Effect of Sowing Date and Plant Density on Cotton Yield,Biomass and Nutrients Accumulation.pdf

1、The most important crop management factors, including plant density (PD) and sowing date affecting cotton yield and quality, are widely adopted in China to obtain higher yields.Consequently, 2-year studies were conducted

2、 in 2014-2015 on the experimental farm of Huazhong Agricultural University, to test the hypothesis if elevated PD has the potential to compensate reduction in cotton yield as a consequence of delayed planting date in Yan

3、gtze River Valley, China.Split plot arrangement with two sowing date (S1, May 20; S2, June 04) across the three plant density (low, D1, 7.5; moderate, D2, 9.0; and high D3, 10.5 plants m-2) were imposed.Results showed th

4、at:
　　1.PD and sowing date significantly altered cotton growth periods, and leaf chlorophyll content (SPAD value).Both of the study factors markedly delayed cotton crop phenology.Cotton growth periods squaring, boll s

5、etting were delayed in later planted (S2) crop with higher density (D3) as well as the whole growth period prolonged throughout the study.Higher leaf chlorophyll content in later sown crop versus earlier with lower densi

6、ty (D1) was observed in both years.
　　2.Sowing date and PD significantly affected cotton yield and yield characters.S1 treatment compared with S2 treatment contributed greater bolls (81.9 m-2) with higher weight (4.4

7、g), lint (50.1％) seed cotton yield (3592 kg ha-1) and lint yield (1794.5 kg ha-1) were achieved in both years except, boll weight and lint ％ were not affected in 2015. While, across the PD more boll m-2, higher seed cott

8、on yield were attained with D2 treatment.Interaction between S*D was significant in both years.The S1 D2 and S2 D2 treatment pursued higher seed cotton and lint yield in both years.
　　3.Morphological characters of cot

9、ton were significantly influenced by sowing dates and PD.Compared to the later one, earlier planted crop resulted long statured plant, total leaves number, green leaves plant-1, more fruiting branches number (FB m-2), ma

10、in stem fruiting node number (FB m-2) and higher ratio of fruiting positions to fruiting branch (FP/FB).While across the three PD all these measurements were higher at D1 treatment.While more FB m-2 numbers recorded at D

11、3.
　　4.Cotton dry matter accumulation was significantly impacted by three densities and two sowing dates in the study.For sowing date S1 and higher PD, both average and maximum speed (kg.ha-1.d-1) of biomass accumulat

12、ion was faster for both total and vegetative organs.While reproductive structures were beneficial at D2 treatment in both years.
　　5.Both average and maximum speed (kg.ha-1.d-1) of Nitrogen, Phosphorus and Potassium (

13、NPK) accumulation was achieved at earlier treatment with higher density compared with later sowing in vegetative organs and total plant.Whilst higher NPK accumulation was observed in reproductive structures with moderate

14、 density D2 in both sowing date.However, the accumulation rate was inferior in later sowing.
　　From this study, it was concluded that sowing in late May improved cotton yield and yield attributes relative to early Jun

15、e.Moderate PD markedly improved cotton yield and yield components.Hence, suggesting that moderate PD with earlier and later sowing in combination has potential for attaining higher cotton yields in the ecological region