Effects of Nitrogen Fertilizer Reduction and Application of Nitrogen Fertilizer as Base Fertilizer on Rapeseed Yield and Nitrogen Absorption

[Objective] The aim was to research effects of N fertilizer reduction and application of N fertilizer （as base fertilizer） on rapeseed yield and N absorption. [Method] Based on Ganyouza No.5, the ratio of N, P2O5 andK2O was set at 1：0.5：0.5; N fertilizers were set involving reduced quantity at 150 kg/hm2 and preferred quantity at 180 kg/hm2; 100%, 80% and 60% of N fertilizers were applied as base fertilizers in the test respectively. In general, field tests were conducted to explore effects of reduced N fertilizer and application of N fertilizer as base fertilizer on rapeseed yield and N absorption. [Resalt] When applied N fertilizer as base fertilizer was the same, plant height, stem diameter, length of major inflorescence, number of effective branch, pod number per plant, seed number per pod, and biomass yield in group with preferred N quantity were significantly higher than those in group with reduced N fertilizer. Rapeseed yield and profits in group with preferred N quantity were signifi- cantly higher than those in group with reduced N fertilizer in field with moderate fertili- ty. In fields with higher fertility, however, the two factors were just a little higher. In group with reduced N fertilizer, use efficiency of N fertilizer, N uptake efficiency, par- tial factor productivity and harvest index of N were all significantly higher than those in group with preferred N fertilizer. Agronomic nitrogen use efficiency in group with preferred N fertilizer was significantly higher than that in group with reduced N fertiliz- er in field with moderate fertility and was significantly lower in field with high yield. With amounts of N, P and K fertilizers fixed, economic characters, yield constitution, yield, profits and N absorption in group, where 60% of N fertilizers were applied as base fertilizer, were significantly higher than those in groups with 80% or 100% of base fertilizer （N fertilizers）. These indicated that rational fertilization would maintain rapeseed yield high and reduce N input to improve use efficiency of N fertilizer. On the other hand, it is effective to improve rapeseed yield.＇to reduce N fertilizer to 150 kg/hm2, and application of 60%. of N fertilizers as base fertilizer is still proved optimal at present. [Conclusion] The research provides.theoretioal and technical references for improvement of yield of rapeseed and efficiency of N fertilizer.

Effects of Reducing Application Amount of Base Fertilizer and Increasing Application Time of Leaf Fertilizer on Corn Yield

This study aimed to investigate the effects of reducing application amount of base fertilizer and increasing application time of leaf fertilizer on corn yield so as to find out the most economical fertilization way for corn. On the basis of protecting environment, the economic benefits will be also increased. The results showed that the corn yield was increased with the increase of application amount of base fertilizer, and was also increased with the increase of application time of leaf fertilizer.For each time of spaying of leaf fertilizer, the corn yield was increased 258-592.5kg/hm^2 with increase amplitude ranging from 2.3%-5.6%.

Sheep manure application increases soil exchangeable base cations in a semi-arid steppe of Inner Mongolia

The long-term productivity of a soil is greatly influenced by cation exchange capacity（CEC）.Moreover,interactions between dominant base cations and other nutrients are important for the health and stability of grassland ecosystems.Soil exchangeable base cations and cation ratios were examined in a 11-year experiment with sheep manure application rates 0–1,500 g/（m2？a） in a semi-arid steppe in Inner Mongolia of China,aiming to clarify the relationships of base cations with soil p H,buffer capacity and fertility.Results showed that CEC and contents of exchangeable calcium（Ca2＋）,magnesium（Mg2＋）,potassium（K＋） and sodium（Na＋） were significantly increased,and Ca2＋ saturation tended to decrease,while K＋ saturation tended to increase with the increases of sheep manure application rates.The Ca2＋/Mg2＋ and Ca2＋/K＋ ratios decreased,while Mg2＋,K＋ and Na＋ saturations increased with increasing manure application rates.Both base cations and CEC were significantly and positively correlated with soil organic carbon（SOC） and soil p H.The increases of SOC and soil p H would be the dominant factors that contribute to the increase of cations in soil.On a comparison with the initial soil p H before the experiment,we deduced that sheep manure application could partly buffer soil p H decrease potentially induced by atmospheric deposition of nitrogen and sulfur.Our results indicate that sheep manure application is beneficial to the maintenance of base cations and the buffering of soil acidification,and therefore can improve soil fertility in the semi-arid steppes of northeastern China.