AGRONOMIJAS VĒSTIS - Latvijas Lauksaimniecības universitāte

AGRONOMIJAS VĒSTIS (Latvian Journal of Agronomy), No.10, LLU, 20085,505,004,504,00Traditional tillage Minimal tillage Direct sowingFigure 1. Winter wheat grain yieldon average in three years, t ha -1We can the calculate efficacy of different soil tillage methods taking into account thattraditional and minimal tillage are more consuming of resources than direct sowing but higher yieldare obtained in these treatments. Comparing additional expenses for soil tillage and additionalobtained yields from both treatments – minimal tillage and traditional tillage – gave additionalprofit on average in three years (Table 2). The highest increase of winter wheat grain yield fromadditional expenses was observed in treatment with minimal soil tillage growing winter wheat inrecurrent sowing and using herbicides – 81.2 kg from 1 additionally expended LVL.Table 2 Yield increase from additionally invested 1 LVL for soil tillage compare to direct sowingon average in three years, kgTreatment Minimal tillage Traditional tillage Average AverageAfter winter With herbicides 81.20 43.61 62.41wheat Without herbicides 12.98 32.19 22.5842.49After winter With herbicides 39.90 25.04 32.47rape Without herbicides 36.96 30.16 33.5633.02On average with herbicides 60.55 34.33On average without herbicides 24.97 31.17xAverage 42.76 32.75The biggest obtained production by investing in soil tillage was in cases of 2 nd wheat wherea herbicide was used – 68.71 LVL in variants with minimal tillage and 66.75 LVL with traditionaltillage (Table 3). The lowest obtained production was in case of minimal tillage in 2 nd wheatwithout herbicides just 8.99 LVL. The average on all variants of previous crops and weed controlwas better in case of traditional tillage – 50.13 LVL. There were also differences from previouscrops where 2 nd wheat was benefited from herbicide use on winter wheat – 67.73 LVL comparedwith 29.67 LVLV in case without herbicide. That shows significant impact from weed control. Onthe other hand, there were no significant differences in weed control in trials of 1 st wheat. Theywhere comparably low in both cases 33.89 LVL and 35.18 LVL. That made the average of 2 ndwheat better than 1 st wheat. This was caused by the significant influence of weeds and volunteers intrials of 1 st wheat which did have an impact on yield reduction.Table 3 Additionally obtained production by investing in soil tillage, LVL on average in three yearsTreatment Minimal tillage Traditional tillage Average AverageAfter winter With herbicides 68.71 66.75 67.73wheat Without herbicides 8.99 50.36 29.6748.70After winter With herbicides 28.86 38.92 33.89rape Without herbicides 25.86 44.51 35.1834.54On average with herbicides 48.78 52.83On average without herbicides 17.42 47.43xAverage 33.10 50.13In 58 % compared cases additionally obtained production covered the expenses of soiltillage if to the treatment with direct sowing. 2002 was characterized by a great amount ofprecipitations in all 8 cases additional production covered the expenses of additional soil tillage butin the very dry year 2003 that was largely not the case. Profit on investment in soil tillage was71