Effects Of Different Multiple Cropping Patterns On Rice Growth And Soil Fertility

Field experiments and laboratory analysis were conducted in order to investigate the laws governing the changes in soil characteristics, in rice growth and development and in nitrogen uptake and utilization under the following three different multiple cropping patterns:milk vetch+double season rice (ZDD), rape+double season rice (YDD), winter-leisure+double season rice (XDD). A systematic study had been carried out from2009to2011to observe the changes of physicochemical and biological properties of soil, rice growth and development, rice nutrition properties and the influences of nitrogen fertilization on rice growth and development. The main results were as follows:1. Different influences on the properties of the tile soil under different multiple cropping patterns.Planting milk vetch and rape in winter improves soil properties, reduces the volume-weight, and increases the density of the total pore space, and the capillary and the hold-water capacity. A combination of increased gap of the pore space, reduced the sand quantity, added silt and cosmid, and planted milk vetch contributes greatly to retaining and even enhancing soil fertility. Compared with the pattern of winter-leisure, this practice has the function of increasing soil temperature before and after growing rice.Planting milk vetch and rape in winter is helpful for improving the nutrition of the soil; Planting rape in winter activates the phosphorus dramatically while planting milk vetch in winter leads to the increase of the reproducing substances, and the declines of PH and Eh value. The total amount of the microbe planting milk vetch in winter>Planting rape in winter> winter-leisure, and the differences are extremely distinctive. The amount of soil organics, the total nitrogen and the unease in the soil, the unease hydrogen peroxide activity has a positive or even extremely positive correlation. So does the relationship between the soil organics, and the total nitrogen and the ability of transforming unease activity, but the differences are not so obvious.2. Different influences on rice growth and development under different multiple cropping patterns.With the same amount of the fertilization, milk vetch can increase the output of the rice for it could replace fertilizers. The range, compared with rape and winter-leisure, is3.38%,3.81%. The output increases mainly because the number of effective spike and the grain number of the every spike have been increased. Planting milk vetch and rape in winter benefits the accumulation of the dry substances. The output rate and the turnover rate of the dry substance assumes ZDD>YDD>XDD, and the differences becomes obvious or extremely obvious during the process.The incremental ratio of the spike-let failure amount and the source library quantity assumes ZDD> YDD>XDD in and after the period of sprouting, positively correlating with the output. The average grout-in rate assumes ZDD>YDD>XDD, and the group ratio has a dramatically positive correlation with the average grout-in ratio.The leaf area index number ZDD>YDD>XDD, the ratio of group canopy sympathetic potential, of the total amount of the storage capacity and the group of potential grain assumes ZDD>YDD>XDD, which negativity correlates with the output.3. Study of the rice nutrition properties under different multiple cropping patterns.Planting Milk vetch and rape in winter helps rice absorb the nutrition of nitrogen, phosphorus and potassium, planting rape in winter is dramatically beneficial for the phosphorus absorption. As for the amount of N, P2O5, KO2to produce100g rice grains, ZDD needs the most while XDD needs the least. P2O5assumes YDD>ZDD>XDD. As for Nitrogen dry substance productivity, the rice grain productivity, ZDD is lower than YDD and XDD, while the uptake and utilization efficiency is higher than that of YDD and XDD. During the two years, the total amount of nitrogen, phosphorus and potassium taken up by the early and late rice has a dramatically positive correlation4. The influences of nitrogen fertilizer on the growth and the development of the rice under different multiple cropping patterns.In the amount of0-180kg nitrogen, different multiple cropping patterns have different results with the increase of the nitrogen, and the differences are distinctive or dramatically distinctive. When the amount exceeds180kg, the output declines dramatically. With the same level of the nitrogen, the match of the Milk vetch and chemical fertilizer increases the output, and both early race and late rice output assumes ZDD>YDD and XDD. The output and the amount of the nitrogen have a quadratic correlation.The amount of the dry substance grows with the increase of nitrogen fertilizer. In the same level of the nitrogen fertilizer, planting Milk vetch and rape in winter contributes to the accumulation of it, and the amount assumes ZDD>YDD>XDD. The nitrogen fertilizer positively correlates with the output of dry substance.As the amount of nitrogen fertilizer increases, it takes more nitrogen for the late and early rice to produce100g rice grain. The average value of nitrogen reproducing dry substance productivity and nitrogen rice grain productivity assumes ZDD>YDD>XDD; the average value of agriculture utilization of nitrogen in ZDD is46.73%, and XDD is41.91%. The amount of nitrogen fertilizer and nitrogen needed to produce100g rice grain positively correlates dramatically.5. Effects of nitrogen management on the rice growth and development under different multiple cropping patterns.When the nitrogen application in180/hm2, as for ZDD early rice, if the ratio between the tallow nitrogen fertilizer and the spike fertilizer is N (7:3), the output reaches the maximum, and the lowest is N (10:0). As for YDD and XDD the highest is N (8:2) while the lowest N (10:0). The same law applies to the late rice. The highest is N (7:3), and the lowest N (8:2). Under ZDD, the application ratio of the spike fertilizer is10percent higher than that of YDD and XDD. When the ratio is the same, planting Milk vetch in winter increases the output. During the four seasons in the2years, the average output value assumes ZDD>YDD and XDD. The correlation between the different tallow and the spike fertilizer and the output of the early and late rice is parabolic.The matter amount of the early rice and the late rice decreases as the spike fertilizer amount decreases in different multiple cropping patterns. Milk vetch replaces some chemical fertilizer, which contributes to the dry matter accumulation; the average value of ZDD is higher than YDD and XDD distinctively. The related analysis presents that the spike fertilizer ratio positively correlates with the output of the dry matter.Decreasing the spike fertilizer ratio does not help the uptake and utilization of the soil nitrogen and nutrition nitrogen. For both early and late rice in ZDD, as nitrogen fertilizer uptake and utilization rate reaches the top, the ratio of the tallow fertilizer and the spike fertilizer is7:3while early rice in YDD and XDD is8:2, late rice7:3.