Effects Of Different Fertilization On Loss Of Nutrient Under Phyllostachy Praecox Stands

Lei bamboo (Phyllostachys praecox f. preveynalis) is an excellent variety for producingbamboo shoots and is widely distributed in the subtropical area of China. In order to improveyields of bamboo shoots, intensive management practices including over-application of chemicalfertilizers, deep plough, and winter-mulching have been adopted by the farmers. Although thefarmers obtain great economic benefits, these practices bring out a serious new problems, such asbamboo grove degradation or even dies, water system pollution from over-fertilization, decline insoil quality and so on. A field experiment including5fertilization treatments (unfertilized control,conventional fertilizer, declining organic fertilizer (DO), declining inorganic fertilizer (DI), anddeclining organic fertilizer and inorganic fertilizer (DOI) was conducted on a Phyllostachyspraecox stand of Lin’an county, Zhejiang province, China in2012to ascertain the effects ofdifferent fertilization on nutrints loses characteristics in the soil under Phyllostacys Praecoxstand.The main results of this study are as follows:1) The results of runoff experiment shown that average concentrations of total nitrogen (TN) andtotal phosphorus (TP) in the runoff water for different fertilization treatments ranged from5.61to10.22and0.99to1.93mg/L, respectively, while the percentages of DN/TN and DP/TP rangedfrom78.35to84.89%and57.64to74.93%, respectively. The concentrations of nitrate nitrogen(NO-3-N), dissolved organic nitrogen (DON) and particulate nitrogen (PN) in the runoff waterranged from3.82~6.82,0.89~1.85, and0.89~1.83mg/L, respectively, which accounting for60.9~68.2%,16.0~18.1%, and15.1~21.6%of total N loss, respectively. The nitrate nitrogenwas the main form of nitrogen loss. The total loss loads of TN, TP, and DOC in runoff water forthe different fertilization treatments ranged1.40to4.50,0.49to0.95, and14.77to18.17kg/hm2,respectively. Compared with CF, DI and DOI reduced nitrogen loss by46.9and23.1%,respectively.2）The results of seepage experiment shown that the average concentrations of N, P, and DOC inseepage water ranged from33.23to111.54,1.05to5.06, and33.69to45.53mg/L, respectively.The concentrations of NO3--N, ammonium nitrogen (NH4+-N) and DON in the leaching waterranged26.2to92.5,0.50to6.42, and6.57to12.6mg/L, respectively. The nutrient concentration in the seepage water was much higher than in runoff water. The total loss loads of N, P, and DOCin theleaching water for the different fertilization treatments ranged96.1to304.9,3.1to15.3, and84.5to138.2kg/hm2, respectively. The treatments of DI, DO and DOI decreasd N and P loss by19.1,41.7,52.1%and2.61,20.3,59.5%, respectively, compared with CF, which suggesting thatreduction of inorganic fertilizer rate and application of organic fertilizer were the useful practiceof decreasing nutrient loss in the soils under Lei bamboo stands.3）In the seepage experiment, the treatments of DI and DOI (reducing nitrogen fertilizer rate of40%) improved fertilizer agronomic efficiency by23.3and43.7%, respectively, compared withCF. However these two treatments did not reduced the yields of bamboo shoots.