Effect Of Different Tillage Method On The Balance Of Potassium And The Potassium Effect In Semi-arid Area

In order to undestand the effect of different tillage method on the balance of potassium and the potassium effect in Semi-arid Area,Having carried out conventional tillage experiment with two rotation sequences (Rotation sequenceâ… : pea→wheat→pea→wheat→pea; Rotation sequenceâ…¡:wheat→pea→wheat→pea→wheat) continuously for five years in the middle of Gansu province, in the fifth year we studied effects of different tillage methods (NT,NTS,NTP,T,TP,TS ) on soil total potassium, soil available potassium and balance of soil potassium in each rotation sequence. And also effects of potassium application on crops in the middle of Gansu province were studied. The results showed as following:1. In all tillage treatments, No tillage with straw cover could increase content of soil total potassium.After four years of continuous rotation cropping, effects of different tillage treatments on soil total potassium in different layers above 50cm were significantly different both before sowing and after harvest. Soil total potassium contents in each layer under NTS were significantly higher than that under other measures. There was no significant difference in soil total potassium contents in different layers below 50cm under different treatments. On the average content of soil total potassium in different measures, sequence of soil total potassium content was: NTS> TS>NT >T>NTP>TP.Compared with soil total potassium content before sowing, it decreased after harvest, and it decreased differently in different treatments. In both rotation sequenceâ… and sequenceâ…¡, the sequence of decreased degree was: NTSTS>NT>T>NTP>TP.Compared with soil available potassium content before sowing, it decreased after harvest, and it decreased differently in different treatments. Sequence of decreased degree was: NTS2O /hm²,18.61 kgK₂O /hm² in TS,37.90 kgK₂O /hm² in NT, 55.44 kgK₂O /hm² in T,55.85 kgK₂O /hm² in NTP and 45.99 kgK₂O /hm² in TP. In rotation sequenceâ…¡,potassium was deficient in NTS with 25.12 kgK₂O /hm²,25.68 kgK₂O /hm² in TS, 32.71 kgK₂O /hm² in T,37.00 kgK₂O /hm² in NT,43.04kgK₂O /hm² in NTP and48.67 kgK₂O /hm² in TP.4. Applying potassium fertilizer on field pea can obviously increase its yield. Compared with CK, yield of field field pea increased 26.7% with potassium application of K₂O37.5 kg/hm². Although yield of wheat increased when applying potassium fertilizer on it, there is no significant difference between treatments. So there was no effect of applying potassium fertilizer on yield of wheat in 2006. By calculation on effect of potassium fertilizer experiment , soil potassium can keep balance with K₂O of 70 kg/hm² on field pea and with K₂O of 35 kg/hm² on wheat.