Effect Of Planting Density And Cotton Plant Retetion On Canola Directly Sown In Cotton Field

In order to find a rapeseed tillage cropping patterns suited to the test set density and cotton stalk removed time two factors. Test using hua shuang number 5 as material under cultivation in the field to study the density and cotton stalk on rapeseed yield and economic characters and the accumulated effects of temperature and humidity of field. At the same time to study nutrient content of cotton stalks and the corresponding changes in soil nutrient content over time, as well as cotton stalk the impact of retention on lodging. The results are as follows:1. Effect on rape growth process, dry matter partitioningCotton stalk removal time on the rapeseed field did not significantly affect the rapeseed growth process, the density factor has some influence on the growth process. Rapeseed with different densities, difference of growth period is insignificant, but as the density increases, the growing time will be shortten. The growth period of transplanted rapeseed is longer 30 days than directiy sown rapeseed.Various organs of the dry weight of rapeseed were significantly affected only the density factor, each index has a different reaction with density changing. The biomass of directly sown rapeseed and economic index are smaller with increasing density. The organ biomass of transplanted rapeseed than direct sown there was a significant increase, which is rapeseed yield per plant to rely on the material basis. Harvest on dry matter of different density distribution of rape found that the percentage of grains per plant as density increases. Rapeseed pod skin basically equal to 0.3 percent, the percentage of transplanted rapeseed pod skin percentage is significantly smaller than the direct sown rapeseed, but the roots and stems and branches have significantly increased the percentage of weight.2. Effect on agronomic traits and yieldThe characters in the different density treatments were significantly different. Rapeseed plant height and density increases with the height of first branch and then decreased, while the root neck diameter, length of main raceme, the effective length of main inflorescence, a number of branches decreased with increasing density. Except the first branch height was significantly lower than direct sown rapeseed, other characters were significantly higher than direct sown rapeseed.Only in the density of yield components were significantly different between factors. Rapeseed main raceme, branches pod number, pods per plant, grains and seed pods were reduced as the density increases, yield increases with density. Compared with the direct sown rape, rapeseed in addition to transplanting significantly reduced grain number pod, the other characters were significantly increased.3. Effect on rapeseed lodging of cotton stalk retentionThe stalk retention test showed that cotton stalk can greatly reduce the presence of high-density level of rapeseed of lodging. The economic characteristics of cotton stalk area more better, more upright shape, pod better photosynthesis and ultimately the formation of higher yield.4. Effects on the accumulated of temperature and humidity of fieldCotton stalk function on the daily average temperature of the field is different with density changing, especially in the colder period of time in the reproductive process. But by the late growth stages, seasonal temperature, average temperature difference between day basically is positive; cotton stalk retention of the accumulated difference between daily temperature and daily average value of similar effect, but in the whole growth period, the accumulated earlier than the pull cotton stalk high; Cotton stalk moisture effect on the field, the conclusion is quite consistent, that the effect of lowering the humidity of the field. The average daily humidity field density increases with the rapeseed, and more slow growth. The analysis shows that the incidence of rapeseed is closely related to disease index and average daily humidity.5. The change of Cotton stalks and soil nutrient contentCotton stalk total nitrogen, total phosphorus, total potassium concentrations are reduced continuously with time, and the plant of nutrients as part of the decrease of slow deceleration. Various parts of cotton stalk total nitrogen and total phosphorus decreased rate very slow, but total K decreased rapidly, to the rapeseed harvest time, almost all the body's potassium released into the soil.Treatment (with cotton stalk) and contrast(no cotton stalks) of soil total N content in size over time, alternating, harvest when the soil nutrient content results showed that cotton stalk with minimal increase in the role of soil total nitrogen content; treatment available N content is always higher than the contrast, and fluctuating with the seasons, which is due to the presence of cotton root change the physical and biochemical characteristics of the soil caused; harvest soil nutrient content results also show that a certain increase in cotton stalk alkali solution the role of nitrogen content on the harvest time. Early sampling, soil total phosphorus than the contrast treatment significantly higher than many, but late January 2009, total P content deal with alternate contrast, showing changes in posture and movements were stabilized; changes in available phosphorus and total phosphorus showed the same situation, the difference is that the content of available phosphorus decreased rapidly over time, to close in February 2009 when the fluctuations around a certain value; the soil nutrient content showed that cotton stalk a certain increase in total phosphorus available phosphorus content with the role on the harvest time.Soil total K content showed a similar M-shaped wave, as a whole shows a growing trend, and cotton stalk continuously over time consistent with the release of potassium. The soil total K and available K were not significantly different on harvest time, which may be relevant with the length of the cotton stalk reserve time.