A clover-rich field grass as a pre-crop
2000
Valgus, T. | Tamm, U. | Zirk, M.
Theeffect of cultivating a clover-rich field grass on a fertilized and now fertilized background as a precrop on a harvest of a post-crop (potato and spring wheat) was compared with the effect of other pre-crops (spring wheat and potato) in a crop-rotation experiment on the soddy-podzolic soil in Olustvere during the five years (1995-1999). The results indicated a varying impact of a pre-crops on a harvest of a post-crops and depended on a weather conditions, fertilizing and other factors. The tuber yields of a potato cultivated after a field grass were in average 14 per cent higher than these of potato cultivated after a spring wheat. The influence of a field grass was unvaried in case of a close-to-optimum nitrogen-phosphorus-potassium fertilizing and was not plausible in a rainy 1998. There was no plausible difference between the experimental years' mean harvest of a spring wheat cultivated after a clover-rich field grass and these of the spring wheat cultivated after the potato. The advantage of a clover-rich field grass appeared only in a rainy year 1998 and the advantage of a potato as a pre-crop to thespring wheat became apparent in a droughty year 1999. The extra yield of a spring wheat achieved via optimum nitrogen-phosphorus-potassium fertilizing were in case of three years out of four higher when the spring wheat was cultivated after a field grass and lower when it was cultivated after a potato
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