application need to be adjusted for sowing date and expected water depth at early pollen microspore