Soil standard for high yield rice

The main results are as follows: (1) the profile is obvious, the plough layer is deep, and the depth of plough layer for high yield rice with good texture is about 20 cm, which requires that the plough layer is thick and soft, the content of aggregates is high, the structure and ventilation are good, and the tillage is suitable. The plough layer is too shallow, the rice root system is underdeveloped; the plough layer is too deep, it is easy to produce floating mud, which is not conducive to rice rooting and early development. The texture is moderate, but the sand is too sticky, the plough is not large when ploughing, it is easy to rake, the paste is not hardened when ploughing, the cracks are not opened when draining and lying in the sun, and the cracks are easy to close after rewatering.

(2) High content of organic matter, sufficient nutrients and coordinated high-yield paddy fields generally require 20.4% organic matter and 0.13%-0.23% total nitrogen, of which hydrolytic fluorine accounts for 510% of total nitrogen and total phosphorus content is more than 0.1% (available phosphorus more than 5 kg per mu or about 13~70ppm). The content of total potassium is more than 1.5% (more than 05 kg per mu of available potassium or more than 8 mg of potassium per gram of soil). At the same time, higher cation exchange capacity (not less than 20 mg equivalent per 100g soil) and higher base saturation (6080%) are required. Soil acidity and alkalinity should be slightly acidic to neutral (pH6~7.5), with abundant major elements and no lack of trace elements. It is also necessary to have a large number of inactive and effective nutrients to balance the supply of various nutrient elements, avoid element deficiency and de-fertilization, and ensure the normal growth of rice.

(3) good performance of water conservation, fertilizer conservation and fertilizer supply, and proper leakage of high-yield rice fields should have better water and fertilizer conservation, and should not leak water and fertilizer, that is, it can not only accumulate and preserve a large amount of nutrients, but also provide a full and lasting supply continuously. When there is a slight difference between the amount of fertilizer and the time of fertilization, the rice field itself has a certain ability of regulation and good buffering performance, so as not to cause premature senescence and crazy growth of rice plants. The paddy field should also have a certain amount of leakage, so that part of the oxygen can seep into the lower layer of the soil, so as to increase the soil redox potential and reduce the accumulation of toxic substances. According to the experiment, the yield of rice fields with daily leakage of about 10 mm is higher. One irrigation should be kept for 5-7 days. If the leakage is too large, it will cause a large amount of nutrient loss, which is also disadvantageous.

(4) the activity of beneficial microorganisms in paddy fields with strong activity and high fertility is stronger than that in general paddy fields, and these microorganisms play an important role in creating and regulating soil fertility. According to the study, the number of nitrogen-fixing bacteria, nitrifying bacteria, ammonium bacteria, aerobic fiber decomposing bacteria and vulcanizing bacteria was positively correlated with fertility. The quantity of high fertility is high, and the biochemical intensity (respiration intensity carbon dioxide mg / kg soil, ammoniation intensity mg / 100g soil) is high, that is, the biochemical effect is strong.