LIBRO-CONGRESO-CITRUS

S10
were evaluated. Yield, fruit quality and tree size were determined every year. Citrus fruit disorders were
evaluated only in the last experimental season. There was a cumulative effect over years of deficit irrigation
on tree growth. In both rootstocks, after five years, DI reduced tree canopy growth by 50%. Yield was only
reduced by DI in the last experimental season by 12-20%. Juice content, acidity and total soluble sugar
concentration were affected by both the rootstock type and the irrigation regime. Puffing of Clementine fruits
was not affected by the irrigation regime. Creasing was only increased by DI in the Carrizo citrange rootstock
while in the Forner-Alcaide 5 the irrigation regime did not affect this fruit disorder.
S10P13
Root distribution of orange trees under two different drip irrigation systems
Fachini E. 1 , and Galbiatti J.A. 2
1 Centro Universitário de Araraquara (Uniara), Agronomia, Brazil; and 2 Universidade Estadual Paulista (UNESP), Engenharia Rural,
Brazil. emfachini@terra.com.br
A study was carried out in two orange groves of irrigation and fertirrigation with a drip irrigation system to
compare root distribution of trees under different management after four years. The experiment was set
up on the commercial grove in Palestina and Altair, State of São Paulo, Brazil. Trees of Natal sweet oranges
on Cleopatra mandarin were 21-year-old. The Altair grove was established with two drip lines per row of
trees, and the Palestina grove with one drip line. The irrigation management in both places used the class
pan evapotranspiration. Soil core samples were collected 1.0, 1.5 and 2.0 m from the canopy edge, either
along the tree row or between rows at the 0-15, 15-30, 30-45, and 45-60 cm soil depth layers. The method of
weight of root dry mass was used to estimate distribution in the soil. The distribution of roots along the tree
row was 3.8 times bigger in the Palestina grove compared to the Altair one. The root distribution in between
rows was 1.4 times bigger in Palestina than in Altair. In this study, the irrigation with one drip line per row of
orange trees limits the root system growth. The distribution of roots within a smaller volume of soil could be
important to increase efficiency of absorption of water and nutrients by trees.
S10P14
The effect of herbicide treatments on soil nutrient availability and plant nutritional status in a
citrus garden
Wu C.Q. 1 , Liao C.X. 2 , Ou Y. 1 , and Xie Y.H. 1
1 Chongqing Academy of Agricultural Sciences (CAAS), Fruit Research Institute, China; and 2 Chongqing agriculture commission (CAC),
China.. cqxieyh@hotmail.com
This paper reports the effects of weed control with herbicides on the nutritional status of Licheng [Citrus
sinensis]. Tested treatments were: control (CK) #1 (41% Nong pan glyphosate IPA salt, 200x diluted) #2
(41% Chun duoduo glyphosate IPA salt 200x diluted) #3 (10% Hai ning glyphosate 30x diluted) # 4 (30%
Feida glyphosate 150x diluted) #5 (Paraquat 200x diluted). Results showed the content of total nitrogen in
the soil did not vary for herbicides compared with CK. On the contrary, the content of available phosphorus
in soil increased 2.0%~15.3% compared to the CK while the effect of treatments #1 and #2 were similar.
Herbicides could decrease the content of available iron in soil, since effects of treatments #2 and #3 showed
a remarkable difference between each other. At the late stage of herbicide use, the manganese content of
soil became slightly higher than CK with no noticeable difference except for treatment #3. Otherwise, the
content of zinc decreased in all herbicide treatments. We also found that total leaf iron decreased 1.9% to
3.7% in the CK compared to treatments # 2, #3 and #4. Herbicide treatments #1, #2 and #4 decreased zinc
content of leaves by 2.3% to 3.7% compared with the CHK. The manganese leaf content could be increased
to an extent of 2.3% to 5.7% in response to herbicide treatments. The nitrogen leaf content behaved was
different in treatments #3 and #4. The content of phosphorus did not vary in all treatments. Therefore,
herbicide use can decrease the content of available iron and zinc to plants in spite of its effectiveness in
weed control.
166 - VALENCIA CONFERENCE CENTER, 18th-23rd NOVEMBER 2012