- T J Koen, W Langenegger en G Smart
- Navorsingsinstituut vir Sitrus en Subtropiese Vrugte, Privaatsak X11208, Nelspruit 1200
- 1989
In twee aangrensende veldproewe is die invloed van verskil/ende peile van N, P en K in ‘n faktoriale proef en vyf peile van stikstof in ‘n ewekansige blokontwerpproef op die produksie en vruggehalte van volwasse lietsjiebome (Litchi chinensis Sonn, kultivar Mauritius) oor ‘n tydperk van vier jaar ondersoek. Verhoogde stikstoftoediening het in albei proewe die produksie aansienlik verhoog – ‘n maksimum gemiddelde produksie van 96 en 105 kg vrugte/boomljaar is onderskeidelik verkry vergeleke met 49 en 36 kg vir die kontroles. Hierdie behandelings het ook die grootste massa bemarkbare vrugte met goeie interne gehalte gelewer. Fosfaattoedienings het produksie in die teenwoordigheid van voldoende stikstof van 68 na 110 kg vrugtelboomljaar verhoog.
Kaliumtoedienings hetgeen invloed op sowel produksie as vruggehalte uitgeoefen nie ten spyte van ‘n aanvanklike grondinhoud van slegs 56 mg K kg-1.
Summary:
The study investigated the effects of different levels of nitrogen (N), phosphorus (P), and potassium (K) fertilization on production and fruit quality of mature litchi trees (cultivar Mauritius) over four years through two adjacent field trials.
Increased nitrogen fertilization significantly increased production in both experiments, with maximum average yields of 96 kg and 105 kg fruit per tree per year versus 49 kg and 36 kg for the controls.
Higher nitrogen treatments also produced the greatest mass of marketable fruit with good internal quality, including better sugar-acid ratios and lower acidity.
Phosphorus fertilization, in the presence of adequate nitrogen, increased production from 68 to 110 kg fruit per tree per year.
Potassium fertilization had no effect on either production or fruit quality despite initially low soil potassium levels.
Soil analyses showed relatively low phosphorus and potassium levels before the trials, and pH declined with increased nitrogen application despite annual dolomitic lime application.
Optimal nitrogen levels were essential for maximizing yield and fruit quality; too low or too high nitrogen levels negatively affected production and marketable fruit percentage.
Phosphorus application significantly improved production and fruit quality when soil phosphorus was low; this effect diminished when soil phosphorus was above a certain threshold.
Potassium did not influence production or quality in the study conditions but may vary with soil type elsewhere.
The authors recommend using soil and leaf analysis to determine optimal fertilization rates to maintain high production and fruit quality.
Results align with earlier studies showing nitrogen’s critical role in nitrogen and potassium importance for root growth, but potassium fertilization effects can vary by soil conditions.