Elimination of weed influence through fruit thinning and fertilisation in apple tree plantings

The objective of this research is to study the effect of two measures (fruit thinning and additional fertilisation - 222 kg calcium nitrate/hectare) compensating the negative influence of weeds (yield loss and reduction of growth) in plantings of Idared cv. In addition, the yield response of two other apple cultivars (Melrose, Gloster) to the exclusion of chemical weed control is discussed in this paper. The obtained results have shown that the differences between yields of individual variants of Idared cv. were smaller and not significant in the first year (2000) of experiment. In the second year (2001), the significant (= 0.05) yield loss (40%) was observed in the case of variant with mowing of weeds and fruit thinning compared with variant with herbicide treatments and additional fertilisation. The influence of measures on Idared cv. growth was not significant. The absence of herbicides has led to yield reduction (27%) of Idared cv. in 2001 in comparison with yield in 2000. However, the difference was not significant ( > 0.1), probably due to the relatively short period of trials. On the contrary, the yield of Gloster cv. observed in 2001 was significantly higher ( = 0.01) than in 2000 even though herbicides were excluded.