新疆棉田土壤速效养分的时空变异特征研究

The Spatio-temporal Variability of Soil Available Nutrients of Cotton Fields in Xinjiang

研究了新疆南疆荒漠绿州棉田皮棉产量1991kg·hm2水平下,2月15日至11月15日内,0～100cm土层土壤碱解氮、速效磷、速效钾的时空分布,0～40cm土层土壤碱解氮和速效钾含量分布特征趋势一致,由2月中旬-6月中旬逐渐升高,到5月中旬-6月中旬时达最大值,进入7月份后,均呈陡然下降特点,9月份开始回升;40cm以下各层土壤碱解氮和速效钾含量变化波动较小;土壤速效磷的时空变异特征,4月和5月,0～60cm土壤中的速效磷呈匀速上升,7月中旬达高峰,但20～60cm土层速效磷含量开始急速下降,9月中旬降至最低点。耕层土壤速效磷含量在27.1～34.3mg·kg1波动变化,变幅较小。

A field experiment was conducted to study the spatio-temporal variability of the soil alkalihydrolyzable nitrogen, available phosphorus and available potassium from the middle of February to the middle of November in oasis cotton fields（0-100 cm soil player） in south Xinjiang, which cotton lint yields was 1991 kg·hm^-2. The results showed that the spatio-temporal variability of the soil alkali-hydrolyzable nitrogen and available potassium in 0- 40 cm soil player were presented the similar trend, and that in 40-100 cm were not obviously changed. The contents of soil alkali-hydrolyzable nitrogen and available potassium in 0-40 cm soil layer were both increased gradually from the middle of February to the middle of June, attained the maximums between the middle of May and the middle of June, decreased dramatically from July to September, and then increased gradually from September. By contrast with June, alkali-hydrolyzable nitrogen in 0-40 cm soil layer in July was decreased by 32.7-37.8 mg · kg^-1. The contents of soil available phosphorus in plough-layer （0-20 cm） were not obviously changed during the whole experiment period, and the contents were between 27.1 mg · kg^-1 and 34.3 mg · kg^-1 , and that of 20-60 cm were decreased dramatically from July to September, and reached the minimums at the middle of September. The contents of soil available phosphorus in 0 -60 cm soil layer were increased gradually from April to July, attained the maximums at the middle of July, and that of 60-100 cm were always the lowest.