Relationship between Field Water Balance with Production of PB260 Rubber Clone

Abstract

ABSTRAK Secara umum produksi karet dipengaruhi oleh fluktuasi curah hujan setiap bulan. Penelitian bertujuan mengetahui pengaruh curah hujan, evapotranspirasi, dan ketersediaan air lahan terhadap produksi karet klon PB260. Penelitian ini dilaksanakan di Kebun Percobaan Balai Penelitian Sembawa, Sumatera Selatan pada tahun 20132016. Plot penelitian yang digunakan adalah tanaman menghasilkan klon PB260 tahun tanam 2002 dengan tekstur tanah clay loam. Penelitian ini dilakukan dengan cara membandingkan produksi tanaman karet pada saat musim hujan dan kemarau dari tahun 20132016. Hasil penelitian menunjukkan bahwa kadar air tanah merupakan parameter yang paling berpengaruh terhadap hasil lateks tanaman karet klon PB260 dibandingkan dengan parameter curah hujan dan evapotranspirasi. Hasil lateks menurun dengan berkurangnya kandungan air tanah pada periode bulan kering. Kurangnya air pada bulan kering menjadi faktor pembatas untuk hasil karet yang optimal. Ketika kadar air tanah turun hingga di bawah 100 mm, hasil lateks maksimal yang dapat dicapai oleh tanaman karet adalah sebesar 18 g/p/s. Kata kunci: kandungan air tanah, klon PB260, neraca air lahan, produksi karet ABSTRACT In general, rubber production was influenced by fluctuation of monthly rainfall rate. This research was aimed to determine the effect of rainfall, evapotranspiration, and soil water content on the production of PB260 rubber clone. This research was conducted at Sembawa Research Centre Experimental Field, South Sumatera from the year 20132016. The observed rubber tree was mature PB260 clone planted on clay loam soil. Rubber productions on the dry and rainy season on 20132016 were compared to determine the effect of rainfall on rubber production. The results showed that soil water content has the closest relationship to rubber production compared to rainfall and evapotranspiration parameter. Latex yield was decreasing as the decrease of soil water content at dry season. Limited water during the dry season became a constraint of optimum rubber yield. When soil water content drops below 100 mm, the maximum attained latex yield was 18 g/t/t.

Prediction of Rubber Yield Based on Soil Water Content

“…Hence the rubber plants are able to extract it from the soil easily. Some research showed that the rubber yield is influenced by fluctuation of rainfall as well as soil water content [6,7]. The low soil water content resulted in drought stress that affected the decrease of stomatal conductance, transpiration rate, and photosynthesis rate.…”

“…Hence the growth rate and yield were decreased [8,9]. For example, the El-Nino phenomenon in 2015 caused a prolonged dry season in South Sumatera that resulted in the decrease of three years old rubber clone PB 260 girth growth rates as high as 65% and the decrease of clone BPM 24 rubber yield [6,10].…”

A review: The development of double row spacing to improve land productivity and income of rubber smallholders

“…Rubber-based intercropping systems offers a practical solution to this issue and increasing overall productivity [3,25]. Benefits of intercropping system between rubber and intercrops compared to monoculture system of rubber are as follows: 1) low weed growth in rubber area [4,5,6,7]; 2) larger girth rubber in intercroping system [8,9,10,11,12]; 3) increased yiled of rubber [13,14]; 4) increase in soil organic matter [15,16]; and 5) increased farmers income [2,10,17].…”

“…Generally, Indonesia farmers plant rubber using single row with a planting distance of 6 m x 3 m (550 trees / ha), or 7 m x 3 m (476 trees / ha) [1,6,10]. Under these planting system, intercrops can only be planted until rubber plants are 1 to 2 years old [18,6,7,10], as the canopies of adjacent rows would have closed by then and the light is light intensity under the canopy would only be 50-60% [19,20]. The area that can be used for intercropping is around 50-60% of rubber total area [19].…”